Need help with climate map

[Vivaporius]

I wanted to know if anyone here had any experience working with climate maps. I'm working on a planet which I would like to have a certain set of climates from particular regions, such as the Swiss and Austrian Alps (valleys and mountains), the southeastern Poland (hilly regions), the Pacific Northwest (temperate rainforest), and for the lack of a better word, a generally "Christmas-esque" feel to the planet. Yes I know. Anyway, I have the details for the background behind the climate worked out, but I really don't know where the limits of the differing climates would be.

Here are the ocean currents.


Please forget my amateurish work, but this was the best I could do. The main continent itself it no larger than North America, so there is some idea of the size of the planet itself. So really some help as to where all of this stuff would go would be fantastic. Sorry if I couldn't explain my request any better, I'm not really good when it comes to questions or talking in general.

[Pixie]

Hi

This planet would be much smaller than Earth, wouldn't it? If something sized like N.America goes from pole to pole...
Now, a much smaller planet would, in principle, have less gravity - that means it will have a different escape velocity at the surface (escape velocity is the velocity at which a particle is moving fast enough to be able to leave the atmosphere). Since the velocity of the molecules in the atmosphere depends on temperature, if you have a planet with similar temperatures to Earth (where water exists in liquid form) atmosphere particles will have the same velocity.

If your planet has less gravity, it cannot hold an earth-like atmosphere at the same temperature. Therefore, you either make it larger or insanely dense (Earth is already the densest planet on the solar system), so that it can have the same mass on a volume (8 times?) smaller. I don't know if there are any simulations that allow you to do this kind of math without knowing physics and math, maybe there are. Or maybe you could just adjust a little bit in all directions - a little larger planet than it is, a little denser than Earth, a little colder. Or, you can skip all this and just "let it be as you say, because you say it".
Any of the above is fine, but I thought I just point this out ;

As to the actual climate your planet (as it is), it depends very much on one variable that maybe only a climatologist could answer - how many circulation cells the planet would have from pole to equator. Mercury doesn't have atmosphere, Mars has 1 cell, Venus is too weird to compare, Earth has 3, Jupiter has 7 to 10. So, it very much depends on planet size.
If you want to figure this out, this is a good starting point: http://www.metoffice.gov.uk/learning...ation-patterns

[Vivaporius]

Thank for your help. As i mentioned beforehand, I figured all of the major details out. A smaller planet could compensate with a larger or denser metallic core, much the same way as Mars (which my world is only a few km smaller than). With a dense core, you could get the same gravity as earth. The reason the Moon has such a low gravity is because its core is larger porous, giving it the "hip-hop" gravity we know of. Anyways, I appreciate your help. You've done more about my climate problem than I have.

Edit: I just noticed you said all of that. Sorry. But yeah, I get your point.

[acrosome]

Here's Geoff's climate page.

If your intent is to be realistic (as opposed to fantastic) then your currents need some work. For instance, the two circumpolar currents should be the same direction. Which way does this world rotate?

You have a current dropping southward from the Arctic along the west coast of the continent listed as warm.

Also, the ocean should have both a northern and a southern gyre.

Then you add in smaller currents. The current in that large bay on the west coast is probably clockwise.

Have a look at this map of Earth's currents. (Earth's northern circumpolar current isn't really visible in this projection- the northern continents reach into very high latitudes.)

Assuming Earthlike rotation it'll be something- very roughly- along the lines of this:



(I'm not sure if the very small size of your world will affect this.)

I'm not sure where your lines of longitude are, so this is admittedly very crude. Your continent may extend far enough poleward to interfere with the circumpolar currents, as on Earth in the north.

But you can tell, for instance, that the western coast of this continent north and south of the large bay will be deserts. West coasts with cold currents from 15 to 30 or so degrees tend to be deserts. Have a look at northern Africa and the middle east on a Koppen map of Earth. The east coast, running from 15 degrees north to 15 degrees south or so will be tropical rainforest- including that small island. As will the east coast of that bay on the west side of the continent around those lakes (between the deserts.) Of course, if your world is generally colder that won't hold true- they may be more like temperate rainforests. But the west coast deserts will still be there. They'll just be cold deserts, like the Gobi.

The moment that you say something like "the world is colder" then there are a lot of second- and third-order effects. If you want a "Christmas-y" setting you might be better off making a full sized world that just has a single large continent at high latitudes, say 45 to 75 degrees, with the rest ocean. Or better yet a polar continent like Antarctica but which has a spur of land extending to 45 or so degrees. Voila, no hot deserts. Damnably hard to map, though. Some kind of conic or azimuthal projection might be best.

EDIT---

However,

An utterly unscientific first-order approximation may just be to make everything one major climactic band colder, thus:



In this I assume that your equator is roughly as hot as the U.S. mid-Atlantic seaboard.
The color key is the usual one that everyone uses:



But bear in mind that these are NOT accurate, in that Earth's Koppen zones don't really apply- in fact you might need to make up your own. What I have marked as Cfb will not, for example, be anything like Earth's Cfb because it's on the frikkin equator! It's temperature will be much less variable, as just one example. So this is all screwed up, but it might give you a start. This is one of those problems that I mentioned that creep up when you make a cooler world than Earth.

But, there are the two western deserts that I predicted, in pink, with surrounding cold steppes in orange. One could argue against the small cool Mediterranean bits, but I included them for formality. As one might expect there are immense boreal areas. Everything but green equatorial climates might see snow at some point. For the purplish montane climates on the equator in the center of the continent that might just be a rare freak occurrence.

Frankly, if anything I may have understated the colder climates at high latitudes. You could probably shift all of those temperature bands 5 or 10 degrees toward the equator. Except the desert and steppes- those are a function of moisture. (And the southern one might need to extend a hair further north. And I can make an argument for the rainshadows of the mountains adding more desert or steppe in the interior as well.) But, heck, even those deserts might behave differently in colder temperatures- that's sort of what I'm saying: climate is very much an unknown once you deviate from Earth normal temperatures.

Your two mountain ranges- assuming that they are Alp or Himalaya equivalents- are pretty much icebound that those latitudes. You may want to move them closer to the equator. You could also argue that the highlands on the equator between the two mountain ranges might just be east-coast maritime climates, rather than the more west-coast type as I have shown. That's certainly how the Appalachians work.

EDIT-- How do I get rid of the older version of the map, in the thumbnail below? :