This study extended a method to evaluate rain microphysics in a shallow cumulus regime using space‐borne radar observational data with a forward simulator of satellite measurements. We compared a two‐moment bulk scheme with a two‐moment bin scheme. A dynamic‐kinematic model was used to isolate cloud microphysics processes from their interactions with dynamics. The relationship between horizontally averaged reflectivity Z_m and optical depth from the cloud top τ_d, that is, the Z_m‐τ_d relationship, was similar between the bulk and the bin schemes for clouds with large updraft velocity and clean cloud condensation nuclei (CCN). However, the differences in the Z_m‐τ_d relationship between the two schemes became more apparent for clouds with smaller updraft velocity or polluted CCN. For these clouds, the differences resulted from differences in the autoconversion rate. We increased the autoconversion rate by decreasing the shape parameter of the cloud droplet size distribution in the bulk scheme. This reduced the differences in the Z_m‐τ_d relationship between the two schemes, indicating that for these clouds, the autoconversion rate of a cloud microphysics scheme can be evaluated by the Z_m‐τ_d relationship derived from satellite observations. Although the clouds with the smaller updraft velocity or the polluted CCN did not contribute to the rainfall amount significantly, the lifetime of these clouds greatly affected the radiation budget. Thus, the improvement in the autoconversion rate for such weak cumulus clouds provides a better representation of precipitation efficiency and is important for global climate evaluations.

中文翻译：

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使用雷达模拟器和数值模型评估雨水微观物理：两步大体积和光谱箱云微观物理方案的比较

这项研究扩展了一种方法，该方法利用星载雷达观测数据和卫星测量的前向模拟器评估浅积云区的雨水微物理学。我们将两时刻批量方案与两时刻仓方案进行了比较。使用动态运动学模型将云微观物理过程与动力学之间的相互作用隔离开来。水平平均的反射率之间的关系Ž_米从云顶部和光学厚度τ _d，即，ž_米-τ _d的关系，是体积和用于云具有大的上升气流的速度和清洁云凝结核的bin方案（之间相似CCN）。但是，Z _m的差异- τ _d的两个方案之间的关系成为云具有较小的上升气流速度或污染CCN更加明显。对于这些云，差异是由自动转换率的差异引起的。在整体方案中，我们通过减小云滴尺寸分布的形状参数来提高自动转换率。这减少了差异ž_米- τ _d的两个方案之间的关系，表明对于这些云中，云微方案的自动转换率可通过评估ž_米- τ _d从卫星观测得出的关系。尽管上升速度较小的云或受污染的CCN并未显着影响降雨量，但这些云的寿命极大地影响了辐射预算。因此，这种弱积云的自动转换率的提高可以更好地表示降水效率，对于全球气候评估非常重要。