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Azelor
07-23-2014, 01:03 PM
I see that lot of people have a hard time with their climates when they are creating their world. I'm not an expert, but I'm trying to make it simpler when it come to the climatic zones.

I used this as the main source of information : Köppen climate classification - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification)
But also other pages and some scientific articles. The information is there (most of it) but it's not very easy to understand. The first part I did was to collect the info on the wiki and also elsewhere to get a clear definition for each climatic zone: what it is but also where to place them: where they are the most likely to appear. It ended in something relatively complex and a long document.



note : My main goal was to find if there was a link between the climate and population density. And if so, to find what density would be for one specific climate.
I realized I had a serious issue with a state with similar climate to India and somewhat similar size but the population was about only 9 millions people. I did not make sense and I had no answers how to get population density numbers right.
I also happened to have no clear idea on where to place the climates. That's why I'm doing this, and hopefully I can work on the second part after this one is finished.

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Real world data : http://www.cartographersguild.com/showthread.php?t=27782&page=3&p=277812&viewfull=1#post277812

The tutorial

Step 1,2,3(elevation, currents, air pressure): http://www.cartographersguild.com/showthread.php?t=27782&page=5&p=280255&viewfull=1#post280255
Step 4, winds: http://www.cartographersguild.com/showthread.php?t=27782&page=5&p=280316&viewfull=1#post280316
Step 5, temperatures: http://www.cartographersguild.com/showthread.php?t=27782&page=6&p=280821&viewfull=1#post280821
http://www.cartographersguild.com/showthread.php?t=27782&page=8&p=285140&viewfull=1#post285140

Step 6, precipitations: http://www.cartographersguild.com/showthread.php?t=27782&page=10&p=287571&viewfull=1#post287571
Step 7, climates: http://www.cartographersguild.com/showthread.php?t=27782&page=11&p=288756&viewfull=1#post288756

Iggy
07-23-2014, 01:31 PM
I tried to open the file but OpenOffice tells me it's damaged. Does that document come in any other format?

Iggy
07-23-2014, 01:37 PM
OpenOffice Writer can read and write .doc files just fine. Except for this one.

Pixie
07-24-2014, 09:42 AM
I've read the whole thing, it is helpful indeed Azelor.

Being a science teacher and an amateur climatologist/geologist (in fact, an amateur world-builder), I can follow all of it pretty easily. Dunno how less science savvy folks will manage it, but it doesn't seem complicated.
I think it is a very valuable add-on to the tutorial I (we) are currently building.

It made me think of one more climate map that would be very useful: a cross-reference between rain pattern and temperature, to make a two-colored map separating areas where evapotranspiration is greater / lower than precipitation. This could perhaps be helpful (do you think it would be helpful?)

Picking up the word usage in my tutorial, what do you think of this?
Lower precipitation than evaporation (DRY seasons)
Very Hot + Moderate/Low/Dry
Hot + Low/Dry
Warm + Dry
Roughly equal precipitation to evaporation (MODERATE seasons)
Very Hot + Wet
Hot + Moderate
Warm + Low
Mild + Low
Cold + Dry
Very Cold + Dry
Higher precipitation than evaporation (WET seasons)
All remaining combos

Corvus Marinus
07-24-2014, 11:32 AM
Breaking down the meaning of each of the letters is really helpful in understanding the details of the system. And I think Part II: Climate Zones will be very useful; it's a lot clearer than Wikipedia. The formulas in Part I, for me (not very science-literate), do not translate into immediate usefulness in worldbuilding; but I can easily take Part II and use it to "proof" my map after it has gone through Pixie's system.

If I am still around when you have a final draft, I will happily check it for spelling/grammar/formatting, if that is something you'd appreciate.

Azelor
07-24-2014, 06:01 PM
I've read the whole thing, it is helpful indeed Azelor.



Good to know.

Were you considering a map or some info graphic like this one : http://powerfulinfographic.com/wp-content/uploads/2011/10/transparency-11.jpg
I don't know about the idea. There is a relation between temperature and minimum precipitations to avoid desertification. Did you know that the Sahara would need between 3000mm and 6000mm of rain per year to become a moderate climate similar to Spain? That's a lot of water and it's just the minimum.

There is a part in the guide where I talk about yearly precipitation not seasonal. The problem with the classification is that it compares the driest month with the wettest without taking in consideration if the driest month is really dry. Sometimes, it's not the case. It's considered dry only because the wet month receive a lot more rain. So the letters s and w are more or less valuable here. At the equator, at least we know that under 60mm it's considered dry.



edit : this ! http://en.wikipedia.org/wiki/Aridity_index

and this : http://upload.wikimedia.org/wikipedia/commons/c/cc/K%C3%B6ppen-aridity-index.png

I'm now using this from the Trewartha wikipedia page: BW and BS mean the same as in the Köppen scheme, with the Köppen BWn climate sometimes being designated BM (the M standing for "marine"). However, a different formula is used to quantify the aridity threshold: 10(T − 10) + 3P, with T equaling the mean annual temperature in degrees Celsius and P denoting the percentage of total precipitation received in the six high-sun months (April through September in the Northern Hemisphere and October through March in the Southern).
If the precipitation for a given location is less than the above formula, its climate is said to be that of a desert (BW); if it is equal to or greater than the above formula but less than twice that amount, the climate is classified as steppe (BS); and if the precipitation is more than double the value of the formula the climate is not in Group B. Unlike in Köppen's scheme, no thermal subsets exist within this group in Trewartha's, unless the Universal Thermal Scale (see below) is used.

Azelor
07-26-2014, 01:03 AM
Hey, I got some numbers!

Replacing this :

• If less than 30% of annual precipitation occurs in the summer : Annual precipitation (mm) < 20 × average annual temperature (°C)
• If more than 70 % of annual precipitation occurs in the summer: Annual precipitation (mm) < 20 × average annual temperature + 280
• Else : Annual precipitation (mm) < 20 × average annual temperature + 140

o If annual precipitation is < 50 % of the threshold = BW: desert climate
o If annual precipitation is between 50 and 100 % = BS: steppe climate

by this:

if the annual precipitation (in centimetres)

are Greater than R= humid
are Smaller than R but greater than R/2= semi-arid
are Smaller than R/2= arid

R=2 x T if rainfall occurs mainly in the cold season (s=summer dry)
R=2 x T + 14 if rainfall is evenly distributed throughout the year (f)
R=2 x T + 28 if rainfall occurs mainly in the hot season. (w= winter dry)
(T= mean annual temperature)

Pixie
07-28-2014, 10:01 AM
Hmm, this complicates things a little bit. But at the same time, it helps. It helps because now we can get a workflow that will yield more accurate climate maps and it complicates because that workflow will be a little more messy now.

I tried to build a humidity map based on this info and on the scheme I mentioned earlier. It doesn't fit with climate predictions made like I suggested in the other thread in some places - namely, areas classified as savanna/monsoonal close to the tropics now seem Arid (desert?) all throughout the year and steppes at higher latitudes now have a properly Humid season, making them maritime/mediterranean.

Azelor, you have definitely raised a point that can't be overlooked. I will need to review my stuff :) Thanks for that (or not! no, seriously, thanks for that)

Azelor
07-28-2014, 07:34 PM
You also need to be cautious with the numbers. For example, Jaipur is classified a steppe but receive a little more than R. Inside one climate one can see huge differences. Lisbon (Csb) is a Mediterranean climate but R=4 it's pretty wet. While Los Angeles (Csa) is barely above 1. It's not always clear because categories includes a broad range of possibilities.

I like these formulas because they take into account that precipitation have a different impact depending when it fall.
Logically, if precipitation evaporate at a slower rate in winter, the water (or snow) will stay longer in the environment and thus will have a bigger impact on nature. In theory.

Two cities receive the same amount of precipitation for the year. City A is summer dry and City B is winter dry. Over the course of the year, which of the two cities will be the driest?





areas classified as savanna/monsoonal close to the tropics now seem Arid (desert?) all throughout the year and steppes at higher latitudes now have a properly Humid season, making them maritime/mediterranean.
plausible, but having a wet season does not always make the steppes a maritime/mediterranean climate. Only if they are not too far from the water.

Pixie
07-28-2014, 08:15 PM
I like these formulas because they take into account that precipitation have a different impact depending when it fall.
Logically, if precipitation evaporate at a slower rate in winter, the water (or snow) will stay longer in the environment and thus will have a bigger impact on nature. In theory.


Yeah, that's the basic reasoning I think. That's what made me review the whole process - I am now going combo by combo, it becomes a huge table.
5 january temperature levels x 6 january rain levels x 5 july temperatures x 6 july rain levels.... 900 entries.
The original idea is to simplify climate prediction, 900 entries isn't simplifying. Still a work in progress...



Two cities receive the same amount of precipitation for the year. City A is summer dry and City B is winter dry. Over the course of the year, which of the two cities will be the driest?
Did I say I am a science teacher? This is easy, when most of the rain falls in winter, moisture is available for longer. Thus, the location with rain in the summer is the driest.
However... plants metabolism is very dependent on sunlight, so the location with rain in summer may have more vegetation cover as both factors for plant growth coincide, and a dry hot summer requires plants adapted to drought, which normally means smaller leaves and slower growth rate.

Azelor
07-29-2014, 08:38 PM
Yeah, that's the basic reasoning I think. That's what made me review the whole process - I am now going combo by combo, it becomes a huge table.
5 january temperature levels x 6 january rain levels x 5 july temperatures x 6 july rain levels.... 900 entries.
The original idea is to simplify climate prediction, 900 entries isn't simplifying. Still a work in progress...


Did I say I am a science teacher? This is easy, when most of the rain falls in winter, moisture is available for longer. Thus, the location with rain in the summer is the driest.
However... plants metabolism is very dependent on sunlight, so the location with rain in summer may have more vegetation cover as both factors for plant growth coincide, and a dry hot summer requires plants adapted to drought, which normally means smaller leaves and slower growth rate.

I think we need to make things complicated in order to understand the simples rules that makes the system. With some advanced statistics, we might be able to find interesting informations. I would like to see the file when it's done if possible.

I got 10 temperature levels, what are your temperature levels?

Pixie
07-30-2014, 05:41 AM
Table isn't finished, but here's what I mean:
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Table is being made in an excel file and the result exported to pdf like you see here. Starting point should be january temperature, then using magic wand on intercept, user would shorten selection with january rain, then july temperature, then july rain... (and, to cover the whole map, repeat that 900 times!)

Any ideas are very welcome at this point.

Also, as you can see, there are lots of combos which I have doubts about or which, even if I apparently don't have doubts I am plainly wrong about.
If you have time, please give it a look - so far I only have these.

Azelor
07-30-2014, 12:15 PM
I'm trying to classify the Dsb climate using your classification but I'm not sure how to.

• Precipitations: moderate
o Summers = wet
o Winters= dry
• Average monthly temperature between -25 °C and 28 °C
o Summer: mild to hot
o Winter: very cold to cold

the problem I'm having is that I know how much precipitation are required yearly but not for the specific seasons.
I think I might have an idea, but it could make the numbers above useless.

Pixie
07-30-2014, 05:25 PM
I'm trying to classify the Dsb climate using your classification but I'm not sure how to.

• Precipitations: moderate
o Summers = wet
o Winters= dry
• Average monthly temperature between -25 °C and 28 °C
o Summer: mild to hot
o Winter: very cold to cold


You're doing it again... Dsb means "dry summer" ;)
I would make it warm summer with arid or semi-arid conditions (low/dry rain patterns) and very cold winter with humid conditions (any kind of rain pattern except "dry" gives humid conditions in a very cold season)
A mild summer would make it Dsc... A hot summer would make it Dsa... this is the sort of reasoning I am making in building the table.

Azelor
07-30-2014, 06:13 PM
I have another idea. It will make it easier to decide if one climate is winter/summer dry or forever wet.

first we need to set these assumptions:

It’s in the northern hemisphere: july is in summer and january is in winter
January is always the coldest month
July is always the hottest month
January is the driest month of the year (w=winter dry)
July is always the driest month of the year (s=summer dry)



f: precipitation levels are either on the same category, 1 category down or up.
w and s: they are separated by at least one category

example: Pixiland receive 30mm of rain in January and 70mm in July. =f because they are just 1 category apart.
Azelor Town receive 15mm in July but 75 mm in January. It's a dry summer, category 20-40 is separating each seasons.

Both climate could be considered humid, maybe one is more humid than the other but that's not too important.
That way, it's simpler than the : precipitation < 1/3 of the wettest winter month
and the numbers are not very different.

Pixie
07-30-2014, 06:54 PM
I see what you mean, and that makes it very easy to decide between a s-climate, a w-climate or a f-climate. But, that's 10 levels of rain.

Say.. we keep the 6 levels of temperature as the current system gave pretty matching results in my test with ascanius and add more levels of rain.
Instead of the existing 7, we add two more levels (could we merge the 0-5 with the 5-10?). The current process gives 7 levels, but I ignore the 6th and 7th.
This can be done adding two layers in the present composition of rain patterns and I think it can be done in a few different ways.
This could work, but it now becomes a 6 x 6 x 9 x 9 set of combinations.... 2916 different combos. That's complex enough, but we're getting to the point where it is impractical.

If I may say, Azelor, you are focused on getting accurate at a given point, knowing the exact conditions, whereas I am focused in getting an overall map of the land. What are we trying to reach here?

Pixie
07-31-2014, 06:24 AM
This post got me thinking about how short is a 6 tier classification for mean temperature... You are using 11 different ratings in this and yet, there are some temperature combos present in more than one kind of climate, which means it becomes useless for classification means if there isn't more information as the same temperature range can be found in two of the climates...

So I thought the way to counter this sort of lists where we get confused is to use a 2-entry table. So I sat down and made one, I went for an 8 tier classification, including your terms "cool" and "severely cold". More than 8 is too much in my opinion.
So this is it. This table would be the source for classifying the entire thing according to temperature (precipitation/humidity) would come at a later stage.

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question 1:
what do you guys think of the use of a 2-entry table?

question 2:
and what about the actual key used to fill in each position?

note:
cold deserts and cold steppes are a miss in this table, as their temperature ranges would be more in the tune with a D-climate - they would have to be determined separately.

note 2:
instead of terming the table X/Y axis as july and january, it could be termed as hottest month vs. coldest month, and then the classifications in each position wouldn't have to be symmetrical, allowing more flexibility - but at the same time, doubling the workload for the user, as it meant working the two hemispheres in separate.

Azelor
07-31-2014, 12:18 PM
I do like your table, it look simple and clean.

The keys look alright to me so far.




I need to go back to what I said initially that was : when climates get colder, less precipitation is require to stay wet.

We have that formula: Precipitation= temperature/2 (+something)
So, every time you move by 2 temperature categories, the minimum rain required move by one
In photoshop, this could translate in having another layer. The original if for the total precipitation, we don't change that. The second and new layer is a modifier added to the original. It take in consideration that more rain is required in hotter climate to stay wet. The first serves only as a reference representing total precipitations and the second represent the ''wetness level'' or ''relative precipitation''?
It could be done by making colder climates appear wetter using the same color scheme as the original.

Pixie
08-01-2014, 10:00 AM
We have that formula: Precipitation= temperature/2 (+something)
So, every time you move by 2 temperature categories, the minimum rain required move by one

It doesn't. It is a linear relationship, it changes the scale (temperature and precipitation are measured in different units anyway), but not the progression. The graphs you showed earlier (temperature vs. precipitation) had that straight line. Twice as much temperature requires twice as much precipitation for the same level of "wetness".



In photoshop, this could translate in having another layer. (...) . The first serves only as a reference representing total precipitations and the second represent the ''wetness level'' or ''relative precipitation''?

That's what I was trying with the "available humidity" map and the column called "humidity" in that reference table. Still, I admit having only arid/semi-arid/humid is too short to accurately classify climates - it's well enough to determine deserts but insufficient for anything else.



What should we use for precipitation level?

if I use the holdridge precipitation on the right combine with a possible equivalent on the left.
very wet/ super humid
wet/ per humid
moderate/ humid
steppe?/ sub humid
steppe/ semi arid
steppe/ arid
desert/ per arid
desert/ super arid

I'll try to come up with a second 2-entry table adding up mean temperature and precipitation pattern. I mean, if I understand your idea (and if this is it I am for it), we will have three maps:
1. mean temperature
2. precipitation pattern
3. "wetness level" / "available humidity" / "humidity" (pick your preferred denomination, I vote for "humidity")

Climate regions would then be determined by finding particular combos of mean temperature and humidity.

Pixie
08-03-2014, 05:22 PM
Great effort there, Azelor. That will help a lot in developing that reference table I mentioned earlier. I am still most worried with the sheer number of possible combinations...

But, I thought of a possible solution. This is a question for expert PSP/Gimp users, as well... If there was a way to set up a filter, in photoshop, that would do a look up based on the color of a pixel in different layers and paint the result of the lookup in a separate layer (did I explain myself in a legible way?) - then we would automate a part of the process.

I mean, automating this tedious task:
- if #color in layer "january mean temperature" is X and #color in layer "january precipitation" is Y and #color in layer ".... (etc.) then #color in layer "CLIMATES" becomes ZZ.

