Calculation of sublimation from tundra snowpack in Alaska

• Main Author: Stockert, Kelsey
• Other Authors: Stuefer, Svetlana, Euskirchen, Eugenie, Schiewer, Silke
• Format: Master Thesis
• Language: English
• Published: 2022
• Subjects: Master of Science in Water and Environmental Science: Hydrology; Arctic; Fairbanks; north slope; Tundra; Alaska
• Online Access: http://hdl.handle.net/11122/14701

Master's Project (M.S.) University of Alaska Fairbanks, 2022 Snow sublimation is the direct transfer of water between the snowpack and the atmosphere, playing a fundamental role in the winter water balance. To date, there are few studies that quantify sublimation by direct measurements. This study uses Eddy Covariance (EC) data from 2010 to 2020 to calculate sublimation from three locations within Imnavait Creek watershed, a small Arctic watershed (2.2 km2) located on the North Slope of Alaska. EC fundamentally measures only surface sublimation, which underestimates total sublimation since it does not consider sublimation from blowing snow. Complementary data were collected at each EC measurement site and analyzed in addition to data from a nearby meteorological station, a borehole, and annual spring snow surveys that measure site environmental conditions and evaluate controls on sublimation rates. For the seven-year time series, mean surface sublimation rates ranged from 0.06-0.07 mm day-1 and 13-16 mm year-1 among the three sites. Linear regressions show that the strongest drivers of sublimation are wind speed, air temperature, vapor pressure deficit, and temperature gradient in this Arctic watershed. The watershed average cumulative annual sublimation rates have significant linear relationships to the duration of above freezing temperatures in the soil active layer, snow cover duration, and number of precipitation days. On average, 11% of the end-of-winter snowpack was returned to the atmosphere by sublimation. The fraction of sublimation from the total winter precipitation is comparable to results reported in the literature by the same method, but daily rates are significantly lower. The findings of this study are an important contribution to the sparse literature on Arctic sublimation measurements and will benefit scientists in their understanding of how site conditions affect sublimation rates and the winter hydrologic cycle.