关键词: 沙漠地区, 扩散参数, 特征分析

Abstract: The pulsations of the component of three-dimensions wind,u,v and w,under various weather conditions in desert area had been observed by means of the instrument made by Department of Atmospheric Sciences of Nanjing University at the Ji Lantai Station,Inner Mongolia,and the Yinchuan Airport Station on April and May,1996.We had calculated the turbulent features according to taylor's theory of Turbulent Statistic and Hay and Pasquill's hypotheses,and analyzed the horizontal e_y and vertical e_z of the diffusion coefficients in turbulent flow.Meanwhile,we had preliminarily analyzed the relation of the diffusion coefficient with the numerical density and mass density of surface layer's sand aerosol in sand dust weather combining the observed data by means of Air Dynamics Particle Sizer(spectrometer) Model 3310A made by U.S.A.The results are as follows:①There are the daily variation features e_y and e_z of turbulent diffusion coefficient apparently.Under clear air condition,both the horizontal e_y and vertical e_z of diffusion coefficients reach maximum value at 14 o'clock and minimum values from 3 o'clock to 6 o'clock respectively.Moreover,under sand dust weather the daily variations of e_y and e_z are clearly different from them under clear weather and they are mostly related to the beginning time of sand dust weather.②The vertical e_z of diffusion coefficient is smaller than the horizontal e_y of diffusion coefficient,and the horizontal e_y of diffusion coefficient is more changeful than the vertical e_z of diffusion coefficient.

Key words: desert area, diffusion coefficient, feature analysis