Observational analysis and numerical simulation of the interannual variability of the boreal winter Hadley circulation over the recent 30 years  

作　　者：SUN Yong ZHOU TianJun ZHANG LiXia 

机构地区：[1]State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences [2]Graduate University of Chinese Academy of Sciences [3]Climate Change Research Center, Chinese Academy of Sciences

出　　处：《Science China Earth Sciences》2013年第4期647-661,共15页中国科学（地球科学英文版）

基　　金：supported by National High-tech R&D Program of China(Grant No. 2010AA012304);National Basic Research Program of China(Grant No. 2010CB951904);National Natural Science Foundation of China (Grant No. 40890054)

摘　　要：The interannual variability of the boreal winter （DJF） Hadley Cell strength during 1979-2008 is investigated using NCEP/NCAR reanalysis data. The results of AMIP simulation of LASG/IAP AGCM GAMIL2.0 are compared against the re- analysis data. Both the reanalysis data and the simulation show that the interannual variability of the Hadley Cell strength has a non-uniform spatial distribution, as evidenced by the 1st Empirical Orthogonal Function （EOF） mode. The change of Hadley cell strength in the tropics is opposite to that in the subtropical regions. Our analysis indicates that a positive phase of EOF1 is associated with an E1 Nifio-like warmer equatorial central and eastern Pacific and a warmer southern Indian Ocean. Above features are also seen in the results of GAMIL2.0 simulation, indicating that the interannual variability of the Hadley Cell strength is driven by the tropical ocean variability. Our analysis also demonstrates that the contribution of the warmer cen- tral-eastern Pacific to the 1st EOF mode is larger than that of the South Indian Ocean. The SST forcing enhances the local Hadley circulation strength in the central Pacific and Africa （30°S-30°N, 150°E-90°W）, while it weakens the local Hadley circulation in other regions （30°S-30°N, 90°-10°W）. The western Pacific anticyclone remotely driven by the E1 Nifio forcing leads to a weakened local Hadley cell in the Northern Hemisphere, while the South Indian Ocean anticyclone driven by the remote E1 Nifio forcing and the local warmer SST anomalies in the southern Indian Ocean results in a weakened local Hadley Cell in the Southern Hemisphere. The enhancement of the Pacific local Hadley Cell is stronger （weaker） than that of the Atlan- tic, the western Pacific, and the southern Indian Ocean in the tropical （subtropical） part, thus for the zonal mean condition the strength of the total Hadley Cell is stronger （weaker） in the tropical （subtropical） limb. The amplitude of the Hadley Cell change in the Northern HemisphThe interannual variability of the boreal winter (DJF) Hadley Cell strength during 1979-2008 is investigated using NCEP/NCAR reanalysis data. The results of AMIP simulation of LASG/IAP AGCM GAMIL2.0 are compared against the reanalysis data. Both the reanalysis data and the simulation show that the interannual variability of the Hadley Cell strength has a non-uniform spatial distribution, as evidenced by the 1st Empirical Orthogonal Function (EOF) mode. The change of Hadley cell strength in the tropics is opposite to that in the subtropical regions. Our analysis indicates that a positive phase of EOF1 is associated with an El Ni o-like warmer equatorial central and eastern Pacific and a warmer southern Indian Ocean. Above features are also seen in the results of GAMIL2.0 simulation, indicating that the interannual variability of the Hadley Cell strength is driven by the tropical ocean variability. Our analysis also demonstrates that the contribution of the warmer central-eastern Pacific to the 1st EOF mode is larger than that of the South Indian Ocean. The SST forcing enhances the local Hadley circulation strength in the central Pacific and Africa (30°S-30°N, 150°E-90°W), while it weakens the local Hadley circulation in other regions (30°S-30°N, 90°-10°W). The western Pacific anticyclone remotely driven by the El Ni o forcing leads to a weakened local Hadley cell in the Northern Hemisphere, while the South Indian Ocean anticyclone driven by the remote El Ni o forcing and the local warmer SST anomalies in the southern Indian Ocean results in a weakened local Hadley Cell in the Southern Hemisphere. The enhancement of the Pacific local Hadley Cell is stronger (weaker) than that of the Atlantic, the western Pacific, and the southern Indian Ocean in the tropical (subtropical) part, thus for the zonal mean condition the strength of the total Hadley Cell is stronger (weaker) in the tropical (subtropical) limb. The amplitude of the Hadley Cell change in the Northern Hemisphere is stronger than that in the Southern

关 键 词：Hadley circulation interannual variability GAMIL2.0 

分 类 号：P434[天文地球—大气科学及气象学]