MAIN HEATING MODES OVER THE TIBETAN PLATEAU IN JULY AND THE CORRELATION PATTERNS OF CIRCULATION AND PRECIPITATION OVER EAST ASIA  

作　　者：段安民 吴国雄 

机构地区：[1]State Key Laboratory of Numerical Modeling Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences

出　　处：《Acta meteorologica Sinica》2004年第2期167-178,共12页

基　　金：the National Natural Science Foundation of China (Grant No.40135020,40221 503 and 40023001);the Chinese Academy of Sciences (Grant No.ZKCX2-SW-210)

摘　　要：Based on the 1958-1999 monthly averaged NCEP/NCAR reanalysis data,the REOF analysis is applied to obtain the main spatial modes of normalized atmospheric heating source over the Tibetan Plateau (TP) in July.Results show that the four leading modes are located over the northeast TP,southwest TP.Kashmir and southeast TP respectively,and the cumulative variances are no more than one third of the total.It indicates that the heating source distribution is very complicated over the TP in July.In other words.it is difficult to depict the heating spatial distribution with a few modes.By using wavelet analysis,a 2--4-year variation period is identified in these modes.Moreover,correlation coefficients between each RPC and zonal wind U, meridional wind V.zonal moisture flux Q,meridional moisture flux Q,and precipitation rate over East Asia are calculated to construct correlation fields,Results show that different heating modes over the TP correspond to different circulation,moisture flux as well as precipitation patterns,Precipitation over North China (or Kashmir) is negatively (or positively) correlated with REOF1.Similarly.notable negative (or positive) correlation can be found between the rainfall over south part of Southwest China.South China,and the Philippines (or Japan) and the REOF3. Due to high localization of diabatic heating over the TP.it is not enough to study the influence of TP thermal forcing on the climate with an area averaged heating index.Based on the 1958-1999 monthly averaged NCEP/NCAR reanalysis data,the REOF analysis is applied to obtain the main spatial modes of normalized atmospheric heating source over the Tibetan Plateau (TP) in July.Results show that the four leading modes are located over the northeast TP,southwest TP.Kashmir and southeast TP respectively,and the cumulative variances are no more than one third of the total.It indicates that the heating source distribution is very complicated over the TP in July.In other words.it is difficult to depict the heating spatial distribution with a few modes.By using wavelet analysis,a 2--4-year variation period is identified in these modes.Moreover,correlation coefficients between each RPC and zonal wind U, meridional wind V.zonal moisture flux Q_v,meridional moisture flux Q_v,and precipitation rate over East Asia are calculated to construct correlation fields,Results show that different heating modes over the TP correspond to different circulation,moisture flux as well as precipitation patterns,Precipitation over North China (or Kashmir) is negatively (or positively) correlated with REOF1.Similarly.notable negative (or positive) correlation can be found between the rainfall over south part of Southwest China.South China,and the Philippines (or Japan) and the REOF3. Due to high localization of diabatic heating over the TP.it is not enough to study the influence of TP thermal forcing on the climate with an area averaged heating index.

关 键 词：Tibetan Plateau (TP) atmospheric heating source CIRCULATION PRECIPITATION 

分 类 号：P46[天文地球—大气科学及气象学]