New World (Help with Tectonics?)

[Azélor]

I'm a bit late to the party, but I'd like to comment that the trade winds are a bit off in this one. If the trades cross the equator, the direction of the coriolis force inverts, and the (originally easterly) trade winds become deflected into westerlies. See the Indian Monsoon, for example, though this happens in Africa too (this is why Somalia is in the rain shadow of the Ethiopian Plateau).

Edit:
Here's another picture of the phenomenon:
Attachment 106383

I need to remember that.

Davoush: I'm not sure how to interpret the climate map. Did you used the script to generate the map?
I might have concerns about the steppes and deserts at high latitude. The model allow to have negative evaporation rate. It is not possible (actually yes, marginally, example if you have snow blown by the winds and the snow melt in the summer, evaporation could be negative if the snow doesn't count as precipitation since it's not falling from the sky)
but it match the reality on the ground that high latitude are extremely unlikely to be arid even if it barely rain/snow.
I am not sure if the logic is the same if we increase the temperature extremes, especially in summer. I have absolutely no idea because negative evaporation never made a lot of sense to me.

About temperature, it could be fairly easy to estimate the temperatures based on solar energy received. The maximum temperature area shift according to the difference in tilt.

The transition seems pretty rapid: Cwa, Dwa, Dwb???, Dfb, Cfb ?
It could be ok. Transitions like that exist on Earth, albeit with different conditions. It is plausible.
The only problem is the Cfb, it would be to cold for that climate. So it could be Dfc or a tundra if temperature are never higher than 10.

On the other continent, the climate goes from summer dry to humid to winter dry... I think the transition is way too small.
I'm not sure what's the best way to solve this but since the continent is not that large, maybe it should have more f climates.
Or it could be a steppe like Argentina.

[Charerg]

If anything else looks very wrong or questionable, please let me know. Thanks!

Attachment 106484

The extent of summer dry climates is probably exaggerated. Also, the summer dry climates in the south-central location of the map are in the wrong place: that is not a "west coast" area (located next to an oceanic high pressure center).

Here's a quick map I made demonstrating what the overall pattern might look like (red=arid, blue=humid, the rest would be s/w). I've marked the erratic summer dry region with a "X":



The above is just intended as a rough demonstration. It's worth noting that the "dry areas" surrounding oceanic high pressure centers typically have a sort of teardrop shape slanting towards the equator. See this map of Earth's average yearly rainfall:



It may also be helpful to check out the climate zones above the ocean as well as overland (see this paper).

Edit:
About Iran, I'd have to do a bit more research to be certain, but I guess it's dry in summer because the monsoon winds blow in a westerly direction towards India, so it gets few onshore winds from the Indian Ocean.

[davoush]

Thank you both for the insightful comments and for taking the time to look at this thoroughly - I very much appreciate it.

I didn't use a script, most of it was 'guesstimate' based on latitude, ITCZ, and prevailing winds, however it looks like I've exaggerated or over-estimated certain parts. I'll be able to post an updated winds map soon, as several inland areas look like they would in rain shadows, but perhaps I overestimated the aridity of rain shadow regions in high latitudes?

@Charerg - thanks for pointing out the erratic Summer-Dry area - my reasoning was the winds were blowing from the high pressure region above, so probably dry, but now I realise that is mostly only equator-ward winds.

Regarding the greater axial tilt - does this mean the horse latitudes (i.e. where deserts tend to be centred) would also be shifted, if so, where? (Tilt = 26/27).

Hopefully attempt number 2 will yield better results...

[Charerg]

@Charerg - thanks for pointing out the erratic Summer-Dry area - my reasoning was the winds were blowing from the high pressure region above, so probably dry, but now I realise that is mostly only equator-ward winds.

Actually that area would very likely be dominated by the westerlies, it's pretty high in terms of latitude, like around 50° (and I doubt summer dries would ever occur that high even if the axial tilt was greater). Also, the region to the west of it would likely have an "East Coast" climate, something like Eastern USA or Southern China: a fully humid climate hit by extratropical cyclones. There's a reason why summer dries are known as west coast climates after all .

[davoush]

Ok, so here are two rough wind maps for January and July. I have also changed the position of the central-southern continent somewhat so it gets more summer-dry on the west coast (hopefully). I don't think it will impact tectonics too much, it just means that it has separated more recently from the main continent to the north (or has been moving slower).

Yellow areas indicate possible rain shadow effects.

A few quick questions (numbers on maps):

1) Will the Polar Easterlies have any affect, or is this very southern part basically just dominated by westerlies?

2) Probably gets some onshore winds and maybe summer storms like China?

3) (July Map) - Would all of this bunch of 'island continents' be within a high pressure zone (they are surrounded by continental shelf) and all get more or less summer dry, or will the eastern-most 'island' be better?

