摘要
利用NCEP/NCAR全球格点资料和TRMM卫星资料,采用改进后的非地转湿Q矢量,对0908号台风"莫拉克"引起的台湾南部特大暴雨过程进行预报应用试验。试验结果表明:(1)850 hPa高度层的非地转湿Q矢量散度及水汽通量散度分布可以预报未来24 h暴雨的落区及其雨带的分布,暴雨发生在Q矢量散度梯度大值区靠近辐合区域,同时该区域要有水汽辐合中心,雨带分布与该梯度大值区分布基本一致。(2)Q矢量辐合区的倾斜式发展很好地描述了暴雨中心强对流系统垂直结构,强对流系统发展旺盛期出现在暴雨发生前的18 h,具有一定预报意义。(3)台风暴雨发生在次级环流的上升支附近,最强次级环流上升支出现在暴雨发生时期;次级环流中的上升气流从低层到高层的倾斜方向较好地描述了雨带的移动,次级环流的调整比雨带移动提前了24 h,具有较好的预报应用价值。
Using NCEP/NCAR data,TRMM data and improved ageostrophic wet Q-vector,the heavy rain process ccurred in the south of Taiwan caused by typhoon Morakot（0908） is analyzed.Results show that：（1） The distributions of ageostrophic wet Q-vector divergence and moisture flux divergence of 850 hPa can be used to forecast the location of heavy rain and the distribution of rain belt in the future 24 h.The heavy rain mainly locates at the high gradient of ageostrophic wet Q-vector divergence area where is the moisture convergence center,the distribution of rain belt corresponds well with the distribution of the high gradient.（2） The inclining development of ageostrophic wet Q-vector convergence can well descript the vertical structure of strong convective system in the heavy rain center.The strongest convection appears 18 h early before the heavy rain,which is a valuable indicator of the intensity of heavy rain.（3） The heavy rain occurs near the ascending branch of secondary circulation,and the strongest ascending branch appears when the heavy rain occurs.The inclination direction of the ascending branch of secondary circulation describes well the moving of rain belt.The adjustment of secondary circulation occurs 24 h early before moving of rain belt.
出处
《气象与减灾研究》
2011年第4期23-29,共7页
Meteorology and Disaster Reduction Research
基金
国家自然科学基金项目(编号:40605016)
关键词
台风暴雨
非地转湿Q矢量
次级环流
Typhoon rainstorm
Ageostrophic wet Q-vector
Secondary circulation.
