Role of planetary waves in the stratosphere-troposphere coupled variability in the northern hemisphere winter

Abstract

The role of planetary waves in stratospheretroposphere coupled variability is investigated using an extended singular value decomposition analysis of zonalmean zonal wind and the vertical component of the Eliassen-Palm (E-P) flux for the winters from 1979/80 to 1995/96. The results suggest a close relationship between anomalies of zonal-mean zonal wind and the convergence zone of E-P flux, which together shift poleward and downward from the stratosphere to the troposphere as time advances. Following enhanced vertical propagation of waves into the stratosphere, the Arctic Oscillation (AO) pattern is seen in the 500 hPa geopotential height field in association with an increased poleward propagation of tropospheric waves. Copyright 1999 by the American Geophysical Union.