What is the surface temperature distribution of Venus?

Question

I can find lots of resources stating the average surface temperature. However, I have found conflicting reports concerning the distribution of temperatures on the surface. For example, the Venus wikipedia page suggests that the coldest spot on the surface is about 650K at the top of Maxwell Montes. However, other resources reporting on the Venus Express probe suggest that the "Venus Express probe revealed that the polar regions have a surface temperature of... 116K", which is significantly different. However, I suspect that this may be a reporting error, and may actually reflect an atmospheric temperature at an undisclosed altitude. Specifically, the paper describing the probe's final data does not seem to mention the word "surface" whatsoever, but is full enough of science-speak that is foreign to me that such a statistic may actually be hidden in there.

In any case, what are some good resources on the actual distribution of surface temperatures on Venus? At the very least, estimated temperatures in a few key areas (equator, poles, mountains, valleys, etc etc) would be desirable.

Answer 1

Venus's thick atmosphere ensures that at a given elevation with respect to Venus's geoid (which is really close to a sphere!) there is precious little variation in temperature across the planet.

Since it appears you want to avoid scientific papers and such articles loaded with "science-speak", I'll steer you to the 2006 Space.com article that shows temperature maps generated from Venus Express (also here) data. Note the range of that temperature scale: 453 to 473 C (726 to 746 K). The great majority of that variation is due to topography: changes in elevation. The map area shown doesn't include Maxwell Montes, which would be significantly cooler.

The vertical thermal lapse rate in Venus's lower atmosphere is about -7.7 K/km (temperature drops ~7.7 K for every km of elevation increase). At the 11.5 km elevation of the peak of Maxwell Montes you'd expect the temperature to be ~88.5 K cooler than the temperature at zero elevation. Using 735 K as the zero-elevation temperature that puts you at ~646.5 K at the top of Maxwell Montes, pretty close to the 650 K from the Wikipedia article you quote.

The thick atmosphere is very efficient at moving heat around, so the temperatures at the poles aren't very different from those elsewhere. In late November of 2018 I was at a workshop at NASA's Glenn Research Center studying possible landed missions at Venus, and our consensus was that you'd see maybe 2 or 3 K cooler temperatures at the poles than at the equator at noon (again, at the same elevation!). Titan, the moon of Saturn, has a similar situation.

I can't imagine where that 116 K figure came from, except from a gross error in reporting. Nothing at Venus is at 116 K! The only figure that could even vaguely resemble that would be -116 C, very roughly the average temperature at Venus's tropopause. But going from -116 C to 116 K requires two rather serious errors in reporting a single number. I'd hope that science reporting isn't that bad!

Answer 2

The article Venus nightside surface temperature shows a global map of Venus using Akatsuki infrared measurements.
They reveal a hot surface with an average temperature of about 698 K and on a global scale, surface temperatures with a spatial variation of about 230 K !

Fig.1 in that article shows a blue region at 60⁰ N. latitude, that according to Fig. 2 is a low lying area, that would have a surface temperature of about 360⁰ Celsius while Maxwell Montes to the right would be 20⁰ hotter !

In addition to the temperature map mentioned in the accepted answer, here's a new temperature map of Venus' southern hemisphere from ESA.