Theia revisited - Climate check (WIP)

[nwisth]

Hi! My name's Niels, and I'm writing a novel.

I started a little over a year and a half ago, and in that time I've been doing a lot of worldbuilding - which, of course, takes maps. I just finished the first draft of the first 90k word part of the first novel in the series (yeah, why not be stupidly ambitious, lol), but as I was browsing the guild forums looking for something to help me make my local area map of the place my second storyline is taking place, I found this amazing climate tutorial by Azélor.

Now, I have prided myself on taking the time to build my world of Theia as realisticly as possible - but when it comes to climate zones, I have to admit it's been mostly guesswork. I want to find out how far off I've been, and if I have to rethink any of the civilized areas where my story takes place.

First, let me share what I have so far:

THEIA (here in HEALPix-projection):



Theia is an earthlike planet, orbiting YBP 1194, a solar twin 2772 light years from Earth. This star is incredibly similar to our sun, but unlike our system it has a massive exoplanet about the size of Saturn, in close orbit around the star. Every seven days, it casts it shadow on Theia, dimming the light by a noticeable amount as the black spot travels across the solar disk.

Theia is smaller than Earth. It has a diameter of 9040 km, and circumference of 28400 km, which gives it a diameter that's 0,7095 of Earth's. That means it has a lot smaller surface area - while Earth has 510.1 million square km, Theia only has 256.8. Since the planet is very iron rich, however, its density is 1,4 relative to Earth's - and has a surface gravity of 1G. It also shares the Earth's axial tilt, to make it easier to replicate Earth-like seasons.

I used the excellent Worldbuilder tool by Experilous to create my land masses. It's a shame it's discontinued - the program really rocked, taking care of tectonics and giving me an elevation map as well as a temperature map based on elevation and other input parameters. Theia has a ring, whose shadow travels up and down the globe due to the axial tilt - which makes a lot less light reach the surface in winter - so I decided to make the world colder and the ice sheets bigger.

After going through a lot of iterations, I found a look that spoke to me, and could continue.

This is the first equirectangular biome, elevation, and temperature maps, straight from Worldbuilder, showing all the continents of Theia:

BIOME:


ELEVATION:


TEMPERATURE:


Worldbuilder also made a wetness map - but I didn't know enough to make sense of it, and as a result, the biome map was hard to interpret. I decided that I had to create my climates manually. Armed with google and wikipedia, I started researching wind and seasonality, and started working in Photoshop.

I decided to use the simplified model, with bands of low and high pressure following the circles of latitude, and winds moving between them. I ended up dividing the world in temperature zones. I read that the sea retains its heat level throughout the year, while it changes overland, so with some clever use of masks I created wind and temperature zone maps for the equinoxes and the two solstices, where I moved the effects of the latitude circles and the following winds up and down, respectively:

SPRING/AUTUMN (with circles of latitude in their proper place):


SUMMER:


WINTER:


Based on these, I masked out the heat map from Worldbuilder and used reds and yellows to paint the heating and cooling from the currents, as well as modify the color according to the seasonal temperature band maps I'd just made:

SPRING/AUTUMN Modification layer example:


The green is just to make the added colors show up. They're set to Soft Light with about 50% transparency. Here are the summer and winter heat maps, after modification. The ring shadow is also present as a yellow reflected gradient centered from 30 degrees.

SUMMER HEAT MAP:


WINTER HEAT MAP:


Now, being very happy with this, I ignored trying to seasonalize the ice caps, and simply started researching climate types, trying to figure out what would go where. I also wanted it to look better - and how to add rivers? More research led me back here, where I found Arsheesh' fantastic tutorial for GIMP & Wilbur.

