NIWR at WERC

Calculation of sublimation from tundra snowpack in Alaska

  • Project Student PI: Kelsey Stockert
  • Project Faculty PI/Co-PI: Svetlana Stuefer
  • Keywords: snowpack measurements, Arctic Alaska, snow water equivalence, Eddy Covariance

Abstract

The Arctic’s water resources predominate in the form of snow and ice for nearly three quarters of the year. Under these conditions, the end of winter water balance is relatively simple: the volume of seasonal snowpack equals precipitation minus sublimation. Sublimation is winter’s equivalent of evaporation, where vaporization or condensation occur without the liquid phase. Because of a lack of available data, most water balance budgets solve for sublimation using the other two terms of the water budget.

Snowpack volume is measured with snow water equivalence (SWE) and these point estimates are good. Conversely, the precipitation gauge measurements suffer windy Arctic conditions and freezing temperatures that lead to large errors from under-catchment of total winter precipitation. As follows, all current Arctic sublimation estimates contain large ranges. Narrowing this range is an important step for improving both scientists’ understanding of the water budget as well as improving the hydrological models that are used to produce useful predictions of water resources.

This project will utilize measurements from the Eddy Covariance (EC) towers located in Imnavait Creek to quantify winter sublimation. EC towers are rare due to the complexity and expense, but it is the most direct means available to measure vertical fluxes, including sublimation. Sublimation measurements will be used to refine Imnavait’s water balance to a higher degree of accuracy than it has to date.