Sunlight, Sea Ice, and Climate: The Sea Ice – Albedo Feedback in a Changing Arctic Ocean
Don Perovich, ERDC-CRREL
This paper was presented at the Art, Science and Applications of Reflectance Spectroscopy Symposium sponsored by ASD Inc. and IEEE GRSS, February 23-25, 2010 in Boulder, Colorado.
Author: Don Perovich
Affiliation: ERDC-CRREL, Hanover, NH USA
Abstract
Solar radiation is a key component of the surface heat budget of the ice and a major driver of the summer melt cycle. The summer extent of the Arctic sea ice cover has decreased in recent decades and there have been alterations in the timing and duration of the summer melt season. These observed changes in sea ice could be amplified by the ice-albedo feedback thereby accelerating ice reduction. Measurements of the temporal evolution of albedo are required to properly include the sea ice albedo feedback in climate models. An Analytical Spectral Devices FieldSpec Pro has been used in numerous Arctic field campaigns to measure the spatial and temporal variability of sea ice albedo and reflectance. Results indicate that the albedo of the ice can be modeled by a five-phase process that includes cold snow, melting snow, melt pond formation, melt pond evolution, and freezeup. The timing of these phases is governed by the onset dates of summer melt and fall freezeup. There is rich spectral information in ice reflectance measurements that is valuable for improving sea ice energy budget models and the interpretation of visible and near – infrared satellite imagery.