Terraformed Venus

[acrosome]

EDIT--

Before you waste your time, I have changed the elevation data set that I was using and re-started several times. If you want to see the current status of the map it starts on page 10.

--END EDIT

Howdy, All.

As I mentioned elsewhere my pet project is going to be a terraformed Venus. I plan to use it for an ultra-low fantasy (no magic) campaign set a few millennia after a cataclysm. Here's a preview:



This is a USGS topo map of the planet with a sea mask and 5-degree lat/long lines superimposed, Mercator projection, and it only goes to 57-degrees north and south. (At the equator a 5x5-degree quad is roughly 328 miles square, so almost 108,000 sq miles- just a bit bigger than Colorado.) It also is compressed quite a bit so that I could post it here- the original is over 27000 px across. I'm going to use this to guide my work on smaller regional maps. I'll also use this to figure out climate.

As a bit of a warning- It'll probably take me years to get any work done on this, so don't expect updates often.

Here are the prevailing winds, before I take into account the continents:



If it looks backwards, remember that Venus rotates the other way- the sun rises in the west.

[foremost]

Sounds like a very neat idea
Excellent detail of all the little islands, looks like back-breaking work.
Are those mountains or swamps?
No pressure on updating quickly, but when you get things done, please do let us know.

FM

[acrosome]

They are mountains (real planetology). I'm not planning on going with the classic "Venus as a swamp-planet" motif.

And on another forum someone just pointed out that I could rotate the map 180 degrees to disguise the fact that the sun rises in the west, to confound those who might otherwise recognize it. Hmm.

Overview:



Prevailing Winds:



I'll presume that the Powers That Be decided to just designate east as "the direction the planet spins," and north is "to your left when facing east," etc. The actual magnetic character of the poles really should have little to do with such things.

[gilgamec]

As part of the terraforming process, has Venus's rotation been sped up? Otherwise, a single day will last so long (240 Earth days or something) that I'm not sure that you can use Earth-based climatic theory. For example, the "day side" of the planet would be receiving light and heat for (Earth-)months at a time, so pressure zones that would form would be more based on continent/ocean size than axial inclination.

[acrosome]

Yes, I'm proposing that the rotation is sped up. 116-day solar days are pretty unworkable. Speeding up Venus's rotation will deform it into a more oblate spheroid- it will bulge at the equator, causing new rifting perpendicular to the equator. This will be roughly 40 miles of extra circumference, so I figured I'd add a new 2-mile rift every 20 degrees or so, plus lesser ones where needed. (This actually gives me a way to drain some basins that would otherwise be inland seas.)

I'm also giving it 20-degrees or so of axial tilt, to generate seasons.

What I haven't decided is whether I'll keep Venus in the same orbit with some sort of sunshade or if I'll move it to a new orbit. Keeping it where it is has the advantage that I need not add a moon to have appreciable tides- solar tides would be about as strong as Earth's lunar tides. Not having a moon probably means more perturbation of axial tilt, but that's an issue on scales of tens of thousands of years. And a Venus year would still be only 224.7 days.

OTOH moving it to a new orbit avoids the need for constant station-keeping on the part of a sunshade. And, heck, if my planetary engineers can move Venus then they might as well snag Triton as a moon for it. About 1/3 of Triton's mass could provide volatiles for the terraforming, too (mostly nitrogen and water), leaving a slightly smaller moon to orbit as a satellite. It would also lengthen the year. Options include moving Venus into a binary relationship with Earth (which would require ejecting the Moon to avoid the N-body problem), moving it into a binary relationship with Mars, or slipping it into its own orbit midway between Earth and Mars. (I worry that this would do something terrible to the orbital resonances of these planets, though.) It cannot be placed on the opposite side of the sun from the Earth, as L3 is unstable. So are L4 and L5 unless one body is much larger than the other, which would not be the case here- eventually they would collide or one would be ejected.

I'm tending towards the position that if my engineers can spin Venus and give it an axial tilt, then they are probably capable of moving it to a new orbit if they feel like it. But I'm not sure what I want for my campaign.

