For a given cloud, whether the cloud top is predominately made up of ice crystals or supercooled liquid droplets plays a large role in the clouds overall radiative effects. This study uses collocated airborne radar, lidar, and thermodynamic data from 12 high‐altitude flight legs during the Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES) to characterize Southern Ocean (SO) cold sector cloud top phase (i.e., within 96 m of top) as a function of cloud top temperature (CTT). A training data set was developed to create probabilistic phase classifications based on High Spectral Resolution Lidar data and Cloud Radar data. These classifications were then used to identify dominant cloud top phase. Case studies are presented illustrating examples of supercooled liquid water at cloud top at different CTT ranges over the SO (−3°C < CTTs < −28°C). During SOCRATES, 67.4% of sampled cloud top had CTTs less than 0°C. Of the subfreezing cloud tops sampled, 91.7% had supercooled liquid water present in the top 96 m and 74.9% were classified entirely as liquid‐bearing. Liquid‐bearing cloud tops were found at CTTs as cold as −30°C. Horizontal cloud extent was also determined as a function of median cloud top height.

中文翻译：

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寒区南部海洋云顶的相特征：SOCRATES的结果

对于给定的云，无论是云顶主要由冰晶还是过冷液滴组成，都对云的整体辐射效应起着重要作用。本研究使用来自南方海洋云期间的12个高空飞行航段的并置机载雷达，激光雷达和热力学数据，辐射，气溶胶运输实验研究（SOCRATES）来表征南部海洋（SO）冷区云顶相（即云顶温度（CTT）的函数）（最高96 m）。开发了训练数据集以基于高光谱分辨率激光雷达数据和云雷达数据创建概率阶段分类。然后使用这些分类来确定主要的云顶阶段。提出了案例研究，以举例说明在SO上不同CTT范围（-3°C <CTTs <-28°C）的云顶过冷液态水的示例。在SOCRATES期间，采样云顶的67.4％的CTT低于0°C。在所采样的亚冻结云顶中，有91.7％的过冷液态水存在于96 m的顶面中，而74.9％的云顶完全归为液态。在CTT处发现的液态云顶温度低至−30°C。还确定了水平云量作为中值云顶高度的函数。