台风“海高斯”和“天鸽”快速加强成因的对比分析

利用欧洲中心ERA-Interim逐6 h再分析资料和国家气象中心提供的逐小时台风业务资料，对比分析了2020年第7号台风“海高斯”和2017年第13号台风“天鸽”的环流形势和强度结构特征，发现二者的尺度都比较小；生成的时间和移动路径比较相似；并且都出现了近海快速加强的过程。从对比分析来看，造成两个台风近海快速加强的共同原因主要有海温异常偏高、环境风的垂直切变较小以及有利的高低层环流配置等，而造成两个台风近海快速加强的不同原因也较为显著，分别从位涡垂直分布、涡度收支和涡度拟能等方面进行诊断分析，得到一些有利于台风强度快速增长的不同因素。

Analysis of the Cause of Rapid Offshore Strengthening of Typhoons Higos and Hato

Using the 6-hourly reanalysis data of the European Center ERA-Interim with horizontal resolution and the hourly typhoon operational data provided by the National Meteorological Center, the circulation situation and intensity structure characteristics of typhoon No. 7 Higos in 2020 and typhoon No. 13 Hato in 2017 are compared and analyzed in this study. The scale of the two typhoons is relatively small. Their generation, moving path, and landing location are relatively similar. In addition, both exhibit rapid offshore strengthening. Comparative analysis results revealed that the common reasons for the rapid offshore strengthening of the two typhoons include the abnormally high sea surface temperature, small vertical shear of wind, and favorable circulation configuration in the upper and lower layers. However, different reasons for the rapid strengthening of offshore waters of the two typhoons are also obvious. The diagnosis and analysis are based on the vertical distribution of potential vorticity, vorticity budget, and vorticity enstrophy. Other factors leading to the rapid growth of typhoon intensity are also obtained.