Anyway, here are some initial climate maps:

January



The equator and 30-degree parallels are shown. The north and south map edge are at 57-degrees. The reddish pseudo-equatorial line is the ITCZ. Major landmasses are labeled.

July



I'd appreciate if you all could point out glaring errors before I start scribbling a few hundred windsock arrows over the maps.

I used The Climate Cookbook and PhysicalGeography.net as guides.

Oddly, I have in some ways recapitulated Earth on these maps- you can see how I have a North and South America, a Eurasia, etc. Thus I leaned on the latter website a lot. The wild card is that my Eurasia sits approximately smack on the equator, so if anyone has any ideas about that I'm listening. Looks like monsoons in Thetis and southwest Ovda?

Also, I can't quite figure out what to do about Alpha and Astkhik. Their land area is probably too low to have a real continental effect, so I think that I perhaps should do the opposite of what I show here, because they are in the equivalent of my Northern Pacific, which looks like it has a honking big low in January and a mellow high in July.

[foremost]

Again, looks like this was a lot of work, tons
of little islands all over your map. Going to
make for a lot more work when the project
progresses. It's obviously been a few weeks
since you updated, so I hope you are still
going.

My question would be "Why is the heat-band
not directly on the equator?" Maybe this is
as it should be, and I'm interested to know
why.

Water takes a longer time to heat up or cool
down than land does, and it's also going to carry
some wind currents along with it. The temperature
should also fluctuate throughout the seasons. Does
Venus have seasons?

Anyway, the coastal areas will have more balanced
temperature, thanks to proximity to the water. Inland
areas might be bone-dry and wicked hot as well.

I'm no expert on this, and if you have information
from those websites you mentioned, please share!

Neat project, hope you continue.

[rgcalsaverini]

Great to see a map with such realism! I tend to rush to drawing before settling some necessary things before. I will be following this eagerly!

[Nathan]

Oh ! I really like that !
Impressive !

[Caenwyr]

Great to see a map with such realism! I tend to rush to drawing before settling some necessary things before. I will be following this eagerly!

Seconded! No patience whatsoever here... though I really should work on that! My sincerest compliments to your perseverence, acrsome!

[acrosome]

Yes, I'm still working on it. Exactly two days total since my last post, but I warned you all about that. Careers suck sometimes...

@foremost: Those aren't "heat bands", they are high- and low-pressure zones. And the ITCZ is just sort of a line near the equator with equal pressure north and south of it. I can't explain it in a pithy manner (especially since my own grasp of it is tenuous at best). If you're interested check out those websites I listed.

Venus terraformed the way that I'm proposing will indeed have seasons. It's been given more axial tilt, and its spin has been increased.

Speaking of which I wasn't happy with the previous climate maps, so I re-did them making some different assumptions. I also added winds and currents. I'm ready to start working out Koppen climate zones soon.

So, yellow are high-pressure zones, blue are low-pressure zones, and the green arrows are prevailing winds:

Here is July:



Here is January:



Here are currents, hot cold and indifferent:



Recall that "hot" and "cold" are relative. I.e. a warm polar current can be colder than a cold equatorial current.

EDIT-- Does anyone have a nice 1000m contour map of the world or of North America, so that I have something to compare to while working out climates? My Google-Fu is failing me.

EDIT-- I decided that I don't like my first world-spanning map (the file size is simply too big to work with) so I'm currently working on re-doing it as eight regional maps instead. Luckily, I found a decent set of USGS base maps that includes the poles, so now I can cover the whole planet. Which is nice, because Ishtar Terra is damned interesting. I've also been struggling with Koppen climate zones, and I'm getting frustrated. I need the climate worked out so that I can decide which basins will be endorheic and which will be inland seas or lakes, etc. But some of these basin seas might be big enough to affect climate. Grr. It looks like most of northeast Aphrodite will be a Sahara-equivalent, and there are a few areas with true monsoons in Manatum and in that large bay at the west end of Thetis.

So, more will follow... eventually.