Aerosol‐Cloud‐Precipitation Interactions in the Context of Convective Self‐Aggregation
Aerosol‐Cloud‐Precipitation Interactions in the Context of Convective Self‐Aggregation
复制标题
对流自聚集背景下的气溶胶-云-降水相互作用
DOI：
10.1029/2018ms001523
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发表时间：
2019
影响因子：
6.8
通讯作者：
C. Hoose
中科院分区：
文献类型：
--
作者：
H. Beydoun;C. Hoose
我们研究了自聚集辐射对流平衡云分辨模式模拟对云凝结核（CCN）浓度的敏感性。实验是在一个长（2,000公里× 120公里）的通道域上进行的，允许出现多个对流团和干燥的沉降区。CCN浓度的增加会导致干燥地区的湿度增加、中层和高层云增加、辐射冷却减少和降水减少。我们发现，这些趋势是由湿静态能量（MSE）方差测量的自聚集强度下降引起的。在我们的模拟中，降水是相关的，无论是在本地和总的MSE异常的分布。因此，我们量化了绝热/非绝热对MSE异常的贡献的变化（Wing & Emanuel，2014，https：//doi.org/10.1002/2013MS000269），并将这些变化与降水变化联系起来。通过一个简单的两列概念模型，我们认为，降水的减少可以解释为减少平均净辐射冷却和削弱面积加权辐射驱动的沉降速度定义为总辐射冷却的比例在干燥地区和静态稳定性的机械。我们解释了系统的响应，以增加CCN作为一个气溶胶对云和降水的间接影响的一个vegetically约束的实现。
We investigate the sensitivity of self‐aggregated radiative‐convective‐equilibrium cloud‐resolving model simulations to the cloud condensation nuclei (CCN) concentration. Experiments were conducted on a long (2,000‐km × 120‐km) channel domain, allowing the emergence of multiple convective clusters and dry regions of subsidence. Increasing the CCN concentration leads to increased moisture in the dry regions, increased midlevel and upper level clouds, decreased radiative cooling, and decreased precipitation. We find that these trends follow from a decrease in the strength of the self‐aggregation as measured by the moist static energy (MSE) variance. In our simulations, precipitation is correlated, both locally and in total, with the distribution of MSE anomalies. We thus quantify changes in the adiabatic/diabatic contributions to MSE anomalies (Wing & Emanuel, 2014, https://doi.org/10.1002/2013MS000269) and relate those changes to changes in precipitation. Through a simple two‐column conceptual model, we argue that the reduction in precipitation can be explained thermodynamically by the reduction in mean net radiative cooling and mechanistically by the weakening of the area‐weighted radiatively driven subsidence velocity—defined as the ratio of the total radiative cooling over the dry regions and the static stability. We interpret the system's response to increasing CCN as a thermodynamically constrained realization of an aerosol indirect effect on clouds and precipitation.
影响因子：
4.9
作者：
T. Stein;C. Holloway;I. Tobin;S. Bony
通讯作者：
T. Stein;C. Holloway;I. Tobin;S. Bony