Climatic Variation of Maximum Intensification Rate for Major Tropical Cyclones over the Western North Pacific
Climatic Variation of Maximum Intensification Rate for Major Tropical Cyclones over the Western North Pacific
复制标题
DOI：
10.3390/atmos12040494
复制
发表时间：
2021-04
期刊：
影响因子：
2.9
通讯作者：
Xiangbai Wu;Xiao‐Hai Yan;Yan Li;Huan Mei;Y. Liou;Gen Li
中科院分区：
文献类型：
--
作者：
Xiangbai Wu;Xiao‐Hai Yan;Yan Li;Huan Mei;Y. Liou;Gen Li
为了分析热带气旋增强率与环境条件变化的关系，提出了一种衡量西北太平洋Saffir-Simpson尺度4-5级热带气旋终生最大增强率的指标。为了定量描述主要热带气旋的增强率，LMIR被定义为水上气旋在24小时内持续风速中的最大加速度。这个新的指数，LMIR，通常与RI频率的指数无关。结果表明，太平洋年代际涛动(PDO)调制了LMIR与厄尔尼诺/南方涛动(ENSO)的年际关系。通过考虑不同PDO位相的LMIR与环境条件的关系，探讨了PDO对ENSO对LMIR影响的调制作用。对于暖的PDO位相，ENSO对LMIR的影响一般是通过影响上层海洋热含量的变化来实现的，而对于冷的PDO位相，ENSO主要影响纬向风和垂直风切变的变化。我们的结果表明，快速转换的TCS在温暖的PDO阶段倾向于获得强烈的增强，而温暖的次表层条件可能允许慢转换的TCS在冷却的PDO阶段也变得强烈增强。这些发现对西北太平洋热带气旋活动的长期预测和RI的预测都有重要意义。
To analyze the dependence of intensification rates of tropical cyclones (TCs) on the variation of environmental conditions, an index is proposed here to measure the lifetime maximum intensification rates (LMIRs) for the Saffir–Simpson scale category 4–5 TCs over the western North Pacific. To quantitatively describe the intensification rate of major TCs, the LMIR is defined as the maximum acceleration in the sustained-wind-speed over a 24-h period of an overwater TC. This new index, LMIR, is generally independent of the indices for RI frequency. The results show that the Pacific Decadal Oscillation (PDO) modulates the inter-annual relationship between the LMIR and El Niño/Southern Oscillation (ENSO). The PDO’s modulation on the ENSO’s effect on the LMIR is explored here by considering the relationship between the LMIR and the environmental conditions in different PDO phases. While the ENSO’s effect on the LMIR for the warm PDO phase is generally by affecting the variations of upper ocean heat content, ENSO mainly influences the variations of zonal wind and vertical wind shear for the cold PDO phase. Our results suggest that fast translating TCs tend to attain strong intensification during the warm PDO phase, while a warm subsurface condition may permit slow-translating TCs also to become strongly intensified during the cooling PDO phase. These findings have an important implication for both prediction of RI and the long-term projection of TC activities in the western North Pacific.