Trends of the Vertical Component of the Wave Activity Flux in the Northern Hemisphere

Long-term trends of the three-dimensional Plumb wave activity flux are studied using data from the JRA-55 global atmospheric reanalysis. The vertical component of the Plumb flux characterizes the propagation of atmospheric planetary waves generated in the troposphere to the upper atmosphere and is used for the analysis of the stratosphere–troposphere dynamic interaction. The study of the wave activity flux covers three latitudinal sectors of the Northern Hemisphere from December to March for a 64-year period since 1958. It is shown that in January and March over the Russian Far East there is a statistically significant trend for an increase in the wave activity flux from the troposphere to the stratosphere, which can contribute to an increase in the frequency of cold wave formation in the mid-latitude troposphere. The study of the stratosphere–troposphere dynamic interaction in general and wave activity fluxes in particular is necessary for solving problems related to both global and regional climatic changes and mixing of long-lived atmospheric components.