Study On Meteorological Elements Of The Atmosphetic Surface Layer Structure Over Desert Area In Spring

The dust weather events have affect people's daily life seriously as one kind of disaster, so we should study on the variation of the meteorological elements deeply during different dust weather. The characteristics of meteorological elements evolution of atmospheric surface layer during clean air, floating dust, blowing sand, and dust storm processes were studied using the observational data of wind speed, wind direction, temperature and relative humidity obtained from 20m meteorological tower in Zhurihe from January, 2005 to April, 2006 and PM₁₀ mass concentration data with weather synoptic. Meanwhile, the processes are analyzed by contrast, the results show:(1) The temperature rises rapidly, the wind speed is maximal and the relative humidity is minimal in spring, which is beneficial to remove the sand, so the sand dust weather is frequent. The wind speed accords with exponential disciplinarian and the exponential m could reflect well the change of wind speed in different altitudes. In the sand storm, blowing sand, clean air and floating dust weather condition, the wind speed of atmospheric surface layer raises gradually in spring. Meanwhile, the turbulent exchange coefficient diminishes gradually in spring. The main wind direction is southwest.(2) The change of temperature during floating dust or blowing sand is affected mainly by long-wave, short-wave radiation and radiative forcing of dust aerosol. Compared to clean air, the average rate of temperature increase is larger in floating dust, less in blowing sand. The temperature diminishes rapidly during dust storm, and the average change of temperature reduces in dust storm which is 0.61℃/h.(3) There is a positive correlation between the average rates of relative humidity decrease and temperature increase, and also between those of relative humidity increase and temperature decrease in all layers. Compared to clean air, the average rate of decrease is larger in floating dust, less in blowing sand. And the relative humidity rises basically, the average change of it enhances in dust storm which is 2.80%/h. However, the change of the relative humidity enhances 32.81% during dust storm on March 9th, 2006.(4) The PM₁₀ mass concentration decreases gradually during the sand storm, blowing sand, and floating dust.