Pixie
08-03-2014, 07:43 PM
Well, if it is a script, a script it is. I might google for a "how-to" later on. But first need to work on that table..

Pixie
08-09-2014, 08:09 PM
I like your idea.

We would need to have a key "color to climate type", wouldn't we?

I'm off on holidays in a couple of hours, but will get back to this in September. That is, if you didn't fully solve the problem by then.

groovey
10-23-2014, 07:08 AM
Oh wow! That's a lot of good work you did to try to figure out climates and how to represent them.

Unfortunately, you already know, I have no idea about it all, so I can only share my absolute wonder on your job. I wish Pixie was around to offer real input.

groovey
08-21-2015, 07:24 AM
Any breakdowns on this? I'm redoing the heightmap to my world and felt brave enough for a second to try and do the new climate myself, but I've re-read this thread and wow, it's scary. Any chance of a version for dummies? Is it even possible?

Azelor
08-21-2015, 02:03 PM
I'm still working on it but it's taking more time than expected.


I might need a guinea pig, are you interested?
Your using photoshop right?

groovey
08-22-2015, 04:40 AM
I do. I'm more than willing to give it a try, but keep in mind how very challenged I am with all the climate stuff, so you'd have to be patient with me.

Pixie
08-23-2015, 10:40 AM
I, for one, am very curious to see what you two come up with. :)

groovey
08-24-2015, 01:56 AM
If you still interested Azelor, my new height-map is almost ready. But for the climate stuff I have to redo the winds and the other stuff right (redo is a funny word, since you did it for me the first time)? That'll take me some time to figure out so I hope the thing I'd try for you isn't for this month's challenge.

Azelor
08-25-2015, 01:08 AM
Now, I will start anew. Well, not really since I intend to keep some of the old data and improve it.
In my attempt to work on a method based on Pixie's tutorial I came up with the idea of recreating the climates of Earth using the tutorial to see what needed improvement. In order to create a realistic climate what model could be better than Earth?

The first attempt failed, mostly because my working method was bad and I used unreliable data. I tried to improve it but it failed again.
For the third attempt, I decided to directly use layers from real data instead of trying to make my own based on pictures found here and there. It does look much better as you will see later but there is still place for improvement. Eventually, I might use better precipitation maps but for now, those that I picked will do just fine as the data is the same (but it's lower quality).

The source of the data is include in these pictures.

The elevation map will be useful later. I have several useless layers in the low altitude, but without them, the map looked too boring.
75636
Temperatures for January and July. No data for Antarctica.
75637
75638
Precipitation for January and July. I might use a better quality data later but this is still good, just does not look that nice.
75639
75640

How to determine if one area is dry ? Using Excel

I changed the precedent formula to this from the Trewartha Wikipedia page:

2(10(T − 10) + 3P)

with T equalling the mean annual temperature in degrees Celsius and
P denoting the percentage of total precipitation received in the six high-sun months (April through September in the Northern Hemisphere and October through March in the Southern)

if evaporation is smaller than the average precipitation = humid
if evaporation is bigger than the average precipitation but smaller than the max = steppe
if evaporation is bigger than max = desert



Thus if one area has an average temperature of 35°C : severely hot + severely hot (probably impossible on Earth) the default minimum precipitation required to assure it's humid is 10(35 − 10) + 0 = 250
Then, we add the % of yearly precipitation falling in the 6 hottest months and multiply by 3. If it fall evenly during the year, the % is 50. So ... 250 + 3(50) = 400
But we still need to multiply by 2, to get 800.
So if precipitation are under 800, it's not humid.

Details:
The average yearly temperature is based on the fact that January and July are always the coldest/hottest months and that the temperature change at a constant rate at each month (of course, it's not like that in real life). Thus, in order to get the yearly average temperature I make the average of the lowest and the highest. As simple as that.

For the precipitation, in order to have the yearly precipitations, I make the summation of the precipitations for summer and winter (by previously multiplying the precipitation of January and July by 6).


Each temperature combo has a different aridity threshold but many do share the same numbers because it's based on the average temperature. Once we have the individual threshold for each (250 for severely hot + severely hot),

we need to figure how much rain each precipitation combination will give and how they are sprayed during the year.


For example, a very wet area receive between 100 and 200 mm of rain in summer but less than 10mm in winter. I need to find the average precipitation here. To do that : min + max/2

min = (6*100mm) + (6*0mm)
min = 600mm
Max=1260mm
600+1260/2 = 930mm that's the average yearly precipitation for one of the 36 rain combinations.

When we have all the 36 averages, we need to find out the T from the formula. Average summer precipitation/ total precipitation.
Total= avg summer + avg winter
avg for a particular season = min+max/2


The example above would give : (100+200)/2 + (0+10)/2
or just divide 930 by 6 = 155
Now (100+200)/2= 150mm falling in summer (July)
so 155/150 = 97% of the precipitations fall in the summer

Thus the total of the Threwartha formula is 2(10(T − 10) = 800
and we add 800+3P = 800 + 3(97)
= 1091mm , that is the precipitations required to keep the place humid.

All that give us the requirements for severely hot + severely hot but just for 1 or the 36 rain combo...
When all the combos are done, we need to do it for the other temperature combinations ( some will share the same numbers)
IF THIS IS NOT CLEAR, I WILL POST THE TABLE MADE WITH EXCEL. It's not quite huge as it look.

With that table, we compare the numbers with the previous table (the one indicating the total yearly precipitation, to find when a temperature combination is humid, steppe, or desert.
When that is done, it gives me a nice huge table with 3600 little square full of colors!



Next, it's with Photoshop. Ideally this process from here can be automated with actions/scripts. That's the step 7 of Pixie's tutorial. A brief description:

What the script does:

-It start by making some dummy layers and adjustments to the different maps for technical reasons in order to be able to select all possible combinations.
-Select the different temperature combination and create a new layer for each.
-Using the temperature layer, he regroup them to create the major temperature zones from Koppen: A,Ca,Cb,Cc,Da,Db,Dc,Dd, tundra and ice caps. The last two don't need to take in consideration the precipitation, so they are done at this stage.
-Select the different rain combination and paint them in black on one layer each.
-Regroup the rain combo with all that share the same characteristic for when a specific temp combo is arid/or not.
Most of the rainy combo will always stay wet no matter how hot they are, I put them aside on a specific layer
Others are selected one by one (or several if they share same characteristics) and then, intersect them with the temperature combination that are not humid in order to separate them on a new layer. So, the part that was not selected should be made of only humid
climate. When we are done with this, we can put the remaining areas with the always wet layer created earlier.
-Now we know where the desert, steppe and humid climate are. We can separate the cold from the hot arid climate or not because I don't think it's really a big deal.
-Taking the wet climates, we intersect the layer with the temperature groups (A,Ca,Cb...) and create a new layer for each. Or we could just delete the arid part based on the arid layers, but it's the same result.
-When it's done, we still have to figure whether it's summer dry, winter dry or normal. Normal (f) have no dry season and it's when the precipitation for each season is no further than 1 category apart. For example: Category 5: over 200mm and Category 4: 100-200mm.
I made a simple table for this and it's nothing complicated. Winter dry have very low precipitation in their dry season, often lower than the lows of summer dry.
-With these w,s and f layer, we separate the temperature groups into Cfa,Csa.Cwa,Cfb...
Now we have the actual climates
-Some corrections to the map seems inevitable. Some deserts are surrounded by humid climate with no transition. Usually it's because the transition would occur inside the driest precipitation category. But since I'm using the average, there is only one value abd the transition is sometimes impossible. We need to add the steppe generally outside of the desert. I will come back to this later but the process is not perfect and still need some tweeking.

The result, I had to make the map 20% smaller to make it fit:

75641

groovey
08-26-2015, 03:24 AM
The result is pretty damn close to the Koppen maps of Earth, almost exactly! So you're definitely on the right track!

I'll wait for your instructions to do the temperature and precipitation layers then. I'm still finishing the redo of the coastal shelves.

Akubra
08-26-2015, 04:23 AM
I agree completely with groovey. The differences with the real climate map of Earth are minimal. Astonishing!

Do you need another guinea pig? I have height, ocean currents and wind maps ready, but I'll have to redo temperature and precipitation maps. I'd be interested to follow your procedure and see what the result of it is.

Cheers - Akubra

Pixie
08-26-2015, 01:51 PM
You are clearly aiming at a high level of accuracy. That is awesome but makes me wonder how do you produce temperature and rain maps with that level of certainty for an imaginary world.. can't wait to see the rest of your tutorial.

Cheers!!

Azelor
08-27-2015, 12:19 AM
Can't wait either, it's better be amazing!
The problem is that I started with the last part of the process (your step 7 if I recall).
Now I got to figure how to make the first part fit.

Ilanthar
09-01-2015, 10:56 AM
You're doing an impressive and very detailed work on this Azelor!

Azelor
09-02-2015, 01:49 PM
You're doing an impressive and very detailed work on this Azelor!

Thanks! Hopefully, it will be simple enough to be considered manageable for those interested.


I'm now working of the altitude vs temperature. It does not give precise results and I don't think it will. Explanation:

I'm using temperature average, not the exact values. The temperature decrease slowly with elevation. If a category includes temperatures between 22 to 28, and the other is between 18 and 22 (for example), the change in the temperature color represents the change from 22 to 21. It's a small change normally. But since I'm using categories, I have no idea what the exact temperature is. Therefore, it's a change between the average of 22-28 (25) and 18-22 (20). From 25 to 20.

It means that the "lowest" temperatures of the first category sometimes appear hotter that what they should be in reality and some areas of the latter category will appear colder. But I have no idea how to do otherwise.
I was thinking I could select an elevation and expand the selection but some area are steep, others are flats, I have no idea what the exact temperatures are and the temperature variation is not the same everywhere.

What I'm going to do is just to use this simple formula: sea level temperature - (6.49 °C/1,000 m)


Using the average of each temperature category, lower the temperature according the the altitude. When the temperature reaches the average of a lower category, lower the temperature to that category.


Unless someone has a better idea?

EDIT: I'm mostly done with the temperature part. I just need to figure how to place some of the most extreme categories and make a final version of the instructions.

Azelor
09-03-2015, 03:07 PM
This is the result. It still need to patching but it's looks pretty god. I just need to make a final version of the instructions and maybe some adjustment to normalize things.
Then, it's onto the precipitations but I think I will take a break before starting the next step.

temperature maps for January and July

75807
75808

Ilanthar
09-04-2015, 12:39 PM
I'm a bit surprised, are the temperature that hot in January, in the south Bolivia/NW Argentina?

Azelor
09-04-2015, 01:10 PM
Yes but actually, it's hard to find data to confirm it. Several places in Argentina are on the fringe between 27 and 28. Paraguay has a few over 28 but barely (28.2).

Mysterious Mapmaker XXIII
09-10-2015, 11:37 PM
Hey!

I'm a conworlder looking to decide my conworld's climates some day, and I love what you're doing with this tutorial! I can't wait to see the full, re-worked version! Especially since it'll be the first version I actually see. :P But honestly, this looks like what I've been looking for in regards to actually doing my climates.

Just for the record, are the bits on page 4 actually part of the tutorial, or just notes? Just trying to get a better idea of what's going on here.

Azelor
09-11-2015, 10:10 AM
It's more like a draft.

Mysterious Mapmaker XXIII
09-11-2015, 01:47 PM
Ah, okay! Looking forward to the full version!

Azelor
09-18-2015, 01:41 PM
Some details, some are more evident than other but might still be educative:

76104
76105

http://www.physicalgeography.net/fundamentals/images/surface_pres_wind_jan.gif
http://www.physicalgeography.net/fundamentals/images/surface_pres_wind_july.gif


Rossby wave. While not unique to America, it have a unique characteristic one this continent as explained in this article : http://www.americanscientist.org/issues/feature/2006/4/the-source-of-europes-mild-climate/3


The Arctic is cold and trapped in ice with low evaporation. A high albedo: reflect a lot of energy to space instead of absorbing. This result in low humidity.

In summer:

One things I haven't really figured out is where the influence of the front ends. I believe that it extends farther south that it's counterpart in Europe, but I don't know where it ends.
America is large enough to create his own modest monsoon. Mexico can be pretty rainy. There is the altitude but there is also a low pressure system around. It's not the ITCZ but possibly and extension of it? Anyway, all of central America is really wet.



July: during the cold season, the coasts receive some rain but it's not much and it's mostly if they are at right angle with the winds coming from the sea. The rest is dry except for the ITZC. Again, the rain belt is mostly a straight line. The Horn is still dry because it receive winds from the interior of the continent blowing toward Arabia...



South America:

January: A lot of things are still obscure about this continent. It receive more rain than Africa. Larger landmasses tend to become hotter and become larger low pressure center. This and apparently, the Amazon forest generates 50-80% of it's the region's precipitations. I've found this data on Earth Stackexchange but, I'm not sure the source is good. The forest must help keeping the place more humid but maybe the influence is smaller.

The reason why there is a larger forested area in SA compared to Africa is probably because the variation of the ITCZ is smaller than in Africa, the center of the continent seems closer to the equator. Just some theories.

Aside from that, Eastern Brazil is drier because it receive drier air from the high pressure system. That relation is inversed in winter but I'll talk about it later.

Mysterious Mapmaker XXIII
09-27-2015, 01:12 PM
Interesting.

Is this to be part of the guide, or just ancillary information?

Azelor
09-28-2015, 08:44 PM
Interesting.

Is this to be part of the guide, or just ancillary information?

I don't know yet.


I might have figured something out. Basically, we can estimate the quantity of rain mostly based on the air pressure and direction of the winds. And with a combination of other factors such as the distance from the water bodies.

Azelor
10-06-2015, 03:41 PM
This is a rough version of the tutorial I'm working on. The rest will follow in another post.


Prerequisites to this guide

• I made this guide for earth-like planets.
• This tutorial is mostly a follow-up of the tutorial made by Pixie : http://www.cartographersguild.com/regional-world-mapping/27118-wip-sort-tutorial-climates-applying-geoffs-cookbook-detail-some.html
• To get a better understanding on climates you really need to read this, the climate cookbook: http://web.archive.org/web/20130619132254/http://jc.tech-galaxy.com/bricka/climate_cookbook.html



Software: You can use any software you like to do this but using multiple layers is almost a necessity. I would recommend Photoshop or Gimp. Personally, I used Photoshop CS3.
I have worked on a script to make step 7 easier. It’s not impossible to do without the script but it’s much faster/easier since it’s automated. I haven't tested it much yet.


Map projection:
Examples where made with the Winkle triple projection, it’s the same projection used by National Geographic. It’s useful because it minimizes all the types of distortions. But you can use other projections too. The euqirectangular is useful if you want to convert it to other projections later. Winkle triple cannot be converted into another projection, use it only if you’re sure you won’t need to convert it later. Otherwise, you’re better to use equirectangular.


Summary of the tutorial:

1. Base elevation map, one level for each 1000m of altitude ideally
2. Ocean currents map: one map will do, currents do not change over the year.
3. Atmospheric pressure systems: these air masses have a big impact on weather; you need one map representing January and one for July.
4. Dominant winds: you need one map representing January and one for July.
5. Temperature map: you still need to make 2 maps
6. Rain pattern: again you need two different version of the map.
7. Climate map: magic!



Step 1 basic elevation map

The first step is to make the elevation map. I made one level of elevation for each 1000m above sea level. I added several others layers of elevation under 1000m but they are mostly aesthetical. It can also be a good idea to include the continental shelf of the oceans because it can have an impact on the oceanic circulation if you have shallow waters.

And by the way, it will also help a lot if you have latitude/longitude lines since we will refer to them all the time.

75636

Great, I made a typo in the title.



Step 2 oceanic circulation, surface currents:

Here are two reference maps for oceanic circulation:

A simple one: http://www.google.com/imgres?imgurl=http://science.kennesaw.edu/~jdirnber/oceanography/LecuturesOceanogr/LecCurrents/0908B.jpg&imgrefurl=http://science.kennesaw.edu/~jdirnber/oceanography/LecuturesOceanogr/LecCurrents/LecCurrents.html&h=618&w=1000&tbnid=130jbciJH-gicM:&docid=wlG_uioTGw9N9M&ei=LfLcVbW5EMvp-QHptKDoDQ&tbm=isch&ved=0CB0QMygAMABqFQoTCPWDzfKpxccCFct0PgodaRoI3Q
And another, more detailed: https://upload.wikimedia.org/wikipedia/commons/6/67/Ocean_currents_1943_%28borderless%293.png

Color signification:



· Blue: Polar currents are cold between the poles and the polar circle. Currents flowing toward the equator are cold if they originate from these regions.
· Red: Equatorial currents are hot, including those flowing from the equator toward the poles.
· White: Mid latitudes currents are mild. Hot current flowing poleward eventually get mild. And cold current become mild when they get closer to the equator. Mild currents also happen when cold and hot water are mixed.


Don’t get fooled, the Pacific is larger than what the map suggest and the currents get cooled before reaching the coasts of North America.
Close to the equator, you can omit the transition to mild because at this latitude, water temperature has little impact unless it’s very cold.


