Numerical Study on the Stability Dependence of Geostrophic Drag and Cross-Isobar Angle

Abstract

The equation of motion on the unstably stratified PBL under stationary, horizontally homogeneous, and barotropic conditions is numerically solved with the use of so-called simple K-theory.
The numerical predictions on the stability dependences of the geostrophic drag coefficient C_g and the surface cross-isobar angle α₀ agree with the observational data of Wangara and AMTEX on the average. In addition, the present calculations predict that α₀ decreases as the value of ratio of the actual height of PBL Z_i to the dynamical scale height kU*/ƒ increases. The tendency is found in the data of Wangara but not found in those of AMTEX.