长波区间太阳辐射对气候模拟的影响

长波区间的太阳辐射在气候模式中往往被忽略。利用国家气候中心BCC_AGCM2.0.1大气环流模式,采用矩阵算子辐射传输算法,研究了长波区间太阳辐射对气候模式辐射通量和温度模拟结果的影响。结果表明,以ISCCP和CERES辐射资料为标准,考虑长波区间太阳辐射后,长波区间晴空大气地表向下辐射通量平均误差减小2.05 W/m2,均方根误差减少1.29 W/m2;长波区间晴空大气模式顶向上辐射通量平均误差减小0.70 W/m2,均方根误差减小0.21 W/m2;长波区间有云大气地表向下辐射通量平均误差减小1.38 W/m2,均方根误差减小1.03 W/m2;长波区间有云大气模式顶向上辐射通量平均误差减小0.99 W/m2,均方根误差减小0.30 W/m2。以ECMWF再分析资料为标准,考虑长波区间太阳辐射后,赤道地区上对流层—下平流层区域温度的冷偏差得到改善,对流层顶温度平均误差减小0.27 K,均方根误差减小0.25 K。

Effect of solar radiation in longwave region on climate simulations

The solar radiation in longwave region is usually neglected in climate models.The matrix formulations for the radiative transfer are applied into the general circulation model (BCC_AGCM2.0.1) developed by National Climate Center to test the effect on simulated radiation flux and temperature after adding the calculation of solar radiation in longwave region.Results show that,relative to the ISCCP and CERES radiation data,the simulated downward radiation flux in longwave region in surface in clear sky is reduced 2.05 W/m² by mean error and 1.29 W/m² by root-mean-square error.The upward radiation flux in longwave region at the top of climate model in clear sky is reduced 0.70 W/m² by mean error and 0.21 W/m² by root-mean-square error.The downward radiation flux in longwave region in surface in whole sky is reduced 1.38 W/m² by mean error and 1.03 W/m² by root-mean-square error.The upward radiation flux in longwave region at the top of climate model in whole sky is reduced 0.99 W/m² by mean error and 0.30 W/m² by root-mean-square error.Relative to ECMWF reanalysis data,the method including solar radiation in longwave region can improve the cold bias simulations of temperature in the region between upper troposphere and lower stratosphere over the equatorial region.The tropopause temperature is reduced 0.27 K by mean error and 0.25 K by root-mean-square error.