Analysis of a Wenzhou-Hitting Exceptionally Strong Rainstorm Associated with a Typhoon Inverted Trough in September,1999

温州“9.4”台风倒槽特大暴雨分析(英文)

Using T106 numerical products, MM5 simulations in conjunction of Q-vector scheme-computed NCEP results, observations and satellite cloud images, study is undertaken for an exceptionally intense rainstorm event afflicting the Wenzhou region of Zhejiang province far away from the tropical storm center happening early on the morning of September 4, 1999 （TS9909 hereinafter）. Evidence suggests that, like previously-studied typhoons landing in autumn south of Xiamen to the eastern part of Guangdong, TS9909 has an inverted trough in the central south of the coastal belt of Zhejiang province that produces the rainstorm from the meso convective complex （MCC） on the warm, moist shear inside; the time and order of the magnitude of the rainfall are bound up with the development of the pattern of strong Q-vector divergence gradients during the event for the study area; the NE - SW coastline and the unique topography of the Yandang mountains inside the region are favorable for air lifting are the major contributors to the torrential rains.

运用T106数值预报产品、MM5模式结合Q矢量计算NCEP资料、天气实况及卫星云图等非常规资料,对1999年9月4日凌晨在远离9909号热带风暴中心的浙江省温州市引发的特大暴雨进行了探讨。发现秋季在厦门以南至广东东部登陆的台风,在浙中南沿海形成台风倒槽,该倒槽内的暖湿切变线的中尺度对流复合体(Mesoscale Convective Complex,MCC)是引起特大暴雨的重要条件。从计算得出的Q矢量散度分布看,本次特大暴雨降水发生时间和量级与该时段内温州经历的强Q矢量散度梯度发展有密切联系。同时,温州呈东北—西南走向的海岸线及境内雁荡山脉有利地形的抬升作用,对本次热带风暴倒槽降水中局地特大暴雨的形成有重要贡献。