摘要
通过应用卫星云图、OLR日平均场、环境场、比湿场、散度场、K指数等资料对0707号"帕布"引起的强降水进行诊断分析,同时把登陆湛江(9615号)、珠江口附近(7908号、0313号)的台风与之进行对比分析,结果表明:越赤道气流和西南季风的增强促使赤道辐合带加强,为"帕布"强降水的维持提供了水汽和热量条件;双台风和环境场的作用使"帕布"在粤西沿海停留时间较长,使强降水的累积雨量增大;低层辐合、高层辐散的配置有利于雷州半岛附近水汽的辐合,雷州半岛附近K指数在35～38之间和垂直纬向风弱切变表明空气不稳定度大有利于水汽上升,使得"帕布"给雷州以南地区带来强降水,另外,对湛江地区4—9月逐日降水作小波分析后得出了暴雨期存在明显的20d周期的低频振荡特征。
Satellite cloud imagery, daily mean OLR data, environmental field, specific humidity, vorticity and divergence fields and the K index are used to analyze diagnostically a torrential rain caused by STS Pabuk, which is compared with typhoons that either made landfall on Zhejiang（No.9615） and or moved near the estuary of Pearl River（No.7908 ＆ No.0313）. The results are shown as follows. （1） The enhancement of cross-equatorial flows and Southwest Monsoon has increased the ITCZ, which provides constant supply of water vapor and heat to maintain the intense precipitation of Pabuk. （2） The joint effect of twin typhoons and the environmental field enable Pabuk to stay relatively long over waters off the coast of western Guangdong, which increases the accumulated rainfall. （3） The allocation of low-level convergence and high-level divergence contributes favorably to the convergence and ascent of water vapor over the Leizhou Peninsula, which has a K index ranging from 35 to 38 and a weak shear of vertical zonal wind, an indication of unstable air, and brings about intense precipitation in areas south of Leizhou. In addition to that, significant 20-day periodic low-frequency oscillations are found during the torrential rain, as shown in a wavelet analysis of day-to-day precipitation for the time April through September in Zhanjiang prefecture.
出处
《热带气象学报》
CSCD
北大核心
2009年第3期373-378,共6页
Journal of Tropical Meteorology
基金
中国气象局预警工程项目:“基于集合预报的中期天气预报业务系统”
公益性行业(气象)科研专项经费项目(GYHY200706037)
广东省科技计划项目(2006B37202004)共同资助
关键词
强热带风暴
强降水
分析
severe tropical storms
torrential rain
analysis
