[WIP] Building a world from tectonics onward

[MrBragg]

Still impressed you were able to get it all running- I took one look at Nikolai's code and turned tail and ran.

Haha yeah, there definitely was a learning curve, but it only took a few crashes before I figured out what was going on

Regarding the pressures, those are things that ExoPlaSim also exports so in theory we could extract these and see how they compare to expectation. There are actually several pressure variables written as outputs--some of which are broken down by atmosphere layer--so the trick here might be figuring out which information is relevant. Something to look into...

[MrBragg]

After a little bit more work on fiddling with CO2 levels, I've managed to get global average temperatures closer to what I was hoping for. I also reduced the planet radius from earth’s value to mine (3100 mi), which probably helps equator-to-pole heat transfer.

300 ppm (22.9 C)
scaled_T42_8mo_scaled.png

180 ppm (19.8 C)
scaled_T42_R_180ppm.png

120 ppm (16.7 C)
scaled_T42_R_120ppm.png

After doing a number of these with different parameters—and looking at the results from Nikolai and discussions with Tiluchi—it’s pretty clear that the ITCZ doesn’t seem to fluctuate quite as much as it should from summer to winter. Even over land it typically doesn’t deviate more than +/- 10 degrees from the equator and, when it does, it tends to be somewhat dry as compared to the areas over the ocean; this latter quality is illustrated really nicely by Nikolai’s figure here where large swaths of land in the tropics have underestimated precipitation while the oceans are overestimated. There’s probably some systematic error with pressures going on here, but I’ve not dug deeply enough to sort out what that might be.

In any case, at this point things are probably good enough to estimate the extent of glaciation on my final continent and finish the topography there before coming back and doing a final pass(es) in ExoPlaSim.

[MrBragg]

Alright, apart from adding a few more hotspot chains, I think a first stab at topography is FINALLY done! So, before I decide this is *the* version, let me know if anything doesn't look right so I can fix it

map7_topography_8bit_small.png
Downsized slightly from 24k x 12k

[worldbuilding pasta]

2 quick notes:

1, I've done some tests lately with exoplasim runs starting with 1 meter of initial global glacial cover; it takes a bit longer for the climate to settle out, at least 50 years whereas they usually are mostly settled within 20 years otherwise, but the resulting glacial cover is a lot more accurate, as well as the global average temperature. it does make some mid-latitude areas even colder than they should be, though.

earth_glactest2 .png

2, I've seen at least some indication that T85 runs are better at reproducing the precipitation patterns in Africa and India, but I've never really got around to fully investigating it; this is a run someone on discord did for just 16 years (and I think it's from back when we used an earlier version of the topography script that was heavily land-biased)

sim.png

[MrBragg]

1, I've done some tests lately with exoplasim runs starting with 1 meter of initial global glacial cover; it takes a bit longer for the climate to settle out, at least 50 years whereas they usually are mostly settled within 20 years otherwise, but the resulting glacial cover is a lot more accurate, as well as the global average temperature. it does make some mid-latitude areas even colder than they should be, though.

This is a really good point and something I'll try soon. Thanks!

... and I think it's from back when we used an earlier version of the topography script that was heavily land-biased)

Out of curiosity, what do you mean by this? I'm guessing (hoping) this isn't the Image2sra_2.0.3.py script that I've been using.

[worldbuilding pasta]

I think this was way back before Ostimeus had released the script anywhere so don't worry about it

[Naima]

I think this was way back before Ostimeus had released the script anywhere so don't worry about it

What do you mean ? I was trying to follow the tut on WBP but i found a bit of confusion on where to put Low pressure circles.

[worldbuilding pasta]

What do you mean ? I was trying to follow the tut on WBP but i found a bit of confusion on where to put Low pressure circles.

Sorry, was replying to bragg earlier regarding the image2sra script, I haven't used old-school forums in ages, I didn't remember how the reply stuff worked.

[Naima]

2 quick notes:

1, I've done some tests lately with exoplasim runs starting with 1 meter of initial global glacial cover; it takes a bit longer for the climate to settle out, at least 50 years whereas they usually are mostly settled within 20 years otherwise, but the resulting glacial cover is a lot more accurate, as well as the global average temperature. it does make some mid-latitude areas even colder than they should be, though.

earth_glactest2 .png

2, I've seen at least some indication that T85 runs are better at reproducing the precipitation patterns in Africa and India, but I've never really got around to fully investigating it; this is a run someone on discord did for just 16 years (and I think it's from back when we used an earlier version of the topography script that was heavily land-biased)

sim.png

Am I wrong or places mediterranean in wrong positions?

[MrBragg]

Am I wrong or places mediterranean in wrong positions?

That output almost looks like it came from one of ExoPlaSim's "snapshot" files, at least when I mistakenly use those to generate climates I get similar weird distributions of Med climates like in that example. I guess it could also come from the fact that a 16 year simulation isn't yet converged, so it could have wacky thermal / precipitation parameters.