Mapping the currents:

1. Close to the equator there are usually two currents flowing westwards. Between the two of them is a counter current flowing eastward. You can ignore this current because it’s much weaker the other two and it’s also a seasonal current that depends on the monsoon winds. Draw these currents in red.

2. As these two currents meet a large landmass (or shallow waters) they get diverged away from the equator, flowing toward the poles. They will stick to the eastern coast of that continent approximately until 40º to 45º of latitude. They are still hot: draw them in red.

3. At about 45º, the Westerlies (West -> East winds) are strong enough to create an eastward current. However, this is no sudden right angle turn, it actually starts much sooner. The warm current you drew earlier is now getting cooler and it’s now moving probably at more or less stable latitude. : draw in red and use white if the current drifts far enough from the continent.

4. When this current meets continental shores, it spreads north and south following the coasts. The currents moving back to equator will get slowly warmer. The part that flows north continues to cool slowly.

5. Poles: If you have polar oceans, you need to close the loops. Cold current flowing back to mid latitudes tends to stick to the coast until they encounter the hot currents mentioned at point 2. They fill the void left by the north-eastward movement of this hot current and then turn abruptly to the east. In the current map: see the Labrador Current east of New England.

Near the poles, the currents are flowing from the east to the west. This only happens at very high latitudes (over 70 degrees approximately), where the polar easterlies are the dominant winds.


Circulation around the North Pole: http://www.google.com/imgres?imgurl=http://www.grida.no/prog/polar/bsc/pict/arccur.jpg&imgrefurl=http://www.grida.no/prog/polar/bsc/fig5.htm&h=540&w=509&tbnid=b1AGtmqNM8sxoM:&docid=2dKTOAbfx1CKZM&ei=qffcVcPICsex-wG6jp6IBg&tbm=isch&ved=0CB0QMygBMAFqFQoTCIPBhJCvxccCFcfYPgodOocHYQ

78220



Step 3 : Atmospheric pressure systems



Reminder: Pressure systems depend on temperature. Hot air means rising air and low pressure at sea level, while cold temperature make the dry air sink and pushes it away. We don’t have the temperature maps yet but we can figure how where the hot and cold spots are. The hottest place is near the equator. It’s the Intertropical convergence zone, ITCZ for short. The poles are the coldest, and the cold air sinks.

Look here for a more detailed explanation of atmospheric circulation: https://en.wikipedia.org/wiki/Atmospheric_circulation

Cold season is January for the northern hemisphere but it's July in the south. Vice-versa for the hot season.

The position of the pressure systems changes over the course of the year, with the ITCZ roughly located where the planet receive the most energy from the star. It should be close to the tropic n the summer but the position is influenced by the actual temperatures. Land heat up more than water and large landmasses will pull it to them. This mechanism is the main engine of the atmospheric circulation.




The ITCZ, a low pressure system

Close to 10-15° normally, since it’s roughly the center (hottest) point of the solar radiation. During the summer, the movement of the ITCZ is strong in Asia but limited elsewhere. In order to have an impact, continents need to be large, hot, with significant landmasses around the tropics.

The relation between the size of the pressure system and the size of the continent is not linear but exponential. If a continent is twice as big, it will have a low system 4 times larger (my theory).

The position of the ITCZ is not always clearly defined. The Intertropical latitudes are always hot and therefore, there is a consistent low pressure system. Since the water is cooler than the land at these latitude, it’s not as low but it’s still making the air converge smoothly.



A. High pressure center


Oversea:
Localization over the oceans (large oceans don’t have larger zones)
Cold season: 30° in a more or less continuous line
Hot season 35° separated, mostly on the eastern side of the oceans


In the oceans, they tend to be located on the eastern side, next to the continents because it’s where the cold currents are flowing and cold mean higher pressure here. The pressure lessens going west as the ocean is less affected by the cold. In winter, the high pressure systems tend to make a more or less continuous band around the planet. In summer, the high pressure system breaks apart as the continents are affected by low pressure systems due to hotter temperatures.

Inland:
Cold season: high pressure systems develop over the continents.
Hot season: hot temperatures prevent the formation of high pressure systems.

The larger and the colder the continent, the larger the system will be.

The inland systems must be poleward of the high pressure systems that are over the ocean (unless they are very large like in Asia). Areas between the tropics are not cold enough to become high pressure although; it does not mean that the pressure is low.

The Mediterranean prevent (lessen) the formation of a high pressure system in winter. The temperature cools off less rapidly than inland locations and thus contributes at preventing the formation of what could be a high pressure system.

Furthermore, during winter, another high pressure system develop over the poles, over 70°

It is much weaker in summer.


B. Low pressure systems:

Overland:
Cold season: No low pressure overland.
Hot season: large landmasses become hot and this makes the pressure drop. It can cover most of the continent if it’s large enough. Moderate landmasses have small to moderate low pressure systems unless most of the land is concentrated between the tropics.


Oversea:
There are other low pressure systems in the higher latitudes. They are at their strongest in winter and fade away in the summer. In winter, they are centered a couple of degrees south of the polar circle (50-60). They move poleward in summer following the movement of the sun. They move by about 5 to 10°. They simply disappear in the north because it’s mostly land.

They are weak in summer in the north because the difference between the temperature of the sea and land is small, but there is a consistent low pressure system around Antarctica because the land is always cold.

January

76569

July

76570

Pixie
10-07-2015, 10:46 AM
Right on, Azelor! There are valuable additions to the method and wording so far. I'm certain this will turn out (finally) to be a self standing complete tutorial.

... And there's a good chance it will become a sort of Geoff's Cookbook 2.0 over the internet ;)

Azelor
10-07-2015, 04:23 PM
Step 4, winds:

Use the pictures to figure out how the winds are blowing. Figure A
All the figures are from the North Pole except E.
Or use the main map at the bottom at the page.
I'm having an easier time to explain it with images than with words.

76626


Dominant winds

• Near the equator, the dominant winds are usually blowing to the west (Trade Winds)
• In mid latitudes, it’s blowing to the east (Westerlies)
• And close to the poles they are blowing to the west again (Polar Easterlies)


Wind usually flow from the highest pressure to the lowest. The larger the difference in pressure between two areas, the stronger the winds will be. Inside a large high or low pressure zone, the winds can be very weak. Figure B

Mid latitudes winds (most common): Starting with your low pressure bands at high latitudes, the Westerlies should blow from west to east where it’s blue, where the pressure is lower, where there is mostly water. They do tend to converge but not as much as with the ITCZ where the air look like it’s sucked out to space by a vacuum cleaner. The Westerlies should extend to much of the area till the high pressure systems.

Low pressure have 2 types:

• Those that really converge like the ITCZ in Asia, see figure F
• And those of the mid and high latitudes, the North Pacific (round , isolated) and the North Atlantic (continuous band of low pressure) Figure G

The high pressure systems at mid latitudes (also called subtropical highs):

• Draw the poleward winds first. They have a curved shaped because they quickly change direction when encountering the Westerlies. Figure C
• Winds blowing from the equatorward side of the system tend to blow toward the equator, or if any, toward the closest low pressure center. Winds are converging near the equator; they tend to blow to the west but not always. Figure D



Polar highs: The high pressure systems on the poles brings dry and extremely cold temperatures. Figure E (South Pole)

Overland highs are spinning according to the schema. See Figure A, or look at Eastern Asia in winter.

January winds

76627

July winds

76628



So far, is it easy to follow?

groovey
10-12-2015, 06:08 AM
Excellent! I guess it's time I get my height-map ready...again. Will let you know when I'm ready to start trying these steps.

EDIT TO AVOID DOUBLE POST:

Hi Azelor.

I've started running your revised tutorial. I'm quite confused at "Step 3 : Atmospheric pressure systems":

For example, at:

"B. Low pressure systems:

Overland:
Cold season: No low pressure overland."

Bu then, in the January map you do paint low pressure (blue) on land.

By the way, I didn't catch anywhere that altitude has much of an influence, so I wonder if these old preassure maps you made long ago (http://www.cartographersguild.com/showthread.php?t=27111&page=26&p=280569&viewfull=1#post280569) are still valid?

Azelor
10-15-2015, 07:31 PM
Sorry, I just noticed this message of yours.

No, I haven't painted blue overland during the cold season. Unless you meant the southern tip of Greenland. It's blue but just because it's surrounded by water and by the low pressure system nearby. Coastal locations can be blue for this reason. But not inland, because the low temperatures are not prone to a low pressure system.

Other than that, I'm gonna say this because maybe it was not obvious: The cold season refer to January in the north but to July in the south. That's why South America is all blue in January
I thought that using cold/hot season was better than using winter/summer since some places have only 1 or 2 seasons but everywhere has a coldest/hottest month around either January or July. (Almost everywhere)

And no, i don't think your pressure maps are still good.

groovey
10-17-2015, 03:49 AM
D'oh! *massive facepalm*.

I forgot to consider cold/hot seasons are opposite in the hemispheres. Now it makes much more sense.

Since your tutorial is bound to stick around as reference for future projects of this kind, you might consider adding the reminder in the step. I'd bet I might not be the only one on the long run who completely forgets about that important detail...

Azelor
10-17-2015, 12:09 PM
Step 5 Temperatures

Temperature categories are loosely based of the Thewartha system
This is the monthly mean temperatures of these categories

Dark magenta - Severely hot: over 35°C
Red – Very hot: 28 to 35°C
Dark orange – Hot: 22 to 28°C
Orange – Warm: 18 to 22°C
Peach – Mild: 10 to 18°C
Yellow – Cool: 0 to 10°C
Green – Cold -10 to 0°C
Turquoise – Very cold -25 to -10°C
Blue – Severely cold: -38 to -25°C
Violet – Deadly cold: under -38°C


5.1 Zone of temperature (use any color you want, these are just for reference):

We will separate the world into several zones to make the distribution of temperature according to the influences each region if subject to. Each zone will have his own temperature placement (different temperatures at different latitudes). These zone are not always the same in January and July.

The different zones are:

Hot current (red) : areas affected by winds blowing from a hot current. Hot current have no impact in summer since the land is hotter than the water and it’s considered normal instead. Also, they have no impact between the tropics.

Mild current (green): Include
Currents that have cooled, or a transition from hot to cold currents.
Any current flowing long enough in the mid latitudes (Westerlies) should be mild like the Northern Pacific current and the Circumpolar current.
Where cold and hot currents meet. Usually around 40-45 degrees: Nova Scotia, Hokkaido, Patagonia
South Africa is located between a hot and a cold current = mild

Cold current (blue): These are the coldest currents on the planet. They make the land colder compared to other locations at the same latitude. They can have a large impact during the hot season.


Normal: based on observation, the default temperature at a given latitude.


Continental: Occur on large landmasses, under high pressure systems in winter but under low pressure systems in summer. Continentality is stronger if the winds have been blowing overland for a long time which tends to occur in the center or the eastern side of the continents. Areas trapped in a sea of ice like the Canadian and Russian Arctic are also considered continental: the ice is limiting the heat exchange and reflect light back to space.

To find out if a sea is supposed to be trapped in ice it needs several things.
1-To be located at least above 50 degrees.
2-To be affected by cold currents or a continental influence.
3-It needs a landmass to stay in place. It will agglutinate around it. Without a landmass, it is going to take more time for the ice to form but it's likely to happen at the poles.
4- A closed or relatively closed sea will help reducing winds, the strength of the currents and prevent heat exchange with warmer water.

Continental plus: Is an extreme version of the above. It requires larger landmasses. The only known case is Central Asia in summer.


January

77057

July

77058

ascanius
10-17-2015, 05:50 PM
Honestly all your work is making me want to go back and redo my climate map with your guide to get everything just perfect. I may do anyway just to get a very detailed climate map, when i have time, probably tomorrow. Keep up the good work, between you and Pixie I think the forum will have two great tools to make extremely realistic, detailed maps.

Pixie
10-21-2015, 02:33 PM
I still didn't understand how temperature is supposed to be worked out. I think we need clearer guidelines, although I understand that you are trying to make the tutorial less "strict" in guidelines than it was before.

In terms of continental influence, one should lower the temperature level/color, right - one step for continental, two steps for continental plus.
But before this, how does one decide what is the level for each area? This isn't clear.

Azelor
10-23-2015, 10:56 AM
But before this, how does one decide what is the level for each area? This isn't clear.


I based my "model" on pure observations.
Take an example, the border between the color yellow and green on that map http://www.cartographersguild.com/attachment.php?attachmentid=75637&d=1440511271
The 0°C isotherm is located roughly at 35°N is Asia and North America. But much further north in Europe and on the American west coast. Thus these area have different influences (ALSO CALLED TEMPERATURE CATEGORIES), the first two are continental, and the others are oceanic.

I am aware that my method feels clumsy (clumsy for lack of a better word).
But it's the best i manage to get.
The ideal solution would involve mathematic algorithms, like that maybe : http://www.cartographersguild.com/showthread.php?t=26931&page=2

johnvanvliet
10-24-2015, 04:01 PM
I still didn't understand how temperature is supposed to be worked out. I think we need clearer guidelines, although I understand that you are trying to make the tutorial less "strict" in guidelines than it was before.



the problem with local area temperatures
is the SYSTEM FEEDBACK

generally the nearer the poles the cooler
BUT not always

the tilt of the planet plays a HUGE role
the earth is a rather mild tilt of about 23 degrees

if this was say 45 Degrees
summers in the poles will be VERY HOT

the entire summer hemisphere will be HOT

and the winter hemisphere will be COLD
-- OR NOT!!!!

if the water currents move a lot of heat around
you might have a rather mild winter in one hemisphere
-- think of England

it SHOULD be covered with SNOW like Michigan and New York
but it is NOT

the ocean current feedback keeps them warm just like Anchorage Alaska


also you have wind patterns

here in the north of the USA the "jet stream" dips
and dips BIG TIME

but just look at a map
it moves back to the north as it approaches the east coast


system feedback as rather complex
it is so complex that the weather models often get some things a bit WRONG

Azelor
10-25-2015, 12:15 PM
Er, I don't understand what you mean by system feedback.

The point of using he influences I mentioned earlier is to take these differences (between Europe and the North American East coast for example)
into consideration. Different areas will be categorized into different influences according to certain criteria, resulting in different temperatures for the same latitude (in some cases).

Pixie
10-27-2015, 03:01 PM
The point about "pure observations", Azelor, is that we don't have them for any other planet, namely and specially, for staggering obvious reasons :D, for an imaginary one.

So, at the very least, you should add an indication about where one can find the 28ºC, 22ºC, 18º, 10º, etc.. isotherms on Earth. (In terms of latitude, that is)

Like groovey, I'm volunteering "my world" for a testdrive of this method, once it's a bit more fleshed out.

Azelor
10-27-2015, 11:59 PM
Yep, we only have Earth as a reference. Meaning that there is no way to verify if one rule is a general one or a specific one. But we got several different continents. We can see weather a phenomenon occur everywhere on just on one of them and try to understand why. One thing I could do is too look into paleoclimatology but I fear I might have a hard time finding good data since I already had to search a lot to find quality data for our own era. I'm not saying the information is not reliable but it's much more limited.

Still, we got the problem of having pretty rigid rules. Which , in theory, work great for an almost 100% Earth-Like planet but what if :
The land placement is really different? (Blocking the oceanic circulation) more land or more water % ...

A different axial tilt (more extreme temperature variation but one would just have to move the important features according to solar radiation, I guess)

Different gravity (might have an impact on the raincycle?)

Thicker/thinner atmosphere (I remember reading that Earth had only 1 air cell, from the equator to the poles, during the Mesozoic. Resulting in a much more temperated planet overall)

Different speed of rotation (Mentioned in Geoff cookbook, faster=more air cells, slower=less air cells. It would impact the winds and thus on the surface currents)

Hotter or colder average temperatures (the obvious consequences would be more low pressure areas if it's hot and more high pressure areas when it's cold but it's only relevant to mention if the differences are greater compared to Earth. Otherwise, it doesn't have any direct impacts)



The model is not general enough to cover all this. It might give some insight but one would need a lot of guesses. We could try to give some answers to the most common changes encountered in fictional world tough.

For fun, I tried to make sense of the climate in A song of ice and fire. I really like the series but I got to admit that it makes no sense from a climatic point of view (I know about the irregular seasons but there is an explanation for that at least). For example, trees grow far beyond the Wall in the north. A wall of ice cold enough not to melt overtime, yet large forest of tree can grow beyond that. The the other thing is the difference of climate between Dorne and the Stormlands. Which is roughly the same as the differences between Morocco and Ireland but they are next to each other with no transition zone.

I will try to provide more information on the isotherms once I sort things out.

Edit: sorry for the confusion, I deleted that part earlier because isotherms are in step 5. It's not clear, I might make a graphic to help visualize the transition.

General temperature placement: should be at 10º N during the northern summer and 10º S during the northern winter.
it seems to work fairly well if the oceanic currents and major winds are done correctly.

*areas between the tropics are not always mentioned
*extreme temperatures are not included

Winter temperature placement: the numbers between the color names indicate the boundary between the two.


