re:Thanks for the info podrock.
From your link: http://hypertextbook.com/facts/2000/LaurenMikulski.shtml
"The atmosphere is made up mainly of carbon dioxide, and its pressure is only about one-hundredth of that on Earth."
The question then is; how does the atmosphere that is mostly carbon dioxide, affect the evaporation or sublimation of water and the temperature of the planets surface?
Another question is; at what height above the Earth does the Earth’s atmospheric pressure match the pressure at the surface of Mars?