CMIP5 Simulated Change in the Intensity of the Hadley and Walker Circulations from the Perspective of Velocity Potential

作     者：Botao ZHOU Ying SHI Ying XU 

作者机构：National Climate CenterChina Meteorological Administration Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science & Technology 

出 版 物：《Advances in Atmospheric Sciences》 (大气科学进展（英文版）)

年 卷 期：2016年第33卷第7期

页      面：808-818页

核心收录：

学科分类：07[理学] 0706[理学-大气科学] 0816[工学-测绘科学与技术] 0825[工学-航空宇航科学与技术] 

基　　金：supported by the National Natural Science Foundation (Grant No. 41275078) the Special Fund for Public Welfare Industry (Meteorology) (Grant No. GYHY201306026) the National Science & Technology Pillar Program (Grant No. 2012BAC20B05) of China 

主　　题：Hadley circulation Walker circulation model evaluation CMIP5 projection velocity potential 

摘      要：Based on the simulations of 31 global models in CMIP5, the performance of the models in simulating the Hadley and Walker circulations is evaluated. In addition, their change in intensity by the end of the 21st century （2080-2099） under the RCP4.5 and RCP8.5 scenarios, relative to 1986-2005, is analyzed from the perspective of 200 hPa velocity potential. Validation shows good performance of the individual CMIP5 models and the multi-model ensemble mean （MME） in re- producing the meridional （zonal） structure and magnitude of Hadley （Walker） circulation. The MME can also capture the observed strengthening tendency of the winter Hadley circulation and weakening tendency of the Walker circulation. Such secular trends can be simulated by 39% and 74% of the models, respectively. The MME projection indicates that the winter Hadley circulation and the Walker circulation will weaken under both scenarios by the end of the 21st century. The weak- ening amplitude is larger under RCP8.5 than RCP4.5, due to stronger external forcing. The majority of the CMIP5 models show the same projection as the MME. However, for the summer Hadley circulation, the MME shows little change under RCP4.5 and large intermodel spread is apparent. Around half of the models project an increase, and the other half project a decrease. Under the RCP8.5 scenario, the MME and 65% of the models project a weakening of the summer southern Hadley circulation.