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Troughs in Ice Sheets and Other Icy Deposits on Mars: Analysis of Their Radiative BalanceIt has long been known that groove-like structures in glaciers and ice sheets can trap more incoming solar radiation than is the case for a 'normal' flat, smooth surface. In this presentation, we shall describe the radiative regimes of typical scarps and troughs on icy surfaces of Mars, and suggest how these features originate and evolve through time. The basis of our analysis is the radiation balance model presented by Pfeffer and Bretherton. Their model considers the visible band radiation regime of a V-shaped groove on a terrestrial ice surface, and shows that absorbed energy can be enhanced by up to 50 percent for grooves with small opening angles and with typical polar values of the solar zenith angle. Our work extends this model by considering: (a) departures from V-shaped geometry, (b) both englacial and surficial dust and debris, and (c) the infrared spectrum. We apply the extended model to various features on the Martian surface, including the spiral-like scarps on the Northern and Southern ice sheets, the large-scale chasms (e.g., Chasm Borealis), and groove-like lineations on valley floors thought to be filled with mixtures of dust and icy substances. In conjunction with study of valley-closure experiments, we suggest that spiral-like scarps and chasms are stable features of the Martian climate regime. We also suggest that further study of scarps and chasms may shed light on the composition (i.e., relative proportions of water ice, carbon-dioxide ice and dust) of the Martian ice sheets and valley fills.
Document ID
20010002430
Document Type
Conference Paper
Authors
Fountain, A. (Portland State Univ. OR United States)
Kargel, J. (Geological Survey Flagstaff, AZ United States)
Lewis, K. (Colorado Univ. Boulder, CO United States)
MacAyeal, D. (Chicago Univ. Chicago, IL United States)
Pfeffer, T. (Colorado Univ. Boulder, CO United States)
Zwally, H. J. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
August 20, 2013
Publication Date
August 1, 2000
Publication Information
Publication: International Conference on Mars Polar Science and Exploration
Subject Category
Lunar and Planetary Science and Exploration
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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