Hot current: 20 orange 30 peach 40 yellow 65-70 green
Mild current: peach 35 yellow 55 green 65-70 yellow
Cold current: dark orange 5 orange 10 peach 35 yellow 55 green
Normal: dark orange 20 orange 25 peach 35 yellow 55 green ...
Con: peach 30 yellow 40 green 45 turquoise
Con+: dark orange 15 orange 20 peach 25 yellow 35 green 40-45 turquoise 50-55


Summer temperature placement: red are only guidelines

Hot current: Is considered normal
Mild current: Red 25 dark orange 35 orange 40 peach 60? yellow
Cold current: dark orange 20 orange 35 peach 55 yellow
Normal: Red 30 dark orange 40-45 (med) orange 45-47 peach 65-70 yellow 70? green
Con: Red 35 dark orange 45 orange 55 peach 0=
Con+: Red 45 dark orange 50 orange 60 peach 70 yellow

Azelor
10-29-2015, 03:15 PM
So, I edited this post http://www.cartographersguild.com/showthread.php?t=27782&page=6&p=280821&viewfull=1#post280821

I improved the influence maps and improved their descriptions. I still need to add more precisions on how to place the continental influences but there are already some guidelines.
Can anyone tell me if it's easy to follow?

Also, about Western Australia, should it be considered a cold current? My logic tells me that it should, but not the temperature maps.

Pixie
10-29-2015, 04:14 PM
From what I understand, you are advocating a more refined mapping of influences, and then use them to adjust a general temperature rule based on latitude. Pretty much the same system as before, is this right?

As for Western Australia, I looked it up - and here's what I found: https://en.wikipedia.org/wiki/Leeuwin_Current
I would say this return current is formed only in Australia because the continent doesn't block the incoming equatorial current from the Pacific, which, on top of it all, is pushed southwards by Indonesia/Borneo. West Australia is the only continental west coast without a cold current with upwelling and it is the only neighbouring a east-west through.

My logic and limited oceanography knowledge wouldn't let me predict this either, but it really makes sense (and I shall be updating my currents map accordingly ;) )

groovey
10-30-2015, 03:44 AM
I'm a dense person, but even I can follow what your saying in step 5, so that's an achievement for both you and me.

Interesting, will you edit the currents step then? To reflect the new toughts, or is not necessary?

Azelor
11-01-2015, 01:32 PM
From what I understand, you are advocating a more refined mapping of influences, and then use them to adjust a general temperature rule based on latitude. Pretty much the same system as before, is this right?

As for Western Australia, I looked it up - and here's what I found: https://en.wikipedia.org/wiki/Leeuwin_Current
I would say this return current is formed only in Australia because the continent doesn't block the incoming equatorial current from the Pacific, which, on top of it all, is pushed southwards by Indonesia/Borneo. West Australia is the only continental west coast without a cold current with upwelling and it is the only neighbouring a east-west through.

My logic and limited oceanography knowledge wouldn't let me predict this either, but it really makes sense (and I shall be updating my currents map accordingly ;) )

Yes, It's probably very similar to the previous version but also different.

So I guess it make sense for Australia.


I'm a dense person, but even I can follow what your saying in step 5, so that's an achievement for both you and me.

Interesting, will you edit the currents step then? To reflect the new toughts, or is not necessary?

I didn't knew this expression... Glad to hear it's not too complicated but it's not over yet.
I don't understand, is there something wrong with the currents?


I'm almost done with the influence/temperature part. I just need to write it properly and provide some images for each steps.

Then, it will be the precipitation part, that I've already started but I got a couple of things to sort out. The model is not too complicated, for the moment.

groovey
11-05-2015, 04:52 AM
With the currents I meant... well I'll be damned, I can't find the exact text that made me ask that question.

I would swear I read somewhere in one of your latest posts how the currents we got with the currents step weren't always the right color/general temperature, because other factors influenced them. But I can't find it so never mind.

And by the way, the climate in A Song Of Ice and Fire makes no sense at all indeed, "it's magic". I was a bit dissapointed when I researched that and found out.

EDIT: a-ha! Found it (http://www.cartographersguild.com/showthread.php?t=27782&page=6&p=280821&viewfull=1#post280821).

"Colors of the currents appear to be a poor indicator to determine the impact on temperature.

Polar currents are cold (including everything between the poles and 66°) , including currents flowing toward the equator if they have been mixed with polar waters.
Equatorial currents are hot, including those flowing toward the poles from the equator.
Mid latitudes currents are mild, including those flowing toward the poles and the equator. The Gulf stream is an exception : it hasn't cooled enough to be considered hot"

Azelor
11-05-2015, 11:19 AM
Ok, I see now. Yes, I don't know if I should change that. I start saying that equatoward currents are cold and then tell that they can be mild or hot is some cases. That might not make a lot of sense.
Perhaps I should just say it's mild because of x,y,z... in the first place?

To be more specific, we should use a gradient (or a map just like for the land temperature) for the water temperature from 0 to 30... something (although surface temperatures at sea level near Antarctica are much colder). That could be doable I guess.

groovey
11-06-2015, 06:16 AM
I'd say editing the currents step would be due only if being more specific with the currents temperatues/colors makes it faster, easier and/or more precise to figure out climate, if it doesn't help much I'd say keeping the indications in mind would suffice.

Facubaci
11-12-2015, 09:45 PM
Hi, I don't have idea about climates, but I'm interested in them. I'm following this thread!

Greetings and thanks for start this discussion.

Azelor
11-19-2015, 12:30 AM
Still haven't edited the current part but I will keep it in mind.

About the precipitation: I got a model, but haven't tested it much to see if it's good.

Quite simple at its roots (until I have to add a bunch of exceptions)

Here's a map to give an overview. It's a nice map to visualize:
77499

So, by combining several already made map (pressure and winds) we can estimate what regions will be wet and those that are expected to be dry. (The map is probably imprecise over the oceans due to a lack of information)
Basically, High pressure are dry as well as the winds coming from them. Shown in white on the map
The opposite, Low are wet. Shown as green on the map.

But not all High are dry and not all Low are wet.
H: the eastern and poleward sides are prone to storms due to the mixing of hot and cold air.
L: can be dry when too far from the water (Central Asia) or when blocked by mountains (Patagonia) or when receiving dry air (Somalia)

Now I can guess what place are wet/dry but I still need to figure out the approximate guidelines. (effect of altitude, distances...)

Deadshade
11-19-2015, 12:02 PM
An advice for precipitation.
I have created a (simplified) model but can tell you that you won't get any realistic values if you don't work in 3 dimensions.
E.g the vertical movements of air are paramount.
The reason for that is that the lapse rate for saturated air such as what exists at ocean surface is about 6°C/km what is huge.
For example if you move 30°C saturated air only 3 km higher like what happens in the Hadley cell at equator, you lower its temperature to 12°C. And that means that you obtain for a single m^3 of deplaced air some 3 mm of precipitation on 1 m². Now multiply by the flow rate of air and you'll see what it gives.
With a 5 k mountain it is even more dramatic.
The vertical movements of saturated air have a much stronger impact on precipitations than horizontal movements which are rarely working with air mass temperature differentials like 15-25°C.

Azelor
11-19-2015, 04:33 PM
I know about the orographic lift. That's why Iran is not completely a desert.

Or does it have something to do with the western disturbances?

Deadshade
11-19-2015, 05:32 PM
Orographic lift is only a small part of the vertical air mass movements because it's localized. Monsoon precipitation regimes are another local example which are also driven by the vertical circulation.
However what is by far the biggest part is the circulation in Hadley and Ferrel cells (ITCZ and around 50° - 60°). It is in those bands that most precipitations take place due to the massive adiabatic cooling of the rising air masses.

Azelor
11-19-2015, 05:55 PM
Ha yes, the "convergent" systems. They are the green bands on the map above. (more or less)

Dagann
11-21-2015, 12:54 PM
Amazing work Azelor.
I can't wait to see the last steps of your tutorial.


Btw, what are the red areas in your last map ?

Mysterious Mapmaker XXIII
12-08-2015, 10:39 PM
Hey, Azelor! It's been a while.

How are things going with this tutorial? What are you working on now, and what do you plan to do next?

ascanius
12-10-2015, 02:45 PM
Hey, so I've been going through the tut for my continent/world to get a nice and detailed map for the 100th time, that's my plan at least. I get very lost at the temp part, I'm not sure what I'm supposed to be doing. I assume it's more or less like it is for pixies tut with different values and variables, right? It's not very easy to follow at that part.

Azelor
12-11-2015, 01:24 PM
Btw, what are the red areas in your last map ?

These are the high pressure systems. For simplicity, it's the same thing as the withe areas.


How are things going with this tutorial? What are you working on now, and what do you plan to do next?

I haven't worked on it a lot recently. I'm finishing the temperature that I might post today.
I've also done some work of the precipitations. That's the next and hopefully, the penultimate step.


Hey, so I've been going through the tut for my continent/world to get a nice and detailed map for the 100th time, that's my plan at least. I get very lost at the temp part, I'm not sure what I'm supposed to be doing. I assume it's more or less like it is for pixies tut with different values and variables, right? It's not very easy to follow at that part.


Are you referring to this post? http://www.cartographersguild.com/showthread.php?t=27782&page=6&p=281530&viewfull=1#post281530

It should be numbered 5.2 but wasn't because it is not finished. I'M working on it.

Azelor
12-11-2015, 05:20 PM
Tell me if this need more maps, more examples, explanations.

Color key

79531


5.2 temperature placement

Tips:



On painting the zones, it will save you time if you paint them following the landscape. In some places, mountains are delimiting two different influences and each side have different temperatures. They don’t need to be very precise; the zones cover large area and fade gradually, unless there is a mountain chain.
When painting temperatures, let some room near the base of the mountains on each side. You will fill it later on the adjustment layer unless the temperature is the side on both sides
It might not be a good idea to paint the temperatures and precipitations too precisely, unless you want these maps as a final result. The reason is that, the combination of the 2 temperature and 2 precipitation maps can give odd overlapping climates at some places.
With the select tool, never select anti-alias.
With the continental influences, the color bands tend to be pulled toward the equator in winter but toward the pole in summer. This is just because the land is more affected by temperature changes.
The mix of hot and cold waters at mid latitudes: You need to bend the temperatures bands. Increase in winter and decrease in summer their temperature slightly compared to the surrounding. See Eastern Canada or Northern Japan.
General temperature placement: Dark orange is centered at 10º N during the northern summer and 10º S during the northern winter.



See graphic, it's easier to follow:

79727


Winter temperature placement:

*Take the second value for a very large continent



Turquoise: If there is an exchange of water north-south near the coast, its turquoise instead of blue
Blue: Blue appear on large landmasses above 50-55 but not on east/west coasts until 70. With a hot current the maximum could be 80-85. The coasts of a sea of ice or a closed sea are going to be blue above 50.
Purple: it is usually in the center of a large blue area.




Summer temperature placement:



Dark orange: not over 40 near ocean, unless it’s a close one.
Red: normally between 20 and 35 but can go below 10 with dry conditions (Eastern Africa). It’s never close to the seas above 30, unless it’s a closed sea with a small exchange of heat from cooler bodies of water. Common along narrow or semi-closed seas (Red sea. Gulf of Mexico, California…). Not near cold or mild waters.
Dark red: surrounded by a large red area or blocked by mountains form milder climates. Low elevation.



Antarctica is slightly colder but mostly in summer: ice reflects light, high altitude areas impact the low lying areas too, circumpolar current. So, I suppose that if you have a large landmass lying on the pole, you should base it on this.



Instructions



Ideally, do only one season and one hemisphere at a time to avoid confusion. I did it in this order: winter north, winter south, summer north and summer south.
Select 1 zone/influence at a time and paint using the numbers provided. See the graphic above.

I recommend starting with the hottest temperatures: dark orange to turquoise.
Do dark red, red, blue and purple after the others because they have specific guidelines.
Ignore the altitude for now, but consider the mountains as walls, they block the heat (Andes).
Adjustment layer: I made another layer. See the adjustments below.
Altitude layers: 1 for each 1000m. See the section on altitude below.
Some other minor corrections.


I did Antarctica separately. It is a bit colder than the northern hemisphere.


Adjustments



Fill the gaps if any.
Make sure that you don’t skip a temperature layer when it was necessary to add one.
When I need to add a temperature category like in Russia (winter) I overlap on normal (no zone).
Plains have smooth transition.
Temperature and altitude are never a perfect match. Look at the real world maps.
If you want to randomize things a bit, keep this in mind: expand a temperature category for plains or contract it in mountainous area to reflect the actual transition of temperature due to altitude.



Attitude:

Pick the file showing the different temperature categories at different altitude and follow the instructions on it. Ideally, this is just a guideline. You should expand the colors into hotter area a bit to give a sense of a transition.
Made with Excel, sorry.

78225


Summary:


Start by selecting all the levels of altitude above sea level (1000, 2000, 3000…).
We will do them one by one, coloring the whole area for summer and winter.
Paint the new colors over the old ones by following the guideline.
The guideline shows the normal temperature at sea level. As the altitude changes, it tells you when to change the temperature accordingly.
Starting at the equator with the hottest temperature.
When one level of elevation is done, we kick it out of the selection but keep the others.
Repeat for the other layers of elevation until you’re done.


After it’s done, you can expand a temperature it into a zone where it’s not indicated but not too much.


Example: Mexico

78226



Here we have the default map without the elevation factored in (The area selected)
The second map shows the modification at 1000m for the dark orange area
The third map adds the modification for the orange area north of the first

The fourth map shows how to try to make things more harmonious, by expanding the cold temperature south. Ideally, we should mostly focus on the center of the area because that where we should expect the highest altitude.


Final results:

January
78264

July
78263

ascanius
12-13-2015, 11:31 AM
So I went through and did a temp map of summer, I need to redo it. I made a few mistakes, one very large mistake too. I have an area the size of texas that is >35 C which makes no sense, don't know what I was thinking. One thing you may want to go back and include the temp instead of/or with the color designation instead of just orange dark orange red dark red. The biggest problem I had was the dark orange, red, dark red etc. It started to get confusing which color you were talking about.

Dagann
12-13-2015, 02:36 PM
I like this new step Azelor, however, i agree with ascanius.
Colors for temperatures are great, but adding figures woul help a lot.

Btw, i don't know if you know this site, it's really amazing and could help understanding climate and making a realistic climate map.
To access the options (temperature, winds, humidity,etc... all per altitude), just press "earth".
http://earth.nullschool.net/#2015/12/12/1800Z/wind/surface/level/orthographic

Azelor
12-13-2015, 02:38 PM
So I went through and did a temp map of summer, I need to redo it. I made a few mistakes, one very large mistake too. I have an area the size of texas that is >35 C which makes no sense, don't know what I was thinking. One thing you may want to go back and include the temp instead of/or with the color designation instead of just orange dark orange red dark red. The biggest problem I had was the dark orange, red, dark red etc. It started to get confusing which color you were talking about.

You mean I should say, very cold, cold, hot... instead of using the colours? I thought it would be less confusing to use the latter.
Or that I should indicate the names of each colours to avoid confusion?

ascanius
12-13-2015, 04:54 PM
You mean I should say, very cold, cold, hot... instead of using the colours? I thought it would be less confusing to use the latter.
Or that I should indicate the names of each colours to avoid confusion?

Me personally I think just using the temp range would be better, like over 35C, 28 to 35C etc. You could do severely hot, very hot and the others too and it would work just as well, using numbers are just my personal taste. Don't get me wrong I like the use of the color key you supplied but with the way it is now I cannot tell which dark orange your referring too. By the way you also have 10 colors for the elevation key but only 8, unless I counted wrong, for the other first key.

Pixie
12-17-2015, 10:45 AM
I shall be trying this out in a near future (that's when I find the time...), but it looks great and easy to follow.

Just wanted to give my thumbs up for your effort, Azelor!

Mysterious Mapmaker XXIII
01-07-2016, 06:47 PM
Hey, Azelor. It's been a while.

So, now that the temperatures are up, what's next? And how soon can we expect it? Thanks.

ascanius
01-08-2016, 11:59 AM
Hey Azelor. OK so I got my Temp maps finished. I think they are fairly accurate, I hope. Are you still working on this?

Azelor
01-09-2016, 12:59 AM
Hey, Azelor. It's been a while.

So, now that the temperatures are up, what's next? And how soon can we expect it? Thanks.

Precipitations


Hey Azelor. OK so I got my Temp maps finished. I think they are fairly accurate, I hope. Are you still working on this?

Yes, but I got lazy. Can you share the results?

I think most of it is not too complicated but I still got to sort out the effect of altitude on precipitation. It's sounds complicated but it's not, I guess, just a lot of data to check. Problem: air cools off linearly but the rain categories are exponential: the upper limit of the categories are defined by 12,5*2^t where t is the number of the precipitation category starting with 0. (the last category doesn't have an upper limit) So, it means that the orographic lift will be stronger where it's dry at the sea level than where it's already wet. The orographic lift was almost invisible in British Colombia for instance. But then we mix 2 different things. The coast of BC and California is really wet because of : 1- the orographic lift or 2- because the mountains prevent the humidity from crossing over to the other side.

ascanius
01-10-2016, 06:33 AM
here are the results.

