Comparison between Two Dust Weather Process Effecting Beijing in 2006
2006年两次影响北京的沙尘天气对比分析

With satellite data,NCEP reanalysis data,and observation data and so on,weather process,cloud variation,dust transport and subsistence are analysed during those two dust storms happened in March and April 2006,respectively.The influence coming from the first one was just passing by,but the latter one brought severe yellow sand into the whole Beijing.Though the dust process from 16 to 17 April,which was in the early period,was not the strongest in the spring of 2006,it caused a very negative social influence.The analysis indicates that 1) strong dust process was caused by Mongolin cyclone and dust source was from the border between China and Mongo,and western inner Mongolia,and strengthened in northern Hetao region,Ordos plateau and Hunshandake sandland.Dust was transported to Northern China,Bohai sea,and northern Huanghai sea with the help of high-level wind.Satellite remote sensing technique not only can monitor the development of dust process,but also can detect the region covered by dust and estimate the value of subsidence.2) the main reason for that during the dust process from April 16th to 17th,the dust layer covered east part of Northern China,Bohai sea and larger area,is that in the boundary layer middle-scale vortex stopped low-level cold front;cold front clouds were obstacled by the scroll clouds staying over the Japan Sea during moving eastward,so the structure of cold front clouds was twisted and collapsed,therefore,severe dust subsidence occurred over Northern China.