RegCM4对中国东部区域气候模拟的辐射收支分析  

The radiation budget in a regional climate simulation by RegCM4 for eastern China

作　　者：韩振宇[1] 王宇星[2] 聂羽[1] 

机构地区：[1]中国气象局国家气候中心,北京100081 [2]国家海洋局海洋减灾中心,北京100194

出　　处：《大气科学学报》2016年第5期683-691,共9页Transactions of Atmospheric Sciences

基　　金：中国气象局气候变化专项项目(CCSF201626;CCSF201509);国家自然科学基金资助项目(41405101);公益性行业(气象)科研专项(GYHY201306019)

摘　　要：利用卫星和再分析数据,评估了区域气候模式Reg CM4对中国东部地区辐射收支的基本模拟能力,重点关注地表净短波(SNS)、地表净长波(SNL)、大气顶净短波(TNS)、大气顶净长波(TNL)4个辐射分量。结果表明:1)短波辐射的误差值在夏季较大,而长波辐射的误差值在冬季较大。但各辐射分量模拟误差的空间分布在冬、夏季都有较好的一致性。2)对于地表辐射通量,SNS表现为正偏差(向下净短波偏多),在各分量中误差最大,区域平均误差值近50 W/m2;SNL表现为负偏差(向上净长波偏多);对于大气顶辐射通量,TNS和TNL分别表现为"北负南正"的误差分布和整体正偏差。3)利用空间相关和散点线性回归方法对4个辐射分量的模拟误差进行归因分析,发现在云量、地表反照率、地表温度三个直接影响因子中,云量模拟误差的贡献最大,中国东部地区云量模拟显著偏少。The net radiation at the top of the atmosphere （TOA） is one of the most important driving forces of the Earth＇s climate system, while the radiation budget of the climate system directly influences atmospheric and oce- anic motion,as well as the atmospheric water cycle.In this paper,the performance of the regional climate model RegCM4 in simulating the radiation budget over eastern China is evaluated.A long-term simulation at a grid spac- ing of 25 km driven by ERA-Interim data for the period 1990--2010 is conducted.The East Asia domain of phase II of the international COordinated Regional climate Downscaling EXperiment （CORDEX） is used as the model domain.The simulation is compared with a satellite dataset and reanalysis over eastern China during 2001--10 in terms of surface net shortwave （ SNS ）, surface net longwave （ SNL）, TOA net shortwave （ TNS）, and TOA net longwave（TNL） radiation.Results show that biases in shortwave fluxes are larger in summer, and biases in long- wave fluxes are larger in winter.However, spatial distributions of the biases in summer and winter are similar.For surface fluxes, biases of SNS are positive （ overestimation of net downward shortwave flux）, with a regional aver- age of nearly 50 W/m2 ,which is the maximum among these radiation flux biases.Biases of SNL are negative（ o- verestimation of net upward longwave flux）.For TOA fluxes,biases of TNS are negative in the north but positive in the south,and biases of TNL are overall positive.Attribution analysis on the biases in radiation fluxes is con- ducted by two methods--spatial correlation and linear regression.The biases in the cloud fraction, surface albedo, and surface temperature are considered.We find that biases in the radiation fluxes can be explained,to a large de- gree ,by significant negative biases in cloud fraction.

关 键 词：辐射收支 模拟评估 区域气候模式 云量地表反照率 

分 类 号：P422.1[天文地球—大气科学及气象学]