The Correlation of Mesoscale Humidity Anomalies With Mesoscale Organization of Marine Stratocumulus From Observations Over the ARM Eastern North Atlantic Site
The Correlation of Mesoscale Humidity Anomalies With Mesoscale Organization of Marine Stratocumulus From Observations Over the ARM Eastern North Atlantic Site
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DOI：
10.1029/2019jd031056
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发表时间：
2019-12
期刊：
影响因子：
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通讯作者：
Xiaoli Zhou;C. Bretherton
中科院分区：
文献类型：
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作者：
Xiaoli Zhou;C. Bretherton
利用基于柱状水汽路径（WVP）中尺度变化的合成方法，可以很好地表征海洋云顶边界层中尺度细胞组织结构。该方法应用于大气辐射测量（ARM）北大西洋东部站点的地面观测。根据一套卫星和地面观测标准，从2015年底到2018年初，选择了381小时的封闭单元病例和227小时的开放单元病例。中尺度过滤后的云性质与闭云区和开云区WVP之间存在很强的相关性。相对于干气柱，湿气柱中云层较厚，顶高底低，降水较强。总的来说，开放和封闭单体的云性质与中尺度湿度扰动的变化相似，但开放单体的液态水路径与WVP的相关性要弱得多。研究了子云性质与WVP的关系。湿润柱的表面等效电位温度和相对湿度高于干燥柱。中尺度过滤后的云下湍流涡旋耗散率与封闭云胞的WVP呈微负相关。这些结果与Zhou和Bretherton（2019）的封闭细胞中尺度环流概念模型一致。
The structure of mesoscale cellular organization in marine cloud‐topped boundary layers is found to be well characterized by using a novel compositing approach based on mesoscale variations in the column water vapor path (WVP). The approach is applied to ground‐based observations from the Atmospheric Radiation Measurement (ARM) Eastern North Atlantic site. Based on a set of satellite and ground‐based observational criteria, 381 hr of closed‐cell and 227 hr of open‐cell cases were selected from late 2015 to early 2018. Strong correlations are found between mesoscale‐filtered cloud properties and WVP for both closed‐cell and open‐cell regimes. In the moist atmospheric columns, the clouds are thicker with higher tops and lower bases, and stronger precipitation compared to that in the dry columns. Overall, cloud properties of open and closed cells covary similarly with mesoscale moisture perturbations, except that the correlation of liquid water path with WVP is much weaker for open cells. The relations of subcloud properties with WVP are also examined. In the moist columns, surface equivalent potential temperature and relative humidity are higher than in the dry columns. A marginally negative correlation between mesoscale‐filtered subcloud turbulence eddy dissipation rate and WVP is found for closed cells. These results are consistent with the conceptual model of closed cellular mesoscale circulations of Zhou and Bretherton (2019).