Surface roughness signatures of summer arctic snow-covered sea ice in X-band dual-polarimetric SAR

• Published in: GIScience & Remote Sensing
• Main Authors: Hyangsun Han, Jae-In Kim, Chang-Uk Hyun, Seung Hee Kim, Jeong-Won Park, Young-Joo Kwon, Sungjae Lee, Sanggyun Lee, Hyun-Cheol Kim
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis Group 2020
• Subjects: sea ice surface roughness; root mean square (rms) height; snow-covered first-year sea ice; synthetic aperture radar (sar); x-band dual polarimetry; Mathematical geography. Cartography; GA1-1776; Environmental sciences; GE1-350; Arctic; Chukchi Sea; Chukchi; Sea ice
• Online Access: https://doi.org/10.1080/15481603.2020.1767857; https://doaj.org/article/f7fad788a86f424081582af1b54820aa

Surface roughness of sea ice is primary information for understanding sea ice dynamics and air–ice–ocean interactions. Synthetic aperture radar (SAR) is a powerful tool for investigating sea ice surface roughness owing to the high sensitivity of its signal to surface structures. In this study, we explored the surface roughness signatures of the summer Arctic snow-covered first-year sea ice in X-band dual-polarimetric SAR in terms of the root mean square (RMS) height. Two ice campaigns were conducted for the first-year sea ice with dry snow cover in the marginal ice zone of the Chukchi Sea in August 2017 and August 2018, from which high-resolution (4 cm) digital surface models (DSMs) of the sea ice were derived with the help of a terrestrial laser scanner to obtain the in situ RMS height. X-band dual-polarimetric (HH and VV) SAR data (3 m spatial resolution) were obtained for the 2017 campaign, at a high incidence angle (49.5°) of TerraSAR-X, and for the 2018 campaign, at a mid-incidence angle (36.1°) of TanDEM-X 1–2 days after the acquisition of the DSMs. The sea ice drifted during the time between the SAR and DSM acquisitions. As it is difficult to directly co-register the DSM to SAR owing to the difference in spatial resolution, the two datasets were geometrically matched using unmanned aerial vehicle (4 cm resolution) and helicopter-borne (30 cm resolution) photographs acquired as part of the ice campaigns. A total of five dual-polarimetric SAR features―backscattering coefficients at HH and VV polarizations, co-polarization ratio, co-polarization phase difference, and co-polarization correlation coefficient ―were computed from the dual-polarimetric SAR data and compared to the RMS height of the sea ice, which showed macroscale surface roughness. All the SAR features obtained at the high incidence angle were statistically weakly correlated with the RMS height of the sea ice, possibly influenced by the low backscattering close to the noise level that is attributed to the high incidence angle. The SAR features ...