A PDF-based hybrid prognostic cloud scheme for general circulation models
A PDF-based hybrid prognostic cloud scheme for general circulation models
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DOI：
10.1007/s00382-008-0489-0
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发表时间：
2009-11
期刊：
影响因子：
4.6
通讯作者：
M. Watanabe;S. Emori;S. Emori;S. Emori;Masaki Satoh;Masaki Satoh;Hiroaki Miura
中科院分区：
文献类型：
--
作者：
M. Watanabe;S. Emori;S. Emori;S. Emori;Masaki Satoh;Masaki Satoh;Hiroaki Miura
介绍了一种新的云参数化方法，它是基于亚网格尺度温度和总含水量波动的预报方程。所提出的方案，称为混合预测云（HPC）参数化，采用简单的概率密度函数（PDF）的水平亚网格尺度的不均匀性，使他们能够改变形状，以响应小尺度的过程，如积云消散和湍流混合。简单的试验表明，HPC方案是非常有利的诊断方案相比，云分数和云水含量在均匀或非均匀强迫。HPC方案的相关性进行了研究，通过实施它的大气成分模式的气候模式MIROC与粗分辨率为T42。对T42模式和全球云分辨模式（GCRM）的短期积分结果的比较表明，HPC方案在一定程度上可以再现GCRM模拟的温度和总含水量的次网格尺度方差和偏度。它还发现，HPC计划显着改变的气候分布在云量，降水量和水分，这都是从使用传统的诊断云计划的模式得到改善。
A new cloud parameterization based on prognostic equations for the subgrid-scale fluctuations in temperature and total water content is introduced for global climate models. The proposed scheme, called hybrid prognostic cloud (HPC) parameterization, employs simple probability density functions (PDFs) to the horizontal subgrid-scale inhomogeneity, allowing them to vary in shape in response to small-scale processes such as cumulus detrainment and turbulent mixing. Simple tests indicate that the HPC scheme is highly favorable as compared to a diagnostic scheme in terms of the cloud fraction and cloud water content under either uniform or non-uniform forcing. The relevance of the HPC scheme is investigated by implementing it in an atmospheric component model of the climate model MIROC with a coarse resolution of T42. A comparison of the short-term integrations between the T42 model and a global cloud resolving model (GCRM) reveals that the HPC scheme can reproduce, to a certain degree, the subgrid-scale variance and skewness of temperature and total water content simulated in the GCRM. It is also found that the HPC scheme significantly alters the climatological distributions in cloud cover, precipitation, and moisture, which are all improved from the model using a conventional diagnostic cloud scheme.