安徽省梅雨空间特征及其对西太平洋副热带高压的响应

Spatial Characteristics of Plum Rain in Anhui Province and Responses to Their Simultaneous Subtropical High

根据梅雨判别标准识别了安徽省江南、江淮和淮北3个区域1957~2016年的入出梅时间,通过Z指数对江南梅雨期时江南和淮北的降水量进行了等级划分,归纳了降水的空间分布类型及其对同期副高的响应。结果表明,仅有一段梅雨期时3个区域的梅雨期平均为6月16日~7月11日、6月19日~7月11日、6月25日~7月14日,梅雨量分别为344.1、234.7、207.8mm;3个区域二度梅分别为7、5、4年,空梅为5、6、9年;江南梅雨期时降水可分为南北正常、南北同丰、南北同枯、南丰北枯和南枯北丰5种,南北正常时副高脊线、强度、面积和西伸脊点与多年均值接近,南丰(南丰北枯和南北同丰)时脊线位置偏南,南枯北丰时脊线偏北,南北同枯时副高强度、面积异常偏小,西伸脊点异常偏东。

The beginning and ending of plum rains of the region of south of Yangtze River(Jiangnan),Yangtze-Huai River(Jianghuai)and the region of north of Huai River(Huaibei)from 1957 to 2016 were identified based on the criterion of plum rain.The Zindex was adopted to divide the precipitation level of Huaibei and Jiangnan during the plum rains period of Jiangnan.The results show that the average plum rains period of Jiangnan Jianghuai and Huaibei are June 16-July 11,June 19-July 11,June 25-July 14,respectively.Correspondingly,the average precipitation of plum rains period over three sub-regions are 344.1,234.7 and 207.8 mm.There are respectively 7,5,and 4 years during the dual plum rains period over three sub-regions,and the void plum rains period are 5,6,and 9 years.During the plum rains period of Jiangnan,the precipitation in Anhui Province can be divided into five types:the precipitation of Huaibei and Jiangnan is both normal,abundant or scarce,abundant in Jiangnan and scarce in Huaibei,abundant in Huaibei and scarce in Jiangnan.When the precipitation is normal in Jiangnan and Huaibei,the subtropical high ridge,subtropical high pressure intensity,subtropical high pressure area index and western ridge point index are closed to their average value.When the precipitation is abundant in two regions,or precipitation is abundant in Jiangnan and scarce in Huaibei,the position of subtropical high ridge line is southward.The high ridge line is northward when the precipitation is abundant in Huaibei and scarce in Jiangnan.When the precipitation of Huaibei and Jiangnan is both scarce,the subtropical high pressure intensity,area index are abnormally small,and the western ridge point are abnormally eastward.