秋季台风倒槽特大暴雨的对流特征和预报难点分析  

Analyses of the convection character and forecast difficulty of autumn typhoon inverted trough heavy downpour

作　　者：范爱芬 彭霞云 娄小芬 王丽颖 傅良 FAN Aifen;PENG Xiayun;LOU Xiaofen;WANG Liyin;FU Liang(Zhejiang Meteorological Observatory,Hangzhou 310057)

机构地区：[1]浙江省气象台,杭州310057

出　　处：《暴雨灾害》2022年第3期298-307,共10页Torrential Rain and Disasters

基　　金：浙江省基础公益研究计划(LGF20D050002)。

摘　　要：利用NCEP 0.5°×0.5°再分析资料、FY-2G卫星、多普勒雷达和地面加密观测等资料,对西行登陆福建的秋季台风“菲特”(1323)、“鮎鱼”(1617)和“杜鹃”(1521)登陆后倒槽特大暴雨的对流特征和预报难点进行了分析。结果表明,三个秋季台风倒槽特大暴雨均由中尺度对流的持续影响造成,特大暴雨出现在低空水汽通量辐合、θ_(se)大值区或锋区以及大尺度强迫抬升的重叠区域,另外在减弱的台风中心附近也出现了水汽辐合、θ_(se)大值区和强迫抬升的持续,倒槽区域较减弱的台风中心附近更为不稳定的大气层结是其出现特大暴雨的主要原因“。菲特”(1323)和“鮎鱼”(1617)的冷空气影响、不稳定能量和大气层结有差异,对流的特征和强度不同“。杜鹃”(1521)基本没有冷空气影响,但在强大暖湿气流北上过程中,急剧增长的不稳定能量在低空切变、地面中尺度辐合和海岸强迫的共同作用下释放,触发中尺度对流发生发展。在业务预报中,由于对倒槽特大暴雨的对流特征、强度和持续时间认识不够,加上数值模式降水量预报偏小,导致预报出现偏差。The cause of heavy downpour in three autumn typhoons with inverted trough after landfall has been analyzed using NCEP 0.5°×0.5° reanalysis data, FY-2G satellite data, Doppler radar data, the intensive observation data and so on. Continuous influences of mesoscale convective systems gave rise to the heavy downpour. There was a continuity or reinforcement of water vapor convergence, θ_(se) and forced lifting near the inverted trough. So was near the weakened typhoon center. The analyses show that more instable atmospheric stratification over the typhoon inverted trough than at the weakened typhoon center was the main cause of heavy downpour occurred at the inverted trough. Different instable energy, atmospheric stratification and way of cold air influence resulted in different convection character and intensity during the weakening of“Fitow”(1323) and“Megi”(1617). For“Dujuan”(1521),there was almost no cold air influence. The mesoscale convection formed and developed when continuous growing instable energy in warm and moist air was triggered by low level shear, ground mesoscale convergence and coast forcing. It leads to operational precipitation forecast deviation that forecasters did not know well about the convection character, intensity and persistent period, in addition to the fact that the rainfall provided by numerical models was less than the observed.

关 键 词：台风 特大暴雨 预报难点 大气层结 对流特征 

分 类 号：P458.124[天文地球—大气科学及气象学]