And of course if anything else looks wrong, please point it out. Thanks!

[Charerg]

Ok, so here are two rough wind maps for January and July. I have also changed the position of the central-southern continent somewhat so it gets more summer-dry on the west coast (hopefully). I don't think it will impact tectonics too much, it just means that it has separated more recently from the main continent to the north (or has been moving slower).

Yellow areas indicate possible rain shadow effects.

A few quick questions (numbers on maps):

1) Will the Polar Easterlies have any affect, or is this very southern part basically just dominated by westerlies?

2) Probably gets some onshore winds and maybe summer storms like China?

3) (July Map) - Would all of this bunch of 'island continents' be within a high pressure zone (they are surrounded by continental shelf) and all get more or less summer dry, or will the eastern-most 'island' be better?

And of course if anything else looks wrong, please point it out. Thanks!

1) Yes, that would probably be covered with glaciers with strong easterly winds blowing away from the glaciated interior (and a permanent high pressure center over the pole). Assuming that it's similar to Antarctica.

2) Yes, in fact the case should be somewhat similar with most of the eastern margins of the continents in similar latitudes. South China, Eastern USA, Eastern Australia and Northern Argentina all have a broadly similar weather pattern (Cfa).

3) Hard to say because there isn't a comparable situation on present day Earth. Depends which of the two high pressure centers would be dominant. Offhand looking at the currents I'd think the center west of "area 3" would be more important, but I could be wrong. In any case summer dries would likely be restricted to the northern margins. The rest could potentially be either arid or something like the Caribbean or Southern USA depending on how strongly those high pressure centers would effect the weather.

[davoush]

Thanks Charerg,

About number 3: The islands span 20-50 latitude (sorry this wasn't indicated clearly). Would the parts falling between 30-40 (which is most of the eastern-most island) have a Caribbean like climate? The tip would be under the influence of the westerlies, but the rest is either receiving winds from the mainland high pressure, or from the high pressure to the west. Does the fact that it's surrounded by a lot of water mean it probably won't be arid? Thanks again.

[Charerg]

Thanks Charerg,

About number 3: The islands span 20-50 latitude (sorry this wasn't indicated clearly). Would the parts falling between 30-40 (which is most of the eastern-most island) have a Caribbean like climate? The tip would be under the influence of the westerlies, but the rest is either receiving winds from the mainland high pressure, or from the high pressure to the west. Does the fact that it's surrounded by a lot of water mean it probably won't be arid? Thanks again.

Probably could be either one. Like I mentioned, there isn't really anything 100% comparable on Earth, so it's a toss up. If there's enough tropical cyclones swept up from the tropical sea to the south it could be Caribbean-esque, but it's also possible that the the weather would be basically dominated by the oceanic high pressure center, making it a desert. I'd think the Caribbean-esque climate would be a bit more likely, but that's just my guess.

[davoush]

Ok, attempt number 2 after taking into account Azélor and Charerg's comments. This isn't produced by a script, just a guesstimate on likely temperatures, precipitation, winds, etc. I have shown the mountain ranges and elevated regions as I'm unsure about some rain shadow.

1) I am really unsure about the transition here. The southern half will be fully humid, so Dfb. The west coast will be Cfb, leading into Csa across the north, as the winter westerlies bring some winter rain. East coast likely winter dry with the tip monsoonal as winds are deflected north towards ITCZ. My question is basically, can Cfb transition right into Cwa? (Same from Dfb > Dwa). What about Csa > Cwa? All these transitions look strange. Am I just confusing myself here?

2) I think this mountain range (very tall like Andes) would produce a bit of a rain shadow arid area, as onshore winds are basically blocked. 2b) is the same, but the mountains are not as high. The westerlies could be blocked, and also onshore winds from the north might not reach that part.

3) I'm not sure about the Csa > Cfa transition on the east coast here. I imagine the north would have a band of Csa. Should Cfa extend inland a bit further, or does Cfb dominate?

4) I think the East Coast might be Cwa as winds are blowing towards southern ITCZ in winter. West coast probably fully humid as it gets precipitation from the little sea?

5) I have left this world's largest mountain range in grey - I think it would effectively block the westerlies, leaving a large arid plateau. Probably similar to Tibetan plateau? The mountains on the east coast also block moisture

If anything else looks strange, please say so.

The climates on the Eastern half of the Northern continent look kind of boring, basically the whole thing is monsoonal. I think this continent needs some more interesting mountains/elevation. I originally wanted more Csa/Csb climates (and they are probably already exaggerated in this map), but I suppose it is simply unrealistic to have so many.

Also random question: In Charerg's 'Jurassic World' climate map, the high latitudes have mild Cfb/CfC climates, and A climates extend to very high latitudes (40s). Given that my world is a few degrees hotter on average with greater axial tilt, does this also mean likely no permanent ice? Perhaps more Cfb on the southern continents. (I haven't really accounted for that yet.)

