ZONAL MEAN STRUCTURES OF THE EXTRATROPICAL TROPOSPHERE

The study of mean circulation fields requires evaluation of eddy foreings in the atmosphere.Due to the difficulty incalculating the eddy forcings on theory,the mean state equations including the eddy forcings were used mostly fordiagnostic studies only.Using the geostrophic perturbation solutions obtained by McHall (1991a),we may deal withtheoretically the eddy fluxes and their convergence.This allows us to employ the mean state equations for the study ofmean circulation fields.It will be found that the time averaged zonal mean structure and circulation of the troposphereat middle and high latitudes can be reproduced basically in terms of the mass and momentum balances in geostrophicwave circulations.