MOTIONS IN THE BOUNDARY LAYER UNDER THE GEOSTROPHIC MOMENTUM APPROXIMATION INCORPORATING A THREE-SECTION K DISTRIBUTION

By use of geostrophic momentum approximation,the analytical expressions of the wind distribution within the planetary boundary layer and the vertical velocity at the top of the boundary layer are obtained when the distribution of eddy transfer coefficient k is divided into three sections:k1z(z0≤zh1),k2(h1≤zh2),and k3(h2≤z).The results are in agreement with the observations.In particular,the wind profile in the surface layer(z0≤zh1) coincides with the logarithmic distribution.The maximum angle between winds near the surface and at the bottom of the free atmosphere is only about 30°.This work improves the work of Wu and Blumen(1982) who introduced the geostrophic momentum approximation to the boundary layer.The solutions in barotropic and neutral conditions have been also extended to the baroclinic and stratified atmosphere.