The Role of the Aerosol Indirect Effect in the Northern Indian Ocean Warming Simulated by CMIP5 Models  

作　　者：HU Ning LI Li-Juan WANG Bin 

机构地区：[1]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University

出　　处：《Atmospheric and Oceanic Science Letters》2014年第5期411-416,共6页大气和海洋科学快报（英文版）

基　　金：supported by Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA05110304);the National Basic Research Program of China (973 Project, Grant No. 2010CB951904)

摘　　要：The northern Indian Ocean （NIO） experienced a decadal-scale persistent warming from 1950 to 2000, which has influenced both regional and global climate. Because the NIO is a region susceptible to aerosols emis- sion changes, and there are still large uncertainties in the representation of the aerosol indirect effect （ALE） in CMIP5 （Coupled Model Intercomparison Project Phase 5） models, it is necessary to investigate the role of the AIE in the NIO warming simulated by these models. In this study, the authors select seven CMIP5 models with both the aerosol direct and indirect effects to investigate their performance in simulating the basin-wide decadal-scale NIO warming. The results show that the decreasing trend of the downwelling shortwave flux （FSDS） at the surface has the major damping effect on the SST increasing trend, which counteracts the warming effect of greenhouse gases （GHGs）. The FSDS decreasing trend is mostly contrib- uted by the decreasing trend of cloudy-sky surface downwelling shortwave flux （FSDSCL）, a metric used to measure the strength of the AIE, and partly by the clear-sky surface downwelling shortwave flux （FSDSC）. Models with a relatively weaker AIE can simulate well the SST increasing trend, as compared to observation. In contrast, models with a relatively stronger AIE produce a much smaller magnitude of the increasing trend, indicat- ing that the strength of the AIE in these models may be overestimated in the NIO.The northern Indian Ocean(NIO) experienced a decadal-scale persistent warming from 1950 to 2000, which has influenced both regional and global climate. Because the NIO is a region susceptible to aerosols emission changes, and there are still large uncertainties in the representation of the aerosol indirect effect(AIE) in CMIP5(Coupled Model Intercomparison Project Phase 5) models, it is necessary to investigate the role of the AIE in the NIO warming simulated by these models. In this study, the authors select seven CMIP5 models with both the aerosol direct and indirect effects to investigate their performance in simulating the basin-wide decadal-scale NIO warming. The results show that the decreasing trend of the downwelling shortwave flux(FSDS) at the surface has the major damping effect on the SST increasing trend, which counteracts the warming effect of greenhouse gases(GHGs). The FSDS decreasing trend is mostly contributed by the decreasing trend of cloudy-sky surface downwelling shortwave flux(FSDSCL), a metric used to measure the strength of the AIE, and partly by the clear-sky surface downwelling shortwave flux(FSDSC). Models with a relatively weaker AIE can simulate well the SST increasing trend, as compared to observation. In contrast, models with a relatively stronger AIE produce a much smaller magnitude of the increasing trend, indicating that the strength of the AIE in these models may be overestimated in the NIO.

关 键 词：Indian Ocean warming aerosol indirect ef-fect CMIP5 

分 类 号：P731.1[天文地球—海洋科学]