An Analysis of the Energetics of the Major Polar Stratospheric Warming of January–February 1973

Abstract

Abstract Energy, temperature and zonal wind during the stratospheric warming of January–February 1973 are investigated for five layers: 100–70 mb, 70–50 mb, 50–30 mb, 30–10 mb and 10–0.4 mb. Temperature and zonal wind patterns, derived from NMC and Oxford satellite radiance data, are compared with results of synoptic studies. Upward flux of geopotential is traced from 100 to 0.4 mb with differences in the vertical used to estimate convergence. Mean and eddy potential and kinetic energies are estimated for each layer, with eddy quantities analyzed separately for the first three wavenumbers. Temperature and zonal wind results compare well with synoptic studies, with the warming appearing to propagate downward. A critical line developed and moved both vertically and horizontally. The warming was preceded by enhanced upward flux of n = 1 geopotential. In general, n = 1 fluctuations dominated the warming process, except for the 10–0.4 mb layer.