SAMIL模式中Tiedtke积云对流方案对热带降水模拟的影响  

The Impacts of the Modified Tiedtke Cumulus Convective Parameterization Scheme on the Tropical Rainfall Simulation in SAMIL Model

作　　者：刘琨[1,2,3] 刘屹岷[1] 吴国雄[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]中国气象科学研究院数值预报中心,北京100081 [3]中国科学院研究生院,北京100049

出　　处：《大气科学》2010年第1期163-174,共12页Chinese Journal of Atmospheric Sciences

基　　金：国家重点基础研究发展规划项目2006CB403607;国家自然科学基金资助项目40925015;40821092;40810059005

摘　　要：目前,大多数全球耦合模式及大气环流模式在降水模拟中普遍存在不同程度的"热带偏差"问题,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所发展的全球大气环流谱模式SAMIL-R42L26也存在这一现象,主要表现在SPCZ(南太平洋辐合区)降水过强且过分东伸、赤道附近降水偏少等方面。本文通过修改SAMIL中的积云对流方案有效地削弱了这一偏差,并进一步探讨其原因,发现对流方案修改后,改变了对流层低层至地面的温度分布状态,进而影响了风速及散度场的模拟,最终通过垂直速度的调整反作用于对流过程。比较修改前后对流过程云底质量通量,发现修改后的方案主要通过削弱浅对流来提高热带降水的模拟性能。In general there exists ＂double ITCZ＂ bias either in coupled models or in atmospheric general circulation models; so docs in the new version of the LASG/IAP （State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics （Institute of Atmospheric Physics. Chinese Academy of Sciences） spectral atmospheric model SAMIL R421.26 ： there is less rainfall near the equator while more rainfall on both the north and south sides. This bias can affect the tropical circulations and global energy balance. However, the bias can be weakened through the modified Tiedtke cumulus convective parameterization scheme. The new scheme can affect the distribution of temperature in the lower troposphere, even on the surface, and the associated wind and divergence fields are also changed, which in turn create conditions for the further development of convection, forming a positive feedback. Finally the eastward extension of precipitation bias along the SPCZ （Southern Pacific Convergence Zone） can be effectively restrained, and at the same time, the insufficient rainfall over the tropical warm pool is increased.

关 键 词：大气环流模式 积云对流方案 降水 热带偏差 

分 类 号：P435[天文地球—大气科学及气象学]