Reducing the climate shift in a new coupled model  

作　　者：Yanli Tang Lijuan Li Wenjie Dong Bin Wang 

机构地区：[1]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences,Beijing 100029, China [2]School of Atmospheric Sciences, Sun Yat-sen University,Zhuhai 519082, China [3]CAS Center for Excellent in Tibetan Plateau Earth Sciences,Beijing 100101, China [4]Ministry of Education Key Laboratory for Earth System Modeling, Center of Earth System Science (CESS),Tsinghua University, Beijing 100084, China

出　　处：《Science Bulletin》2016年第6期488-494,共7页科学通报（英文版）

基　　金：supported by the CAS Strategic Priority Research Program (XDA05110304);the National 973 Basic Research Program of China (2015CB954102);the National Natural Science Foundation of China (41330527, 41205079, and 41305040)

摘　　要：Climate drift refers to spurious long-term changes that may be inherent in coupled models when external forcing factors are fixed. Understanding the sources of this drift and tuning the drift are crucial for obtaining reasonable simulations from coupled models. To prepare for the upcoming Coupled Model Intercomparison Project Phase 6, a new coupled model has been constructed based on the Community Earth System Model and the Grid-point Atmospheric Model of IAP LASG version 2. However, the surface temperature predicted by the new model is too underestimated, and this underestimation is caused by a type of climate drift, i.e., ‘‘initial shock.'' This study analyzes the source of the cold surface temperature from the perspective of energy balance and attempts to reduce the surface temperature drift by tuning the relative humidity threshold for low cloud.Climate drift refers to spurious long-term changes that may be inherent in coupled models when external forcing factors are fixed. Understanding the sources of this drift and tuning the drift are crucial for obtaining reasonable simulations from coupled models. To prepare for the upcoming Coupled Model Intercomparison Project Phase 6, a new coupled model has been constructed based on the Community Earth System Model and the Grid-point Atmospheric Model of IAP LASG version 2. However, the surface temperature predicted by the new model is too underestimated, and this underestimation is caused by a type of climate drift, i.e., ‘‘initial shock.’’ This study analyzes the source of the cold surface temperature from the perspective of energy balance and attempts to reduce the surface temperature drift by tuning the relative humidity threshold for low cloud.

关 键 词：Climate drift CESM–GAMIL2 Initial shock Relative humidity threshold 

分 类 号：P467[天文地球—大气科学及气象学]