The result showed that the strong storm followed by mesoscale squall line was primary cause of strong sandstorm producing, steps and ladders short wave trough of 500 hPa was great criterion triggering system for the mesoscale squall line producing, the essential dynamic condition was provided by distortion field and the mesoscale low pressure of 700 hPa for the strong sandstorm forming and maintaining in mid-west of Hexi Corridor, the deep vertical circulation development condition was basic power that urged squall line to occur and sand dust to curl up, which was provided for the deep convection development by superimposition of lifting movement before ground cold front and ascendant current of secondary circulation in upper air jet entrance region, temperature and the barometric gradient around the cold front was enlarged by enhancement of ground thermal low and temperature diurnalvariation of afternoon, by which essential thermal energy unstable condition was provided for the gale and strong sandstorm eruption, the strong sandstorm appeared in downstream of -200 m^2s^(-2) center of vertical helicity, the vertical helicity had good instruction significance for development of squall line and landing region of sandstorm, the mesoscale squall line occurred in unstable stratification, basic condition of potential energy transforming as kinetic energy was provided by strong unstable stratification for the strong sandstorm forming and developing.

結(jié)果表明：中尺度颮線所伴隨的強風(fēng)暴是產(chǎn)生強沙塵暴的主要原因小黄片毛片在线；500 hPa階梯短波槽是中尺度颮線產(chǎn)生的大尺度觸發(fā)系統(tǒng)，河西走廊中西部700 hp變形場与子的性关系视频、中尺度低壓為強沙塵暴形成和維持提供了必要的動力條件国产吞精口爆一区二区；地面冷鋒前上升運動與高空急流入口區(qū)次級環(huán)流的上升氣流的疊加，為深對流發(fā)展提供了深厚的垂直環(huán)流發(fā)展條件国产S性爱视频，是促使颮線發(fā)生和沙塵卷起的基本動力无码毛片视频一区二区99；地面熱低壓的加強和午后氣溫的日變化加大了冷鋒前后的溫度和氣壓梯度，為大風(fēng)毛片基地在线视频无码、強沙塵暴爆發(fā)提供了必要的熱力不穩(wěn)定條件国产精品久久久久影院老司；強沙塵暴出現(xiàn)在垂直螺旋度為－200平方公尺/s^2中心的下游午夜福利黄色片，垂直螺旋度對颮線的發(fā)展和沙塵暴的落區(qū)具有較好的指示意義欧美亚性爱小说视频一二三四；中尺度颮線發(fā)生在不穩(wěn)定層結(jié)內(nèi)，較強的不穩(wěn)定層結(jié)為強沙塵暴形成最新男人网址、發(fā)展提供了位能轉(zhuǎn)化為動能的基本條件日韩欧美一本。