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Albedo of the South Pole on Mars Determined by Topographic Forcing of Atmosphere DynamicsThe nature of the martian south polar cap has remained enigmatic since the first spacecraft observations. In particular, the presence of a perennial carbon dioxide ice cap, the formation of a vast area of black slab ice known as the Cryptic region and the asymmetric springtime retreat of the cap have eluded explanation. Here we present observations and climate modelling that indicate the south pole of Mars is characterized by two distinct regional climates that are the result of dynamical forcing by the largest southern impact basins, Argyre and Hellas. The style of surface frost deposition is controlled by these regional climates. In the cold and stormy conditions that exist poleward of 60 degrees S and extend 180 degrees in longitude west from the Mountains of Mitchel (about 30 degrees W), surface frost accumulation is dominated by precipitation. In the opposite hemisphere, the polar atmosphere is relatively warm and clear and frost accumulation is dominated by direct vapour deposition. It is the differences in these deposition styles that determine the cap albedo.
Document ID
20050186555
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Colaprete, Anthony
(NASA Ames Research Center Moffett Field, CA, United States)
Barnes, Jeffrey R.
(Oregon State Univ. Corvallis, OR, United States)
Haberle, Robert M.
(NASA Ames Research Center Moffett Field, CA, United States)
Hollingsworth, Jeffery L.
(San Jose State Univ. Moffett Field, CA, United States)
Kleffer, Hugh H.
(Geological Survey Flagstaff, AZ, United States)
Titus, Timothy N.
(Geological Survey Flagstaff, AZ, United States)
Date Acquired
August 23, 2013
Publication Date
May 12, 2005
Publication Information
Publication: Letters to Nature
Volume: 435
Subject Category
Lunar And Planetary Science And Exploration
Funding Number(s)
OTHER: 21-680-20-1C
Distribution Limits
Public
Copyright
Other

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