Phase Characterization of Cold Sector Southern Ocean Cloud Tops: Results From SOCRATES
Phase Characterization of Cold Sector Southern Ocean Cloud Tops: Results From SOCRATES
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DOI：
10.1029/2020jd033673
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发表时间：
2020-11
期刊：
影响因子：
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通讯作者：
T. J. Zaremba;R. Rauber;G. McFarquhar;M. Hayman;Joseph A. Finlon;D. Stechman
中科院分区：
文献类型：
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作者：
T. J. Zaremba;R. Rauber;G. McFarquhar;M. Hayman;Joseph A. Finlon;D. Stechman
对于一个给定的云，云顶是否主要由冰晶或过冷液滴组成在云的整体辐射效应中起着很大的作用。这项研究使用了在南大洋云、辐射、气溶胶传输实验研究（SOCRATES）期间来自12个高空飞行段的并置机载雷达、激光雷达和热力学数据，以表征南大洋（SO）冷扇区云顶阶段（即，云顶温度（CTT）的函数。开发了一个训练数据集，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相位分类。这些分类，然后用来确定占主导地位的云顶阶段。案例研究显示了在SO上不同CTT范围（−3°C < CTTs < −28°C）的云顶过冷液态水的例子。在SOCRATES期间，67.4%的采样云顶的CTTs小于0°C。在取样的冰点以下云顶中，91.7%在顶部96米处存在过冷液态水，74.9%完全被归类为液体。在CTT中发现了液态云顶，温度低至-30 °C。水平云量也被确定为云顶高度中值的函数。
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.