The Köppen–Geiger climate classification made simpler (I hope so)

[Azélor]

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]

I went and finished the process manually, and here is the resulting climate map (including the climatologically relevant oceanic currents, for easy reference):



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



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.

[Azélor]

I took your maps and used them to run the script. It should be functional now. The result is at the bottom.

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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).

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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.

[Azélor]

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.

• 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.

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

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.

Azelor climates.zip
For the manual version:

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



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]

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.

[Azélor]

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.

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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



July

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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)



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.

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July:



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.

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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:

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January, the pressure looks alright.



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.

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July:



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.

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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



And July

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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]

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:


July:


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.

[Azélor]

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.

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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.



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.

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July:



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

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I here are the precipitation layers in png

January



July

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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]

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.

[Azélor]

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.



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.