1111号热带气旋“南玛都＂引发莆田特大暴雨成因分析

Analysis of the causes of Heavy Torrential Rain over Putian of Tropical Cyclone NANMADOL （1111）

本文利用1°×xl°NCEP再分析资料、FY-2E卫星红外云图TBB资料、自动站观测资料和多普勒雷达组合反射率资料等，对2011年9月1日发生在福建省莆田市的特大暴雨天气过程的触发机制进行分析。结果表明：（1）这次特大暴雨过程是“南玛都”低压环流在闽南一带停滞少动的环流背景下产生，低压环流东侧的偏南暖湿气流为莆田地区特大暴雨产生提供充足的水汽和能量条件；（2）低压环流东侧低层暖式切变、突然增强高温高湿的南风气流和对流层中高层入侵的露点锋区为特大暴雨产生提供了动力触发条件。（3）高层干空气入侵到低层暖湿气流上空造成大气层结强不稳定，有利于对流云团的强烈发展和深对流的形成和维持，对强降水的产生具有增幅作用。（4）TBB等值线疏密对未来一段时间的降水有很好的指示意义，TBB等值线密集梯度明显加大时，中尺度对流系统发展，对强降水的增幅有加大趋势；TBB等值线呈疏散趋势时，降水强度有减弱趋势。（5）强降水的组合反射率雷达回波的列车效应特征对特大暴雨的短时预报有指示信号作用。

In this paper, 1°×l°gridded NCEP reanalysis data, FY-2E satellite IR TBB data, observation data from automatic weather stations and Doppler radar composte reflectivity data were used for analyzing on the heavy torrential rain process occurred in Putian City, Fujian Province on September 1, 2011. The results showed that： 1） The heavy torrential rain resulted＇ from the background of the low pressure circulation of ＂Nanmadol＂ detaining in southern Fujian. In the east by south of the low circulation, as to the Putian region, the warm and wet current provided abundant water vapor and engine condition. 2） The dynamic trigger of heavy torrential rain were warm shear on low layer in the eastern of low pressure circulation, hot and humid southerly increasing unexpectedly and dew front invaded from middle-high troposphere. 3） The high stratification instability caused by higher-level dry air intruding on lower-level warm-wet air, which was beneficial to intensive development.of convective cloud cluster and the formation and duration of deep convection. 4） TBB contour density had a good indication for precipitation forecasting, i.e. the mesoscale convective system developed with increasing TBB contour density gradient, and vice versa. 5） The train-effect of radar composite reflectivity echoes had an indicative significance for heavy torrential rain forecast.