【摘要】 本文对北京城郊近地面层的大气湍流特征做了初步的研究.结果表明,以局地稳定度参数z/L代替通常的Monin-Obukhov稳定度参数,对湍流的二阶矩以及谱和协谱的惯性副区特征而言,均匀近地面层湍流的相似理论可以推广到城郊近地面层湍流的情形,但谱和协谱的低频(含能区)特征发生显著的变化:含能区谱密度往往由许多尖峰构成;在某些低频范围上,湍流运动的垂直分量可能比水平分量强得多.在城郊近地面层中,湍流动能的产生与耗散基本上是平衡的.更多还原

【Abstract】 The turbulent characteristics in the atmospheric surface layer over Beijing suburb are preliminarily studied in this paper. The results show that similarity theory of the atmospheric surface layer over a horizontally uniform site can be extended to the case of the suburban atmospheric surface layer through replacing the normal Monin-Obuk-hov stability parameter by a local stability parameter z/L1, as far as second moments and inertial subranlge spectra and cospectra of turbulence are concerned. However, it would lead to remarkable changes occurring in the characteristics of spectra and cospectra over the low-frequency (energy-containing) range, i.e. spectral densities tend to be composed of several peaks, and vertical components of turbulent motion may be much more vigorous than horizontal ones. In the suburban surface layer, the production rate of turbulent kinetic energy is essentially balanced by the dissipation rate.更多还原