内蒙古河套地区久旱转雨诊断分析

Diagnostic analysis of prolonged drought transfering to rain at Hetao area in Inner Mongolia

2008年冬季至2009年初春,内蒙古中西部地区降水量持续偏少,农田土壤出现旱象。2009年3月1日,一个短波槽自新疆东部移入内蒙古西部地区,同时,低纬度地区的南支系统迅速建立,高空低槽与南风急流汇合,在内蒙古河套地区产生了小-中雨夹雪的降水过程,极大地缓解了内蒙古中西部地区的冬春旱情。文中利用常规高空、地面观测、数值产品等资料,对此次久旱转雨天气过程的机制进行了诊断分析。

Precipitation was few and the farmland soil presented the sign of drought from the winter of 2008 to the early spring of 2009.A short wave trough moved into Inner Mongolian mid-west area from Xinjiang on March 1,2009.Simultaneously,a south system at low latitude area established rapidly.The convergence of upper air trough and jet stream produced the precipitation at Hetao area in Inner Mongolian.The sleet precipitation alleviated the enormous drought situation of Inner Mongolian mid-west area.We studied the mechanism of the prolonged drought transfering to rain by using conventional data,surface observations and value products.