On the standing-eddy sensible heat transport reversal in the polar region of the northern hemisphere during winter

Abstract

Harmonic analysis of the standing-eddy transport of sensible heat in the Northern Hemisphere polar latitudes shows that the equatorward sensible heat transfer in these latitudes in January is due to different zonal harmonics at different latitudes and isobaric levels. A comparison of the transports of sensible heat by the standing eddies, up the meridional temperature gradient, in the midlatitude lower stratosphere and the polar troposphere, shows that these up-gradient transports are due to different mechanisms. The former is caused by a relative maximum of time-and-zonal average temperature in the midlatitude stratosphere which owes itself to the mean meridional circulation, and does not involve any meridional changes in the structure of the standing eddies; but the latter is due to cross-latitude changes in the direction of tilt of the vertical axis of the standing eddies.