0604号强热带风暴“碧丽斯”演变特征及灾害成因初步研究

Primary Research of the Evolvement Characteristics and Disaster Reasons of Strong Tropical Storm BILIS (0604)

0604号强热带风暴“碧丽斯”是一个怪异的热带气旋,具有“偏心结构”、外围风速远大于中心附近、登陆后残留低压长时间维持、登陆西行过程中引发华南和江南南部地区持续强降水等特点,强降水给南方六省(区)造成重大灾害。分析表明,风暴中心与北侧副热带高压之间的强气压梯度造成外围更大的梯度风,华南和江南南部地区持续性强降水是风暴残留低压与外围螺旋云带、季风云涌相互作用所致;而小流域洪水、泥石流等灾害正是由于持续性强降水所造成的。

The strong typical storm BILLS （0604） is a oddball typical cyclone. Its structure is eccentricity, and the wind speed in its periphery is greater than that in its center. The storm persisted for a long time after landfall, and it gave birth to heavy rain for a long time in southern China and the southern Yangtze River basin, which produces severe disasters in six provinces. The analysis finds that the greater pressure gradient between the storm center and its northern subtropical pressure, the stronger gradient wind in the storm＇s periphery. The durative rainstorm in southern China and the southern Yangtze River basin in longer period is the action production one another among remnant low pressure, twist cloud zone and monsoon cloud surge; moreover, it is the heavy rainfall that caused the disasters, such as flood, mud-rock flow, landslip of the mountains, failing and the downthrow of the earth etc. in some smaller valleys.