ВЛИЯНИЕ НИЗКИХ ШИРОТ НА КЛИМАТИЧЕСКИЕ УСЛОВИЯ НА ВОДОСБОРАХ ГЛАВНЫХ СИБИРСКИХ РЕК

Abstract

It was previously shown that atmospheric and oceanic transports of heat and moisture play an important role in the development of Arctic warming, and sea surface temperature anomalies at low latitudes have a significant effect on the formation of these transports. Atmospheric circulation, transferring heat, moisture and precipitation, also affects the climatic conditions in the catchment areas of 3 main Siberian rivers Ob, Yenisei and Lena with runoff that it about half of the average annual inflow of river waters into the Arctic Ocean. According to the reanalyses and data arrays for the period 1979-2019 air temperature and precipitation in the catchment areas of Ob, Lena and Yenisei are rising. The greatest increase in precipitation was noted in the spring months. The spring months (March and April) also have a maximum positive air temperature trend. To assess the effect of low latitudes on changes in climatic conditions in the catchment areas reanalysis data ERA5, HadISST, precipitation gridded data of the GPCC project were used. The indexes of zonal, meridional and general circulation were calculated based on the mean monthly surface air temperature at the nodes of the geographic grid in the Northern Hemisphere. To determine the connections between the indexes and climatic parameters the methods of multivariate cross-correlation analysis were used. It was defined that zonal atmospheric transports have a significant impact on climatic conditions most of all in the cold part of the year, especially in November and March. In summer amplification of zonal circulation is accompanied by a decrease in air temperature in the catchment areas, but meridional transports enhance the air temperature. The greatest influence of meridional transport was observed in spring and summer. The climatic change in low latitudes has the greatest impact in autumn on meridional transport in spring and on zonal transport in the cold part of the year, especially in March, with time lag of 2 years. The influence of low latitudes on the climatic conditions in the catchment areas is presented in the form of correlation graphs between climatic parameters and indexes of circulation on the generalizing diagram.