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Winter Precipitation, Sublimation, and Snow-Depth in the Pan-Arctic: Critical Processes and a Half-Century of Change

PI: Roger A. Pielke Sr. Co: Glen E. Liston Co: Larry J. Mahrt Co: Matthew Sturm Institution: Colorado State University

Abstract

This project will investigate winter sublimation processes in order to improve and develop models and methods, which will accurately and reliably estimate sublimation rates. This study encompasses a five-year field campaign using eddy correlation tower to measure surface fluxes of hat, moisture and momentum. Eddy correlation observations will provide the total moisture flux from the snow surface, which can be attributed to sublimation in cold conditions. The measurements will be made along a transect extending from Fairbanks in the boreal forest, across the tundra of the Arctic Alaska and on to the sea-ice in Prudhoe Bay. The field measurement program is designed to cover the key environments found throughout the Arctic and will be conducted during a wide range of temperature, humidity and win conditions as well as landscapes covered by continuous and discontinuous snow covers containing forests, tundra, shrubs lakes and ice. This sampling process will determine sublimation processes applicable throughout the Arctic. This will further guide formulation of new physical models of sublimation.

In the Arctic, the winter surface moisture budget is a function of precipitation and sublimation. An improved knowledge of sublimation from the field and modeling components coupled with snow-depth information will allow for the determination of precipitation in areas where precipitation is either not reported or inaccurate. Using past data records, a long-term pan-Arctic reanalysis data set of precipitation, sublimation and snow-water equivalent on the ground will be generated. These data will allow trend analysis and relate changes to climatic conditions.