ESTIMATES OF THE STRATOSPHERIC RESIDUAL CIRCULATION USING THE DOWNWARD CONTROL PRINCIPLE

The transformed Eulerian-mean momentum and continuity equations are us ed to calculate the residual mean meridional circulations for the lowe r stratosphere and troposphere. Momentum and temperature fluxes requir ed for the computation are estimated from U. K. Meteorological Office (UKMO) analyzed geopotential heights. National Center for Atmospheric Research (NCAR) CCM2 model output is used to assess the errors associa ted with the calculation. The model comparisons showed that the method works reasonably well for solstice seasons, but is inadequate for equ inox seasons. In addition, it is found that some parameterization of g ravity wave drag needs to be included with the planetary wave forcing to accurately estimate the residual mean circulation using this method .