There is very little insolation of the surface of Venus. 10% has already been mentioned.
"2. What is the explanation for the fact that the night side of Venus can maintain average surface temperatures given the length of "night" on Venus?"
Venus's atmosphere has a total mass around 100x that of Earth's, so it has a huge total heat capacity. It is principally co2 which has a higher specific heat capacity than our air. The atmosphere of Venus acts like a huge heat sink, much as our oceans do.
The reason that the night side of the planet stays warm is that the lower atmosphere is rotating very quickly. Our atmosphere essentially co-rotates with the earth, but venus's does not. Its atmosphere rotates around the planet in approximately 5 of our days. This keeps the heat fairly uniformly distributed.
"3. What would be the (Venus) average surface temperature if all parameters were fixed except:
A. Surface pressure was equal to Earth at 1 bar?
B. CO2 concentration was equal to Earth at 0.04%?"
There are too many other variable at play in question 3 to have a crack at it. Does the albedo stay the same? What is the remainder of the atmosphere made of? Has the atmospere's mass changed too? (100 bar to 1 bar pressure change). I'll leave this to someone else. However, if it was earths atmosphere on Venus, with double the insolation, but without our free water (ie without clouds, or the ocean transport of heat to the colder poles) then it would be a LOT hotter.
"4. What role does CO2 band saturation play in the Venus greenhouse effect?"
Co2 traps the heats, Venusian clouds scatter the heat rather than absorb it like our water clouds. Downwelling radiation on Venus is huge in comparison to Earth, so the lower atmosphere is heated much more than ours.
Anyone, please correct any mistakes I've made here... they're only my best guess from my limited understanding of Venus.
I am not qualified to answer the questions but the temperature at different altitudes is interesting. It shows significant increase in temperature at greater pressures toward the surface.
I would guess that the night temperatures remain high due to the shear mass of the atmosphere. In this way, the atmosphere behaves almost like our oceans.
That french site is, well, weird. Here is a better discussion of Venus:
http://www.realclimate.org/index.php/arc...
Of course, you won't believe it at all. But the point is that Venus is hot because of the greenhouse effect of its dense atmosphere. It is not hot because the atmosphere is so dense.
edit: Jim, that is because Venus nearly perfectly follows a dry adiabatic lapse rate profile in the lower atmosphere. I am surprised you didn't recognize the significance of that, being a scientist and all.
edit2: OM, I apoligze. I thought you could follow the links on your own. See here:
http://www.esa.int/Our_Activities/Space_...
and here:
http://www.realclimate.org/index.php/arc...
both of these answer all your questions, well, except the thought experiment one, which has the obvious answer of "a lot cooler" but it's irrelevant to addressing the question of why Venus is as hot as it is.
Your many many hundreds of prior fake questions here show beyond the slightest doubt that you have no interest in science or truth, Mike. You are simply trying to get background info in order to look less silly when trying to cover-up a future copy-lamely-disguise-and-paste of some denier lie about Venus like this one:
http://stevengoddard.wordpress.com/2012/...
None of your copy-pasted BS questions has any effect whatsoever on the solid findings of a century of scientific research.
U.S. National Academy of Sciences, 2010:
http://books.nap.edu/openbook.php?record...
“Climate change is occurring, is caused largely by human activities, and poses significant risks for a broad range of human and natural systems.”
http://www8.nationalacademies.org/onpine...
“Choices made now about carbon dioxide emissions reductions will affect climate change impacts experienced not just over the next few decades but also in coming centuries and millennia…Because CO2 in the atmosphere is long lived, it can effectively lock the Earth and future generations into a range of impacts, some of which could become very severe.”
http://www.physics.fsu.edu/awards/NAS/
“The Academy membership is composed of approximately 2,100 members and 380 foreign associates, of whom nearly 200 have won Nobel Prizes. Members and foreign associates of the Academy are elected in recognition of their distinguished and continuing achievements in original research; election to the Academy is considered one of the highest honors that can be accorded a scientist or engineer.”
... ... ...
I'd like to ask a series of questions about Venus. First, some facts about Venus:
- average surface temperature: 464C (Earth is about 15C)
- diurnal temperature variation: ~0C (Earth? more than zero)
- bond albedo: 0.85-0.90 (Earth ~0.30)
- CO2 concentration: 95% (Earth 0.04%)
- water vapor: 0%
- surface atmospheric pressure: 92 bars (Earth 1 bar)
- rotational period: 225 days
- cloud cover: virtually 100% with 30–40 km thick clouds with bases at 30–35 km altitude.
Here are some questions related to the surface temperature of Venus and the CO2 concentration levels:
1. Given the bond albedo of Earth and Venus, cloud cover and their relative distances to the Sun, how much solar energy reaches the surface of Venus compared to Earth?
2. What is the explanation for the fact that the night side of Venus can maintain average surface temperatures given the length of "night" on Venus?
3. What would be the (Venus) average surface temperature if all parameters were fixed except:
A. Surface pressure was equal to Earth at 1 bar?
B. CO2 concentration was equal to Earth at 0.04%?
4. What role does CO2 band saturation play in the Venus greenhouse effect?