Jan
78959

July
78960

I'm still a little uncertain about a few areas, mostly where the islands are, though the western one could almost be it's own continent, It is roughly the size of the eastern US or half of Australia. Thats been my biggest area of trouble is trying to figure out how much of an influence those seas and islands have on everything. For the pressure centers I simply pretended that they were part of overall land mass, which is somewhat seen with the July temps. I also figured that the mountain ranges are going to act as a barrier for the pressure centers and thus temp which is seen with the January temp and how it bends around the area of mountains with the lakes. With the high pressure center in Jan it's actually two, one to the north and one large one to the south of the mountain range. One thing to keep in mind though is that this entire continent is roughly the size of Europe and Asia shifted north.

Azelor
01-10-2016, 08:29 PM
I checked it and it's mostly good except some point. Yet, I could be wrong.
78984
78985

Color code:
Blue is colder
Dark blue is 2 categories colder
Red is hotter, same principle

Summer changes:


Made the south west coast hotter (like California)
North West, large landmass can be quite hot, but less so on the coast
The same is true for the east, where the coast is cooler but interior hotter
Hotter central sea because semi closed bodies of water accumulate more heat
Eastern tip, influence of the cold current is more limited


Winter

Made the south west hotter but the center colder since large landmasses are cooling more than the oceans
North West is colder
Interior seas are colder, at this latitude, the water receive less energy and these seas are covered with ice. And most of these seas have little heat exchange with the oceans
About the pole, the pole is a dot in reality, yet here it is represented as a line. It needs to be of the same color (namely blue). It does look odd considering the area the south of the pole is actually colder but that’s a trick from the projection. Okhotsk sea, even covered with ice the temperature is moderated by the flow of water from the Pacific. About the pole, the pole is a dot in reality, yet here it is represented as a line. It needs to be of the same color (namely blue). It does look odd considering the area the south of the pole is actually colder but that’s a trick from the projection.


Other than that, my precipitation model is nearly finished. I just need to sort out 2 or 3 things.

The most problematic is my little understanding behind the Eastern Asia winter monsoon. I know there is a large anticyclone (Siberian High) rotating clockwise, pushing the cold air to southern China and possibly beyond.

So there is a sharp gradient of temperature north /south. I got this but it's not the only place there is one.
There is apparently a semi-stationary front over central china in the winter months. This cold front brings cloudy and rainy conditions. This is caused by the mixing of cold dry air from the north and the hot moist air of the Pacific.
It is close to the tropic, so the westerlies are probably weaker.

That is how I understood it. Am I missing something?
One thing that I'm not sure I understand is how the air from the Pacific is able to travel that far inland.

ascanius
01-12-2016, 09:49 AM
Thanks Azelor, So far I'm thinking that this guide is working well. You may want to make the suggestion of going through the guide twice one for practice and one version to keep and use.



About the pole, the pole is a dot in reality, yet here it is represented as a line. It needs to be of the same color (namely blue). It does look odd considering the area the south of the pole is actually colder but that’s a trick from the projection. Okhotsk sea, even covered with ice the temperature is moderated by the flow of water from the Pacific. About the pole, the pole is a dot in reality, yet here it is represented as a line. It needs to be of the same color (namely blue). It does look odd considering the area the south of the pole is actually colder but that’s a trick from the projection.
[/LIST]

Doh! Yeah, I feel stupid. I forgot the pole is a single point. The only thing I don't understand is why you made the north west peninsulas warmer in winter? Other than that I understand all the other fixes you did, they make sense once I look at them.



Other than that, my precipitation model is nearly finished. I just need to sort out 2 or 3 things.

The most problematic is my little understanding behind the Eastern Asia winter monsoon. I know there is a large anticyclone (Siberian High) rotating clockwise, pushing the cold air to southern China and possibly beyond.

So there is a sharp gradient of temperature north /south. I got this but it's not the only place there is one.
There is apparently a semi-stationary front over central china in the winter months. This cold front brings cloudy and rainy conditions. This is caused by the mixing of cold dry air from the north and the hot moist air of the Pacific.
It is close to the tropic, so the westerlies are probably weaker.

That is how I understood it. Am I missing something?
One thing that I'm not sure I understand is how the air from the Pacific is able to travel that far inland.

I spent about two hours looking at the eastern Asia monsoon. I don't really think the winds have much to do with it. I'm almost willing to bet it is due to the difference in temp and the humidity level and their change throughout the year, It makes more sense in my mind. Sorry I cannot be more help.

Azelor
01-13-2016, 12:35 AM
You, I should recommend reading the whole guide before starting?

The north east is warmer... I was going to say that you confused east with west but I did it too in my previous message. The pink means it's 1 category warmer.
I think the blue is too cold to be on the coast, maybe on a closed sea it would be cold enough.

Deadshade
01-13-2016, 04:51 AM
The most problematic is my little understanding behind the Eastern Asia winter monsoon. I know there is a large anticyclone (Siberian High) rotating clockwise, pushing the cold air to southern China and possibly beyond.

So there is a sharp gradient of temperature north /south. I got this but it's not the only place there is one.
There is apparently a semi-stationary front over central china in the winter months. This cold front brings cloudy and rainy conditions. This is caused by the mixing of cold dry air from the north and the hot moist air of the Pacific.
It is close to the tropic, so the westerlies are probably weaker.

That is how I understood it. Am I missing something?
One thing that I'm not sure I understand is how the air from the Pacific is able to travel that far inland.

All large scale circulation phenomena are better understood in the vertical plane than in the horizontal plane.
Also temperatures say generally more and are more causal for large scale features than pressures. This has a reason - energy exchages are better described by temperatures than pressures.
I have always seen that people who start modelling climates by trying to locate high and low pressure zones generally struggle to get Something consistent because the causalities are confusing.
The monsoon engine in the vertical plane is quite simple, one needs :
- a large land body (at rather low latitude, say around tropics)
- a large ocean body

As the ocean body is large, it is not far from being isothermal throughout the year.
The land body on the other hand strongly oscillates (the larger the amplitude, the stronger the effect) so that half of the year its temperature is above ocean and half of the year below.
Assuming N hemisphere, in summer the air above land is hot so it rises (corollary is that we have a low pressure but this is irrelevant)
Then in high altitude it must go somewhere. If it goes towards the ocean (here is the difficulty because it is not easy to say where the high altitude air will go) then it will sink above the ocean (corollary is that we have high pressure there).
Then because of mass conservation, the loop must be closed and the wet cold air goes again towards land on ground.
The result is that when this wet air rises again above the heated land, it expands and précipitations occur.

In winter it is opposite. It is the same vertical loop but it rotates in the opposite direction.

All this are necessary conditions but afaik the sufficient conditions for a monsoon regime to occur are not clearly known. Apparently the shape of the land/continent and oceanic currents (or their absence) play a role so that this becomes quite complicated.
For mapping purposes I have always adviced that if you have a large land mass beside an ocean (preferably eastwards) around the tropics and want a monsoon, just put it there.
You will find nobody who would argue that there should be none because nobody knows :)

ascanius
01-13-2016, 08:35 AM
You, I should recommend reading the whole guide before starting?

The north east is warmer... I was going to say that you confused east with west but I did it too in my previous message. The pink means it's 1 category warmer.
I think the blue is too cold to be on the coast, maybe on a closed sea it would be cold enough.


Yeah sorry, I forgot to proofread. Honestly I don't remember what I was trying to say. Anyway keep up the good work.

Azelor
01-13-2016, 01:40 PM
All large scale circulation phenomena are better understood in the vertical plane than in the horizontal plane.
Also temperatures say generally more and are more causal for large scale features than pressures. This has a reason - energy exchages are better described by temperatures than pressures.
I have always seen that people who start modelling climates by trying to locate high and low pressure zones generally struggle to get Something consistent because the causalities are confusing.
The monsoon engine in the vertical plane is quite simple, one needs :
- a large land body (at rather low latitude, say around tropics)
- a large ocean body

As the ocean body is large, it is not far from being isothermal throughout the year.
The land body on the other hand strongly oscillates (the larger the amplitude, the stronger the effect) so that half of the year its temperature is above ocean and half of the year below.
Assuming N hemisphere, in summer the air above land is hot so it rises (corollary is that we have a low pressure but this is irrelevant)
Then in high altitude it must go somewhere. If it goes towards the ocean (here is the difficulty because it is not easy to say where the high altitude air will go) then it will sink above the ocean (corollary is that we have high pressure there).
Then because of mass conservation, the loop must be closed and the wet cold air goes again towards land on ground.
The result is that when this wet air rises again above the heated land, it expands and précipitations occur.

In winter it is opposite. It is the same vertical loop but it rotates in the opposite direction.

All this are necessary conditions but afaik the sufficient conditions for a monsoon regime to occur are not clearly known. Apparently the shape of the land/continent and oceanic currents (or their absence) play a role so that this becomes quite complicated.
For mapping purposes I have always adviced that if you have a large land mass beside an ocean (preferably eastwards) around the tropics and want a monsoon, just put it there.
You will find nobody who would argue that there should be none because nobody knows :)

I got this but the point I don't understand and as you said yourself:

In winter it is opposite. It is the same vertical loop but it rotates in the opposite direction.

the winter monsoon should be dry cold air but it is not and I want to know if my explanation above make sense.

Example:
https://en.wikipedia.org/wiki/Wuhan#Climate
https://en.wikipedia.org/wiki/Changsha#Climate
https://en.wikipedia.org/wiki/Nanchang#Geography_and_climate
https://en.wikipedia.org/wiki/Fuzhou
https://en.wikipedia.org/wiki/Hangzhou#Geography_and_climate

I could possibly ignore the winter monsoon of China, after all, a city like Wuhan receive possibly over 1200mm of rain during the 6 hottest months. It's enough to keep it humid.
But I would rather have it.

Azelor
01-14-2016, 12:38 AM
Step 6, precipitations:

General explanations:

What cause rain? : When the air gets colder. Colder air masses have a smaller moisture retention capacity than the hotter ones, and it fall to the ground. If the temperature of the air remains constant, it won’t rain. You need something to provoke it. How can this happen?

· Rising air in low pressure areas: the Intertropical convergence zone (ITCZ) and the polar front.
· Polar front, when hot air masses encounter cold air masses. This is called a cold front.
· Orographic lift: Air rising above the mountains. Side facing the dominant winds is rainy.

-China: I still can't tell why, but there is a semi-stationary front over central China during the winter, giving a moderate amount of precipitation where is should be dry normally. While I don't know the reason, there are several characteristic that might favor this: A large temperature gradient (north/south), dominant winds are from the north but turn toward the land due to the Coriolis effect possibly bringing moisture from the Pacific inland where it clashed with the cold temperatures. If you have something similar, it could result in a low pressure system over the area in winter.


General tips

· Precipitation tends to decrease when moving away from the source of water.
· In summer, some islands and peninsulas are drier than inland locations but wetter in winter. Ex: Nova Scotia.
· If the winds are blowing directly from sea to land, there are more precipitations.
· Inland precipitation follows the directions of the winds. See the Asian monsoon in Mongolia.
· Precipitation categories spread a lot over flatlands.
· Size and shape of wet systems are influenced by dry systems. It bends and is push it away. Ex: Africa ITCZ.
· Higher latitudes tend to be drier than those close to the equator.


Temporary green/wet and white/dry map

I recommend making a map like the one in white and green, with the arid and wet areas. For the sake of explanation and simplification, we can classify the different areas on the planet, according to whether it’s a dry air mass or a wet one mostly by using just the air pressure and wind directions. Here are the different zones. You can do a map like this to help you if you wish. Green is for rainy areas, white is dry. See green and white maps.

Air rise at the ITCZ and the polar front (mid latitudes)
but sinks near the tropics (subtropical ridge) and at the poles.

January and July

79114 79115

To put it simply, 1,2,3,4 are roughly the same thing. They are dry.
5 and 6 are pretty similar but have a different cause, and the ITCZ is without a doubt a rainier then the other low pressure areas. They are wet.
7 It’s just to represent the fact that the cold polar air is drier but not completely dry either.
I will refer to these later to explain where to put what level of precipitation.

1· High pressure systems (H, for short) are dry and the areas receiving dry air are dry as well.
2· The equatorward east side of the oversea H is usually really dry.
3· Equatorward west of H is dry
4· Equatorward west side tend to be dry in winter. Dry but can have some rain at right angle from the sea. Never rain with cold currents. Orographic rain possible. In summer, they make the weather drier as in Brazil.
5· The west and poleward sides of H are wet. This is where the cold air from the poles and the hot air from the tropics collide. Strom formations are more common. They don’t travel as far west in winter as in summer because the continents have a higher air pressure above them due to low temperatures.
6· Low pressure systems (L) are wet if there is water avaible and if the winds are not blocked by mountains. Inland winds are dry even if they are located in a low pressure area as it’s the case in North Africa in January.
7· In summer especially, the areas receiving the cold air from the pole are drier.


Mapping the precipitation using the 6 categories

Now, time to map the precipitation. I would recommend using the color scheme provided to paint it if you intend to use the script later. Using other color render the script useless but the colors can still be edited later.

There are 6 categories for precipitations, from 0 to 5:

Category 0: The first one is pink/magenta and is actually a penalty I added later to get a more precise results on the dry and cold areas. It can have a huge impact there but very little on hot places.
Category 1: The second category used to be the default first one. It doesn’t have a color, it’s transparent. To paint it, simply don’t put anything.
The other colors are as indicated in the document, with white being the wettest.

79177

''Painting''

1· ITCZ was already mentioned and it’s the number 6 above. It can cover rather large area. Cover the whole area until stopped by mountains, or something else. The size and shape of the rainy area is affected but wet and dry winds. For example, Africa ITCZ is smaller than in South America presumably, because it receives half of its winds from the dry Sahara.
Ideally the ITCZ is centered on the center of the low pressure, following the direction of the winds
Have the highest precipitations (5), the size depend on the winds and the moisture they carry. More moisture=larger wet area.
Also, the Amazonian forest generates 50-80% of its own rain with its own transpiration. Less trees means less precipitation but this will only affects you if the forest is cut down which is unlikely to happen by natural means.

January and July

79106 79107


2· High latitudes dominant Westerlies: located mostly on west coasts. Number 6

Winter: Poleward of 30
Category 4 is on coasts at right angle mostly, on peninsulas and small islands.
Category 3 covers a distance of 10 to 15 degrees inland from the source of water. (1 degree is about 111,11km at the equator)
Category 2 is covering a large area 2000 or 3000 km from the sea.

Summer: Poleward of 40-45
Category 4 is at right angle with the sea.
Category 3 is almost the default at mid latitudes as far as 2000-2500 km inland.
Category 2 is near the poles instead of 3.
Outside the poles, Category 2 is only a transition to the dry areas.

January and July

79108 79109


3· Extratropical storm path: Located in mid to high latitudes, west of oceanic high pressure centers. Number 5
Explanation: The High over the water pushes hot air toward the land and toward the pole, clashing with the colder air coming from the pole. The clash is a cold front, a rapid cooling of the air, generating the precipitations. Area is smaller in winter due to the H overland.
When the Westerlies become dominant, this influence gets weaker. Ex: Patagonia.

Winter: poleward of 20-25
Category 4 is on coasts if direct winds, can go 10 degrees inland near tropics, otherwise it’s marginal.
Peninsulas and direct onshore winds are wetter are also category 4.
Category 3 covers a distance of 10 to 15 degrees inland from the source of water.
Category 2 is a much shorter transition: 5 degrees or less.

Summer: poleward of 25 more or less
Category 4 can go10-15 degrees inland but the distance gets considerable shorter by getting close to the polar circle (60-66).
Past 40-45 of latitude: Category 4 becomes less common on coast but still possible inland
Category 3 is the default category at mid latitudes.
Category 2 is near the poles instead of 3.
Outside the poles, Category 2 is only a transition to the dry areas.

January and July

79110 79111


4· Winter Monsoon: near the sea in winter, on the east coasts. Represented by 1,3,4
Need winds from ocean, strength of precipitation depend on the angle between the sea and the land . High at right angle but low or null if parallel (see graphic).
Precipitation decrease quickly when moving away from the coast.

January and july

79112 79113


Poles summer: hotter water means more precipitations, with the eastern side usually drier than the west because of the dominant wind direction and warmer waters.

Orographic lift effect

Precipitations fall because the cooling of the air saturates in with water. The water only falls if the air is saturated.

Notes
· Precipitations are centred on the flanks not on the ridges
· Large areas have a larger effect and a rapid increase in elevation has also a bigger effect
· Orographic have little impact on late categories, because the maximum precipitation of each categories is defined by an exponential equation while the precipitation “generated” by the change of temperature (due to the increased altitude) is linear.
· Moreover, the Orographic lift is weak at places where the air is already rising (ITCZ and Polar front mostly).
· High pressure zones with cold currents do not generate an Orographic lift: example Atacama Desert.
-Polar winds do not have orographic lift either.

Tip: when painting the precipitation related to the orographic lift, I've found it was easy to do it as follow. Select one level of precipitation and look at the elevation graphic to see at which altitude the precipitations should increase and use the paint tool on that color. This way, you will cover all the map in 1 click. Do this for the different altitude level if necessary.

