Winter Season Stratospheric Circulation in the SAMIL/LASG General Circulation Model  

作　　者：任荣彩 吴国雄 Ming CAI 宇婧婧 

机构地区：[1]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 [2]Department of Meteorology, Florida State University, Tallahassee, Florida 32306, USA

出　　处：《Advances in Atmospheric Sciences》2009年第3期451-464,共14页大气科学进展（英文版）

基　　金：supported by the National Basic Research Program of China (2006CB403600);the National Natural Science Foundation of China under Grant Nos. 40575041, 40523001, 40221503;the Public Sector Special project GYHY200806006

摘　　要：In this paper, we examine the performance of the 26-level version of the SAMIL/LASG GCM （R42/L26） in simulating the seasonal cycle and perpetual winter mean stratospheric circulation as well as its variability by comparing them with the NCEP/NCAR reanalysis. The results show that the model is capable of repro- ducing many key features of the climatology and seasonal variation of the stratospheric circulation despite that the model＇s mean polar vortex is stronger and more zonally symmetric compared to the observation. ~rther diagnosis of the results from a perpetual-January-run of the SAMIL/LASG GCM indicates that the dominant winter-season oscillation mode in the model＇s stratosphere exhibits a similar inter-seasonal timescale with similar spatial patterns as those inferred from the NCEP/NCAR reanalysis. In particular, the simulated polar vortex oscillation mode exhibits a dominant inter-seasonal timescale of about 120 days, and is accompanied with the simultaneous poleward and downward propagation of temperature anomalies in the stratosphere and the equatorward propagation of temperature anomalies in the troposphere. More encouragingly, the 26-layer version of the SAMIL/LASG GCM is able to produce three strong Stratospheric Sudden Warming events during the 1825 days of perpetual-January integration, with the polar westerly jet completely reversed for a few weeks without imposing any prescribed anomalous forcing at the lower boundary.In this paper, we examine the performance of the 26-level version of the SAMIL/LASG GCM （R42/L26） in simulating the seasonal cycle and perpetual winter mean stratospheric circulation as well as its variability by comparing them with the NCEP/NCAR reanalysis. The results show that the model is capable of repro- ducing many key features of the climatology and seasonal variation of the stratospheric circulation despite that the model＇s mean polar vortex is stronger and more zonally symmetric compared to the observation. ~rther diagnosis of the results from a perpetual-January-run of the SAMIL/LASG GCM indicates that the dominant winter-season oscillation mode in the model＇s stratosphere exhibits a similar inter-seasonal timescale with similar spatial patterns as those inferred from the NCEP/NCAR reanalysis. In particular, the simulated polar vortex oscillation mode exhibits a dominant inter-seasonal timescale of about 120 days, and is accompanied with the simultaneous poleward and downward propagation of temperature anomalies in the stratosphere and the equatorward propagation of temperature anomalies in the troposphere. More encouragingly, the 26-layer version of the SAMIL/LASG GCM is able to produce three strong Stratospheric Sudden Warming events during the 1825 days of perpetual-January integration, with the polar westerly jet completely reversed for a few weeks without imposing any prescribed anomalous forcing at the lower boundary.

关 键 词：SAMIL/LASG GCM （R42/L26） winter stratospheric circulation 

分 类 号：P434[天文地球—大气科学及气象学]