Okay, I'm trying to put together a planet, and I'm attempting to get as much of the land area as possible to fit the descriptions of
WWF biomes 04 to 12. (Alternatively, basically anything you'd find north of 40 degrees N, with a few dips southward to grab on to the American Southwest, the coastal Med and the Fertile Crescent, and the African savanna.)
That said, before I go about doing that, I have a few more general questions:
It is my understanding that land at the poles usually means a much, much larger area of ice, tundra, and taiga in northern regions. Is this generally the case, or is there some list of strange caveats I need to know about?
If I recall correctly, this is true, generally. The poles typically are under the domain of the northern/southernmost air cell, so there is going to be prevailing high pressure zone in that region. Now, the caveat is that I would say this only holds if the pole is all land, or all ocean. An all land/ocean pole would be under a relatively uniform paradigm and thus would be basically a high pressure or low pressure cell depending on the season.
Now if you break it up with land, altering currents (say with a Gulf Stream analogue going up
north of Greenland instead of towards Europe) you change the dynamic. Water and Land heat and cool at different rates which gives you different localized pressure cells which gives you different prevailing weather patterns (this is of course, very generalized, but I would say for the sake of a story you don't need super-computed models). See the link below for a decent picture of those air cells, this also helps with prevailing winds.
http://www.newmediastudio.org/DataD...terly_Waves/Trade_Winds/Trade_Winds_fig01.jpg
What effects would having effectively no land at the tropics/equatorial region look like? Would it keep all that warm water circulating in its own current, and keep it from heading north to create a Gulf Stream-like moderation of temperatures in the more northerly regions?
I think this is tricky. As you may know, down in the Antarctic we've the Circum-antarctic current which makes for powerful storms and waves as they can fly around the Earth again and again unimpeded.
However, if we look at a map of the
thermohaline circulation we can also see that the cold water currents follow the general C-A path too. Judging from the path of the TH circulation, it looks like the rotation of the Earth might even play a role in the imparting of momentum to the water as it does to the air.
I suppose you
could see a storm system march all the way around the equator and become gigantic, but that disregards the effects of currents coming in from north or south, where landmasses ought to disturb any planet-lapping patterns.
I also imagine that, in such a scenario, monsoons and hurricanes would be horrifyingly monstrous, but would rarely do much more than scrape the edges of the continents- and I'm not exactly sure about seasonal effects, but I just suddenly got a horrifying and wondrous vision of a neverending tropical storm circling the equator and preventing inter-hemisphere transit until a roughly modern technology level is reached. (This is more a matter of curiosity than an actual idea for this particular conworld.)
Even if you had a storm system that lapped the world, wouldn't it have a nucleus that would rotate much like the Great Red Spot, leaving a relatively calm wake that might be traversed with luck/skill/God's good Grace?
I would think that so long as you have North-South ocean access, the TH circulation is going to cut into any circum-equatorial superstorms. The water being heated at the equator will fuel the storm, yes, but it will also be under thermodynamic forces that will effectively cause it to migrate to where colder water is sinking. (This is, after all, the basic mechanism of the Gulf Stream and the overall TH circulation.)
And on other matters- desertification. I imagine that, to prevent grasslands, savanna, prairie, steppe, chaparral, scrublands, rain shadows, etc from becoming either deserts proper, cold deserts proper, or tundra (in the more polar areas), it would be prudent to add large numbers of lakes, rivers, and oceanic passages to retain irrigation and moderate rains.
I would agree, but in regards to this my modelling generally has been in a single year snapshot mode. You would have to actually model it for years at a time to determine any changes over time spans greater than a year.
Now, the way I minimized deserts and the like in my world (Tellus, see earlier in the thread), was by instead of having massive continents and massive oceans, I distributed the mass around. The 'Atlantic' is a mite smaller, yes, but I took that space and put it into the 'Arctic' to make it a different shape which changed the patterns of weather.
I would also imagine that smaller coastal and near coastal mountain ranges like the Appalachians and the Olympics/Coast Ranges would help in, on the one hand, creating cold rainforest, and on the other hand, moderating storms in the more inland regions, but I also imagine that, deep in a large continent, prairie rainstorms would be hard to prevent without a lot of big mountains like the Rockies or the inland European/Eurasian ranges (Alps, Balkans, Urals, Zagros, Himalayas, for example.).
