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Extinction of Near Ultraviolet and Visible Light in Summer Antarctic Sea Ice
Timothy Quakenbush, Gerd Wendler, and Carl Byers
Geophysical Institute / University of Alaska
P.O. Box 757320
Fairbanks, AK 99775-7320Abstract
High wavelength resolution measurements of downward traveling light were taken from several depths in Antarctic sea ice during early January. Spectral extinction was calculated in the ice layers where the measured light levels were proportional to downward flux in the ice. The wavelength range was 350 to 700 nm with a resolution of 1 nm. The derived extinction values were being examined as a function of the physical characteristics of the ice.
Extinction values in the near ultraviolet varied from 0.7 to 5 m- 1 for different ice floes and layers in the ice. There was a minimum in extinction in the 450 to 500 nm band where absorption by ice and water is small. Extinction increased to values between 2 and 9 m- 1 at 700 nm varying with the physical properties of the ice layers. Absorption by contaminants produced an absorption peak at 400 nm at all depths of one ice floe. Extinction in the 450 - 500 nm band was strongly dependent on contaminant concentration, and weakly dependent on ice depth and inclusion volume in the ice.
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