First-year sea ice melt pond fraction estimation from dual-polarisation C-band SAR - Part 2:Scaling in situ to Radarsat-2
Sea ice melt pond fraction (f p ), linked with lower sea ice surface albedo and increased light transmittance to the ocean, is inadequately parameterised in sea ice models due to a lack of observations. In this paper, results from a multi-scale remote-sensing program dedicated to the retrieval of le...
| Published in: | The Cryosphere |
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| Main Authors: | , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
2014
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| Subjects: | |
| Online Access: | https://hdl.handle.net/1983/b23b27e3-51cb-4f7a-af34-73985ca2c7a3 https://research-information.bris.ac.uk/en/publications/b23b27e3-51cb-4f7a-af34-73985ca2c7a3 https://doi.org/10.5194/tc-8-2163-2014 http://www.scopus.com/inward/record.url?scp=84912134858&partnerID=8YFLogxK |
| Summary: | Sea ice melt pond fraction (f p ), linked with lower sea ice surface albedo and increased light transmittance to the ocean, is inadequately parameterised in sea ice models due to a lack of observations. In this paper, results from a multi-scale remote-sensing program dedicated to the retrieval of level first-year sea ice (FYI) f p from dual co- and cross-polarisation C-band synthetic aperture radar (SAR) backscat-ter are detailed. Models which utilise the dominant effect of free-water melt ponds on the VV/HH (vertical transmit and vertical receive/horizontal transmit and horizontal receive) polarisation ratio at high incidence angles are tested for their ability to provide estimates of the subscale f p . Retrieved f p from noise-corrected Radarsat-2 quad-polarisation scenes are in good agreement with observations from coincident aerial survey data, with root mean square errors (RMSEs) of 0.05-0.07 obtained during intermediate and late stages of ponding. Weak model performance is attributed to the presence of wet snow and slush during initial ponding, and a synoptically driven freezing event causing ice lids to form on ponds. The HV/HH (horizontal transmit and vertical receive/horizontal transmit and horizontal receive) ratio explains a greater portion of variability in f p , compared to VV/HH, when ice lids are present. Generally low HV channel intensity suggests limited applications using dual cross-polarisation data, except with systems that have exceptionally low noise floors. Results demonstrate the overall potential of dual-polarisation SAR for standalone or complementary observations of f p for process-scale studies and improvements to model parameterisations. |
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