Some Features of the Climatology of the Middle Atmosphere Revealed by Nimbus 5 and 6

Abstract

A scheme for deriving three-dimensional horizontal and vertical velocity fields from global satellite temperature data is described and applied to the new COSPAR International Reference Atmosphere (CIRA) to illustrate some features of the climatology of the stratosphere and mesosphere. The scheme produces horizontal winds that compare well with existing mesospheric climatologies derived from radar and rocket data. This is because the drag on the zonal flow is taken into account: the drag is large in the mesosphere and is consistent with that produced by breaking gravity waves. Calculations of q?y indicate the possibility of unstable waves in the summer and winter mesosphere. In the stratosphere, the scheme yields diagnostics of planetary wave propagation which are sometimes similar to those produced by winds from schemes based on just the horizontal momentum equations but, in the October southern stratosphere for example, there are occasions when the effects of the drag on the zonal flow are required in the upper stratosphere.