Mission of Gravity -- Rapidly Spinning World

[Peter Toth]

I've recently learned some basic 3-D modeling in Blender, which I've used to render the realistic satellite view below, overlain with Frodo's physical parameters. (Axis is rotated by about 10 degrees; northern ice cap (at periapsis) is visible.)

Globe Parms.png

By the way, does anyone know how to use ExoPlaSim to calculate the effective temperature? Using worldbuilding pasta's spreadsheet, I got a value of 30 Celsius, which seems way too high considering the extent of Frodo's ice caps. Another question: what is the difference (referring especially to Clima-Sim) between total albedo and effective albedo?

Anyways, thanks for viewing.

Peter

[worldbuilding pasta]

My spreadsheet, clima-sim, and exoplasim have different levels of complexity and flexibility which mean they might not be consistent with each other, exoplasim should generally be trusted over the others; the first one in particular rather clunkily relies on you to decide what the albedo is. Effective temperature is a somewhat odd parameter to be concerned with for a planet, there are probably ways to work it out by summing the outgoing radiation but for any application where effective temperature really matters, a few degrees difference isn't much of a problem. There are also a number of different ways to define albedo, you'd probably have to dig around a lot in its documentation to figure out exactly what clima-sim is using. Ultimately I guess I'm wondering what these specific parameters are for, because they might be a lot of work to figure out.

[Peter Toth]

My most recent update has finally dealt with an important but previously undefined climatic variable: ocean currents. Using data derived by worldbuilding pasta (thank you Nikolai!), I discovered that Frodo theoretically has nine circulation cells per hemisphere, although due to eddies in the atmosphere, these won't be very well defined but instead rather chaotic. (I don't know if it's even practical to be defining ocean currents on such an unusual world, but I've done so anyway, hoping for some feedback from those more knowledgeable.) Also, due to ice caps, only 6-7 circulation cells actually exist.

Currents.png

Now, all I have to do is consider the effects of all the currents acting on the continent relevant to the story (the one with defined mountain ranges), and calculate the climate accordingly. I'm not certain how many degrees to adjust the climate by, although worldbuilding pasta has calculated that on Earth, only those currents between 50 to 70 latitude should be affected by about 10 to 15 degrees Celsius. Because the temperature on Frodo changes so dramatically away from the tropics (and factoring in Frodo's larger size), I'm guessing that the currents would have a stronger effect on modulating temperatures there. (15 or so degrees of heating/cooling as well, perhaps?)

I've also defined the ice cap at periapsis (whitest layer capping the poles) and apoapsis (baby blue, relevant only in northern hemisphere), factoring in the ocean's ability to circulate heat towards the poles. As I've tried to depict, the melting of ice at periapsis allows one more cell of circulation to operate in the northern hemisphere during the hot season. Due to axial tilt, eccentricity, and the orientation of Frodo's orbit, the southern hemisphere ice cap does not melt at periapsis.

At any rate, please let me know what you think.

Peter