“4.24”民勤特强沙尘暴过程初步分析

特强沙尘暴是干旱区一种破坏性极大的灾害性天气现象,文中分析了2010年4月24日民勤特强沙尘暴过程中地面气象要素和近地面沙尘浓度的变化,同时对大气动力、热力学参数进行了计算和分析。结果表明:在强沙尘暴过境时地面水平风风向经历了从稳定到多次调整,再到稳定,最后崩溃的演变。风向调整时,风速减弱,而调整之后,风速加大,同时伴有很强的上升气流。强沙尘暴使地表发生非常严重的风蚀起沙现象,近地面沙尘浓度迅速升高200多倍。沙尘暴天气来临前,地面空气呈干热状态处于低气压控制之下,而在沙尘暴过境时和过境后,地面空气显得相对湿冷,地面气压急剧上升,并处于高压控制之下。沙尘暴的强度与相对风暴螺旋度有很好的对应关系。

Analysis on the strong sandstorm in minqin on April 24,2010

The strong dust storm is a disaster weather with serious destruction in arid areas.In this paper we analysed the change of ground meteorological elements and near ground sand dust concentration of the strong dust storm on April 24.2010 in Minqin.In addtion atmospheric dynamical and thermodynamic parameters were calculated and analyzed.The results showed that horizontal wind direction experienced stable to several times adjustments,and finally to collapse.In the ajustments of wind,the wind speed became weaker,after the adjustment,the wind speed increased,accompanied by a strong updraft.The serious dust wind erosion occurred during the strong sandstorm,dust concentrations increased 200 times near-ground.The atmospheric stratification was hot and dry,and under the control low pressure of before the sand duststorm.After the sand storm the air became cold and wet,with a sharp rise in surface pressure and under the control of the high-pressure.The value of relative storm had close corresponding relation with the dust storm intensity.