Prognostic Precipitation in the MIROC6‐SPRINTARS GCM: Description and Evaluation Against Satellite Observations
Prognostic Precipitation in the MIROC6‐SPRINTARS GCM: Description and Evaluation Against Satellite Observations
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DOI：
10.1029/2018ms001596
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发表时间：
2019-03
影响因子：
6.8
通讯作者：
T. Michibata;Kentaroh Suzuki;M. Sekiguchi;T. Takemura
中科院分区：
文献类型：
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作者：
T. Michibata;Kentaroh Suzuki;M. Sekiguchi;T. Takemura
一个全面的双矩微物理方案被纳入到microc6 - SPRINTARS环流模型（GCM）。新方案包括雨雪预报降水，并考虑其辐射效应。为了评估不同降水处理方法的影响和相关的辐射效应，我们采用传统的诊断方案和新的预测降水方案进行气候模拟，并对后者进行了考虑雪的辐射效应和不考虑雪的辐射效应的测试。预报降水在多个时间步长中维持大气中的降水，它模拟的吸积与自转换的比率大约比诊断方案高一个数量级。这种微物理过程速率的变化倾向于降低云水敏感性，因为自转化过程是气溶胶影响降雨形成的唯一途径。在预报降水方案中，由此产生的人为气溶胶效应减少了约21%。微物理过程速率的改变也改变了水成物的垂直分布，使单层暖云的发生率增加了38%。新方案减轻了先前方案产生的过冷液态水的过剩，并增加了冰水成物的总质量。这两个特征与CloudSat/CALIPSO检索结果一致。雪的辐射效应在长波和短波波段均显著（分别为6.4和5.1 W/m2绝对值），可通过对降水的能量控制来改变降水场。这些结果表明，包括辐射效应在内的预测降水方案对提高气候模式的可靠性作出了不可或缺的贡献。
A comprehensive two‐moment microphysics scheme is incorporated into the MIROC6‐SPRINTARS general circulation model (GCM). The new scheme includes prognostic precipitation for both rain and snow and considers their radiative effects. To evaluate the impacts of applying different treatments of precipitation and the associated radiative effect, we perform climate simulations employing both the traditional diagnostic and new prognostic precipitation schemes, the latter also being tested with and without incorporating the radiative effect of snow. The prognostic precipitation, which maintains precipitation in the atmosphere across multiple time steps, models the ratio of accretion to autoconversion as being approximately an order of magnitude higher than that for the diagnostic scheme. Such changes in microphysical process rates tend to reduce the cloud water susceptibility as the autoconversion process is the only pathway through which aerosols can influence rain formation. The resultant anthropogenic aerosol effect is reduced by approximately 21% in the prognostic precipitation scheme. Modifications to the microphysical process rates also change the vertical distribution of hydrometeors in the manner that increases the fractional occurrence of single‐layered warm clouds by 38%. The new scheme mitigates the excess of supercooled liquid water produced by the previous scheme and increases the total mass of ice hydrometeors. Both characteristics are consistent with CloudSat/CALIPSO retrievals. The radiative effect of snow is significant at both longwave and shortwave (6.4 and 5.1 W/m2 in absolute values, respectively) and can alter the precipitation fields via energetic controls on precipitation. These results suggest that the prognostic precipitation scheme, with its radiative effects incorporated, makes an indispensable contribution to improving the reliability of climate modeling.