Evidence of a mean meridional circulation in the atmosphere from surface wind observations

Surface‐wind observations in the Northern Hemisphere are analysed and fields of mean meridional and zonal motion obtained. From these, profiles of mean meridional motion as a function of latitude are deduced. The results are consistent with a direct meridional circulation in low latitudes and an indirect circulation in mid‐latitudes, both attaining speeds of 1 to 2 m/sec at the surface. This scheme is found to be consistent with a decrease of upward flux of westerly momentum with height (convergence) in the surface layers in low latitudes and a decrease of downward flux in mid‐latitudes.