Color altitudes for reference (see graphic)

Green: 0-1 km (the different colors don't have an impact below 1000, they could but it's just too complicated)

79116

Explanation: so far, we have painted all the precipitations at sea level, that is your basic level of precipitation but now we what to add the effect of the elevation. We do this by taking each category at a time and increasing the precipitation at these places only if the altitude is high enough.
When the default precipitation category at sea level is x, increase the precipitation. Example:
Category 1(default, no color): 1km=2/ 2 km=3/ 3 km=4
Mean that the category 1 (no color) will have 2 for precipitation instead of one if the elevation is between 1 km and 2 km. If the elevation is between 2 km-3 km, increase the precipitation to 3. And if it’s between 3 km-4 km, increase to 4.

Every ridge provoking an Orographic rain effect lowers the %moisture and makes the remaining air drier. It also means that in order to re-saturate the air of water, colder temperatures are needed.

Category 0 (magenta) no Orographic lift
Category 1(default, no color): 1km=2/ 2 km=3/ 3 km=4
Second ridge: 2 km=2/ 3 km=3

Category 2: 2 km=3/ 3 km=4
Category 3: 2 km=4/ 3 km=5
Category 4: 2 km=5

79574

Magenta, category 0

· The last part is to add the magenta penalty for the really dry places. Precipitations are so low than we consider them negligible.
· Should be put only where no other colors are present
· Less likely at higher altitudes
· Spread out on plains but close with rugged terrain.

Final results:

January
79117
July
79118

Deadshade
01-14-2016, 08:30 AM
I got this but the point I don't understand and as you said yourself:


the winter monsoon should be dry cold air but it is not and I want to know if my explanation above make sense.

Example:
https://en.wikipedia.org/wiki/Wuhan#Climate
https://en.wikipedia.org/wiki/Changsha#Climate
https://en.wikipedia.org/wiki/Nanchang#Geography_and_climate
https://en.wikipedia.org/wiki/Fuzhou
https://en.wikipedia.org/wiki/Hangzhou#Geography_and_climate

I could possibly ignore the winter monsoon of China, after all, a city like Wuhan receive possibly over 1200mm of rain during the 6 hottest months. It's enough to keep it humid.
But I would rather have it.

It is not clear to me why you think that there is Something special to be explained.
There is no "winter monsoon" in this location - there is just a classical gaussian precipitation monsoon profile with a maximum around may-june. Precipitation in winter is low as expected.
The only phenomenon Worth to be noticed is that the temperature time derivative is strongest when passing from spring to summer. That means that the rate of temperature increase is at its maximum a bit before the summer when also the precipitation maximum is located.
If you want to understand what happens in that region (which is quite large going from Japan to East China) then there is a stationnary front (caused by the inverted monsoon like loop) where the wet air from pacific meets the very cold continental air.
This happens when the derivative is strongest (see above) and after that the front moves northwards so that the summer/fall are drier.
That shows that this is Something completely different from a monsoon - the cause of monsoon précipitations is adiabatic expansion while the cause of the east china-japan precipitation maximum is a stationary front.
Why the front is stationnary and regular, I don't know but it may be studied somewhere if I had the patience to Google "Meiyu front".

Azelor
01-14-2016, 01:53 PM
Meiyu, or plum rain start in late spring and continue during early summer: http://glossary.ametsoc.org/wiki/Mei-yu_front

Monsoon just mean an inversion on the winds pattern. It doesn't mean that it's going to be rainy. In this case roughly
summer: from sea to land
winter: from land to sea


My research so far had given me no satisfying answer. That is why I'm asking here, in case someone knew about it.


But if it's a stationary front, I just wanted to be sure.

Deadshade
01-15-2016, 09:49 AM
My research so far had given me no satisfying answer. That is why I'm asking here, in case someone knew about it.


But if it's a stationary front, I just wanted to be sure.

Yes it is definitely a stationnary periodical front.

Azelor
01-15-2016, 08:28 PM
I would advise to wait before doing the precipitation step because I rushed it a bit. I still need to revise it just in case. Still, comments are welcome.

So, now for the last step..

My first try was a mess and the second one was too complicated.
This one is much simpler but unlike the previous one, it's not 100% automatic. The 2nd one generated all the temporary layers. While technically possible, it would be really complicated to do so now.
So, my best option is to upload a .psd file. The file would include all the dummy/temporary layers set at the right place, in the right order and with already written names. One will just have to fuse his layers with the ones already present.
This should guarantee that everything will work as intended.

Except that the size of the file might be too small or too big compared to the map, so people will need to adjust that. I made the temporary layers to be in the top left corner, and they are as small as possible (about 80 by 80 pixels).

mbartelsm
01-17-2016, 04:09 PM
Hey Azelor, would it be possible for you to still explain how to do the last step manually? for those who don't use photoshop

Azelor
01-18-2016, 12:36 PM
Well, I would have hoped that it could still work on Gimp. I'm not an expert, but I saw there could be a plugin maybe?

Anyway, it's possible to do it manually since that's what I need to do to record the script.


Basically, to find the resulting climates, we need to combine the temperature and precipitations layers, the 4 of them.
The main problem is that it result in around 3600 different combinations. It depends on the magic wand to select each combination and depending on the colors used, your likely to push the magic beyond capacity. Eliminating so of the by simplifying the table get the tola to 640. But the color problem is still there.

It was not easy to find colors where 2 combo are sure to be unique. Obviously, the basic colors are nice but really useful since they cover the whole color spectrum, I had to convert them. I tried different things and although there might be other options, this on is working well. I can't simply change the colors in the tutorial because it would really not be intuitive, as explained below.

Here what I did, a summary:

January temperature: from hottest to coldest, I replaced the colors with saturated blues, from bright to dark
July temperature: from hottest to coldest, I replaced the colors with saturated reds, from bright to dark
Combine the 2, and it give purple-ish colors. 100 combos

Here, we can isolate the combinations for tundra and eternal ice since the precipitations are not important to determine these. They are the 25 combos in the bottom right.total-tundra/ice= 100-25 = 75
We can simplify the table because now the temperatures are reversible: a cold January/ hot July is the same as a hot January/ cold July. Which further limit the possible combos. (75-5)/2=40
So we have 40 combinations for the temperatures. Some are extremely unlikely but still possible, especially on an alternate-earth.

Winter precipitations: blue, from bright to dark
Winter is in January in the north but in July in the south. So the precipitation map for January should have the top blue and bottom red. The opposite for July (Top:red bottom:blue)
Summer precipitations:red from bright to dark

Now, I realize that this part is not necessary because, the resulting combos can be simplified. Form 25 to 16. It's based on some mathematics: example 2 temperate cities will have the same climate even if they receive 1000mm and 20000mm of rain annually. After a certain pint the extra rain does not affect the climate (not based on the categories we are using). I decided to convert the remaining combinations in green. So I end up with the 3 primary additive colors: red, blue, green.

Then, we need to combine the temp and precipitation layers to get the final combination. And by using the right color key, we can identify all the specific climates.


I will provide more images later.

Mysterious Mapmaker XXIII
01-19-2016, 11:47 PM
Nice to hear we're finally getting to determining the actual climate.

So, are you still doing the "automation" step or not? I'd like to know.

Charerg
01-20-2016, 02:33 AM
The tutorial is shaping up nicely. So far I've managed to follow it pretty easily, though I guess it might help that I went through Pixie's earlier tutorial previously, so I'm somewhat familiar with the subject.

I thought I'd post my "steps" that are part of the tutorial here, since that way it's a bit easier to get feedback. There's also a WIP thread (http://www.cartographersguild.com/showthread.php?t=31774) that includes some of the tutorial-related maps (currents and atmospheric pressures), but I'll throw them into the attachments so anyone reading this won't have to dig through the WIP thread to find the relevant maps.

So far I've completed the steps of the tutorial for January temperatures and precipitations. There's some room for improvement in the details, but I think it will be easier to just fine-tune the eventual climates if something seems a bit off, rather than trying to perfect the temperature and precipitation maps. Anyway, criticisms and suggestions are welcome.

January temperatures:
79335

January precipitation:
79336

Azelor
01-20-2016, 01:45 PM
Nice to hear we're finally getting to determining the actual climate.

So, are you still doing the "automation" step or not? I'd like to know.

Yes, It's almost working. It's getting it right til the 3/4 and messes everything else.



@Charerg I will look at your world as soon as I can make the script work.

Charerg
01-24-2016, 07:44 AM
I went and finished the process manually, and here is the resulting climate map (including the climatologically relevant oceanic currents, for easy reference):

79474

For purposes of comparison, here is a prior version of the climate map I did back during the summer:

79470

Overall, I think it's a pretty big improvement over the previous map, which was partly done based on Pixie's tutorial and mostly done by just looking at Earth's Köppen climates on similar latitudes, or with making "educated guesses".

Although it has to be said that the final climate map shown here has been heavily "corrected" manually at places. It turned out that I screwed up with the precipitations, and Mediterranean climates were practically nonexistant, so I had to put them in manually. Also, I narrowed down the temperature combinations into 20 (from the maximum 100 possibilities) after merging the temperature maps, removing any weird "fringe areas". I didn't bother with refining the merged precipitation map, since I essentially did this manually by first selecting a temperature category (from the merged temperature map) and then going through the different precipitation areas within said temperature category. Theoretically, this would still result in 720 possible combinations, though not nearly all actually turned up.

Still, it took a long time. In hindsight, it might've been better to reduce the temperature categories still more, theoretically you only need 10 to do the different climates (I think). Merging the precipitation maps also resulted in a lot of "fringe areas" with weird combos, especially in mountainous areas. If I were to do this manually again, I'd consider maybe refining the merged precipitation map a little before defining the climates. In any case, what this tells to anyone doing this process via script: don't expect a perfect result, there will probably be a lot of weird fringe areas that will require manual corrections. Also, you need to be pretty careful when doing the precipitation maps, since at least I found it's pretty easy to rush them, and the accuracy of the climate map suffered as a result.

What I also found out in the process is that for purposes of fantasy mapping it might actually be worth it to expand the Köppen classification to include dry polar climates (in my map, I added ES and EW, steppe tundra and polar desert). Present day Earth doesn't really have these climates (as far as I know), but during the Ice Ages they would have been pretty widespread. I think the reason why dry polar climates are marginal nowadays is because all glaciated landmasses are practically islands, with no major non-glaciated areas. This means that tundra climates only occur in maritime areas, without extending far inland.

That said, it's common in fantasy maps to include landmasses that are only partially glaciated (essentially similar circumstances to Ice Age Eurasia). In these kinds of circumstances, you'd probably have an Ice Cap climate (EF) surrounded by polar desert (EW), transitioning into steppe tundra (ES).

EDIT:
It's also worth mentioning that I didn't quite realize until comparing with Earth's Köppen climates that the influence of the Winter Westerlies extends all the way to the Hindu Kush and Pamir mountains, resulting in "dry summer" climate types. It might be worth it to add a footnote about this into the precipitation section. At least I seriously underestimated how far inland the effect of the Winter Westerlies extends.

Azelor
01-25-2016, 12:46 AM
I took your maps and used them to run the script. It should be functional now. The result is at the bottom.

The Mediterranean climates do exist in my version of the map, they cover maybe a quarter of what you have on your modified map (in number of pixels not in km2).

Yea, your right, some combination exist but they are really unlikely.


Still, it took a long time. In hindsight, it might've been better to reduce the temperature categories still more, theoretically you only need 10 to do the different climates (I think). Merging the precipitation maps also resulted in a lot of "fringe areas" with weird combos, especially in mountainous areas. If I were to do this manually again, I'd consider maybe refining the merged precipitation map a little before defining the climates. In any case, what this tells to anyone doing this process via script: don't expect a perfect result, there will probably be a lot of weird fringe areas that will require manual corrections. Also, you need to be pretty careful when doing the precipitation maps, since at least I found it's pretty easy to rush them, and the accuracy of the climate map suffered as a result.

It might be a good idea to reduce it further but it make the distinction between the arid, semi-arid and humid areas even less accurate. There are 10 different climate base solely on temperature: A, Ca, Cb. Cc, Da, Db, Dc, Dd, tundra, Ice. (without getting too much into details, we can't really identify Cc fro Cb with only 2 temperature maps)

The arid climates are defined by the aridity level, which depend on the evaporation (based on temperatures) and the precipitations. This means that although I have 16 temperature combinations for A,each combo will have a different aridity level and some will be steppes or deserts.

Fringes areas where pretty limited in y test. One thing I will mention (I mentioned it already but it was several months ago) is that the transition zone between the deserts and the humid climates is often missing. This happens often when the aridity changes rapidly due to a combination of a higher temperature and lower precipitations, and the fact that there are 4 layers with more or less random borders. You might end up with artefacts, or small odds colors.

Weird climates are almost to be expected in mountainous areas because, as mentioned earlier, the temperature and precipitations can change a lot over a small area. Like in the Andes.



What I also found out in the process is that for purposes of fantasy mapping it might actually be worth it to expand the Köppen classification to include dry polar climates (in my map, I added ES and EW, steppe tundra and polar desert). Present day Earth doesn't really have these climates (as far as I know), but during the Ice Ages they would have been pretty widespread. I think the reason why dry polar climates are marginal nowadays is because all glaciated landmasses are practically islands, with no major non-glaciated areas. This means that tundra climates only occur in maritime areas, without extending far inland.

By following the default classification, tundra and ice caps are only defined using the temperature. It's so cold and the evaporation rate so low that they can't be dry, or barely even if they receive a small amount of precipitations. I think, but the formula I'm using for the aridity tend to give weird results at low temperatures.

The dry tundra might be interesting though. Even if, form a demographic point of view, the population density on the tundra is really low and would be even lower with an arid climate.


tundra climates only occur in maritime areas, without extending far inland.
And in mountainous ones, especially in Tibet. But the reason they occur mostly on the coasts is because the temperature gradient is smaller than inland. Large landmass get hotter especially in summer making it too hot for a polar climate and even to hot for a tundra as in Yakutsk for example.


It's also worth mentioning that I didn't quite realize until comparing with Earth's Köppen climates that the influence of the Winter Westerlies extends all the way to the Hindu Kush and Pamir mountains, resulting in "dry summer" climate types. It might be worth it to add a footnote about this into the precipitation section. At least I seriously underestimated how far inland the effect of the Winter Westerlies extends.

Western disturbances as Indian climatologists calls it. I decided to include it with the orographic lift effect since it only rain at higher altitude (for this area and others at similar latitudes).




79503

The original I took on the forum were a bit blurry so there's a lot of unwanted small dots here and there, but we can have the general picture. I haven't made any transition areas on this, it's just as it came out after running the script. That partly explain why the desert are about twice as big.

Other things worth mentioning:

No Da: Da requires cold and below in winter and hot and above in summer. The only places with these temperature are too dry (either steppes or deserts)
No Dd: requires at least mild in summer and not warmer than deadly cold in winter.

Other than that, it looks plausible but I haven't looked at the temp and precipitation maps to see if they contain errors.

Azelor
01-25-2016, 01:07 AM
Step 7, the script/the climates (manual version at the bottom)
Instruction in order to use the script. Explanations to do it manually will come later.
I will also explain how to improve the map after running the script.



MAKE SURE YOUR NOT USING THE ORIGINAL OF YOUR LAYERS, KEEP THEM IN ANOTHER FILE BECAUSE THE SCRIPT WILL MODIFY THEM.
ALSO, DON'T PUT OTHER LAYERS THAN THE 4 MENTIONED ABOVE.
Make sure your layers were made in an RGB file (it should be the default color mode if you never touched it). If your not sure, you can check the colors to see if they match.


Possible problems while running the script:

Some areas are not selected and there are no climates: make sure your colors matches those I used in the tutorial. And make sure that you are only using these colors on the layers.
The script stop saying that he can't find a specific layer: this is a language issue. My PS is in French and name the layers copie instead of copy when duplicating them.


INSTRUCTIONS

Download the zip file
Open climates.psd
Expand the Canvas size in order to have the same size as your map. Expand it toward the right and bottom to make sure the default layers stays at the top left: the position of these layers is important.
Place your 4 layers (2 for the temperatures and 2 for the precipitations) in the file. Position them so your not missing a part.
Fuse each of these layer with the corresponding already named layer. Make sure to keep the default names and the same order (for the layers).
Fill the missing Background part with a pure black
Make sure all the layers are made visible
Load the script: go to window, script, click on the symbols with a triangle with three lines on the right side on the window, select load a script
click on play to activate the script


79781

Improving the climate map:



Cfc climates are not really accurate. The script cannot differentiate them properly from Cfb. Therefore, most of the Cfc are actually Cfb. Cfb is much more common than Cfc. Normally the poleward climate progression should be either Cfb,Dfb,Dfc... if the climate is more continental or Cfb,Cfc,Tundra is the climate is more oceanic. Inland we could have Dfb climates right next to Cfc but never north of it.
Some steppes are missing. When you see a desert and a humid climate without a steppe in between, it needs to be added manually. Expand the steppe inside the desert. Expand a lot if it's a plain and just a thin line if there is an elevation.


79768
For the manual version:

I hoped it's not too badly written, English is my second language and PS doesn't have a spellcheck.

79603

Also, these are the files I used for the script at their real size. I would recommend using these instead on the ones in the example above since they are smaller. And the larger one might contain some errors.

Charerg
01-27-2016, 04:09 PM
Great work getting the script working!

