晴天地表太阳辐射的参数化

Parameterization of Clear-Sky Surface Solar Radiation

摘要:

讨论了晴天地表太阳总辐射和地表太阳净辐射瞬时值的参数化方法。首先利用辐射传输模式和中纬度夏季标准大气廓线,分谱带计算晴天各种大气条件下地表反射率取定值时的地表太阳总辐射,并把所得的结果作为标准资料,提出参数化方案。然后将地表反射率的影响作为误差项进行订正,从而得到各种地表反射率条件下的晴天地表太阳净辐射的计算方法。该方法的拟合精度较高,拟合值与辐射模式标准值的平均相对误差在0.3%以下。该参数化公式可以用于大尺度数值模式中地表辐射平衡的计算,以期达到地表辐射平衡计算与模式积分同步进行的目的。

关键词:晴天太阳总辐射;反射率;参数化

Abstract:

The previous methods to parameterize instantaneous clearsky surface total radiation and net radiation is discussed.The surface solar total radiation is first calculated when albedo is fixed under clear-sky varying atmospheric conditions by using the radiation transfer model and the model atmosphere profile of the middle latitude summer,and a parameterization scheme is then proposed based on the result.The parameterization of clear-sky surface solar net radiation under the conditions of various albedos is obtained through the error correction due to albedo variation.It is found that the fitting accuracy is higher and the mean relative error between fitted and standard value is less than 0.3%.The formula can be used to calculate surface radiation budget (SRB) in large-scale numerical models,to make it possible that the calculation of SRB is synchronized with model integration.

Key words:clear-sky solar total radiation;albedo;parameterization