Again, talking about things like that get beyond the broad patterns and so my general rule on that is look to what we have on Earth. Compare terrain features, latitudes, currents, winds, etc., and you'll get a fair approximation of what you should see in your own world.
Edit: And while it's in my mind, another question- how much is climate affected by vegetation? Obviously, plants will grow in areas suited to them climatically, to climate has a huge effect on vegetation, but for instance, scrub brush in a desert can do a lot to prevent the formation of large sand dunes, for example, but how detailed can climate modelling be without knowing something about the biologics of a region?
Well, my thought on that matter is thus:
If you take guidance from the current theories of Evolution, or even if one is to follow from a theological position (for example, the Judeo-Christian Creation account, as I hold to), you have in both basic cases Terrain and Oceans first, plants and animals next. (The differences between the two paradigms are not immediately relevant to my admittedly simplified response here.
)
Animals ultimately require plants, plants require water. Watered land requires wind to carry the water up towards the mountains to fall as rain to form streams to form rivers to flow into the oceans. Therefore, start with your topography, determine climate zones, and then compare to what Earth has (and one can always change things for the sake of a story, but don't change too much or you make your previous modelling efforts moot), and viola - A living world.
Map 3, Winter (January) Winds/Pressures.
Green is High Pressure (HP), Red is Low (LP). The pale band around the equator is the Intertropical Convergence Zone (ICZ). Black are your prevailing wind patterns at that point in the year.
I'll use the following nomenclature for the rest of the details: NC for the continent in the northwest. NCA for the archipelago trailing southwards. PA for the Pseudo-Africa/South America in the center of the map. PE for the Pseudo-Europe in the Antarctic. PNA for Pseudo-North America.
Now, assuming January represents northern winter, NC looks to be dominated by a HP, surrounded by LP ocean. Likely, this means you'd see dry winters in the interior but potentially stormy weather along the coasts of the north and for sure you'd see inclement weather in the part of the NC south of the mountains leading down into the NCA.
You can see an HP on the northern part of PA, generating similar wind patterns as NC, but now we have the ICZ crossing the continent, which is generally going to pull in moisture from the HP cell over the southern oceans. This makes me think you'd see basically the biomes of Africa inverted on PA. Sahara in the north, where it looks like southern Africa, then working to savanna, then rainforest, and then probably temperate forests along the southern coast.
the NCA is going to probably always be relatively well watered, but I imagine there will be lots of storms and powerful currents about them.
PE, as it is in it's Summer, looks to have a very wet summer - perhaps akin to the weather on the North European Plain? You see that circular zone? That could be a relatively stormy zone - those mountains could be quite ominous. You'd also not likely see much of a rain shadow emerge because you've moisture channels all over. One side of a range might be temporarily in the shadow for a particular weather pattern, but not necessarily the next one.
PNA, very similar to PE. I think it could be readily compared to North American climate zones, just inverted as it's in the southern hemisphere.
The incredibly small HP in the north is likely even smaller in reality. I'd imagine those could generate HP cells that are carried off by the prevailing wind, drawing storms in towards the islands.
Map 4: Summer (July) Winds/Pressures
Northern Summer, Southern Winter
PA - Hooboy but she's going to be a massive LP! Perhaps monsoons! As you can see by the black arrows, from the NE, the E, SE, S, and SW the interior is in a rainshadow. From the NW and W, however, there is a channel for water to be brought in. The coastal regions would likely be wracked with storms.
I didn't draw the ICZ on this map, but you could imagine it running the length of the warped equator here. This suggests quite a nice belt of rain forests all around the planet.
PA - during this season you'd likely see the only rains to the north.
NCA - more storms and currents. If you're an excellent navigator I'd imagine these to be quite the spot.
PE - generally it looks like a dry winter, with snow storms along the coast and perhaps winter rains/snow along the interior sea. Certainly something in those mountains.
PNA - again, similar to PE.
Looking at this world, you have a situation much like mine, in that you inadvertently used topography to keep it moist!
