What are the major environmental factors influencing the intensification rate of tropical cyclones in the western North Pacific?

The intensification rate (IR) of tropical cyclones (TCs) is influenced by environmental conditions. Atmospheric and oceanic conditions for TC intensification are non-uniform in the western North Pacific (WNP). This study compares environmental factors of slow intensification (SI) and rapid intensification (RI) TCs and their spatial dependence in the WNP during 1980–2021. SI and RI TCs are classified into two clusters using the K -means clustering method. The cluster 1 and cluster 2 TCs are located in the western and eastern WNP, respectively. It is found that the effects of mid-level humidity anomalies are larger in the eastern than western WNP and sea surface temperature anomalies have a negative effect on SI TCs in both the western and eastern WNP. A quantitative analysis based on the decomposition of the genesis potential index reveals that low-level vorticity is the dominant factor influencing TC IR, mid-level relative humidity and VWS have a secondary contribution, and the oceanic condition has a small effect in both the western and eastern WNP. 该研究比较1980-2021年西北太平洋缓慢和快速加强热带气旋的环境条件和其空间依赖性.鉴于西北太平洋大气和海洋条件的不均匀分布, 利用K-均值方法将缓慢和快速加强热带气旋分成两类, 它们分别位于西北太平洋的西部和东部.分析发现中层湿度异常作用东部大于西部, 而海表温度异常对缓慢加强热带气旋都是不利的.对潜在生成指数分解的定量分析说明低层涡度是影响热带气旋加强率的最主要因子, 中层相对湿度和垂直风切变作用为次, 而海洋状况的影响较小.