Acta Scientiarum Naturalium Universitatis Pekinensis

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Characteristics of Cloud Systems and Environment of Persisting Rainstorms over Huaihe River Basin during the Summer of 2003

ZHENG Yongguang1,CHEN Jiong1, 3,FEI Zengping2,WANG Hongqing2,ZHANG Yan2   

  • Received:2005-12-17 Online:2007-03-20 Published:2007-03-20


郑永光1,陈炯1, 3,费增坪2,王洪庆2,张焱2   

Abstract: Based on the conventional observational data, NCEP final analysis and infrared images of GOES-9, the characteristics of cloud systems, large-scale environment, water vapor sources, and precipitation of persisting rainstorms over Huaihe River Basin during June 21-July 22 of 2003 were studied. This persisting-precipitation period can be separated to three stages, and the first stage has the maximum precipitation. The cloud systems are characterized by a large-scale cloud band associated with the Meiyu front and embodied smaller-scale active meso-scale complex systems (MCSs). According to the analysis from temperatures of black body (TBB) of infrared images, the MCSs with TBB less than -52℃ are the key synoptic systems caused heavy rains. It is found that there were 34 MCSs over Huaihe River Basin during June 21-July 22 of 2003. Most of these MCSs only locally occurred and dissipated over Huaihe River Basin and neighbor regions, and no MCS was found moving from Tibetan Plateau. In the lower troposphere, there are three currents transporting water vapor. One of the currents is from southwest. It crosses the equator and is most important for transporting water vapor. The second one is from South China Sea. It is the weakest one. The third is from the tropical Pacific Ocean to the east of Philippines.

Key words: rainstorms over Huaihe River Basin, cloud systems, statistics of TBB, MCS, water vapor transport

摘要: 用常规观测资料、NCEP分析资料与GOES-9卫星云图资料对2003年6月21日—7月22日淮河流域持续暴雨的降水概况、云系特征及大尺度环境条件与水汽来源进行了分析。从降水特征来看,持续暴雨可以划分为3个阶段,降水主要集中在第一阶段(6月21日—7月2日)。从云系特征来看,淮河流域为稳定维持的大尺度梅雨锋云系,在梅雨锋云系上有多个中尺度对流系统活动,红外亮温频率统计表明亮温低于-52℃的强对流是导致淮河流域强降水的重要天气系统。对6月21日—7月22日时段的卫星云图进行普查发现影响淮河流域的中尺度对流系统(MCS)共有34个,其中10个α中尺度对流系统(M-αCS)和24个β中尺度对流系统(M-βCS);大多数MCS在淮河流域及其邻近地区产生与消亡,并未发现直接来自青藏高原地区的MCS。从水汽来源来看,淮河流域对流层低层有3股水汽输送带,第1股气流为越赤道气流,水汽的输送作用最强;第2股气流来自南海地区,水汽的输送作用最弱;第3股气流来自菲律宾以东的热带太平洋地区。

关键词: 淮河暴雨, 云系, 红外亮温统计, 中尺度对流系统, 水汽输送

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