Extended Abstract (296K)17A.6
Meso-scale diagnosis of a torrential rainfall caused by a tropical depression
Hui Yu, Shanghai Typhoon Institute, Shanghai, China; and X. Liang and Y. Duan
On 5 August 2001, Shanghai was struck by a torrential rainfall coming together with a tropical depression reentering the sea. The rainfall intensity is the strongest in recent 50 years. A set of meso-scale re-analyses data is used to understand the physical mechanism of such a heavy rain. Results show that the outburst of a southerly jet in low atmosphere triggered the explosive development of cyclonic vertical vorticity in the region with steep potential temperature surfaces in the front of a moist and warm air mass. That was slantwise vorticity development. While in the upper atmosphere, cyclonic vorticity increased notably as the air flew from west to east and entered a region with small vertical stability. The simultaneous sharp development of cyclonic vorticity in both low and upper atmosphere should be the main cause for the torrential rainfall.
Session 17A, Tropical Cyclone Observations and Structure VI(Parallel with Sessions 17B and 17C)
Friday, 3 May 2002, 11:00 AM-12:30 PM
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