Thanks!

[Charerg]

Ok, attempt number 2 after taking into account Azélor and Charerg's comments. This isn't produced by a script, just a guesstimate on likely temperatures, precipitation, winds, etc. I have shown the mountain ranges and elevated regions as I'm unsure about some rain shadow.

1) I am really unsure about the transition here. The southern half will be fully humid, so Dfb. The west coast will be Cfb, leading into Csa across the north, as the winter westerlies bring some winter rain. East coast likely winter dry with the tip monsoonal as winds are deflected north towards ITCZ. My question is basically, can Cfb transition right into Cwa? (Same from Dfb > Dwa). What about Csa > Cwa? All these transitions look strange. Am I just confusing myself here?

I'd like to point out that Cwa is actually relatively rare and generally limited to tropical highlands and regions located deep inland. The major exception is Southeast Asia with its seasonal monsoon (here's a fairly good Köppen map of Earth for reference). But looking at this continent I'd think the east coast would be more like Argentina or USA, so probably just Cfa for the most part, transitioning into Cfb or maybe Dfa if there's a cold winter.

2) I think this mountain range (very tall like Andes) would produce a bit of a rain shadow arid area, as onshore winds are basically blocked. 2b) is the same, but the mountains are not as high. The westerlies could be blocked, and also onshore winds from the north might not reach that part.

The winds there would be blowing largely from the south/southeast direction (air circulates around the oceanic high pressure centers in a clockwise direction), especially if there's a strong summer monsoon (a low pressure center over the continent would draw winds from the southeast). Therefore I think the arid area is unlikely in this location. The other cold steppes are a bit dubious too, being located well within westerly influenced areas and extending close to the polar ocean. Keep in mind that the "westerly winds belt" just means the wind blows usually from the west. In reality there are individual low pressure centers moving in a westerly direction around the globe, meaning that on the local scale the wind direction varies.

It's also worth noting that since you have warmer summers that would also cause a more rainy climate in these regions than is the case on present day Earth, as warmer air has higher humidity than cold air.

3) I'm not sure about the Csa > Cfa transition on the east coast here. I imagine the north would have a band of Csa. Should Cfa extend inland a bit further, or does Cfb dominate?

Csa->Cfa is a completely acceptable transition. The only difference between Ca and Cb is the summer temperature. Cfa climates have essentially tropical summers, Cfb has a more temperate summer.

4) I think the East Coast might be Cwa as winds are blowing towards southern ITCZ in winter. West coast probably fully humid as it gets precipitation from the little sea?

East coast would likely receive more precipitation than the west. Think Eastern USA, Eastern Australia or Argentina (or even the east coast of South Africa), those areas receive precipitation all year round because the winds circulate in a clockwise circle around the high pressure centers.

5) I have left this world's largest mountain range in grey - I think it would effectively block the westerlies, leaving a large arid plateau. Probably similar to Tibetan plateau? The mountains on the east coast also block moisture

Well, the Tibetan Plateau has a tundra climate. Also, this area is in quite high latitudes, making deserts somewhat unlikely because of low evaporation, but I guess it could be steppe if the mountains are high enough to block most of the moisture.

Also random question: In Charerg's 'Jurassic World' climate map, the high latitudes have mild Cfb/CfC climates, and A climates extend to very high latitudes (40s). Given that my world is a few degrees hotter on average with greater axial tilt, does this also mean likely no permanent ice? Perhaps more Cfb on the southern continents. (I haven't really accounted for that yet.)

The A climates probably reached well into the 45 during the Jurassic. Areas as high as 70 had flora like umbrella ferns that doesn't tolerate any frost at all. It was simply a megathermal climate, it's likely that the oceans literally never froze at all, except perhaps at the poles themselves (if even there). I should also note that those Cfc climates were a bit of a fluke generated by the script for the most part, since the tutorial can't accurately define the b/c boundary (it's based on the number of months with mean temp above 10 °C) the distribution of Cc tends to be wildly exaggerated. In reality those regions were probably Cb apart from perhaps the extremely high latitudes or mountain areas. There are fossils of Mesozoic alligators from Alaska, the high latitudes were subtropical to temperate back then.

In your case you also have a larger axial tilt, meaning colder winters, so it's not quite as simple as "just make everything warmer". Especially the southern continent could have a very cold winter with the polar ice caps as well as giant mountains with a cold and arid plateau. That could well generate something comparable to the Siberian High, and also those mountains would likely limit oceanic influence severely.

The northern continent, on the other hand, could be quite warm, as it doesn't extend into subpolar and polar latitudes, meaning that the ocean to the north of it would likely remain free of ice all year round. This would limit arctic influence and probably mean relatively mild winters even with the greater axial tilt.