Quantitative study of snow sublimation in the Altai Mountains

Abstract

The sublimation of snow has a major impact on the global climate. We present a simple empirical formula that allows snow sublimation to be quantified on the interannual scale in the Altai Mountains. This empirical formula is based on the fitting of measured temperature and snow water equivalent (SWE) data for midwinter collected between 2011 and 2018 at the Koktokay snow station, located at the outlet of the Kayiertesi River Basin. The results suggest that there is a best-fitting linear relationship (r = −0.98; p < 0.001) between the temperature and snow sublimation rates. The low sublimation rate, which was only 0.2 mm day⁻¹, corresponded to a low air temperature and high relative humidity, and the sublimation loss accounted for 2.6 % and 5.6 % of the annual precipitation and snowfall, respectively. Based on the proposed empirical formula and the hourly meteorological data from the ERA5 Land reanalysis, we calculated the sublimation rate in the Irtysh River Basin from 2011 to 2018. The results reveal that the cumulative snow sublimation loss was 14.3 mm y⁻¹, comprising 8.2 % of the snowfall and 3.9 % of the annual precipitation. Due to the relative ease of collecting field observations of the temperature and SWE, this simple formula, which has a high level of goodness of fit, is more applicable to the study of issues related to snow mass balance over long time scales in the Altai Mountains, and it also provides support for local snowmelt flood warning and water resource management.