2011年6月江淮梅雨暴雨主要影响系统特征

Characteristics of the main influential system of Jianghuai Meiyu Storm in June 2011

利用江淮梅雨期逐日降水资料与NCEP/NCAR的FNL分析资料,对2011年夏季江淮梅雨主要影响系统及环流特征进行了分析。结果发现,与典型梅雨期阻塞形势不同,2011年梅雨期中高纬阻塞形势有移动性特征,冷空气由于中高纬环流的发展导致极涡分裂南下而至;中高纬弱阻塞形势引起的切断槽提供了梅雨暴雨的动力条件;西北太平洋副热带高压脊线的变动是梅雨暴雨发展的决定性因素。同时分析了梅雨锋面系统、急流及其引发的高低空次级环流和干冷空气的侵入对暴雨的影响机制。

Based on daily rainfall data and NCEP/NCAR 1 °× 1 ° FNL data during the Jianghuai Meiyu period in the summer of 2011,the main influential system and its circulation characteristics of the Meiyu were analyzed.It was found the features of the blocking situation in the 2011 Meiyu period and those during other typical Meiyu times were different：High-latitude blocking had mobility and the main cold air in the 2011 Meiyu period was from the polar vortex splitting southward caused by development of the middle-high latitude circulation.Moreover,the cutting trough caused by the weak resistance situation in middle and high latitude provided the dynamic condition for the Meiyu.It was also found the development of the Meiyu rainstorm was associated with the oscillation of the Northwest Pacific subtropical high ridge.In addition,the influence mechanism of Meiyu front system,the jets and the sub-circulation triggered by them as well as the dry cold air＇ s intrusion on the rainstorm were discussed.