Unfortunately I'm using GIMP, and I don't think there's a way to make *.atn files work with it (as far as I know). Anyway, if it's not too much trouble, would you mind running a 2nd "test run" of the script for me?

I refined the precipitation maps considerably, and they should now be much more accurate than the previous admittedly somewhat rushed versions. Also, I put these maps in *.png format and left the graticule out, so that should take care of the random dots showing up. The temperature maps are unchanged for now, since I think they're acceptable, and it should be interesting to see how much the results differ with just better precipitation data. There won't be any Dd climates without changing the temp maps, but since Dd is very rare in any case, I don't think it's too much of a flaw if it's missing.

Regarding dry tundra: I suppose the sort of Ice Age-era "steppe tundra" might be represented with just "cold steppe" using the default classification, it's after all more or less the same thing. I'm not sure if anyone has attempted to use Köppen classification to re-construct Ice Age climate, but as far as I know the steppe tundra is thought to have supported a surprisingly rich fauna, inlcuding large herds of herbivores like horses, saiga antelopes, bison, mammoths and so forth. All in all, in terms of human population, it may have been a better environment than modern "wet tundra" because of this. Indeed, perhaps even better than the taiga, at least for a hunter-gathering culture. The dry climate would have also been an advantage in winter, leading to less thick snow.

Azelor
01-28-2016, 12:32 AM
I did the climate for you world by myself to see if i was getting the same results, in case the tutorial could be improved. It took a long time even if I rushed it a bit, hopefully it will be worth it.I'm going to start with the temperature maps since there is less stuff to talk about.

*I have to warn you that I might make some small changes to the temperature section , more details about it later. Also, I change the explanations in the section on the effects of altitude and added a new picture but it's still the same thing as before.

To set the table for the temperature maps, i did 2 influence maps.

The color mean:
Red; hot current
Green: mild current
blue: cold current
yellow: continental
no color normal
and continental plus is not there, the climate is not extreme enough

January

79583

July

79584


January: Before reading this, i need to say that I'm 100% sure that i skipped some place regarding the temperature changes due to elevation. But most of it should be on the maps.

I did not notice it as first but there is a problem with the temperature at higher elevation. I don't know if you used the table I provided but you seemed to take inconsideration that the temperature scale was linear. It's actually pretty erratic. It's true that you need to lower the temperature of 1 category for each 1000m for the hottest one but other (especially the coldest) cover a wider range of temperatures. So, for example, the north eastern continent summits would be much milder. If the base temperature at sea level is yellow: it's between 0 and 10, or 5 degree on average to make it simpler. Since the elevation is brown, it's 4000m high. The time lapse (cooling of the temperature with a rising altitude) is somewhere between 6 and 9 for 1000m depending on humidity. I took 6,5 for simplicity. So, for each 1000m, you lower the temperature by 6,5 degree Celsius.

*You can have a look at the temperature progression based on a linear scale to see the difference. Some bars are bigger than others.

4km x 6,5 = 26 degrees
since the temperature was around 5 at the base: 5-26 = -21
which mean that the high central range it should be either turquoise (dark green if you prefer) if the base color was yellow or green if the base is warmer.

I made the image smaller but the originals were blurry. Anyway, your maps just need some tweaking. I assume that use haven't put everything on the same layer? (I might need to warn people about it)

79585

I will cover the map point by point. A lot of places have slightly different temperature due to some randomness I suppose.

1- I used a mild oceanic influence, which explain that the coast is cooler. But I think your is more accurate. Also, I believe that the interior should be hotter at that latitude.
2- Same as above, the interior should be pretty hot.
3,5, and 6 : there is a maritime influence there and the temperatures should be more spread out.
4- I think it should be warmer. it's a hot current.
7- we could compare the climate of this coast with eastern Greenland and Svalbard. The current is kinda mild and it should be warmer than Antarctica. That is true for most of the polar coast except in the middle where it should be colder because of the ice and the small heat exchange from the warmer seas.
8- a bit warmer maybe. I used a hot current influence there.
9- mild influence and as above, the temperature tend to be more spread out. Think about Chile and Argentina.
10- The change of temperature due the the altitude is smaller.

July:

79586

1- it's winter and made it cooler because of the rather mild oceanic influence.
2- The orange stretch to much to the south. On the other hand, maybe your right and I've put too much dark orange in the small sea.
3- It is a very narrow band of land with a very strong maritime influence, I doupt it could be that hot, maybe in the valleys inland but not on the coast.
About this continent , and in general where the winds are blowing from west to east, you should move the maximum temperature a bit more to the east maybe. In my version, i considered that the mountains in the west somewhat blocked the winds which limited the air flow from the sea, hence higher temperatures.
4-The ocean is actually kinda cool and since winds are blowing from north to south east (approximately) it makes the climate milder, especially on the coast.
5- I'm not sure it should be that hot.
6- Personally, I made it milder, taking southern Asia as a reference.
7 and 8 - I expect the sea to be trapped under a layer of ice with really cold temperature. The winds are blowing from the pole toward the continent which push the cold air inland. Maybe I pushed a bit too far since the continent is also affected by the westerlies, which should bring milder air from the western ocean.

That's it for the temperature maps.


Precipitations are a bit more tricky, partly because my system is a bit rigger ? (To make or construct something (in haste) or in a makeshift manner)

Anyway, maybe I can improve it.

Starting with the pressure maps:
January, the pressure looks alright.

79587

About the winds, there is a lot of guesses and most of them are not really changing the weather too much
1- I don't think it changes much but I think it's mostly under the westerlies, which means the wind have a tendency to flow to the east. If the did converge to the north, I don't think it change the precipitations much.
2- I actually have no idea
3- Exact direction of the winds seems irrelevant since it's dry
4- At first, when looking at the continent, I thought that it looked like North America, but it lacks a huge mountains range to separate the high pressure system in the west from the rest of the continent. Therefore, it makes the winds blow more from west to east. Winds coming from the south are deflected in a clockwise fashion.
5- I don't think this should have such a large impact on the winds.
6- I don't see a reason why the winds should blow toward the south.
7- More a general note than a specific one: from here, the winds tend to get deflected more toward the north by the high pressure systems of the interior of the continent. As it is the case in Russia during winter.


July:

79588

1- the air should converge but I'm not sure how exactly but again, i think the westerlies should stronger. Maybe there could be some easterly winds from the eastern ocean in the southern areas. My guess it that it should look a bit like the American summers. But from my point of view, it's the continent that I have the most uncertainties.
2- In most case, the bending direction of the arrow is not so important but the direction of the wind is.
3- On my map, I made the winds from the north converge and then flow to the east and eventually they would be deflected to the north probably.
4- This area reminds me a lot about the Indian subcontinent, same shape, same latitude. I made it a low pressure area.
5- I almost forgot about this area... Just like in Ecuador, the air converge under the ITCZ. Since the south is colder, the ITCZ tend to stay more on the northern side.
6- The direction of the winds here is just really confusing, I'm just going to ignore that area and do it roughly.

I think the rest was pretty good.

I made the green and white maps, even if they are just temporary, they can help with the precipitation maps. Green is humid and white is dry.
Yea, I know, I'm more the visual type of person. I need the illustrations.

January

79581

And July

79582


I will stop there for today.
There are about 39 points I wish to talk about just for the precipitations so it's might be another long post.
I would like if you could give some feedback, if something in the tutorial was poorly explained in light of the point I mentioned in the post. Of course, there are things that depend mostly on guesses so I could be wrong on a couple of things but it's not easy to know.

Charerg
01-28-2016, 04:53 AM
Wow, that's a lot of work you've done! My thanks for putting in the effort!

I'll post a more detailed response once I've gone through your post in detail, but for now I should mention that I updated the Atmosphere & Winds maps from the previous versions before making the new precipitation maps.

Jan:
79608

July:
79609

I haven't read through your comments about my previous Wind maps yet, but I think these ones are a bit more "readable" (and should be a lot more accurate).

Edit1: Ok, went through your comments Re: Winds. I agree that the previous maps had quite a few inaccuracies (as you pointed out). Comparing your comments to my updated wind maps, I think I already managed to correct the previous inaccuracies, but do point out if I missed something.

Regarding the tutorial, I think it might be helpful to actually draw the ITCZ as part of the process of determining wind directions, since the winds tend to converge there. At least I found it useful. Secondly, it might be useful to draw a few tiers of pressure like I did in my new maps, since this can make it easier to visualize the effects the high pressure centers have on the winds. That said, this does complicate the tutorial, and I guess it depends on just how accurate the person going through the tutorial wants the results to be, so maybe it should be an "optional" step.

Edit2: Temp maps

I have to admit that my temps maps were pretty "rough" and I just ramped up the temperature one category for each 1km elevation or so regardless of latitude. In this case, it's more of a case of "not reading the instructions until the work is already finished" than a fault with the instructions themselves! With that in mind, your versions of the temp maps should be more accurate (generally speaking). It should be interesting to see how this will affect the climates.

Edit3:

The maps should be visible now.

Azelor
01-28-2016, 12:13 PM
I can't see you files, they haven't uploaded. This tends to happen when you take too long to write the message, if you get disconnected.

But as I said in the other message the temperature at sea level should be good but not the ones at higher elevation. I can't guarantee that I haven't missed an altitude layer.



Now for the precipitation maps

January: I did the precipitation for the orographic effect, but they were made roughly. From what I can see, they seems pretty similar to yours.
It is possible that I have confused the several maps while I was writing the numbers on them. I will specify it when I wrote the number for nothing.

79598

5,6,11, never mid, it's pretty much the same. But 6 might have a lake effect like Northern Iran.

1 and 17 -One of the biggest mistake on the map. This area is supposed to be dry like the coast of South Africa because it's a cold current.
4- is exactly like South Africa (Cape Town)
3- (sorry if I don't follow the order of the numbers) Close to the Equator is the ITCZ. Reminds me a lot of Ecuador.
12- The landmass becomes hot since it's close to the tropic. It draws the air fro the sea toward the south. It's borderline between the ITCZ and the polar front.
2- That's the effect of the ITCZ. Mountains are not high enough to block all the precipitations since the water contain so much moisture and there ar e many wide valleys where the air flow is not interrupted. The remains dies out somewhere over the continent.
Also, the souther semi-closed sea is much more humid since it receives the winds from the ocean. Evaporation is the sea also help giving more precipitable water. But the precipitation don't go as far inland.
7 and 14: these are likely Mediterranean climates. It's supposed to be their rainy season. The winds are blowing more or less following the latitude lines. 14 is actually not so bad, the exact position of t he dry are is not the same in America and Europe for example.
8- With the westerlies blowing, the precipitation can go far inland.
10- I'm not sure about the precipitations on the east coast. I'm not sure if the area between 30 and 40 degree of latitude should be drier or wetter. Since the high pressure centerr in the west have a stronger impact of the winds, it might make more sense if the area was drier like in your version. I'm not sure.
9- They got the winds in their face, it should be more humid. Norway and Chile are not really good example since they got mountains blowing the flow of air.
15- the polar air is pretty dry. The continent on the center is protected by the mountain ranges in the north from some of the cold air.
16- I'm not sure the range is big enough to block all the moisture. It's definitely drier but not so much. But I could be wrong and maybe it's like northern Venezuela.
18- it's really dry in winter but polar ocean do bring some moisture during the summer.



July:

79599

5,6,7,10,15(India),18, 19 and 21 seems alright, never mind.

1 and 16- Same as mentioned for the other map. Mountains should be drier in that kind of area.
2- The ITZC, we could debate on where to actually put it, but it doesn't seems so bad either way.
3 and 13- like in Europe, the climate is dry til around it reaches the 40 degree.
4- The interior of the continent is hot and a low pressure system. It gets some dry air from the west but the moisture roam freely in the north due to the Westerlies and it also come from the south east like it does in North America.
11- I wasn't sure f it was supposed to be dry since it's close to a high pressure center.
8- Is affected by the polar front and should be more humid. But 9 is not.
20- Like in South Africa, the precipitation are limited to the coast here.
12, since the winds are blowing mostly from west to east, they carry more moisture. But it's still drier than on the south pole summer because it's colder and there is less water available for evaporation.
14- I made the precipitation follow the flow of the wind. In my model, he continent is smaller than Asia, meaning the westerlies are stronger at this latitude. Meaning is not as humid as the south.
17- Not sure

I here are the precipitation layers in png

January

79600

July

79601


Btw I edited the step 7 post to include manual instructions. But once you layers are improved, I don't mind running the script if you send them to me or put them here as PNG. PNG is a good format if your using plain colors (the opposite of pixilated textures) and you won't need to compress them.

Charerg
01-28-2016, 05:00 PM
Ok, I finished updating the temp maps. They're essentially more or less copied from your versions, with a few minor differences here and there, and possibly a few corrections with a couple of mountain ranges. Nothing major, in any case. At this point, I think it would be ideal if you could run the climate script with both your version of the precipitations and mine (posted in *.png in post #105), since it would be nice to see what the results look like before I return to the precipitation maps (in any case, I think a slight break is in order before I revisit the precipitations).

Also, another reason why I'd like to see the results is that while I agree with a lot of your suggestions, like area 2 (in your january map), I'm a bit on the fence with a few areas, namely 1, 4, 12 and 17 (again, january map). With area 12, the large peninsula (called Akanrias) forming the southern portion of the large western continent (Eocidar) has a pretty mountainous coastline creating a rain shadow (even if the mountains are not that high for the most part), and I think the Westerlies are blowing too much "along the coast" to fully cover the interior. Hence, I think it should be (relatively) dry, probably something like Patagonia, at least in the interior. That said, I confess it's possible I overestimate the effect of the mountains, after all the Alps don't seem to create much of a rain shadow.

The climate patterns of Southern Eocidar are also complicated by a monsoon cycle, since the landmass in question is very large, and at least I postulated that the ITCZ would reach almost 30 S latitudes during Southern Summer, causing a strong monsoon affecting the coastal areas north of the 30 S latitude. The Western coast is also very mountainous, so there would certainly be a lot of orographic lift. All in all, I think the height of the mountains alone would likely prevent "extremely dry" climates along the coast, except a narrow strip of coastal desert. That said, it's possible I made the "rainy area" reach too far south, since the region is (as you mentioned) influenced by a cold current.

Although I don't think the said cold current would be as cold as the Humboldt current, since the really "Arctic" water would be deflected into the large channel between Eocidar and Nomune (the southernmost continent), most of the water flowing along the southwestern coast of Eocidar would be 30-50 latitude water. Also, the southern waters of the "Outer Ocean" (Agalhain) might not be as cold as the Pacific, since the "Antarctica" of this world is located north rather than south. Still, I might have made it too wet, it definitely shouldn't be wet enough for a rainforest climate, but I still think your version is too dry.

Re: area 17. Again, I think here the orographic lift should prevent dry climates, except in the "rain shadow" of the mountans and the very tip of the peninsula (called Menduine).

Anyway, it should be interesting to see what sort of climates turn up. The revised temp maps are in the attachments. Oh, and many thanks for putting a lot of effort into this, it's always a lot easier to see potential flaws when an alternate opinion is available!

EDIT: In case you haven't run the script yet, I did actually update the precipitation maps slightly. Some your suggestions are implemented in the new versions, namely southwestern Eocidar is drier (though not as dry as in your version), and a few other adjustments too. The new maps are in the attachments.

Azelor
01-29-2016, 12:07 PM
While you might have a point in that the Drake passage is much narrower, yet it doesn't have a very large impact. The passage south of Africa is much wider and it result in a very similar climate for Namibia, vs Chile. Same thing for California and the Mediteranea. All these place have very similar climates.

If we compare them more in details, we see a small difference between the north and south hemisphere. The coldest currents do seems to have an effect of precipitations (or it could be something else) but it's not an huge difference.

79638

That is pretty much what I followed but I don't think this model can be applied on the central eastern continent very well.
In the other areas, although we could play with the parameters, it would still be mostly dry.


I wasn't entirely sure how to treat 12, my guess was that it would draw moisture from the north AND the south, since it's pretty hot and close to the ITCZ.

17, Was a bit harsh I agree but it does remind me of Chile (similar coastline and climate).

About the mountains: as far as I can tell, there is very little effect on precipitation near the oversea high pressure centers. I'm not exactly sure why. The is nowhere in these areas where the mountains have higher precipitations, not even in the Atlas where the winds are blowing directly from the Mediterranean sea. Yes there is a major effect in Iran (for example) but it's only in winter when the high pressure system moves to the south, away from the Mediterranean sea. So the precipitation from the orographic lift should more or less follow the above image as well. It's clear that I painted every mountains without even thinking if it was supposed to be rainy or not. The orographic lift effect is completely wrong at these places.

Charerg
01-29-2016, 12:43 PM
You're probably right about the cold currents. In the most recent version the "rainy area" reaches approximately 15 S latitude, which, if you look at Africa, is about where the Namib desert ends. All in all, I envision southwestern Eocidar as more or less comparable with Western Africa in terms of climate (in other words, not a desert, but not very rainy either for the most part). Considering that the African monsoon reaches all the way to the Sahel during the rainy season, I think the recent version is reasonable, with possibly the area west of Eocidar's "inner sea" a bit too wet in january, but it's hard to judge whether the precipitations are too high without seeing the climates themselves, since the equatorial latitudes mean a lot of evaporation even the areas with light rain are probably going to end up with a dry climate type.

