BCC大气环流模式对亚澳季风年际变率主导模态的模拟  

Simulation of the leading mode of Asian-Australian monsoon interannual cariability with the Beijing Climate Center atmospheric general circulation model.

作　　者：王璐[1,2] 周天军[1] 吴统文[3] 吴波[1,2] 

机构地区：[1]中国科学院大气物理研究所LASG,北京100029 [2]中国科学院研究生院,北京100049 [3]中国气象局国家气候中心,北京100081

出　　处：《气象学报》2009年第6期973-982,共10页Acta Meteorologica Sinica

基　　金：财政部/科技部公益类行业专项(GYHY200706010;GYHY200706005);国家自然科学基金(40625014;40821092;90711004)

摘　　要：利用观测海温驱动下的北京气候中心大气环流模式(BCC-AGCM)1979—2000年的模拟数据,从亚澳季风(A-AM)年际变率的角度,对该模式的性能进行了分析。通过季节依赖的EOF分析方法(S-EOF)得到观测第1模态,与ENSO从暖位相向冷位相的转变相联系,并伴随东南印度洋和西北太平洋的降水异常随季节变化。该模态具有准2a和4—6 a周期的谱峰。分析结果显示,BCC模式可以很好地模拟出第1模态的时间变化特征,及其与ENSO位相的同步关系。但是,模式模拟的降水空间型与观测存在偏差,这主要是由于模式对环流场模拟的偏差造成的,具体表现在西北太平洋(WNP)反气旋和南印度洋(SIO)反气旋的季节锁相模拟偏差。前者与模式模拟的环流场整体偏东有关,后者是由于SIO反气旋的发展和衰亡过程受印度洋局地海气相互作用影向,而单独大气模式则无法合理地反映这一过程。另外,模式模拟的第一模态降水空间型在夏季效果较差,原因在于模式模拟的夏季平均降水量存在偏差,尤其是东南印度洋的降水量模拟偏少。进一步分析表明,这可能与对流参数化方案的选择有关。The performance of Beijing Climate Center（BCC） atmospheric general circulation model version 2.0.1（BCC-AGCM） was evaluated in reproducing the leading mode of Asian-Australian monsoon（A-AM） rainfall interannual variability forced by historical sea surface temperature covering the period of 1979—2000.The observed first mode revealed by the seasonal-reliant EOF analysis is associated with the turn about of warming to cooling in the（ENSO） and is featured by the seasonal evolution of the precipitation anomalies over the southeastern Indian Ocean and the western North Pacific Ocean.This mode has a quasi biennial oscillation and a low frequency component（4-6 year）.The corresponding model results indicate that the model can reasonably reproduce the year-to-year temporal variations of the first leading mode,as well as its relationship with ENSO evolution.The deficiency of BCC-AGCM lies in reproducing the spatial pattern of the first mode,which is possibly related to the model biases in simulating general circulation.The observed western North Pacific（WNP） anticyclone is onset in D（0） JF（1）,while the simulated one is onset in SON（0）.This deficiency may be due to the systematic eastward shift of simulated circulation over this region.In addition,the phase locking of the South Indian Ocean（SIO） anticyclone reproduced by BCC is boreal winter,one season later than its counterpart in observation.It may be related to the strategies of the stand-alone AGCM simulation in which the local air-sea coupling process that is important for the evolution of the SIO anticyclone is neglected.Furthermore,the model has the lowest skill in reproducing rainfall distribution in boreal summer.Further discussion suggests that this lowest skill may be related to simulated bias in mean state of summer rainfall,especially the lack of precipitation over the southeastern Indian Ocean,which is possibly resulted from the convection scheme.

关 键 词：亚澳季风 年际变率 大气环流模式 

分 类 号：P435.2[天文地球—大气科学及气象学]