Comparison of Freeboard Retrieval and Ice Thickness Calculation From ALS, ASIRAS, and CryoSat-2 in the Norwegian Arctic to Field Measurements Made During the N-ICE2015 Expedition
Comparison of Freeboard Retrieval and Ice Thickness Calculation From ALS, ASIRAS, and CryoSat-2 in the Norwegian Arctic to Field Measurements Made During the N-ICE2015 Expedition
复制标题
挪威北极 ALS、ASIRAS 和 CryoSat-2 的干舷反演和冰厚计算与 N-ICE2015 探险期间进行的现场测量的比较
DOI：
10.1002/2017jc013233
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发表时间：
2018
影响因子：
--
通讯作者：
G. Liston
中科院分区：
文献类型：
--
作者：
Jennifer King;H. Skourup;S. Hvidegaard;A. Rösel;S. Gerland;G. Spreen;C. Polashenski;V. Helm;G. Liston
我们提供了机载激光扫描仪(ALS)、机载合成孔径和干涉雷达高度计系统(ASIRAS)和CryoSat-2卫星雷达高度计的超高测量；直升机和地面电磁测深的冰厚测量；以及冰特性的点测量。该案例研究于2015年4月在北冰洋考察期间在斯瓦尔巴特群岛以北的北冰洋进行。该地区的代表是厚达1.12米的积雪和普遍存在的负干涉区。结果表明，CryoSat-2和ASIRAS的主散射面更接近ALS测得的积雪干板，而不是现场测量的冰干板。这一案例研究证明了雷达测高中超高反演的复杂性。我们表明，即使在寒冷(低于−15°C)的条件下，雷达干板也可以在数十公里的区域尺度上接近积雪干板。我们从CryoSat-2得到了研究区域的模式海冰厚度为3.9m，而测量的总厚度为1.7m，导致海冰厚度被高估了2倍。我们的结果也强调了关于积雪深度和密度的逐年区域尺度信息的重要性，因为这影响了海冰干板和雷达穿透，并且是用于将雷达干板转换为海冰厚度的静力平衡方程的关键组成部分。
We present freeboard measurements from airborne laser scanner (ALS), the Airborne Synthetic Aperture and Interferometric Radar Altimeter System (ASIRAS), and CryoSat-2 SIRAL radar altimeter; ice thickness measurements from both helicopter-borne and ground-based electromagnetic-sounding; and point measurements of ice properties. This case study was carried out in April 2015 during the N-ICE2015 expedition in the area of the Arctic Ocean north of Svalbard. The region is represented by deep snow up to 1.12 m and a widespread presence of negative freeboards. The main scattering surfaces from both CryoSat-2 and ASIRAS are shown to be closer to the snow freeboard obtained by ALS than to the ice freeboard measured in situ. This case study documents the complexity of freeboard retrievals from radar altimetry. We show that even under cold (below −15°C) conditions the radar freeboard can be close to the snow freeboard on a regional scale of tens of kilometers. We derived a modal sea-ice thickness for the study region from CryoSat-2 of 3.9 m compared to measured total thickness 1.7 m, resulting in an overestimation of sea-ice thickness on the order of a factor 2. Our results also highlight the importance of year-to-year regional scale information about the depth and density of the snowpack, as this influences the sea-ice freeboard, the radar penetration, and is a key component of the hydrostatic balance equations used to convert radar freeboard to sea-ice thickness.
影响因子：
4.4
作者：
Hertig, E.;Jacobeit, J.
通讯作者：
Jacobeit, J.