Wilbur was awesome. I put the height map from Worldbuilder into Wilbur, and after fumbling around a while, I managed to get some rivers:



At this point, Theia was really beginning to come alive! I couldn't wait to start telling stories in it. I recolored the result to give me a nice grassland base color, and then used various brushes and masks to paint in mountains, jungle, desert, forest and plains in the areas where I figured the conditions matched those of Earth:



Here it was - a world of my own, full of endless opportunity. But I had to zoom in. In my story, humanity only exists on one continent, having developed from a single point of origin. I picked the most interesting-looking one, and started anew, running the height map through Wilbur once more, adding a large inland sea in the lowest elevated basin. My continent-map will have to wait for another post, but here's a closer look at it, in the Lambert Conformal Conical projection (made with NASA's awesome G.Projector):



I've tried my best to place realistic climates. I decided to simplify, so instead of using Köppen, I divided my continent map into Sub-Arctic (Scandinavian), Coastal Temperate (French/British), Chaparral (Mediterranean), Dry Sub-tropical (Spanish/Maroccan), River Highland (Inland temperate rainforest), Highland Steppe, and Tropical regions. By counting hexes and using historical European population figures from 1000-1500, I found the population density my various countries could support, and have made an enormous excel sheet which calculates everything from average distance between villages to happiness scores. But that's probably not something you want to hear about on a cartography forum.

My point is, I have done a lot of work to try and make this as realistic as possible. But, seeing the Köppen climate tutorial by Azélor. I realized there was a lot I hadn't done, and a lot of guesswork. How about precipitation? How about a height map that actually shows height above sealevel? What will my map look like, if it goes through the scripts made by these master cartographers?

I have to know how far off my guesses are. Can I manage to get a detailed Köppen map if I follow the seven-step program?

I will try, and post the results here.

-Niels

[nwisth]

By the way - does anyone know why the upper images of the first post appear as "Attachment XXXX" while the lower ones show a thumbnail? As far as I could tell, I have used the exact same forum code to place them.

-Niels

[J.Edward]

I'm getting an invalid attachment error.
My first thought is that they may be larger than file size allowed.
I don't immediately recall what the size limits are atm.

[nwisth]

Strange. It doesn't seem to be the file size - the first HEALpix map is just 3739 x 1872 pixels and 716 KB, while the lower ones that work are 6000 x 3000 pixels and between 1,5 and 2 mb. *scratches head*

[Azélor]

Maybe the forum disconnected you while you uploaded the files. You need to check the ''remember me'' box under the login section.

---

I see a few strange things on your map:

The elevation is odd: most of you continents are flat plateaus. There is a significant elevation different near the coasts but most of the rest is flat.
Hence the heat maps also look strange. In summer especially, the coasts would be cooler than the interior assuming the elevation is similar.

Your mountains seems to form blobs instead of ranges.

You have only a few but very large river systems. Some cover almost all the continent.It is possible but considering the flat elevation, I would expect more rivers and smaller ones.

Heatmaps: some areas remain blue: what does it mean?

[nwisth]

Thanks for the heads up! I've re-uploaded the images and now it seems to work.

I will answer your other comments later - the missus is waiting.

-Niels

[nwisth]

Thanks for pointing out things, Azélor!

When it comes to the flatness of the elevation, I guess that's simply how the Worldbuilder program works. It creates a bunch of random tectonic plates, and pushes them together, making some rise and some fall. They're made from a hex grid, and then mashed up and distorted. The blobiness of the mountains is probably a result of me using the major and minor turbulence scale sliders, as well as the tectonic plate stress blur slider - but to me the way the plates rise and fall make at least a little bit of sense, even though they haven't been moved back and forth over billions of years. Now, THAT would be a cool piece of simulation software. What do you use to create your initial height maps?

The huge river systems are made by Wilbur. I agree that the plateaus themselves are too flat and uniform at this scale, but I haven't found a good way to add noise to the height map that would allow Wilbur to carve out more realistic river systems. I would like ripples in the crust that go parallel to the tectonic impact lines. If anyone knows any techniques or brushes that would do this job adequately, I'm all ears!

