积云参数化方案对热带降水年循环模态模拟的影响  

The Annual Modes of Tropical Precipitation Simulated with LASG/IAP AGCM:Sensitivity to Convection Schemes

作　　者：张丽霞[1,2] 周天军[1] 曾先锋[1,2] 陈昊明[3] 包庆[1] 

机构地区：[1]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室,北京100029 [2]中国科学院研究生院,北京100049 [3]中国气象科学研究院,北京100081

出　　处：《大气科学》2011年第4期777-790,共14页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金资助项目40890054;40821092;财政部/科技部公益性行业专项GYHY200706005;GYHY200706010

摘　　要：本文利用中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室(LASG)发展的大气环流模式(SAMIL),采用Zhang-McFarlane(ZM)和Tiedtke(TDK)两种积云对流参数化方案,讨论了积云对流参数化方案对热带降水年循环模态模拟的影响。结果表明,两种积云对流参数化方案均能合理再现热带降水年循环模态的基本分布特征。SAMIL两种对流方案中热带太平洋地区的春秋非对称模态偏差较大,印度季风以及北澳季风区季风模拟强度偏弱,西北太平洋季风以及非洲季风、美洲季风模态偏强。SAMIL两种参数化方案模拟的季风模态偏差主要来自于模式对北半球夏季西北太平洋降水的模拟。西北太平洋夏季,SAMIL两种参数化方案的对流层温度低层偏暖,高层偏冷,如此造成的对流不稳定是西北太平洋对流异常偏强,降水偏多的原因之一,同时模式中经向温度梯度模拟偏低,直接影响到东亚副热带西风急流偏弱,是急流出口区右侧的西北太平洋对流异常的动力条件。两种参数化方案的差异主要体现在ZM方案中的西北太平洋地区季风模态降水强于TDK方案,ZM方案低层比湿明显强于TDK方案与观测,是ZM方案夏季西北太平洋季风降水强于TDK方案与观测的重要因子之一。西北太平洋地区温度和湿度场的改进是SAMIL后续发展过程中需要重点解决的问题之一。The annual modes of tropical precipitation are simulated with a Spectrum Atmospheric General Circulation Model（SAMIL） developed by LASG/IAP.Sensitivity of the model＇s response to convection schemes is discussed.Two convection schemes,i.e.the revised Zhang-McFarlane（ZM） and Tiedtke（TDK） convection schemes,are employed in two sets of AMIP-type SAMIL simulations,respectively.The major characteristics of the annual mean precipitation can be reasonably reproduced in both simulations.There are some uniform simulation biases when using the ZM and TDK schemes.Both of them show bad performance in the simulation of spring-fall asymmetric mode.The simulated Indian monsoon and northern Australian monsoon are weaker,while the western North Pacific,African and American monsoons are stronger than the observations.The simulated bias of monsoon mode is derived from the simulation of the western North Pacific（NWP） precipitation in the boreal summer.In the boreal summer,the simulated temperature with both the schemes is cooler than that from the NCEP data in the upper troposphere and warmer in the lower troposphere,which results in convective instability in the NWP and heavier precipitation there.The mean temperature from the surface to the tropopause is cooler than the observations in the simulations.It leads to the weaker temperature gradient and weaker westerly jet over the NWP.The weaker westerly jet provides favorable dynamic condition for the convection anomaly over the NWP.Nonetheless,there are also some differencs between the TDK and ZM schemes.The simulated monsoon mode in the western North Pacific is stronger with the ZM scheme than with the TDK scheme.The simulated specific humidity is larger with the ZM scheme than with the TDK scheme.It is one of the reasons that the simulated NWP summer monsoon precipitation is heavier with the ZM scheme.The performance of the SAMIL in simulating the tropospheric temperature and humidity over the NWP deserves further improvement.

关 键 词：积云对流参数化 全球季风 降水年循环模态 

分 类 号：P435[天文地球—大气科学及气象学]