Spatio-temporal analysis of climatic factors of the Ob River runoff formation

The analysis of the influence of climatic factors on fluctuations in the flow of the Ob River is carried out. Based on the analysis of long-term series of annual and seasonal runoff of the Ob and differential integral curves, the phases of change in river flow ar e revealed. Spatial features of changes in precipitation and air temperature in different periods of water content have been studied. Mathematical and statistical processing of cartographic images made it possible to identify areas of the predominant influence of various climatic factors on the volume of river flow. The areas of the basin where climatic fluctuations had the greatest impact on the change in the Ob River flow in 1930–2017 have been identified. One of these areas is confined to the basin of the Tobol River, the second is adjacent to the Ob and Yenisei watershed. It is shown that the increase in winter water runoff is largely due to fluctuations in precipitation and air temperature. It is impossible to completely exclude the impact of permafrost degradation on the volume of Ob runoff, but it is obvious this factor is not significant.