基于改进的累积气旋能量指数评估西北太平洋TC活动与ENSO的关系

摘要

采用1977-2008年日本气象厅(JMA) TC最佳路径集资料和美国气候预测中心(CPC)的ENSO资料,设计了一个考虑热带气旋(TC)尺度信息的累积气旋能量指数(SACE),据此分析了西北太平洋TC活动与ENSO之间的关系.结果表明:相比于不考虑尺度效应的ACE,引入TC尺度信息的SACE增加了较大强度、较大尺度TC活动水平的权重,能够更加准确地刻画TC强度及其影响,其与Ni(n)o指数的相关性进一步增强.SACE能够更好地表征西北太平洋TC活动与ENSO年际变化的关系,其对ENSO位相的依赖性相对于ACE更为敏感,是一个能更好预测ENSO状态的因子.TC强度、生命史、频数以及尺度均对SACE有一定的贡献,但生命史的贡献最大,这一方面说明ENSO主要通过调制TC生命史来影响SACE,另一方面也说明相对于强度、频数和尺度而言,TC生命史更能影响SACE中的ENSO信号.%By using the 1977-2008 best Tropical Cyclone (TC) track dataset of Japan Meteorological Administration and ENSO indices from the Climate Prediction Center (CPC),the relationship between the TC activities and ENSO was investigated based on the improved accumulated cyclone energy index (SACE) of TC scale.Results show that with the introduction of TC scale effect,the SACE increases the weight of TC activity with heavier intensity and larger scale s compared to the Accumulated Cyclone Energy (ACE) without scale effect.The SACE can describe the TC intensity and influence more accurately than the ACE,so it has a more positive correlation with the ENSO indices.The relationship between TC activities and ENSO can be better represented by SACE than that by ACE.Moreover,SACE is more sensitive to ENSO's phase and is a better predictor for ENSO.Interannual variations in the annual mean intensity,lifetime,scale and frequency of TC all contribute to the SACE,but the lifetime effect is the most important.On one hand,ENSO affects SACE by moderating TC lifetime,on the other hand,the TC lifetime contribute to the ENSO signal more significant than the intensity,scale and frequency of TC.