Assessment of Arctic Sea Ice Thickness Estimates From ICESat-2 Using IceBird Airborne Measurements
Assessment of Arctic Sea Ice Thickness Estimates From ICESat-2 Using IceBird Airborne Measurements
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DOI：
10.1109/tgrs.2020.3022945
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发表时间：
2021-05
影响因子：
8.2
通讯作者：
Xiaoyi Shen;C. Ke;Qimao Wang;Jie Zhang;Lijian Shi;Xi Zhang
中科院分区：
文献类型：
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作者：
Xiaoyi Shen;C. Ke;Qimao Wang;Jie Zhang;Lijian Shi;Xi Zhang
冰、云和陆地高程卫星2号(ICESat-2)的成功发射为北极海冰厚度(SIT)估计提供了一种新的先进工具。然而，ICESat-2对SIT估计的性能仍然未知。在本研究中，使用三种反演方法检验了从ICESat-2得出的SIT估计，即两种合并了积雪深度和经验积雪深度的浮力方法(分别为BMA和BME)和一种经验估计方法(EEM)，并将这些估计与2019年4月冰鸟飞行任务的几乎同时进行的空中测量进行了比较。总体而言，ICESat-2总干板与几乎同时进行的冰鸟任务的结果吻合得很好，平均偏差为2.5厘米，这表明ICESat-2数据用于SIT估计的高可靠性。然而，ICESat-2和Icebird对SIT的估计比总干板更明显的差异表明，其他参数(例如，雪深和雪/冰密度)可能会增加SIT估计的不确定性。总体而言，BMA是最好的SIT估计方法，其厚度分布与冰鸟资料最接近，平均偏差为0.11m，其次是BME和EEM方法。浮力法估算SIT的主要误差源是冰密度和积雪深度，需要在今后的研究中进一步研究。
The successful launch of the Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) provides a new and advanced tool for sea ice thickness (SIT) estimations in the Arctic. However, the performance of ICESat-2 for SIT estimations still remains unknown. In the present study, SIT estimates derived from ICESat-2 are examined using three retrieval methods, namely, two buoyancy methods with the merged snow depth and empirical snow depth (BMA and BME, respectively) and one empirical estimation method (EEM), and these estimates are compared to near-simultaneous airborne measurements from the IceBird mission in April 2019. Overall, the ICESat-2 total freeboard registers quite well with that from the near-concurrent IceBird mission with a mean bias of 2.5 cm, which demonstrates the high reliability of ICESat-2 data for SIT estimation. However, the much more evident difference between SIT estimations than total freeboard from ICESat-2 and IceBird indicates that other parameters (e.g., snow depth and snow/ice densities) may bring increased uncertainties to the SIT estimation. Overall, BMA is the best method for SIT estimation and has the closest thickness distribution to that of IceBird data with a mean bias of 0.11 m, followed by the BME and EEM methods. The dominate error sources for SIT estimation using the buoyancy method are ice density and snow depth that require further investigation in future studies.