A New Algorithm for Daily Sea Ice Lead Identification in the Arctic and Antarctic Winter from Thermal-Infrared Satellite Imagery
A New Algorithm for Daily Sea Ice Lead Identification in the Arctic and Antarctic Winter from Thermal-Infrared Satellite Imagery
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DOI：
10.3390/rs12121957
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发表时间：
2020-06
期刊：
影响因子：
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通讯作者：
F. Reiser;S. Willmes;G. Heinemann
中科院分区：
文献类型：
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作者：
F. Reiser;S. Willmes;G. Heinemann
海冰覆盖中海冰铅的存在是极地地区的一个关键特征，因为它控制了相对温暖的海洋和寒冷大气之间的热量交换，这是因为湍流、感热和潜热的通量增加。海冰铅促进了海冰的产生，是影响海洋环流的致密水的来源。大气和海洋模式严重依赖观测数据来描述各自的海冰状态，因为数值模式不能明确地产生海冰铅。对于北极，一些铅数据集是可用的，但对于南极，还没有这样的数据。本文提出了一种自动识别卫星热红外图像中引线的新算法。通过使用模糊逻辑，使用各种导联度量来区分真实导联和检测伪影。我们评估输出并提供像素级的不确定度。我们的数据分别以1平方公里的分辨率绘制了冬季月份的每日海冰铅地图，分别为11-4月2002/03-2018/19(北极)和2003-9月-2019年4-9月(南极)。超前频率分布的长期平均值显示出与两个半球的水深结构有关的明显特征。
The presence of sea ice leads in the sea ice cover represents a key feature in polar regions by controlling the heat exchange between the relatively warm ocean and cold atmosphere due to increased fluxes of turbulent sensible and latent heat. Sea ice leads contribute to the sea ice production and are sources for the formation of dense water which affects the ocean circulation. Atmospheric and ocean models strongly rely on observational data to describe the respective state of the sea ice since numerical models are not able to produce sea ice leads explicitly. For the Arctic, some lead datasets are available, but for the Antarctic, no such data yet exist. Our study presents a new algorithm with which leads are automatically identified in satellite thermal infrared images. A variety of lead metrics is used to distinguish between true leads and detection artefacts with the use of fuzzy logic. We evaluate the outputs and provide pixel-wise uncertainties. Our data yield daily sea ice lead maps at a resolution of 1 km2 for the winter months November– April 2002/03–2018/19 (Arctic) and April–September 2003–2019 (Antarctic), respectively. The long-term average of the lead frequency distributions show distinct features related to bathymetric structures in both hemispheres.