The Abnormal Water Vapor Transportation of Tibetan Plateau and The Heavy Rain System in Yangtze River Valley
Xu Xiangde (1), Wang Jizhi (1), Chen Lianshou (1)
(1) Chinese Academy of Meteorological Sciences
In this paper, the behavior of the cloud system on the Tibetan plateau that caused the torrential rain in Yangtze River Valley in the last ten days of July was traced through the composite analysis method, based on the NCEP reanalysis water vapor transportation flux data, the Doppler radar echoes in middle plateau of GAME/Tibet, the satellite water vapor imagery, the time cross section of satellite remote sensed TBB and the dynamic variation of satellite imagery. As shown in Fig.1, an apparent southerly water vapor channel from the water vapor source in lower latitude of India ocean (90-130E, the area with high correlation of water vapor) to Bay of Bengal and South China Sea is found in the summer flood year of Yangtze River Valley. Besides, the strong southerly water vapor flow would turn to the east on the east of Tibetan Plateau and form the southwesterly water vapor transportation belt in Yangtze River Valley. The result also discloses the water vapor transportation mechanism of the water vapor source has close relationship with the monsoon systems such as plateau and mid-lower latitude circulation and the subtropical high system. The tracing analysis shows that the development and eastward motion of the meso-scale convective system in middle plateau is directly related to the torrential rain in Yangtze River valley in 1998. The covective cloud on the plateau looks like popcorn and thus is so called as "popcorn cloud". There is apparent formation, development and organization phase in the life cycle of the meso-scale convective system. The development and eastwards shifting of the meso-scale convective system over Tibetan plateau results in the torrential rain process in Yangtze River valley. Namely, the meso-scale cumulus developed, became mature meso-scale cloud system and began moving to the east at 18 UTC on July 19, 1998. These cloud systems had great influence on the flood of Yangtze River Valley in 1998. The torrential rain happened in Wuhan while the cloud system moved eastwards there.
Submittal Information
Name :
Date :
Prf. Xu Xiangde
30-May-01-15:29:09
Organization :
Theme :
Chinese Academy of Meteorological Sciences, CMA, China
Theme 5
Address :
Presentation :
Chinese Meteorological Administration, Zhongguancun South Street, 100081, Beijing, China
