Influence of Low Latitudes on Climatic Conditions in the Water Catchment Area of the Main Siberian Rivers

Abstract

It has been previously shown that atmospheric and oceanic heat and moisture transfers play an important role in the development of Arctic warming, and ocean surface temperature anomalies at low latitudes have a significant effect on the formation of transfers. Atmospheric circulation, which transports heat, moisture and precipitation, also affects climatic conditions in the catchment areas of the three main Siberian rivers—the Ob, Yenisei, and Lena—the flow of which is approximately half of the annual average inflow of river water into the Arctic Ocean. According to reanalyses and archival data for 1979–2019, air temperature and precipitation in the Ob, Lena, and Yenisei catchment areas are increasing. The greatest increase in precipitation is recorded in the spring months. There is also a maximum positive trend in air temperature in the spring months (March and April). To assess the impact of low latitudes on changes in climatic conditions in the catchment areas, data from ERA5, HadISST reanalyses, and the GPCC project precipitation gridded gauge-analysis data are used. Based on the average monthly surface air temperature at the nodes of the geographic grid in the Northern Hemisphere, the indices of zonal, meridional, and general circulation are calculated. To determine the relationships between indices and climatic parameters, the methods of multivariate cross-correlation analysis are used. It has been found that zonal atmospheric transfers have a significant impact on climatic conditions most of all in the cold part of the year, especially in November and March. In summer, the increase in zonal circulation is accompanied by a decrease in air temperature in the catchment areas, and meridional transfers increase the temperature. The greatest influence of the meridional transport is noted in spring and summer. Climate changes at low latitudes have the greatest effect in autumn on meridional transport in the spring season and on zonal transport in the cold part of the year, especially in March, with a delay of 2 years. The influence of low latitudes on climatic conditions in water catchments is presented in the form of graphs of correlations of climatic parameters and circulation indices on a generalized scheme.