This Query is part of the Worldbuilding Resources Article.
I'm working to build a procedure that will help me understand the climate of the worlds I create. I'm beginning with simple and building to complex because, frankly, lacking anything that could be construed as a PhD in climatology in even the weakest light with Def Leppard playing at distracting levels in the yard next door, I need to begin at the beginning.
So let me pause and tell you a joke. The Mob was tired of fending off the cops when they fixed the races, so they "invited" a physicist to build them a simulator that would predict the winning horse every time. After months of "motivated" labor, the physicist finally produced his masterpiece. A delighted mob bet big on "Haley's Shadow," with odds 9-to-1 to win — and lost everything. When the Mob suggested that a bit more than a pound of the physicist's flesh would be required, the very perplexed man said, "I don't understand! It worked fine with my spherical horse!"
So, let's start with a spherical horse.
What are the specific weather patterns that would develop and (I presume) stabilize over time under the following conditions?
Given the sphere (I hesitate to use the word "planet" at this point) is always within the star's habitable zone.
Given a sphere of mass and volume similar to Earth.
Given an atmosphere with Earthlike composition and density.
Finally (and this is the important part), the sphere DOES NOT rotate, DOES NOT orbit, has a perfectly smooth surface, and the surface DOES NOT contribute to climatological effects. (I believe there's enough fiction in this single bullet to justify asking the question here... but y'all can tell me otherwise.)
I'm looking for a first-step explanation. Simple, simple, simple, simple, simple. With one exception...
It would be cool if the answer could accomodate variations in solar luminosity and the sphere's (OK, the planet's) volume. Or, if it's more appropriate, an explanation as to why solar luminosity and planetary volume don't matter.
I can actually imagine an argument like, "as luminosity increases, the habitability zone is pushed out, ditto with planetary volume, thus the general effect is always the same... at least if you want human-like life....
Which, of course, I do.
When I say the surface of the sphere does not contribute to climate effects, I mean that I want to deal with water, soil, elevation, etc., in a later question. Please assume this question is about the atmosphere and only the atmosphere. It's a gas dynamics question around a shape that provides gravity for the sake of the atmosphere and nothing else.
Yes, this question will lead to a good understanding of how climate works on a tidally-locked planet. But that's an issue for later.
Yes, assuming no orbit, no rotation, no surface effects is absurd. By the same token, all freshman physics classes are absurd becasue they all start with spherical horses. I did that on purpose, folks. It's impractical to hand a first-year physics student a graduate-level textbook in an effort to just jump to the solution. (If you don't believe this, it's been a while since you were a freshman....)