STRATOSPHERIC NO2 .2. GLOBAL BEHAVIOR

A discussion is provided of observations of the total daytime stratospheric column abundance of NO//2 made over the range in latitude from 40 degree S to the North Pole. The equatorial abundance is less by a factor of 2 than at mid-latitude. A summer maximum in the northern hemisphere exists, and the amplitude of the seasonal variation increases from 2 at mid-latitude to over 6 at 65 degree N. In winter, when there is not a warming in progress in the stratosphere and there is strong zonal flow, there is an abrupt drop in NO//2 abundance near 50 degree N. The decrease occurs over only a few degrees of latitude where the temperature near 30 km exhibits a poleward drop as well. During a warming, the 'cliff' disappears as a result of rapid meridional transport of mid-latitude stratospheric air into the Arctic.