【作者】 王川； 李韬； 侯建忠；

【Author】 WANG Chuang, LI Tao, HOU Jian-zhong (Shaanxi Meteorological Observatory, Xi’an 710015, China;)

【机构】 陕西省气象台； 陕西农业遥感信息中心；

【摘要】 利用实况资料和WRF模式预报场,对2006年4月9日-11日西北地区一次大范围沙尘天气进行动力诊断及数值模拟分析,结果表明:此次过程属于蒙古冷槽型,地面强冷空气的爆发直接导致了沙尘天气的发生,沙尘发生在冷锋后及锋面过境时。高空急流的发展、移动对沙尘天气有预示作用,沙尘发生区次级环流在过程发展中有明显变化,下沉气流和上升气流并存。有利的散度场促进了上升及下沉运动的加强,涡度场的变化影响蒙古气旋,对沙尘天气的发生发展有指示意义。稳定的大气层结和近地层较大的垂直风切变是两个特征。WRF模式对此次沙尘天气有较好的模拟能力。更多还原

【Abstract】 By using the routine observation data and WRF model result, a sand-dust weather event in Northwest China was diagnosed and analyzed. The results show that this event belonged to Mongolia Cold Trough, and the main reason of the sand-dust event was explosion of very cold-air mass on surface, in which the sand-dust weather occurred at rear of ground cold front and frontal transit. The development and movement of upper-level jet had predictive function for sand-dust weather. Vertical secondary-circulation changed evidently, at the same time, ascending air current and descending air current coexisted which the matchable divergence field enhanced them. The vorticity field was important just because it can affect the Mongolia Cyclogenesis. Stable stratification and distinct low-level vertical wind shear were two characters during the sand-dust event. The WRF model also gave a well performance in this event.更多还原