So, MrBragg was kind enough to run my grayscale map through ExoPlaSim (thanks again! Seriously much appreciated!), and I've been comparing the output with what I got from doing things manually. Since I haven't yet done a manual climate map we won't get to that yet, but the great thing about ExoPlaSim is that it outputs a bunch of climatological maps, including stuff similar to what one would put together with the Azelor tutorial or with earlier versions of the Worldbuilding Pasta tutorial. In case it's useful to others, I'll be going through the ExoPlaSim outputs and comparing them with my own results to see where it differs. ExoPlaSim definitely got some things right where I went wrong, but there are also a number of areas where I'm skeptical of ExoPlaSim's results, most of which seem to boil down to the lack of ocean currents in their climate model.
1. Air pressure:
My initial outputs for January and July are below, along with ExoPlaSim's lower-res (but better-looking) pressure maps.
Overall the results are fairly similar, which is reassuring. However, there are a few differences in interpretation:
1. ExoPlaSim pretty strictly places thermal lows (summertime overland low pressure systems) around 30 degrees, while mine were offset a little based on topography. ExoPlaSim is probably more correct here, and I'll shift them accordingly.
2. While Earth has a semi-permanent high pressure area at very high altitudes (mainly the Himalayas and the Andes), ExoPlaSim doesn't always model this; I'm going to go ahead and keep these high pressure areas as it seems otherwise high mountain plateaus would be modeled as wetter than they really are.
3. ExoPlaSim either understates or omits entirely the overland highs that I had near the poles in the wintertime. Comparing results from ExoPlaSim's earth modeling and real-world data (as seen on Worldbuilding Pasta here), it seems to model polar regions as somewhat warmer than they really are, and I wonder if this is why. At any rate, I'm going to keep my wintertime highs as I want to make sure the areas I imagined as ice caps really are ice caps.
4. ExoPlaSim tends to model subtropical overseas highs as one mostly-contiguous ridge of high pressure, rather than as a series of anticyclones centered near west coasts. While my initial work probably kept high pressure a little bit too concentrated in the anticyclones, from eyeballing the winds it seems like ExoPlaSim kind of understates anticyclonic winds in general. I suspect this is because ExoPlaSim doesn't model currents, and equatorward cold currents are a primary driver of the subtropical highs. At any rate, I'm opting to split the difference and spread my subtropical highs out a little more laterally, but still keep the highest pressure concentrated in the western part.
Overall though I'm pretty happy with how close my initial model was to the ExoPlaSim output.
2. Winds:
Just a quick note on this one, as I don't really like the way ExoPlaSim outputs wind maps. From what I can tell the model seems to strongly favor the prevailing easterlies and westerlies, de-emphasizing cyclonic and anticyclonic winds. I'm not sure if it's a resolution thing or what, but that's in contrary to pretty much any wind map I can find for Earth, where prevailing winds in a given season tend to have a northeast-southwest or northwest-southeast angle, particularly in the tropics. It's also contrary to the example I can see on the Worldbuilding Pasta tutorial, so this is probably user error, though I have no idea how. At any rate, my revised winds are just going to be based on the revised pressure maps, since for the moment I don't trust what I'm getting from ExoPlaSim.
With that in mind, here are maps of my revised winds and pressure systems for January and July:
3. Temperature:
Temperature is where we start to really see some differences between my initial results and the ExoPlaSim model. Maps for January and July are below:
The main differences I can see are:
1. ExoPlaSim has some really eye-poppingly high temperatures on large continents: it puts average temperatures well over 50 degrees celsius (sometimes closer to 60 degrees C) in the centers of some continents, and has those areas staying above 40º C even in the wintertime. I don't know enough about climate modeling to say why that is, but I'm pretty skeptical of those figures. The model is probably right that I was understating the temperature effect of thermal lows a little bit in my temperature maps, but I'm going to go ahead and not put in the huge swathes of unsurviveably hot temperatures that it's telling me to.
2. On the same token, ExoPlaSim calls for much warmer winter temperatures near the poles than I had; while I have large areas below 25º C in the wintertime (turquoise in my temperature map), the lowest ExoPlaSim calls for is 20º C. Partly that's probably because it somewhat understates the effect of overland high pressure systems near the poles, but also I think the average temperature is just too warm overall. That said, the model mostly agrees about relative temperatures; in other words relatively cold areas in ExoPlaSim's map are also relatively cold areas in my map, so that's good.
3. As expected, the effects of currents aren't really taken into account, so coastal areas with cool currents are somewhat too hot, and temperate areas with warm currents are somewhat too cold. That's because ExoPlaSim doesn't really do currents, and thus I'll keep the effects of currents in my map as they are.
4. Some highland areas are too warm, which is probably just because of limited resolution, as well as the generally very hot average temperature the model is calling for; I'm certainly not going to have 40º C temperatures at over 1,000 meters above sea level. That said, the difference isn't as pronounced as I thought it might be, and again looking at relative levels ExoPlaSim's temperatures and mine mostly align.
With all this in mind, I revised my temperature maps based on the relative temperature output by ExoPlaSim, rather than the absolute values; there are some areas that ExoPlaSim says should be relatively hotter where it's probably correct, but I'm not going to dial it up to the stupidly high temperatures it calls for. I'm also revising them based on my new winds and pressure, though that will have more impact on precipitation than on temperature.
Next is precipitation, which is probably the most complex part of all this, but I'll save that for another post since I have no idea how long it will take me. Anyway, thoughts or reactions are welcome! This is very much not my area of expertise, so I may well be missing something obvious about climates here...
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