一次秋季暴雨过程的物理成因分析

Analysis on Physical Causes of a Heavy Rainstorm in Autumn

对2017年9月21—22日新疆克州阿合奇大尺度天气系统中小尺度局地暴雨形成进行诊断分析。分析表明,此次暴雨受主导系统欧洲脊东移南下引导北方冷空气与西南暖湿气流在博州上空交汇形成降水,高空冷空气侵入释放不稳定能量;中高层强冷空气入侵配合地面中尺度低压发展;强有力中尺度抬升系统和强垂直风切变引发强对流,并使强对流持续维持。

The local rainstorm occurred on September 21-22 in Aheqi of Xin- jiang was diagnosed and analyzed. The results showed that the rainstorm was caused by the eastward movement of the European ridge to the south and the converge of north cold air and southwest warm and wet flow over Bortala Mongol Autonomous Prefecture. High-altitude cold air intrusion released unstable en- ergy. The strong cold air intrusion in the middle and high floors was coordinated with the development of mesoscale low pressure on the ground. Strong mesoscale lifting system and strong vertical wind shear initiated the rainstorm and main- tained it for a long time.