View Full Version : World Weather Patterns Input

03-26-2012, 04:43 PM
Attached is a WIP of a world long in the works and finally making it into Photoshop. What I have slapped down here are the major continents and islands with a rough pass of the ocean surface currents in light blue. Also, you will find the tropics of Cancer and Capricorn as well as arctic and antarctic lines. The highlighted Equatorial belt is the baseline ITCZ 5 degrees north and south of the equator.

My primary curiosity is what kind of weather would we expect where the ITCZ runs between the two continents? The ITCZ would likely produce thunderstorms 3-4 pm most days through here, and what would the sailing be like?

The world is earth sized with typical trade winds etc, no major deviances from Earth there.

NOTE: that area with red and blue lines in the northwest between two continents is supernatural, so reality concerns there are limited, LOL.

Other than that! Any and all thoughts on ocean currents, winds and weather would be greatly appreciated.

03-26-2012, 04:45 PM
OH! The second curiosity is how much climate affect would the southern polar current, which gets kicked into temperate zones, change the climate of the polar land mass and other continents it flows by? That would bring warmer waters to the Polar Molo (antarctic) coast.

03-27-2012, 01:34 PM
I really need to save this as like a word file, I keep having to go back through old posts to avoid typing it all again.

First: what I am about to say is a generalization and there are exceptions. but generally...

Generally, mountains affect climate. Clouds and rain are carried by winds that tend to blow in the same patterns. When clouds hit mountains, they dump their rain, causing lush forests. But on the other half of the ridge, there is no rain and a desert is created. a wonderful example of this is Northern California vs Nevada. As you go over those mountains you go from forests, strawberry farms, and wineries to slat flats and cacti.

Certain general worldwide patters (caused by the earths rotation) are shown on this map:
Exceptions are common, for example this is how winds generally are:

These rainfall areas will affect multitudes of other things as well. Winds coming off deserts will be warm; one of the reasons for the warmth of europe is the wind from the sahara. If you compare southern France with Maine and you will see a vast difference in climates despite similar latitudes.

Here, for reference, is a map of Europe's Topography:
And here, a map of the Rainfall, with a strong correlation between changes in altitude and a massive dumping of rain.

Once again, there are exceptions, but just think about this before placing major mountain ranges.

Finally; USE AN EQUIRECTANGULAR PROJECTION. if you use one and decide later you want to re-project it there is a simple and easy to use piece of software that will do it for you. if you use something else, you will have to do it by hand. details on the equirectangular projection can be found at this link:http://en.wikipedia.org/wiki/Equirectangular_projection
But basically, the x-axis is Longitude and the y-axis is Latitude.

03-27-2012, 01:54 PM
Your map looks pretty realistic so far. I just messed with oceanic currents on mine and I must say all of this is very informative. Good luck!

03-27-2012, 04:40 PM
Your gyres look good!

Is there a reason that you've drawn in the equatorial countercurrent without the northern and southern equatorial currents? In particular, I suspect the countercurrent would lose to the normal (leftward) equatorial current in that really narrow gap on the equator between the green and brown continents.

03-28-2012, 05:45 AM
The projection is currently equirectangular and I left most of the mountains out (except on the continent of Kūtu where weather patterns are all higgly piggly anyhow) in order to get a clean look at what the baseline weather patterns with currents and wind would be. Rainshadows are good fun but they aren't a lock, the lee side of mountains will certainly trend to less rain but there are many other potential climate factors to offset this and prevent desertification. And the most dangerous thing about them is that being from the US I tend to think of weather traveling west to east (per your example) and my rain shadows tended that way for a long time, but I am getting them corrected slowly but surely. The Himalayas have one heck of a northern rain shadow, so without knowing the specific direction rain travels in particular regions rain shadows are a bit tricky to plot. Tracking the ITCZ through its seasonal shifts over land will yield a good deal of climate information.

I also have orthographic projections of the world, which I really need to play around with, sometimes things get real screwy when all you look at is the equirectangular.

The lack of normal equatorial currents is just a visual thing from the quickie nature of the drawing. I assume the bottoms and tops of the gyres, respectively, to make up those east to west currents. A good point on the countercurrent losing out, I think. Would the Countercurrent even make it beneath those two westerly continents?

I will post further maps here, particularly one with continental names so as to make it easier to reference things, LOL.