Projection of the Future Changes in Tropical Cyclone Activity Affecting East Asia over the Western North Pacific Based on Multi-RegCM4 Simulations

Abstract

Future changes in tropical cyclone (TC) activity over the western North Pacific (WNP) under the representative concentration pathway RCP4.5 are investigated based on a set of 21st century climate change simulations over East Asia with the regional climate model RegCM4 driven by five global models. The RegCM4 reproduces the major features of the observed TC activity over the region in the present-day period of 1986–2005, although with the underestimation of the number of TC genesis and intensity. A low number of TCs making landfall over China is also simulated. By the end of the 21st century (2079–98), the annual mean frequency of TC genesis and occurrence is projected to increase over the WNP by 16% and 10%, respectively. The increase in frequency of TC occurrence is in good agreement among the simulations, with the largest increase over the ocean surrounding Taiwan Island and to the south of Japan. The TCs tend to be stronger in the future compared to the present-day period of 1986–2005, with a large increase in the frequency of strong TCs. In addition, more TCs landings are projected over most of the China coast, with an increase of ∼18% over the whole Chinese territory.

摘要

使用区域气候模式RegCM4在5个全球气候模式分别驱动下, 所进行的东亚区域25km水平分辨率气候变化试验结果, 本文对RCP4.5排放路径下未来西北太平洋热带气旋活动的变化开展了集合预估分析。结果表明, RegCM4可以模拟出当代(1986-2005年)西北太平洋地区热带气旋活动的主要特征, 但对热带气旋的生成数量、强度和登陆中国的数目的模拟存在偏少、偏弱的不足。预计到21世纪末期(2079–98年), 西北太平洋的热带气旋生成频率和路径频数将分别增加16%和10%。RegCM4模拟结果对热带气旋路径频数的增加有较好的一致性, 其中以台湾岛附近和日本以南海域的增加幅度最大。相比当代, 未来强热带气旋的生成频率将大幅增加。此外, 预计中国沿海大部分区域将会有更多的热带气旋登陆, 全国总计将增加18%。