WIP (sort of tutorial to be) : Climates, applying Geoff's Cookbook at detail (some)

[Pixie]

Now it's time to work out the dominant winds. This stems directly from the previous work, the distribution of atmospheric pressure, and it's simply adding on top of it.

So get a new layer to scribble and a rather thin and simple brush. This time all you do is drawing arrows.

Keeping the previous work in sight (but you can reduce its opacity, to clear the view if you need, like I did in the example below), your job is to "preview" which way air moves near the surface. The key point is that air whirls instead of moving in straight lines, like the whirlpool in the tub. And it circles in opposite directions in the northern and in the southern hemisphere, as well as in low pressure and high pressure areas.

Here's a kind-of-step-by-step approach:

1. northern hemisphere: air surrounds the high pressure circles clock-wise. It will drift into the PF moving eastward and into the ITCZ westward.
2. southern hemisphere: high pressure circles get surrounded counterclockwise, resulting in drifting into the PF and ITCZ in the same direction as before.
3. even if pretty far from any high pressure center, air gets sucked into ITCZ or the PF just like you worked out before.
4. low pressure centers in each hemisphere suck air, it whirls into them in the opposite direction to the high pressure centers in that hemisphere.
5. winds north of the polar fronts: they always draw a kind of curve from the pole to the west, into the PF.

If you get confused whether it's clockwise/counter-clockwise (as I did so many times), use this for reference:


Now, don't shy from drawing arrows but don't draw arrows very far away from any of these influences. There are effectively areas in a planet where the winds just never blow strongly...

Again, this can be of assistance if you want to compare your prediction with a planet that we actually know well
Atmospheric Circulation and Winds

Here's my result:
... July

And since this example has absolutely no land out of the PF, I didn't bother drawing wind arrows close to the poles on this one
... January