Using Radiative Convective Equilibrium to Explore Clouds and Climate in the Community Atmosphere Model
Using Radiative Convective Equilibrium to Explore Clouds and Climate in the Community Atmosphere Model
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DOI：
10.1029/2021ms002539
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发表时间：
2021-11
影响因子：
6.8
通讯作者：
K. Reed;Levi G. Silvers;A. Wing;I. Hu;B. Medeiros
中科院分区：
文献类型：
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作者：
K. Reed;Levi G. Silvers;A. Wing;I. Hu;B. Medeiros
介绍了在社区大气模式版本5（CAM 5）和版本6（CAM 6）中遵循辐射-对流平衡模式相互比较项目（RCEMIP）协议的辐射-对流平衡（RCE）气候状态的特征和基本差异。本文利用不同的参数化方案，分析了CAM 5和CAM 6中RCE状态下的云、水汽、降水和环流特征，以及热带地区对地面增暖的响应。总体而言，CAM 5模拟了更高的降水率，导致更大的全球平均降水量，尽管与CAM 6相比，输出长波辐射较低。云的结构，特别是云液的量和垂直位置的差异，存在于CAM版本之间，并且可以部分地与浅对流和边界层过程的不同表示有关。CAM 5和CAM 6都模拟了云分数、相对湿度和云冰的相似峰值，这与使用类似的深对流参数化有关。这些铁砧云的上升和下降的程度是对地表变暖的反应。更普遍的是，极端降水、对流聚集和气候敏感性随着CAM 5和CAM 6的变暖而增加。该分析为未来的研究提供了一个基准，探索云，对流和气候在CAM与RCEMIP协议，现在可在社区地球系统模型。这些结果进行了讨论的背景下，现实的气候模拟使用CAM 5和CAM 6，突出了有用的分层建模方法来了解模型和参数化的敏感性，以告知模型的开发工作。
Characteristics of, and fundamental differences between, the radiative‐convective equilibrium (RCE) climate states following the Radiative‐Convective Equilibrium Model Intercomparison Project (RCEMIP) protocols in the Community Atmosphere Model version 5 (CAM5) and version 6 (CAM6) are presented. This paper explores the characteristics of clouds, moisture, precipitation and circulation in the RCE state, as well as the tropical response to surface warming, in CAM5 and CAM6 with different parameterizations. Overall, CAM5 simulates higher precipitation rates that result in larger global average precipitation, despite lower outgoing longwave radiation compared to CAM6. Differences in the structure of clouds, particularly the amount and vertical location of cloud liquid, exist between the CAM versions and can, in part, be related to distinct representations of shallow convection and boundary layer processes. Both CAM5 and CAM6 simulate similar peaks in cloud fraction, relative humidity, and cloud ice, linked to the usage of a similar deep convection parameterization. These anvil clouds rise and decrease in extent in response to surface warming. More generally, extreme precipitation, aggregation of convection, and climate sensitivity increase with warming in both CAM5 and CAM6. This analysis provides a benchmark for future studies that explore clouds, convection, and climate in CAM with the RCEMIP protocols now available in the Community Earth System Model. These results are discussed within the context of realistic climate simulations using CAM5 and CAM6, highlighting the usefulness of a hierarchical modeling approach to understanding model and parameterization sensitivities to inform model development efforts.