Solar Radiation in the Mcmurdo Dry Valleys, Antarctica
- John C. Priscu
Published Online: 16 MAR 2013
Copyright 1998 by the American Geophysical Union.
Ecosystem Dynamics in a Polar Desert: the Mcmurdo Dry Valleys, Antarctica
How to Cite
Dana, G. L., Wharton, R. A. and Dubayah, R. A. (1998) Solar Radiation in the Mcmurdo Dry Valleys, Antarctica, in Ecosystem Dynamics in a Polar Desert: the Mcmurdo Dry Valleys, Antarctica (ed J. C. Priscu), American Geophysical Union, Washington, D. C.. doi: 10.1029/AR072p0039
- Published Online: 16 MAR 2013
- Published Print: 28 JAN 1998
Print ISBN: 9780875908991
Online ISBN: 9781118668313
- Desert ecology—Antarctica—McMurdo Dry Valleys
Solar radiation is an important driving force for hydrological and biological systems in the dry valleys, influencing sublimation and melting of the glaciers, heating of the soils and air, and providing energy for photosynthesis by the microbial communities in the streams, soils, and perennially ice-covered lakes. We analyzed two years of solar radiation data from eleven meteorological stations positioned on glaciers, lake shores, and lake ice in Taylor, Wright, and Victoria Valleys. Average annual incoming solar radiation ranged from 84 to 117 W m−2 during 1994 and 1995. We attribute differences among stations primarily to terrain effects, but coastal cloudiness and orographic effects may also be factors. Average annual net solar radiation was 59 to 76 W m−2 at the soil-covered sites, while net solar radiation at glacier and lake-ice sites was lower, 18 to 52 W m−2, due to the high albedo of snow and ice. Terrain obstructions were especially apparent in diurnal time series for Lake Hoare, even in December when the sun is at its highest position. Because of the importance of terrain on solar radiation patterns, we applied a topographic solar radiation model to Taylor Valley, using in situ pyranometer data to drive the model. Considerable topographic variability in solar radiation occurs over the region, even averaged over a monthly time scale, with north facing slopes receiving more energy than south facing slopes. In the valley bottom, differences in incident radiation were discerned among lakes, with Lake Fryxell receiving uniform amounts of energy while Lakes Hoare and Bonney received less energy along their northern shores due to terrain shading. Hourly radiation maps and pyranometer data illustrate that the terminus of the glaciers receive higher levels of solar radiation than their surface, but this intense illumination is of short duration, occurring only when the sun directly strikes the cliff face.