两次影响低纬高原西行台风降水成因对比分析

Comparative Analysis of Precipitation Mechanism of Two Westward Typhoons Affecting Low-latitude Plateau

利用地面观测资料、FY-2卫星TBB资料和NCEP 1°×1°每6 h再分析等资料,对1002号台风"康森"和1003号台风"灿都"进入低纬高原后引发云南强降水天气的成因及其在陆上维持机制进行对比分析。结果表明,西行台风"康森"和"灿都"生成源地不同、登陆地点不同,2个台风登陆后自身均携带水汽,"康森"进入云南之前还有来自孟加拉湾西南急流卷入,水汽强辐合区出现在台风低压西侧和孟加拉湾西南急流区,强降雨落区与水汽通量散度辐合中心一致;2次台风登陆前后低压东侧低空均有较强的南风急流,对台风低压维持有重要作用,孟加拉湾西南急流卷入有利于"康森"台风低压加强和维持;低纬高原的高能环境、地形动力抬升作用和台风低压温湿特征对称结构,是"康森"和"灿都"能深入低纬高原经久而衰的重要原因。

Based on surface observational data, TBB data of FY-2 satellite and reanalysis data of NCEP （ 10 × 10,4-times-a-day＇ s） ,the cau- ses of heavy rainfall induced by No. 1002 typhoon ＂CONSON＂ and No. 1003 ＂Chanthu＂ entering low latitude plateau, and their maintaining mechanisms on land were compared and analyzed. The results showed that origins and landing locations of two typhoons were different, but both of them carried vapor. There was southwest jet from Bay of Bengal before ＂CONSON＂ entering Yunnan, strong vapor convergence areas appeared at west of Typhoon depression and southwest jet zone, and strong rainfall areas were in correspondence with the center of moisture convergence. The southerly jets, existed at east of typhoon depressions before and after these two typhoons landing, were important for maintai- ning typhoon depressions. The southwest jet from Bay of Bengal was beneficial to strengthening and maintaining of ＂CONSON＂ typhoon de- pression. The important reasons of typhoon No. 1002 ＂CONSON＂ and No. 1003＂ Chanthu＂ after entering low-latitude plateau maintained for a long time were higher-energy environment of low-latitude plateau, terrain dynamic effect, symmetric low pressure, temperature and humidity of typhoon.