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

Abstract

Based on the data of ERA5 reanalysis, the dates of spring and autumn changes in the stratospheric circulation on isobaric surfaces of 30, 20, and 10 hPa in the latitude zone of 30°–90° N in the period 1979–2020 have been obtained. Of the 42 cases of spring changes, 10 are early, 15 are middle, and 17 are late. The spread in the dates of spring changes on the surface of 10 hPa is 69 days. Most often, the spring changes of the circulation occurs from top to bottom; in some years, the delay of spring changes on the surface of 30 hPa relative to the surface of 10 hPa reaches 22–25 days. Autumn change 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 changes of the stratospheric circulation with solar activity and large sudden winter stratospheric warming is shown. An analysis of the fields of anomalies of daily temperature values and zonal wind velocity in the 1000-1 hPa layer in the period of January–May showed their significant spatiotemporal difference in the case of early and late spring changes. 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.