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Seasonal evolution of L-band SAR backscatter over landfast Arctic sea ice
Remote Sensing of Environment ( IF 13.5 ) Pub Date : 2020-12-01 , DOI: 10.1016/j.rse.2020.112049
Mallik S. Mahmud , Vishnu Nandan , Stephen E.L. Howell , Torsten Geldsetzer , John Yackel

Abstract We construct and present the first baseline, time series evolution of L-band SAR microwave backscatter (σ0HH) for landfast Arctic first-year (FYI) and multi-year (MYI) sea ice from ALOS PALSAR. We compare the winter to freeze-up seasonal L-band σ0HH signatures with C-band RADARSAT-2 SAR imagery and Ku-band QuikSCAT scatterometer data. We also explored the utility of L-band σ0HH to detect FYI and MYI melt onset dates. For both ice types, L-band exhibited a similar σ0HH evolution to C- and Ku-bands. A rise in L-band σ0HH was observed from winter to melt onset, however, with a lower magnitude attributed to the larger penetration of L-band microwaves through the snow-covered sea ice medium. Over FYI, L-band σ0HH exhibited the most robust response and greater diversity in melt onset signature, compared to C- and Ku-bands. Over MYI, L-band σ0HH declined during the winter to melt onset transition contrasting the C- and Ku-band evolution of σ0HH during melt onset. Although, a distinct L-band σ0HH response was not found during pond onset, a very strong σ0HH response was found during sea ice break-up, which could operationally be utilized to identify sea ice break-up timing. During freeze-up, L-band σ0HH showed greater diversity compared to C- and Ku-bands. Our study also found that, L-band detected melt onset dates were up to 6 days later than C- and Ku-band detected dates, for both ice types. The melt response was the strongest at L-band for FYI, where C-band detected a robust melt onset date for MYI. Therefore, for operational sea ice monitoring, L-band suits better for FYI, whereas C-band is still a better choice for MYI. In the warming Arctic, where FYI has become the dominant ice type, L-band demonstrates promise to be the optimal choice for sea ice operational monitoring with high spatiotemporal data acquisition from existing, upcoming and proposed L-band SAR missions.

中文翻译:

L 波段 SAR 后向散射在近陆北极海冰上的季节性演变

摘要 我们构建并展示了来自 ALOS PALSAR 的北极第一年 (FYI) 和多年 (MYI) 海冰 L 波段 SAR 微波反向散射 (σ0HH) 的第一个基线时间序列演化。我们将冬季与冻结的季节性 L 波段 σ0HH 特征与 C 波段 RADARSAT-2 SAR 图像和 Ku 波段 QuikSCAT 散射仪数据进行比较。我们还探索了 L 波段 σ0HH 在检测 FYI 和 MYI 熔化开始日期方面的效用。对于两种冰类型,L 波段表现出与 C 和 Ku 波段相似的 σ0HH 演化。从冬季到融化开始,观察到 L 波段 σ0HH 的上升,然而,较低的幅度归因于 L 波段微波通过积雪覆盖的海冰介质的更大穿透。仅供参考,与 C 和 Ku 波段相比,L 波段 σ0HH 表现出最强劲的响应和更大的熔融起始特征多样性。在MYI,L 带 σ0HH 在冬季下降到熔化开始转变,对比了 σ0HH 在熔化开始期间的 C 和 Ku 带演化。尽管在池塘开始时没有发现明显的 L 波段 σ0HH 响应,但在海冰破裂期间发现了非常强烈的 σ0HH 响应,这可以在操作上用于识别海冰破裂时间。在冻结期间,与 C 和 Ku 波段相比,L 波段 σ0HH 表现出更大的多样性。我们的研究还发现,对于两种冰类型,L 波段检测到的融化开始日期比 C 和 Ku 波段检测到的日期晚 6 天。FYI 的 L 波段熔化响应最强,其中 C 波段检测到 MYI 的稳定熔化开始日期。因此,对于操作海冰监测,L-band 更适合 FYI,而 C-band 仍然是 MYI 的更好选择。在变暖的北极,
更新日期:2020-12-01
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