Sublimation Measurements of Tundra and Taiga Snowpack in Alaska

Abstract. Snow sublimation plays a fundamental role in the winter water balance. To date, few studies have quantified sublimation in tundra and boreal forest snow by direct measurements. Continuous latent heat data collected with eddy covariance (EC) measurements from 2010 to 2021 were used to calculate snow sublimation at six locations in northern Alaska: three Arctic tundra sites at distinct topographical and vegetation communities in the Imnavait Creek watershed on the North Slope underlain by continuous permafrost and three lowland boreal forest/taiga sites of differing permafrost conditions and ecosystems in interior Alaska near Fairbanks. Mean surface sublimation rates range from 0.08–0.15 mm day-1 and 15–27 mm year-1 at the six sites, representing 20 % of the measured solid precipitation and 8–16 % of the cumulative annual water vapor flux to the atmosphere (evaporation plus sublimation). The mean daily sublimation rates of the lowland boreal forest sites are higher than those of the tundra sites, but the longer snow cover period of the tundra sites leads to greater mean annual sublimation rates. We examined the potential controls, drivers, and trends of the sublimation rates by using meteorological data collected in conjunction with EC measurements. This research offers results to better understand how site conditions affect sublimation rates and the winter hydrologic cycle. Our study contributes to the sparse literature on tundra and boreal sublimation measurements and finds comparable rates to sublimation estimates in other northern climates.