Saturday, December 14, 2019

Summary of Venus clouds

Over Venus the clouds are densest at 48.5 km up and extend up to 70 km. Between the 50° latitudes, and I’m pretty sure in the 50s° bands themselves, our cities float in the middle layer, from 50-56 km. It is Figure 1.3, here (Yeon Joo Lee's thesis pdf).

If I am reading this right, the middle layer is best rated as “foggy” (and shady). Thicker clouds float below and above, but nobody at 55 km is going to see them. Wind speed: 55 ms-1, so 125 mph. Mostly zonal although slight (< 10 m/s) cloudtop meridional direction poleward.

This layer gets cooler north / south of the 50° N / S latitudes. 60° is where the circumference is cosine-60° half that of the equator, so here a 125 mph wind should return to its start in 345000 seconds. 96 hours; four Earth days. Just like what Is Known about the cloudtops at the equator.

60-70s° are the polar collars, famously colder at high altitude but, I think, cloudier. Winds are more erratic, especially north/south. Within the 70s° polar circle, is the respective polar vortex. Its eye is not at the pole itself, but offset –and shifting.

From the viewpoint of continent Ishtar it is difficult to recommend a floating midlayer city north of 60°. Fortunately the southernmost part of Ishtar extends south of that; so at the tradeoff of a bit more heat and pressure, the farms can get some starter surface camps.

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