On the solution of the stationary,baroclinic Ekman-layer equations with a finite boundary-layer height |
| |
| Authors: | F T M Nieuwstadt |
| |
| Institution: | 1. Royal Netherlands Meteorological Institute, De Bilt, The Netherlands
|
| |
| Abstract: | The stationary, Ekman-layer equations have been solved in closed form for two expressions of the eddy viscosity as a function of height, z: v τ=cu*z(1?z/h)and v τ=cu*z(1?z/h) 2, where u* is the friction velocity, h the boundary-layer height and c a constant. The main difference between both solutions is that the quadratic K-profile leads to a velocity discontinuity at the top of the boundary layer, while the solution for the cubic profile approaches the geostrophic wind at z=h smoothly. We discuss the characteristics of the solutions in terms of a dimensionless parameter C=fh/cu*, where f is the Coriolis parameter. The dependence on C can be interpreted in terms of a varying boundary-layer height or in terms of stability. The results for C ~ 1 are related to a neutral boundary layer. They agree well with results of a second-order model. The limit C → 0 is investigated in detail. We find that the stress profile becomes linear. The velocity profile shows different characteristics depending on whether we consider a shallow or a very unstable boundary layer. The results agree with observations. Finally we consider the influence of baroclinicity on the wind and stress profiles. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
