A Re-examination of the “Leipzig Wind Profile” Considering some Relations between Wind and Turbulence in the Frictional Layer

The “Leipzig Wind Profile” is a unique example of a representative wind distribution in the frictional layer which resulted from MILDNER’S set of 28 pilot-balloon observations with two theodolites on October 20, 1931, near Leipzig for a stable weather situation. It is shown, that the vectors of geostrophic motion and ground drag follow from the wind profile when a scalar austausch is assumed. The re-computed vertical austausch-distribution indicates that the energy for maintaining the turbulence in a steady frictional wind profile is taken from the potential energy of the horizontal pressure field by means of the steady flow of air across the isobars. The frictional layer is the atmospheric layer adjacent to the ground where turbulent stresses are significant. Consequently, the frictional layer is characterized by considerable deviations of the observed wind from the theoretical air motion which follows from the pressure distribution with the aid of the equations of motion when friction is neglected. Let us assume that the wind in any given horizontal plane is a steady uniform rectilinear flow. Then, the variations of the turbulent stresses in the horizontal directions are negligible such that only the vertical variations need be considered. The equation of motion for this case is T’ = efi (V e) (1) when the prime denotes the partial differentiation with respect to height z (meters) and T = horizontal vector of turbulent stress, v = horizontal wind vector, m/sec; + = horizontal geostrophic wind vector, f = Coriolis parameter = 0.0001458 sin @, dyneslcmz ;