1979—2019 年影响中国沿海的热带气旋与 ENSO 变化关系初探

A preliminary study on the relationship between tropical cyclones affecting the coastal areas of China and ENSO during 1979-2019

中文关键词:  热带气旋  累积气旋能量  ENSO  海表温度  海洋上层热容量

英文关键词:tropical cyclones  accumulated cyclone energy  ENSO  sea surface temperature  upper ocean heat content

中文摘要:

      采用 1979—2019 年热带气旋最佳路径资料，分析影响中国沿海的热带气旋的时空演变特征，并结合 Nio3.4 指数、海表温度和海洋上层热容量资料，对热带气旋与 ENSO 变化关系进行初步探讨。结果表明，近 40 年来影响中国沿海的热带气旋经历了 1990 年代减弱，2000 年代增强的变化过程，且在 2000 年以后呈现显著向岸迁移趋势。影响中国沿海的热带气旋与表征 ENSO 的 Ni觡o3.4 指数的相关关系在 2000 年发生突变，具体表现为 ACE 与 Nio3.4 指数在 2000 年前呈显著正相关， 2000 年后二者相关性明显下降。通过将 ACE 分解成平均强度 ACE1、持续时间 ACE2 和频数 ACE3 这三个分量，发现 2000 年 前 Ni觡o3.4 指数与平均强度 ACE1 呈显著正相关，但 2000 年后 Ni觡o3.4 指数与 ACE1 相关关系减弱，这可能是导致 ACE 与Nio3.4 指数的相关关系在 2000 年左右发生突变的主要原因。持续时间 ACE2 与 Nio3.4 指数一直保持显著正相关，频数ACE3 则与 Ni觡o3.4 指数不存在显著线性相关关系。分析影响中国沿海的热带气旋活动与海表温度异常和海洋上层热容量异常在空间上的相关性，所得结果可以证实以上结论。

英文摘要:

      Tropical cyclones are one of the most devastating natural disasters in terms of their average destructiveness and annual frequency affecting coastal regions. By using the best-track dataset of tropical cyclones, Nio3.4 index, sea surface temperature, upper ocean heat content and other indices of tropical cyclone activities were used to analyze the spatiotemporal variability of typhoon activities affecting the coast of China during 1979-2019. The Accumulated Cyclone Energy (ACE),mean intensity and lifetime variables of tropical cyclones presented strong interdecadal variations, decreasing in the 1990s and increasing in the 2000s. Coastal migration of tropical cyclone activities was also identified after 2000 in the CMA besttrack dataset. The ACE and Nio3.4 index presented positive correlation before 2000, with larger ACE value in El Nio years and smaller value in La Nia years. However, the correlation between ACE and Nio3.4 index experienced an abrupt decrease around the year of 2000. After 2000, variations in the ACE were not synchronized with Nio3.4 index, which may be mainly contributed by the mean intensity ACE1 variation. While the duration of tropical cyclones ACE2 was significantly modulated by the sea surface temperature anomalies in Nio3.4 regions, the frequency of tropical cyclones (ACE3) was not linearly correlated with that. The result was confirmed by analyzing the spatial distribution of the correlation between tropical cyclones affecting the coast of China and sea surface temperature anomalies as well as upper ocean heat content anomalies.