摘要
利用NCEP/NCAR再分析资料与日本气象厅区域谱模式的融合资料,采用WRFV2.2模式研究了热带气旋"泰利"(0513)降水增幅过程中的大别山地形效应。结果表明,大别山地形对"泰利"降水影响明显,改变了降水增幅的中心位置,降水强度增幅约为15%,但是降水增幅是否发生与大别山地形无关。大别山地形的存在导致了地形辐合线和中-β尺度低涡的形成和发展,使得迎风坡气流辐合加大和维持。随着"泰利"的移动,其东北侧环流和地形配置发生变化,降水范围和中心也随之变化,强降水主要发生在大别山东坡和南坡,降水中心多位于辐合线和地形迎风坡相交之处。降水增幅期间不同的地形高度造成不同的中低层涡度、散度和上升运动,随着地形的升高,涡度、辐合和上升运动总体加强。增幅期间,地形强迫垂直运动占模式最低层总垂直运动的50%左右,地形强迫对上升运动有明显影响。地形强迫垂直运动极大值出现在峰顶附近的东坡,降水量极大值出现在峰顶和地形强迫垂直运动极大值之间。
Using the synthesizer of NCEP/NCAR reanalysis data and Japan regional spectral model data,WRF V2.2 model is employed to investigate the topographic effect on the rainfall reinforcement associated with tropical cyclone ＇Talim＇（0513）.The results show that Dabie mountains can impact rainfall obviously by shifting its center and increasing the intensity of rainfall reinforcement about 15%.However,there is no relation between the occurrence of rainfall reinforcement and the topography.Convergence line and meso-β vortex formation and development due to the terrain effect may strengthen the convergence to increase the intensity of rainfall reinforcement and shift its center to upslope of mountain.The centers tend to locate in the superposition region of the convergence line and terrain upslope.The higher terrain,the stronger low-level vorticity,convergence and upward motion will induce.During the period of rainfall reinforcement,the terrain forced vertical motion at the lowest model level accounted for total vertical motion of the weighting at 50%;terrain forcing has a significant impact on the ascending motion.Maxima of terrain forced vertical motion appear in east slope near mountain top,rainfall maxima situate between the top and maxima of terrain forced vertical motion.
出处
《高原气象》
CSCD
北大核心
2011年第3期700-710,共11页
Plateau Meteorology
基金
浙江省气象科技开放专项(kf2010002)
国家重点基础研究发展计划项目(2009CB421504)
国家自然科学基金项目(40730948,40505009,40975032)
中国气象科学研究院基本科研业务费专项(2007Y006)
上海台风所研究基金项目(20085T11)
浙江省科技厅面上社会发展项目(2008C23014)共同资助
关键词
地形
热带气旋
降水增幅
数值研究
Topography
Tropical cyclone
Rainfall reinforcement
Numerical study
