Low‐Level Marine Tropical Clouds in Six CMIP6 Models Are Too Few, Too Bright but Also Too Compact and Too Homogeneous
Low‐Level Marine Tropical Clouds in Six CMIP6 Models Are Too Few, Too Bright but Also Too Compact and Too Homogeneous
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六个 CMIP6 模型中的低层海洋热带云太少、太亮，但也太紧凑和太均匀
DOI：
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发表时间：
2022
影响因子：
5.2
通讯作者：
T. Ogura
中科院分区：
文献类型：
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作者：
D. Konsta;J. Dufresne;H. Chepfer;J. Vial;T. Koshiro;Hideaki Kawai;A. Bodas‐Salcedo;R. Roehrig;Masahiro Watanabe;T. Ogura
多项研究表明，大多数气候模型低估了云量并高估了云反射率，特别是热带低层云。在这里，我们分析了六个气候模型模拟的低层热带海洋云的特征，这些模型在 CMIP6 项目中提供了 COSP 输出。 CALIPSO 激光雷达观测和 PARASOL 单向反射率用于模型评估。研究发现，这些模型仍然存在“太少、太亮”的偏差。当云量较低时，反射率尤其会被高估。模型不模拟任何光学薄云。它们无法重现所观察到的随着对流层稳定性降低而增加的云光学深度。这些结果表明，大多数模型没有充分考虑云属性中小尺度空间异质性或观察到的网格尺度上云类型多样性的影响。
Several studies have shown that most climate models underestimate cloud cover and overestimate cloud reflectivity, particularly for the tropical low‐level clouds. Here, we analyze the characteristics of low‐level tropical marine clouds simulated by six climate models, which provided COSP output within the CMIP6 project. CALIPSO lidar observations and PARASOL mono‐directional reflectance are used for model evaluation. It is found that the “too few, too bright” bias is still present for these models. The reflectance is particularly overestimated when cloud cover is low. Models do not simulate any optically thin clouds. They fail to reproduce the increasing cloud optical depth with increasing lower tropospheric stability as observed. These results suggest that most models do not sufficiently account for the effect of the small‐scale spatial heterogeneity in cloud properties or the variety of cloud types at the grid scale that is observed.