Surface roughness signatures of summer arctic snow-covered sea ice in X-band dual-polarimetric SAR
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 ex...
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| Format: | Article |
| Language: | English |
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Taylor & Francis Group
2020-07-01
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| Series: | GIScience & Remote Sensing |
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| Online Access: | http://dx.doi.org/10.1080/15481603.2020.1767857 |
| _version_ | 1797679064196055040 |
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| author | Hyangsun Han Jae-In Kim Chang-Uk Hyun Seung Hee Kim Jeong-Won Park Young-Joo Kwon Sungjae Lee Sanggyun Lee Hyun-Cheol Kim |
| author_facet | Hyangsun Han Jae-In Kim Chang-Uk Hyun Seung Hee Kim Jeong-Won Park Young-Joo Kwon Sungjae Lee Sanggyun Lee Hyun-Cheol Kim |
| author_sort | Hyangsun Han |
| collection | DOAJ |
| description | 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 at the mid-incidence angle showed a statistically significant correlation with the RMS height of the sea ice, with Spearman’s correlation coefficient being higher than 0.7, except for the co-polarization ratio. Among the intensity-based and polarimetry-based SAR features, HH-polarized backscattering and co-polarization phase difference were analyzed to be the most sensitive to the macroscale RMS height of the sea ice. Our results show that the X-band dual-polarimetric SAR at mid-incidence angle exhibits potential for estimation of the macroscale surface roughness of the first-year sea ice with dry snow cover in summer. |
| first_indexed | 2024-03-11T23:08:58Z |
| format | Article |
| id | doaj.art-f7fad788a86f424081582af1b54820aa |
| institution | Directory Open Access Journal |
| issn | 1548-1603 1943-7226 |
| language | English |
| last_indexed | 2024-03-11T23:08:58Z |
| publishDate | 2020-07-01 |
| publisher | Taylor & Francis Group |
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| series | GIScience & Remote Sensing |
| spelling | doaj.art-f7fad788a86f424081582af1b54820aa2023-09-21T12:34:16ZengTaylor & Francis GroupGIScience & Remote Sensing1548-16031943-72262020-07-0157565066910.1080/15481603.2020.17678571767857Surface roughness signatures of summer arctic snow-covered sea ice in X-band dual-polarimetric SARHyangsun Han0Jae-In Kim1Chang-Uk Hyun2Seung Hee Kim3Jeong-Won Park4Young-Joo Kwon5Sungjae Lee6Sanggyun Lee7Hyun-Cheol Kim8Kangwon National UniversityUnit of Arctic Sea–Ice Prediction, Korea Polar Research InstituteUnit of Arctic Sea–Ice Prediction, Korea Polar Research InstituteUnit of Arctic Sea–Ice Prediction, Korea Polar Research InstituteUnit of Arctic Sea–Ice Prediction, Korea Polar Research InstituteUnit of Arctic Sea–Ice Prediction, Korea Polar Research InstituteUnit of Arctic Sea–Ice Prediction, Korea Polar Research InstituteCentre for Polar Observation and Modelling, University College LondonUnit of Arctic Sea–Ice Prediction, Korea Polar Research InstituteSurface 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 at the mid-incidence angle showed a statistically significant correlation with the RMS height of the sea ice, with Spearman’s correlation coefficient being higher than 0.7, except for the co-polarization ratio. Among the intensity-based and polarimetry-based SAR features, HH-polarized backscattering and co-polarization phase difference were analyzed to be the most sensitive to the macroscale RMS height of the sea ice. Our results show that the X-band dual-polarimetric SAR at mid-incidence angle exhibits potential for estimation of the macroscale surface roughness of the first-year sea ice with dry snow cover in summer.http://dx.doi.org/10.1080/15481603.2020.1767857sea ice surface roughnessroot mean square (rms) heightsnow-covered first-year sea icesynthetic aperture radar (sar)x-band dual polarimetry |
| spellingShingle | Hyangsun Han Jae-In Kim Chang-Uk Hyun Seung Hee Kim Jeong-Won Park Young-Joo Kwon Sungjae Lee Sanggyun Lee Hyun-Cheol Kim Surface roughness signatures of summer arctic snow-covered sea ice in X-band dual-polarimetric SAR GIScience & Remote Sensing sea ice surface roughness root mean square (rms) height snow-covered first-year sea ice synthetic aperture radar (sar) x-band dual polarimetry |
| title | Surface roughness signatures of summer arctic snow-covered sea ice in X-band dual-polarimetric SAR |
| title_full | Surface roughness signatures of summer arctic snow-covered sea ice in X-band dual-polarimetric SAR |
| title_fullStr | Surface roughness signatures of summer arctic snow-covered sea ice in X-band dual-polarimetric SAR |
| title_full_unstemmed | Surface roughness signatures of summer arctic snow-covered sea ice in X-band dual-polarimetric SAR |
| title_short | Surface roughness signatures of summer arctic snow-covered sea ice in X-band dual-polarimetric SAR |
| title_sort | surface roughness signatures of summer arctic snow covered sea ice in x band dual polarimetric sar |
| topic | sea ice surface roughness root mean square (rms) height snow-covered first-year sea ice synthetic aperture radar (sar) x-band dual polarimetry |
| url | http://dx.doi.org/10.1080/15481603.2020.1767857 |
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