Seasonal Variations in Stratospheric Circulation and Interactions between the Troposphere and the Stratosphere

Abstract

Based on the data of the ERA5 reanalysis, the dates of spring and autumn rearrangements of the stratospheric circulation on isobaric surfaces of 30, 20 and 10 gPa in the latitude zone of 30–90° C. in the period 1979–2020 were obtained. Of the 42 cases of spring restructuring, 10 belong to the early, 15 to the middle and 17 to the late. The spread in the dates of spring rearrangements on the surface of 10 hPa is 69 days. Most often, the spring restructuring of the circulation occurs from top to bottom, in some years, the delay of spring restructuring on the surface of 30 gPa relative to the surface of 10 gPa reaches 22–25 days. Autumn perestroika takes place from the bottom up and their terms at the 3 levels under consideration are close to each other. The relationship between the timing of the spring restructuring of the stratospheric circulation with solar activity and large sudden winter stratospheric warming is shown. Analysis of the fields of anomalies of daily temperature values and zonal wind velocity in the 1000-1 hPa layer in the period January-May showed their significant spatio-temporal difference in the case of early and late spring perestroika. Thus, foci of positive anomalies of temperature and wind speed are formed initially in the upper stratosphere, and then shifted from top to bottom. The interrelations between the layers of the atmosphere in different seasons are considered.