Spectral Albedos of Sea Ice and Incident Solar Irradiance in the Southern Beaufort Sea

摘要

Spectral albedoes and incident spectral irradiances were measured over the wavelength range 400 to 2400 nm on the sea ice near the Naval Arctic Research Lab. (NARL) at Pt. Barrow, Alaska. The observation interval extended from mid-May, when the ice was still relatively cold, until mid-June, when summer melting was fully established. The temporal dependence of albedo for the available surface types was obtained over this time interval showing a general decrease from snow and snow-covered ice to blue ice and melt ponds. Data was also obtained for glacier ice on the Athabasca glacier, for melting lake ice, and for certain other nonice surfaces in the vicinity of NARL. Snow and ice albedoes are characteristically highest at visible wavelengths, decreasingly strongly in the infrared because of the increase in absorption by ice and water. Local maxima in the spectra correspond to minima in the ice and water absorption, Variations in albedo are due primarily to differences in the vapor bubble density, crystal structure, and free water content of the upper layers of the ice.