Gary,
Very well put.
Some models of the martian atmosphere and climate suggest that triple point conditions for water are possible over a sizable portion of the martian surface for brief moments during the course of any one martian year. Unfortunately the very same conditions that lead to possible fleeting triple point conditions have left these same areas virtually dessicated at the surface.
Those who run around stating that the data suggests some kind of meaningful diurnal water cycle that can support microbial life at the surface are simply using the available data too selectively. Don't get me wrong, I wouldn't rule out such life completely at the surface...just that if its there, its going to be rare and located within some kind of well protected micro-climate.
Donald
Space/Science » in reply to Water vapor on Mars
re: Water vapor on Mars