Also, the Atlas mountains do receive rain during winter if I'm not mistaken? At least historically Northern Africa was "the bread basket" of the Roman Empire so it's not really desert (if not very rainy, necessarily). All in all, I think it's rare to find mountains with a true desert climate, except in the heart of the Sahara perhaps. So, I think a modest degree of rain along the mountain ranges during the "wet season" is justified. Although again, a bit hard to judge based on just the precipitation maps, I may have exaggerated the effect or made the rainy area too large.

Azelor
01-29-2016, 02:04 PM
Western Africa ? which country exactly? Lagos got a very season precipitation pattern, dry winter wet summer. https://en.wikipedia.org/wiki/Lagos

The bread basket of the Empire was Egypt if I remember correctly, and although it is one of the most fertile land is the world, it barely rains.

It would make sense to have dry mountains if the surrounding air is also dry, the water needs to come from somewhere.I edited the precipitation layer to include the orographic lift with the westerns mid latitudes drier, like I mentioned in the other post.

here are the results

79641

79642

Charerg
01-29-2016, 03:55 PM
Egypt was another breadbasket, but Northern Algeria (to an extent) and especially Tunisia were also very productive (the former Carthaginian heartlands).

Anyway looking at the climate maps, I think the temperatures are probably fine now. Af climate looks overall a bit too widespread compared to Earth. That, and deserts are overall too widespread compared to the steppes. Also, you're right that southwestern Eocidar could be maybe a bit drier at places, though I think your version is a bit exaggerated since it's essentially nothing but desert (and the occasional tundra) almost all the way to the Equator. Also, the southeastern continent (Anapar) is too dry in both our maps, the deserts there should be largely confined to the interior since most of the continent isn't really in desert latitudes. I think the peninsula of Akanrias (the large southern peninsula in southern Eocidar) should be "somewhere in the middle", it's too dry in my version and too wet in yours. There also seems to be a few weird high-latitude steppes in my version that should really be D climates (guess I need to increase precipitation there further).

That said, I'm pretty satisfied how most of the map turned out. I think it will maybe take one round of further fine-tuning the precipitations and then the climate map should be "good enough" that it can be finished with some manual adjustments here and there. Btw, do you think Dc is a bit too narrow strip between the tundra and Db climates? It seems slightly thicker on Earth, although maybe it's just the differences in latitude.

By the reference to Western Africa I mean the area in general, there's a lot more BSh, Cwa and Aw than there are BWh, Am or Af. Although in my case the interior of the "supercontinent" will be inevitably largely desert, I think the intermediate steppe climates still cover way too little area compared to similarly dry areas on Earth.

In any case, my thanks for running the script, it spares me a lot of work not having to do all that manually!

EDIT:
I also think that the interior of the northernmost non-polar continent (called Neraduhr) should probably be "winter dry" because of the presence of vast glaciers to the north. It looks like some Dwb turned up in my map, which is good, but I still need to adjust the precipitations so the Dc climates in the interior are Dwc rather than Dfc. Do you think I'm right about this, or should it just be Df climate?

EDIT2:
Actually, I guess I do need the touch the temperature maps somewhat, since Cfc covers rather large areas in the northern half of the map (when they should be either Dfb or Cfb). Another question, do you think the island chain south of Neraduhr (the northernmost non-polar continent) should be Cfc, as it is now?

EDIT3:
Ok, here are the updated versions. I made the winters slightly colder in general (especially in the north, where I feel the Arctic glaciers would lead to more extreme winters), to make continental climates a bit more widespread. In places, I also ramped up the summer temperature a tier in order to eliminate Cfc climates (although I left some islands and mountains as Cfc).

In terms of precipitation, in general I tried to make steppe climates more widespread, and also to make the tropics less of "rainforest or desert". Southwestern Eocidar should be a bit drier now, with the desert more widespread, while the large equatorial area on the eastern side of the supercontinent (called Magatel) should have more BS and Aw (I hope). But we'll see how the results turn out. I think this will be the last "run of the script" unless there are some glaring problems, and the climate map can be finished with manual adjustments from here on out. The relevant maps are in the attachments.

Once again, many thanks for running the scipts for me (as well as otherwise spending a lot of time on improving my world)!

mbartelsm
01-30-2016, 09:21 AM
Azelor, one question. When saving the monsoon climates, why do you choose only those two? wouldn't climates with more extreme variations also be considered monsoon?

EDIT: Would you also be interested in someone turning this into a PDF? I'm a graphic designer by trade and would be more than willing to turn this into a properly designed document (it's kind of hard to navigate it on the forum)

Azelor
01-31-2016, 12:56 PM
Some steppes needs to be added manually between the humid climates and the deserts. A large band when it's a plain and a narrow one if there is an elevation. In some places, it makes the whole deserts dissapear.

The tundra at the equator is not wrong if you look at the temperature maps, which are both between 0 and 10. This is something to be expected at this altitude http://koeppen-geiger.vu-wien.ac.at/pdf/kottek_et_al_2006_A4.pdf

Anapar, it make sense if there is really a high pressure center right next to it, but I'm not entirely sure of that.

Akanrias: my version but a bit drier sounds ok.


Dc: I think it's because you lack landmasses in the appropriate latitudes. In some places, the Db would turn Dc if it was not tempered by the ocean.

Dwc, increasing the precipitations in summer should be enough (summer 4, winter no color). Decreasing it further in winter, I'm not sure it's a good idea.
Btw, the w climates require to have their driest mouth to receive less than 10% of the wettest month. In summer, you would need one the two wettest category and in winter, you need one of the tree driest. So you need both extremes.

Of the Cc, only Cwc is included (because it's alwals located at higher altitudes, so it's rather easy to place).
Csc barely even exist in the real world.
Cfc is not on the map. Because the differnece between Cb And Cc is the number of months with a certain temperature and we don't know the actual temp since we are using average. Still, there is an unknown color it the north and I will investigate... I could be Cfc.

The north is mostly covered by tundra, Dfc and Dfb. And some Dfa, which is nice.

Charerg
01-31-2016, 01:50 PM
Cfc: I could be wrong, but I think the climate that shows up in the north is actually Cfc. At least I don't see what else it could be. Anyway, for clarity I marked the climates on your version of the map:

79712

Anapar: I think the high pressure center probably is located west of the continent only during southern winter (July), and it would retreat into the channel between Akanrias and Nomune during the southern summer (January). Of course, there's always some guesswork involved, but I think this model is reasonable. That said, the recent versions aren't too far off, it just needs the BS areas added in.

Azelor
01-31-2016, 03:25 PM
Yes it make sense. But then, most of this Cfc is actually Cfb.

And I have to admit that I am surprised by the dryness of some areas: the inland sea and the western northern continent (on the eastern side).

The inland sea: these are mountains which mean more precipitation and lower temperatures. Yet, it is really dry.

The other continent, even if most of it turns into a steppe, I would have expected that it would be more humid.


anyway, the results: I added the steppes this time.

79722

mbartelsm
01-31-2016, 06:55 PM
I spotted a couple of bugs (or miss-uses) of the script. The first is that during the "climate 1" script it tries to select a couple of copied layers, the thing is that you Ps seems to be in french so the layers are named with the word "copie" while my Ps generates them with the word "copy".

The other problem is that the script doesn't seem to be selecting my level 1 precipitations properly, I tried leaving them transparent and with pure black, it doesn't work. In the end those areas are just left without processing and end up being transparent (no climates outputted)

Azelor
01-31-2016, 07:55 PM
I fixed the script and it should fix both problems. I was aware of the language issue and I think that naming a layer as soon as it is duplicated should solver the problem. If not well yes, copie is copy, just select it and continue the script. It's because I managed to record the script without noticing that this layer was not properly named.

And sure, you could do a .pdf once it's finished, which should be soon. I edited the first message to include links to all the steps.


Now on the biomes and the equivalent climates: a simplified version of this http://www.cartographersguild.com/attachment.php?attachmentid=70631&d=1423197614
Right now, there are 13 different biomes but I feel that some of redundant.

Alpine is a meta climate and can include all of them. It's used for practical reason since it's not possible to indicate all the climates in some mountainous areas.

Ice: EF
Tundra: ET
Boreal forest (mostly pine trees) : Dd, Dc
Temperate: Cfb, Cfc, Dwa, Dfa, Dfb, Dwb, Cwc?
Subtropical forest: Cfa, Cwa, Cwb (have a winter but temperature usually stick above 0)
Mediterranean: Csa, Csb, Csc?, Dsa, Dsb (dry summer)
Tropical rainforest: Af, Am (tropical have a small temperature variation over the year)
Tropical dry forest: As, Aw

Savanna: hot steppes (BSh) (the dry season is normally in winter but I'm not sure if it's really different form the Mediterranean biome, both should have a forest with open canopies)
Grassland: BSk and BSh as a transition between the Savanna and the desert climate.
Scrubland: a desert with some vegetation like cacti.

Desert: a desert devoid of vegetation.

Charerg
02-01-2016, 05:21 AM
There's a slight typo in the biome reference file, you refer to "Af" climate in Tropical dry forest and Monsoonal forest sections, I assume the reference should be Aw?

Btw, when you ran the script last time, did you use the updated temperature maps? Because it looks like Cfc still shows up, and the northern climates seem largely unchanged in general. And I'm pretty sure I "rigged" the temperature maps in such a way that the Cfc climates should have disappeared (the tundra border should be slightly different too).

In any case, if you don't mind running the script another time, I suppose it might be worth modifying the precipitation maps a bit further to see if I can make those Aw climates turn up. I guess there still needs to be more contrast between July and January precipitations. Also, I guess the Neraduhrian summer rains need to be ramped up in order for Dwc to appear.

Actually, now that I compare the precipitation maps, it appears that "Winter 1 (transparent) + Summer 3" combo results in Dwb climate, but "Winter 0 (pink) + Summer 3" combo means Cfc instead of Cwc, even though the contrast is higher in the latter case! Looking at the precipitation maps, I can see why you did this (so Earth's climates turn up more accurately, since even Eastern Siberia is Dfc), but it's still a bit weird (to my logic, anyway).

Edit: Ok, here are the precipitation maps. Hopefully, this time they're truly "final"! The main difference is that the tropical regions now have a much more pronounced dry season than previously, so Af should be confined to a more realistic area. Also, remember to use the updated temperature maps (in post #113).

Azelor
02-01-2016, 01:02 PM
Yes, I fused the two biomes. Monsoon is also a dry forest because it's mostly the same thing.

No I forgot to use it and as I already explained, you can't get rid of the Cfc. You'll need to edit it manually if you want to change the Cfb,Cfc,Dfb transition.


I see that there is a problem here. The w climates should be : 0-5, 1-5, 2-5, 0-4, 1-4 and 0-3 , but not 1-3

About Siberia, we will see what the results will be but they could become Dw something. Normally, it should be Df something but since my rain model is simplistic, southern Siberia is drier than what it's supposed to be. Maybe I will change the instruction regarding the placement of the pink layer.

Charerg
02-01-2016, 01:36 PM
Actually, the Cfc should be possible to remove via temperature map editing. The regions that turned into Cfc climates had "Cool" winter (Yellow) and "Mild" Summer (Peach). If one ensures that this temperature combination doesn't turn up, then Cfc climates should not appear. Anyway, what I did should replace Cfc partly with Dfb, partly with Cfb (although I left several islands as Cfc). Of course this could be done manually, but it's also possible to eliminate Cfc via temperature map changes. Also, I did change a few other areas too that I felt were in the wrong temperature category. For example, in the extreme south there is a Tundra->Dfb transition, I edited the temperature maps so there should now be a narrow band of Dfc between the tundra and the Dfb.

w climates: Ok, so the Dwb was a bit of an anomaly then. Although I guess it should still appear since I increased the summer precipitations in Neraduhr (there's now a large area of lvl 4).

Edit: Fixed my typo with the southern D climates (originally wrote "C" instead of D).

Azelor
02-01-2016, 03:21 PM
Mild and cool is the only combo for Cc and even then, some Cfb also fit in it. For example, London and Reykjavik are in the same combination, one is at the lowest values possible and the other is closer to the maximum values.
For now, I prefer to let keep Cfc and add more information about it.

Ok, i did patch one color that was miscategorized but for the rest, there isn't much i can do. Else it will turn a lot of forests in America and Russia to Dwb/Dwc.


While I don't see any Cfb->tundra transition, there is some Dfb->tundra and it would be better with a Dfc in between.

Charerg
02-01-2016, 05:43 PM
Yeah, I guess the dicciculty is in classification. In some areas (like the extreme north) level 3 rain would realistically probably be pretty much the maximum value outside of islands and coasts. So the scale runs effectively from 0-3 in those latitudes rather than from 0-5 like in the tropical latitudes. Close to the tundra region even 0-2 could potentially be a "w" climate, but probably not in tropical areas.

Yet the same classification needs to cover both areas. And the tropical areas are probably more significant, since Df and Dw have (broadly speaking), similar vegetation and animal life (since winter is never a growing season in the north, regardless of whether it rains or not). As such, for fantasy mapping it's perhaps a bit unnecessary to classify D climates that accurately, although I find it interesting personally.

Azelor
02-01-2016, 08:42 PM
The thing is that in real life, the category 0 can have precipitations as low as 0. Literally meaning that if the precipitations in summer are greater than 0, it's going to be w something. But by using the average of 5 instead, we eliminate a bunch of them and put them in f instead.

Yes, the impact of f/s/w on D climates is somewhat less critical than with hotter climates: especially with Dc and Dd climates. Anyway, the population of the Dd in pre-industrial times would be very close to 0. The whole of Siberia had a ridiculously low population density, with most people packed on the southernmost part.


EDIT: And here is my latest version of the biomes: 79769


I'm still undecided as to whether the scrubland should be a specific biome or not.Btw, have you finished with the modifications you talked about?

Charerg
02-02-2016, 02:58 AM
I thought I was finished, but I did spot a few areas that could be improved a little. Namely the eastern portion of the northeastern continent (Rheada), which transitions straight from the dry climates into Df or Cw climates, even though this area roughly resembles Manchuria, so there should be a narrow fringe of Dw climates between the steppes and the coastal Df climates. I think the summer temperatures in the area were a bit too high in general. I tried to increase the summer rains in the eastern portion of the continent to reduce the dry areas somewhat, some Dwa should turn up now.

I guess the area could be tuned manually, but in case you haven't run the script yet, these are the (hopefully) final temperature and precipitation maps.

Azelor
02-02-2016, 12:39 PM
If this is not the last test, for the next time, could you change the purple for deadly cold? The color is a bit off.


79787

Charerg
02-02-2016, 02:21 PM
Looking at the climate map, I believe the map has now reached a level of accuracy that it can be considered "final", apart from minor adjustments that are best done manually. Once again, many thanks, without your assistance it wouldn't have been possible to make this many tests with different temperature and precipitation maps!

Overall, the climates seem pretty "balanced" now, the amount of Af looks realistic (apart from a few weird instances that will have to be fixed manually). One minor criticism is that Am seems to be pretty rare, although I guess it's not that common on Earth either. But the Am transition zone can be manually added between Af and Aw now that those two are ok. Btw, did you adjust the steppes manually, or are the ones appearing on the map script-generated?

Azelor
02-02-2016, 02:44 PM
Am is about as common as they are in real life since it' a transition area.

I adjusted the steppes manually and it should be ok.

mbartelsm
02-03-2016, 06:40 PM
Azelor, what scale did you use for precipitations? I want to try my hand at defining biomes with the maps I've already made, but I don't think guessing the scale you used will do me any good

Azelor
02-03-2016, 10:28 PM
I think this is what you are looking for. http://www.cartographersguild.com/showthread.php?t=27782&page=3&p=277812&viewfull=1#post277812

mbartelsm
02-04-2016, 11:14 AM
Must've missed it, thanks!

I made this biome placement tutorial (http://www.cartographersguild.com/showthread.php?t=32998&p=289932#post289932)as a follow up of this guide. To help people interested in defining their biomes as well as their climates.

I will now begin working on formatting this guide into a pdf and will post again when finished.

Mysterious Mapmaker XXIII
02-13-2016, 12:09 PM
Hey there! Been a while!

So, now that the actual climate step is done, what's next?

Azelor
02-24-2016, 05:10 PM
Hey there! Been a while!

So, now that the actual climate step is done, what's next?

There is nothing else planned except maybe polishing the existing tutorial.
And there was also the biomes right after the climates.

Other things I considered implementing but were bad ideas:
type of soil (strongly correlated to climates but I don't see why someone would bother with this)
population density (the correlation between climates and density is really weak)

Mysterious Mapmaker XXIII
02-26-2016, 04:27 PM
I assume that "polishing" includes compiling the whole tutorial into one document? Or at least a more easy-to-look up format?

Anyways, I love your work on this tutorial, and look forward to using it for my own world.

Mysterious Mapmaker XXIII
03-10-2016, 08:32 PM
Okay, normally I'd never even consider double posting, but this thing's dropped to nearly the bottom of the second page of this forum.

In any case, anything new to report with this? Thanks.