Cloud Properties Observed From the Surface and by Satellite at the Northern Edge of the Southern Ocean
Cloud Properties Observed From the Surface and by Satellite at the Northern Edge of the Southern Ocean
复制标题
从南大洋北缘表面和卫星观测到的云特性
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
A. Protat
中科院分区：
文献类型：
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作者：
S. Alexander;A. Protat
2013年7月至2014年2月，我们在南大洋北部边缘的澳大利亚格里姆角（40.7°S, 144.7°E）部署了一个拉曼去极化激光雷达，通过该雷达我们确定了云边界、云相、冰virga和云有效顶高。我们将地面激光雷达与格里姆角1000公里范围内的雷达/激光雷达（DARDAR）数据集的结果进行了比较。DARDAR将来自CloudSat和云气溶胶激光雷达的信息与正交偏振（CALIOP）仪器相结合。我们提取的单层云足够薄，信号可以出现在云的背面，并且具有液态云顶相。这些条件最大限度地提高了地面激光雷达和雷达同时观测同一云的垂直范围的可能性。这些单层云的低层云出现频率的差异表明，与基于地面的激光雷达相比，DARDAR低估了0.2-1.0 km高度的云。当存在多个云层时，该高度区域的低估约为2.5倍。格里姆角激光雷达在中层层状过冷水云中观测到的非均匀冰川作用与之前在南大洋附近的地面观测报告相似，其中一半云在云顶温度为- 20°C时沉淀冰。在DARDAR数据集中，这种转变发生在- 15°C左右，这种差异可能是由于地面激光雷达在探测降水冰时的灵敏度低于地面雷达所能观测到的。
A Raman depolarization lidar was deployed at Cape Grim, Australia (40.7°S, 144.7°E), at the northern edge of the Southern Ocean from July 2013 to February 2014 from which we determine cloud boundaries, cloud phase, ice virga, and cloud effective top heights. We compare surface‐based lidar with results from the raDAR/liDAR (DARDAR) data set within 1,000 km of Cape Grim. DARDAR combines information from the CloudSat and Cloud‐Aerosol Lidar with Orthogonal Polarization (CALIOP) instruments. We extract single‐layer clouds that are sufficiently thin for signal to be present on the farside of the cloud and which have a liquid cloud top phase. These conditions maximize the likelihood that both surface‐based lidar and DARDAR are observing the full vertical extent of the same clouds. Differences in low‐level cloud occurrence frequencies for these single‐layer clouds reveal that DARDAR underestimates cloud at 0.2–1.0 km altitude by a factor of 3 compared with the surface‐based lidar. When multiple cloud decks are present, the underestimate in this altitude region is around 2.5 times. Heterogeneous glaciation observed by the Cape Grim lidar in midlevel stratiform supercooled water clouds is similar to that reported by previous surface‐based observations adjacent to the Southern Ocean, with half of these clouds precipitating ice at cloud top temperatures of −20°C. This transition occurs around −15°C in the DARDAR data set, and this difference is likely due to the reduced sensitivity of surface‐based lidar in detecting precipitating ice compared with what a surface‐based radar could observe.
影响因子：
4.4
作者：
Delanoe, Julien;Hogan, Robin J.
通讯作者：
Hogan, Robin J.