Факторы пространственной изменчивости речного стока в Центральной Якутии

Abstract

Based on the analysis of the daily discharges for all active and recently closed hydrological posts at the small and medium-sized rivers of Central Yakutia, it was found that the mean annual runoff and its variation coefficient significantly vary although precipitation and evaporation values are relatively stable in space. Precipitation of previous years largely influences the river runoff formation of the current year. Small-sized rivers have a delayed runoff response to rainfall compared with the larger rivers of the region at the yearly and monthly time scale. The higher the proportion of alas-type type, that has many thermokarst lakes and depressions, the lower and less stable runoff (the variation coefficient is higher, the runoff duration is shorter). The higher the proportion of slope-type terrain, the higher the mean annual and maximum daily river runoff, as well as the longer runoff duration. The mean annual evaporation correlate with the share of the slope-type terrain. Many thermokarst depressions, that are typical for the alas-type terrain, cause a low flow presumably due to the absence of water discharge of thermokarst lakes and their local catchments into the river and increased evaporation from the lake surface. It was shown that the landscape factor has leading role in the runoff formation of the small and medium-sized rivers in Central Yakutia.