Regime of snow cover in the Baikal region under the climate change

Abstract

Spatial and temporal variability of dates of snow cover setting-up and loss (dates of the snow cover appearance and disappearance, and formation and destruction of stable snow cover) and duration of stable snow occurrence on a territory of the Baikal region were analyzed from data of observations made at meteorological stations in 1981–2010. Compared to the previous long-term period prior to 1980, mean monthly air temperatures rose in every month during the cold season. Significant changes in dates of the snow cover setting-up were observed only at individual stations, while the duration of the snow occurrence does not show such changes. Typical period of fluctuations for the last characteristic is the quasi-biennial, and more rare it is 3-4 years. In relation to the previous multi-year period, the largest variability of dates of the snow-cover setting-up as well as increase of number of dates and so duration of its occurrence (up to 19 days) take place on the South-West‑ ern coast of Lake Baikal (Bolshoe Goloustnoe). In plain and mountain regions of the Baikal region, variability of these dates does not exceed 10–15 days. Compared to the earlier period (before 1980), it was noticed that the snow appear earlier and disappear later (with the difference of about five days). In most cases, deviation of ear‑ lier dates of formation and destruction of stable snow cover is within 10 days. During 1981–2010, a number of days with snow cover increased in river valleys of the taiga belt in the Eastern Sayan (GMR Verchnyaya Gutara) by 11 days, while in the mountain Khamar-Daban (GMS Khamar-Daban) – by 15 days.