I re-ran Wilbur on my continent map, getting a LOT more and smaller rivers - as well as a few huge ones - and I've kept adding more manually on my country maps.

Regarding the heat maps: While the white shows sea-ice, the blue shows land areas at sub-zero temperatures. The original temperature map up top doesn't show any sea ice, and simply gives temperature of both land and sea. The reason why most of the interiors are colder than the coast is their elevation.

-Niels

[nwisth]

Alright! Time for part two, as I start working through Azélors tutorial.

Step 1: HEIGHT MAP

First off, I wanted to get the elevation better defined. Creating a new gradient preset based on the colors in the example, I made a Gradient map adjustment layer, then used Levels to tweak the black and white height map until I got the elevation scale I wanted.



Step 2: SEA CURRENTS

Then I redid the currents, removing the ice caps this time, since water obviously flows fine under sea ice, and adding an extra level of differentiation with the mild waters in white:



Step 3 & 4: AIR PRESSURE & WINDS:

In my first attempt, I had simply placed areas of high and low pressure according to the parallels. Now, with this excellent guidance on where to put them - as well as the epiphany about the ICTZ actually wriggling around like a snake around the equator, I could make these maps of pressure and winds:

Summer:


Winter:


Step 5: TEMPERATURE

Now, this presented me with a bit of a boggle. Should I try to paint this manually? There were a lot of things to consider. Currents, elevation, and not to forget Theia's ring shadow in the winter. I decided to use my previous heat map technique, painting influences in red and yellow on the height-based temperature map from Worldbuilder. After that, I used Select / Color Range to pick out the various temperature bands, and used levels and masks to change them into solid bands of the correct colors from the tutorial. It took a bit of fiddling around to get right, but I think the result is a lot better than what I could possible have done by hand.

Summer:


Winter:



So far so good, I hope! Now I'm going to start working on getting the precipitation right.

I really hope the temperate rain forest areas that I've already written about don't end up being horribly misplaced!

-Niels

[nwisth]

Step 7: PRECIPITATION

Precipitation is a difficult science! I am sure I could spend days tweaking and adjusting this map to get it right, but I really want to progress to the next and final stage. As it is, I ended up finishing these two first draft maps:

Summer:



Winter:



Tomorrow I hope I'll find time to run the scripts! So excited...

-Niels

[Azélor]

Other things I noticed:

Saturn is not big enough to create a shadow. It would at best if well aligned with the planet, reduce the solar input.
That planet orbit really close to the star. It can get as close as 8-9 million km, compared to 46m for Mercury.
We don't know a lot about that planet and I will just assume that all that information is true.
Still my biggest issue is the distances. The solar winds might push the gases into space overtime turning the planet into a barren landscape, more like Mercury.
Whether the planet is only solid of a gas giant, it's still massive but definitely smaller than Saturn.

First it lacks an atmosphere. Probably
Second, planets so close to stars tend to be made of denser/heavier material like iron.

Also, you said a few billion years without tectonic activity. Considering your star has a lifespan of 9-10 billion years, that means the star is pretty old.
Maybe what I said about the geography was wrong but I'm not the expert on that matter.
Without tectonic activity, the landscape will smooth out overtime. Leaving no mountain ranges but plateaus with smoothed cliff sides.
I'm guessing that most of the coasts waters are shallow and the oceans deepens gradually.
I'm not sure what it should look like but Mars could be a good place to look. The geography is a little strange when compared to Earth because of the lack of tectonic movement. Mars lacks mountain ranges but does have very impressive canyons.

Some use Gplates to simulate tectonic activity, but I don't know if it can simulate erosion.

Regarding the heat maps: While the white shows sea-ice, the blue shows land areas at sub-zero temperatures. The original temperature map up top doesn't show any sea ice, and simply gives temperature of both land and sea. The reason why most of the interiors are colder than the coast is their elevation.

The temperatures would still fluctuate.