两个相似路径台风深入内陆所致暴雨对比分析

Comparative analysis of rainstorms caused by two typhoons with similar path deep inland

使用中国气象局热带气旋年鉴、FY-2云顶亮温资料、常规观测资料及NCEP/NCAR再分析资料,对两个路径相似北上深入内陆,发生变性并直击黑龙江省的1215号超强台风“Bolaven(布拉万)”和1913号超强台风“玲玲(Lingling)”特征和降水差异进行对比分析。结果表明:(1)两次台风暴雨过程均与中尺度锋生有关。较强冷空气侵入促使“布拉万”西北侧锋区强烈锋生,深厚的上升运动形成中尺度对流区,降水强度大,使其变性快,移动慢。(2)“玲玲”北上到相同纬度时具有更大的强度,更深厚的湿层和低层更大的比湿,但由于仅有扩散南下的弱冷空气侵入台风环流,使其变性慢,移动快,台风中心北侧锋生作用弱,降水强度和范围均较小。(3)对流结构和降水强度有较大差异,“布拉万”云系东侧减弱消散,西侧和北侧与冷空气相互作用触发对流;“玲玲”云系结构基本维持不变,中尺度对流云团出现在台风中心及中心北部。(4)“布拉万”过程,大气具有强对流不稳定性,暴雨区域内对流活跃,强降水持续时间长。“玲玲”北上时,仅在低层有弱对流不稳定,对流较弱,强降水持续时间较短。暴雨区低层对流不稳定、中层湿对称不稳定,有利于强降水的维持和发展。

Typhoons Bolaven(1215)and Lingling(1913)were two typhoons that went directly north to hit Heilongjiang province and caused heavy rain.Both of them changed in the process of going north to the inland.The tropical cyclone yearbook,Fengyun cloud top brightness temperature data,conventional observation data and NCEP/NCAR reanalysis data were used for comparative analysis of the characteristics and precipitation differences between the two typhoons.The results are as follows.(1)The rainstorm processes of the two typhoons were both related to mesoscale frontogenesis in the typhoon circulation.The strong cold air intrusion promoted the strong frontal growth in the northwest frontal area of Bolaven.The deep ascending movement formed mesoscale convective zone and the precipitation intensity was high.Strong cold air made Bolaven denaturated fast and moved slowly.(2)Lingling had greater strength,deeper wet layers and greater specific humidity at lower levels as it travelled north to the same latitude.As only weak cold air spreading southward intruded into the typhoon circulation,Lingling became degenerated and moved quickly.The northern front of the typhoon center was weak,and the precipitation intensity and range were small.(3)The convective structure and precipitation intensity were significantly different:the east side of Bolaven cloud system weakened and dissipated,while the west side and north side interacted with the cold air to trigger convection.The structure of the Lingling cloud system was basically unchanged,and mesoscale convective clouds appeared in the center and the north of the center.(4)Bolaven process showed that the atmosphere had strong convective instability,the convection was active in the rainstorm area,and the duration of heavy precipitation was long.When Lingling moved north,there was only weak convective instability in the lower layer,which was weak,and the duration of heavy precipitation was short.The convective instability in the lower layer and the symmetrical instability in the middle layer of the rainstorm area were conducive to the maintenance and development of heavy precipitation.