Improvement of the Simulation of Cloud Longwave Scattering in Broadband Radiative Transfer Models
Improvement of the Simulation of Cloud Longwave Scattering in Broadband Radiative Transfer Models
复制标题
宽带辐射传输模型中云长波散射模拟的改进
DOI：
10.1175/jas-d-18-0014.1
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发表时间：
2018
影响因子：
3.1
通讯作者：
King, Michael D.
中科院分区：
文献类型：
--
作者：
Tang, Guanglin;Yang, Ping;Kattawar, George W.;Huang, Xianglei;Mlawer, Eli J.;Baum, Bryan A.;King, Michael D.
云长波散射在大气环流模式（GCM）中通常被忽略，但最近的研究表明，它在大气能量收支中起着重要且高度不确定的作用。为了减少由于忽略云长波散射而引起的误差，提出了两种新的辐射率调整方法，以保持宽带辐射传输模拟的计算效率。特别是，两个现有的缩放方法和两个新的调整方法中实现的快速辐射传输模型（RRTM）。然后将结果与基于离散纵标辐射传输模型（DISORT）的结果进行比较，该模型明确地考虑了云的多次散射。这两个缩放方法被证明是提高光学薄云的辐射传输模拟的准确性，但光学厚云有效。然而，调整方法在很宽的范围内减少了计算误差，从光学薄云到厚云。采用该校正方法后，由于忽略云长波散射而引起的误差，对于大气顶部的向上辐照度小于2 W m-2，对于地面向下辐照度小于0.5 W m-2。调整计划被证明是更准确和有效的四流近似，明确占多次散射。忽略云的长波散射会导致地面向下辐照度的低估（冷却效应），但通过调整方法几乎消除了这种误差（变暖效应）。
Cloud longwave scattering is generally neglected in general circulation models (GCMs), but it plays a significant and highly uncertain role in the atmospheric energy budget as demonstrated in recent studies. To reduce the errors caused by neglecting cloud longwave scattering, two new radiance adjustment methods are developed that retain the computational efficiency of broadband radiative transfer simulations. In particular, two existing scaling methods and the two new adjustment methods are implemented in the Rapid Radiative Transfer Model (RRTM). The results are then compared with those based on the Discrete Ordinate Radiative Transfer model (DISORT) that explicitly accounts for multiple scattering by clouds. The two scaling methods are shown to improve the accuracy of radiative transfer simulations for optically thin clouds but not effectively for optically thick clouds. However, the adjustment methods reduce computational errors over a wide range, from optically thin to thick clouds. With the adjustment methods, the errors resulting from neglecting cloud longwave scattering are reduced to less than 2 W m−2for the upward irradiance at the top of the atmosphere and less than 0.5 W m−2for the surface downward irradiance. The adjustment schemes prove to be more accurate and efficient than a four-stream approximation that explicitly accounts for multiple scattering. The neglect of cloud longwave scattering results in an underestimate of the surface downward irradiance (cooling effect), but the errors are almost eliminated by the adjustment methods (warming effect).
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影响因子：
6.8
作者：
Kuo, Chia-Pang;Yang, Ping;Mlawer, Eli J.
通讯作者：
Mlawer, Eli J.
影响因子：
8.9
作者：
Simone M. Costa;K. Shine
通讯作者：
Simone M. Costa;K. Shine
一种通过观测内部散射辐射场确定云单次散射反照率的方法
DOI：
--
发表时间：
1981
期刊：
影响因子：
--
作者：
M. King
通讯作者：
M. King
光学深吸收介质中的内部辐射——I 一维模型的精确解
DOI：
--
发表时间：
1973
期刊：
影响因子：
--
作者：
G. Kattawar;G. Plass
通讯作者：
G. Plass
影响因子：
--
作者：
J. Foot
通讯作者：
J. Foot