Intercomparison of Convective-Aggregation States with two Cloud Resolving Models: DATASET

Radiative-Convective Equilibrium (RCE) is an important modeling paradigm for the tropical atmosphere. In this paradigm, cloud clustering can occur spontaneously, affecting the energy budget of the atmosphere. Here, two models, run in RCE, exhibiting this convective aggregation have been compared with each other and with the results of the Radiative-Convective Equilibrium Model Intercomparison Project (RCEMIP). The two models studied, the SAM (System for Atmospheric Modeling) and the ARPS (Advanced Regional Prediction System), are different in the physical and numerical formulation, allowing us to compare the sensitivity to processes related to the phenomenon of convective organization. In General, the two models present similarities in what concerns precipitation, warming, and drying of the atmosphere and anvil cloud area reduction. All these factors are also within the spread of the RCEMIP values. However, the two models differ both in the convective organization feedback and in the degree of organization. SAM is strongly organized and ARPS is weakly organized. SAM achieves convective organization through clouds-radiative feedback and ARPS achieves it through moisture-convection feedback. These differences can be traced back to the interaction between the microphysics and the sub-cloud layer properties. We suggest that when studying climate sensitivity, climate models should include both types of convective organization mechanisms.

辐射对流平衡（Radiative-Convective Equilibrium，RCE）是热带大气研究中重要的模拟范式。在该范式下，云团簇可自发形成，并对大气能量收支产生影响。本研究针对两种运行于RCE框架下、表现出对流聚合现象的模式开展了对比分析，同时将结果与辐射对流平衡模式比对计划（Radiative-Convective Equilibrium Model Intercomparison Project，RCEMIP）的成果进行了比对。
本研究涉及的两款模式分别为大气模式系统（System for Atmospheric Modeling，SAM）与先进区域预报系统（Advanced Regional Prediction System，ARPS），二者在物理过程与数值方案上存在差异，这使得我们可以对比不同模式对对流组织相关过程的敏感性。
总体而言，两款模式在降水、大气增暖与变干，以及砧状云面积缩减等方面表现出相似性，且上述特征均处于RCEMIP结果的离散区间内。
不过，两款模式在对流组织反馈与组织程度上均存在显著差异：SAM表现出强对流组织特征，其通过云-辐射反馈实现对流组织；而ARPS则呈现弱对流组织特征，其对流组织依赖于水汽-对流反馈。
上述差异可追溯至微物理过程与云下层属性之间的相互作用。我们建议，在开展气候敏感性研究时，气候模式应同时涵盖这两类对流组织机制。