“05．6”华南特大暴雨过程大尺度水汽输送特征

利用NCEP／NCAR再分析资料、FY-2C卫星逐时云顶亮温TBB资料（0．05°×0．05°分辨率）、自动气象站逐时降水资料、实时地面加密观测资料和实况探空资料等，对“05．6”华南持续性暴雨过程期间大尺度水汽输送特征进行了深入分析。结果表明：南海夏季风的活动与本次暴雨过程水汽输送有密切关系。南亚季风在经过中南半岛后与伸入南海的副高西侧气流汇合，使得西南气流发生“S”形转换，从而演变为副热带季风并持续向华南地区输送水汽。暴雨期间，来自南海中北部和孟加拉湾的水汽输送带一直稳定在18°-27°N，水汽通量大值输送带和水汽通量辐合大值带均随高度向北明显倾斜，显示偏南方向的水汽输送特征，来自南海中北部的水汽是最主要源地，而来自孟加拉湾的输送通道仅对本次过程起到补充作用。过程期间，由于南北向净流入明显大于东西向净流出，故华南地区水汽总收支为净流入，水汽净流入量以低层横向（南北）为主，以行星边界层的水汽输入为最大。

CHARACTERISTICS OF THE LARGE-SCALE WATER VAPOR TRANSPORTATION DURING THE"05.6"HEAVY RAIN EVENT IN SOUTH CHINA

The NCEP/NCAR reanalyzed data, the 0.05°×0.05° satellite TBB data, the hourly automatic observation data, and other meteorological observation data were used to study the characteristics of large-scale water vapor transportation during the ＂05.6＂ heavy rain event in South China. The results showed that the monsoon activity in South China Sea is closely related to the water vapor transportation of the ＂05.6＂ heavy rain event. The meeting of the southwest flow of the South Asia monsoon with the current in the west part of subtropical high causes the southwest current an S-shape transformation and developing into subtropical monsoon, which persistently transports water vapor to South China. During the ＂05.6＂ heavy rain, the water vapor transportation belts originated from the north and middle of South China Sea and the bay of Bengal stabilized between 18°--27°N, the high value regions of water vapor flux and its convergence inclined towards north in vertical orientation, which meant that the main transportation import of water vapor was from the south and South China sea was its main water vapor resources with the bay of Bengal as a supplement. During the ＂05.6＂ heavy rain, there was net inflow of water vapor in South China duo to the inflow in the south-north direction being larger than the outflow in the east-west direction, and the maximum inflow of water vapor flux mainly took place within the planet boundary layer.