Effect Of Inversion Winds On Topographic Detail And Mass Balance On Inland Ice Sheets

Steady-state gravity flow of air (inversion wind) on sloping snow-covered ice sheets is analyzed for sensitivity to local topography. Topographic features of the order of a few kilometres or less in length are too small to affect the direction and speed of this air flow. Air flow on a longer scale s...

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Bibliographic Details
Published in:Journal of Glaciology
Main Author: Whillans, I.M.
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 1975
Subjects:
Online Access:http://dx.doi.org/10.1017/s0022143000013423
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000013423
Description
Summary:Steady-state gravity flow of air (inversion wind) on sloping snow-covered ice sheets is analyzed for sensitivity to local topography. Topographic features of the order of a few kilometres or less in length are too small to affect the direction and speed of this air flow. Air flow on a longer scale should however conform cosely to topography. Surface roughness on ice sheets is consistent with these results. Features of length shorter than a few kilometers (drifts and sastrugi) are transient, but longer features (surface undulations) remain essentially unaltered for many years. On the longer scale, inversion wind speed and therefore the amount of drifting and blowing snow should vary with the surface slope even where slope changes by as little as 1/10%. Observed variations in surface mass balance (aceumulated snow) in upper Marie Byrd Land, Antarctica, support this hypothesis. Snow drift and inversion winds thus constitute a feed-back mechanism on the form of ice sheets and some of the topographic detail, formerly attributed to ice-flow character alone, may be in large part due to this mechanism.