梅雨期持续性暴雨过程云—辐射—降水的关系

Cloud-radiation-precipitation associations over the persistent heavy rainfall events during Meiyu periods

本文利用站点观测数据以及ERA5再分析资料分析了2006—2020年14次长江中下游地区梅雨期持续性暴雨的基本特征以及过程中云—辐射—降水的关系。结果表明,在梅雨期持续性暴雨过程中,降水呈纬向分布;云量分布随高度向南倾斜,中云分布与降水分布对应良好,高云分布在降水区南侧;降水发生时,梅雨锋北侧中低云增加,南侧高云增加,北侧中低云辐射降温以及南侧高云温室效应和暖平流共同作用造成梅雨锋两侧温差增大,锋面加强使得持续性暴雨得以维持。

This paper analyzed the basic characteristics and the cloud-radiation-precipitation associations of 14 Persistent Heavy Rainfall Events(PHREs) during 2006-2020 Meiyu periods in the middle and lower reaches of Yangtze River by using site observation data and ERA5 reanalysis data.Results show that during the PHREs of Meiyu period,it is found that the precipitation was zonally distributed;the distribution of cloud cover inclines southward with height,the distribution of medium cloud cover corresponds well to the distribution of precipitation,and the high cloud cover is distributed over the south of the rainfall area.When the precipitation started,the low and medium cloud cover increased on the north side of Meiyu front,and the high cloud cover increased on the south side of Meiyu front.The radiation cooling effect of low and medium clouds in the north and the combination of high cloud greenhouse effect and warm advection in the south made the temperature difference between the two sides of Meiyu front increased,and the strengthening of Meiyu front made heavy rainfall maintained.