一次海南秋季台风暴雨的特征和成因分析

利用ECMWF再分析资料、TRMM-3B42降水资料及FY2E卫星TBB资料综合对2013年一次海南秋季台风“海燕”的暴雨特征及成因进行了诊断分析。结果发现:(1)台风内的中尺度云团是造成海南大暴雨的直接影响系统, 地形抬升作用和弱冷空气的入侵加剧了海南大暴雨的强度, 暴雨中心落在五指山迎风坡; (2)偏南气流和东南气流的辐合及低空急流的存在是触发和维持大暴雨的有利条件; (3)暴雨产生在θ_e面陡峭密集区, 陡立密集导致了倾斜涡度发展。MPV1和MPV2与强降水有很好的对应关系, 暴雨发生时, 对流层低层MPV1 < 0, 同时MPV2>0;(4) 850 hPa垂直螺旋度正值区对未来6 h强降水落区有很好的指示意义。 

ANALYSIS OF THE CHARACTERISTICS AND CAUSES OF AN AUTUMN TYPHOON RAINSTORM IN HAINAN

ECMWF reanalysis, precipitation data of TRMM3B42 and TBB data of FY2E satellite are used to synthetically analyze the characteristics and causes of an autumn typhoon "Haiyan" caused heavy rain in Hainan. The results showed that: (1)The mesoscale cloud cluster in the typhoon is the direct affecting system which causes heavy rain in Hainan; the terrain lifting effect and the invasion of weak cold air increased the intensity of torrential rain in Hainan, the maximum precipitation of the rainstorm process occurred in the windward slope of Five Fingers Mountain; (2)The convergence of south and southeast airflows and the presence of a low-level jet are favorableto trigger and sustain heavy rain; (3) The heavy rain events occurred in the very stiff and dense section of the concentrated region, which can lead to the development of slantwise vorticity; The center of rainstorm has a very good correspondence with MPV1 and MPV2, the rainstorm will probably happen when MPV 1 < 0 and MPV 2 > 0 in the low troposphere; (4) The positive area of the helicity at 850hPa will be indicative in forecasting where the 6 h heavy precipitation will fall.