Rheia: one final try at ground-up worldbuilding

[worldbuilding pasta]

Some useful notes regarding the exoplasim comparison:

Air Pressure:

2: Probably a resolution issue. Generally expect exoplasim outputs to be not totally reliable for mountains

3: See later notes on temperature

4: For somewhat thin continents this is not necessarily unrealistic, compare to Earth's southern hemisphere. Also bear in mind that panoply is sort of auto-fitting the color range to the range of pressures in the output; when comparing the color maps between the model output and Earth or your own drawings, make sure they're on roughly the same scale before reading too deep into them.

Winds:

MrBragg is right, you're seeing top-of-atmosphere winds there. I would suggest going to the highest-level winds of the output, closest to the surface; For an Earth-like pressure profile with 10 layers I think even 1 layer up is something like 1-2 km above the surface.

Temperature:

1: That sort of temperature range isn't necessarily out of the question for a hotter climate, that may have existed in some areas in the Cretaceous. Did you change any parameters of the model other than topography?

2: It seems like your overall average temperature is a bit higher than you were aiming for, you might want to adjust down CO2. Even aside from that, exoplasim tends to output somewhat too warm poles because it underestimates glacial cover; I mentioned to Mrbragg in their thread that starting the model with 1 meter of global glacial cover seems to get a more realistic distribution, though it does also make the model take longer to balance out.

4: Resolution issue again.

Precipitation: When looking at precipitation outputs directly I'd recommend putting them on a logarithmic scale, because rains in the tropics are just so much higher than everywhere else that they drown stuff out. Again, beware of reading too much into the map colors when panoply is just auto-fitting these to the data range without using any sort of objective scaling. Also be aware that the "precipitation" zones used for hand-drawn climate processes are not really meant as direct proxies for precipitation, but moreso the precipitation/evapotranspiration ratio. A hotter region will require more precipitation to remain wet compared to a colder area. This is part of the utility of koppen zones, this complexity is accounted for in how wet and arid zones are defined.

1: Probably a resolution issue again, it's something I have to investigate further, but in this case it may also be related to the over-warm poles.

4: This may also be partially a resolution issue, the model may not be able to capture the full profile of coastal lowlands between a mountain range and the sea. I think this is also why it tends to mark tropical islands a bit too dry, if an island only occupies a single cell it may not capture the orographic effects that encourage rain there.

[Tiluchi]

Some useful notes regarding the exoplasim comparison:

Air Pressure:

2: Probably a resolution issue. Generally expect exoplasim outputs to be not totally reliable for mountains

3: See later notes on temperature

4: For somewhat thin continents this is not necessarily unrealistic, compare to Earth's southern hemisphere. Also bear in mind that panoply is sort of auto-fitting the color range to the range of pressures in the output; when comparing the color maps between the model output and Earth or your own drawings, make sure they're on roughly the same scale before reading too deep into them.

Winds:

MrBragg is right, you're seeing top-of-atmosphere winds there. I would suggest going to the highest-level winds of the output, closest to the surface; For an Earth-like pressure profile with 10 layers I think even 1 layer up is something like 1-2 km above the surface.

Temperature:

1: That sort of temperature range isn't necessarily out of the question for a hotter climate, that may have existed in some areas in the Cretaceous. Did you change any parameters of the model other than topography?

2: It seems like your overall average temperature is a bit higher than you were aiming for, you might want to adjust down CO2. Even aside from that, exoplasim tends to output somewhat too warm poles because it underestimates glacial cover; I mentioned to Mrbragg in their thread that starting the model with 1 meter of global glacial cover seems to get a more realistic distribution, though it does also make the model take longer to balance out.

4: Resolution issue again.

Precipitation: When looking at precipitation outputs directly I'd recommend putting them on a logarithmic scale, because rains in the tropics are just so much higher than everywhere else that they drown stuff out. Again, beware of reading too much into the map colors when panoply is just auto-fitting these to the data range without using any sort of objective scaling. Also be aware that the "precipitation" zones used for hand-drawn climate processes are not really meant as direct proxies for precipitation, but moreso the precipitation/evapotranspiration ratio. A hotter region will require more precipitation to remain wet compared to a colder area. This is part of the utility of koppen zones, this complexity is accounted for in how wet and arid zones are defined.

1: Probably a resolution issue again, it's something I have to investigate further, but in this case it may also be related to the over-warm poles.

4: This may also be partially a resolution issue, the model may not be able to capture the full profile of coastal lowlands between a mountain range and the sea. I think this is also why it tends to mark tropical islands a bit too dry, if an island only occupies a single cell it may not capture the orographic effects that encourage rain there.

Thanks! This is indeed all super useful, much appreciated. No parameters were changed with the model- unfortunately I don't have the processing power or programming knowledge to run ExoPlaSim on my computer, but MrBragg was kind enough to run the basic model for me. You're right that a lot of this is a mix of resolution issues and the fact that ExoPlaSim tends to model things quite a bit hotter than we expect. I've been adjusting my climate map based on the ExoPlaSim output and the output I got from doing things manually- ultimately the results aren't particularly far apart with a couple notable exceptions. Will probably stick to this approach since I can't really run the model on my own, but having ExoPlaSim output is definitely useful for checking if my intuition on some complicated things like precipitation is correct.