Martian north pole summer temperatures: dirty water ice

Science. 1976 Dec 11;194(4271):1341-4. doi: 10.1126/science.194.4271.1341.

Abstract

Broadband thermal and reflectance observations of the martian north polar region in late summer yield temperatures for the residual polar cap near 205 K with albedos near 43 percent. The residual cap and several outlying smaller deposits are water ice with included dirt; there is no evidence for any permanent carbon dioxide polar cap.