Heat exchange during snow ablation in plains and mountains of Eurasia

Rates of snow water equivalent (SWE) decrease were obtained as a difference between two successive values of SWE at 189 stations in the former Soviet Union (FSU). The required distribution of duration of snow ablation (snowmelt plus sublimation) was obtained from longterm data on average dates of maximum SWE and dates of snow disappearance. Stations were grouped by dates of snow disappearance and beginning of ablation. The amount of ablated snow for the 10‐day periods, normalized by the maximum mean SWE at a station, was averaged throughout stations with the same dates of snow disappearance and beginning of snow ablation. On plains and foothills, up to 80% of snow ablated during the last 10 days of snow cover. At high altitudes in mountains, about 40% of snow ablated during the penultimate 10 days of snow cover. During the ablation season, the amount of energy used to melt snow was of the same order as the combination of other components of the heat budget (e.g‥ heat associated with atmospheric advection, radiation balance, and turbulent heat exchange). Heating of the air would have been 3 times higher if snowmelt had not occurred. Over the continental plains of the FSU, maximum energy used to melt snow occurred in the foothills of the Urals and the northwest portion of the Srednerusskaya upland. Over the mountains, maximum energy to melt snow per unit area was observed in the northern and western Tien Shan where most snow accumulation occurred. A maximum mean energy used to melt snow was observed in the beginning of April over the plains and in June over the mountains.