Observation of Sea-Ice Thickness Using ENVISAT Data From LÜtzow-Holm Bay, East Antarctica

To investigate the suitability of synthetic aperture radar (SAR) polarization data to estimate the sea-ice thickness in early summer in Lutzow-Holm Bay, Antarctica, we compared in situ ice thicknesses with the corresponding backscattering co-efficient for each polarization and the VV-to-HH backscattering ratio. The VV-to-HH backscattering ratio was derived from data acquired by ENVISAT Advanced SAR (ASAR). This ratio is related to the near-surface dielectric constant of the sea ice, which is, in turn, related to the developing process of ice and, thus, its thickness via changes in the near-surface sea-ice salinity. The sea ice encountered in the study area is close first-year pack ice and fast ice. For these old and relatively rough sea-ice types, the VV-to-HH backscattering ratio can be expected to depend on salinity-driven changes in the near-surface dielectric constant rather than changes of the surface roughness. We applied the empirical relationships between the ice thickness and the VV-to-HH backscattering ratio with the linear and logarithm fits to ASAR data. The linear fit gave the reliable result, with an rms error being 0.08 m and a correlation coefficient being 0.91, when compared to in situ fast-ice thickness.

[1]  Rick Hudson,et al.  Annual measurement of sea-ice thickness using an upward-looking sonar , 1990, Nature.

[2]  Hiroyuki Wakabayashi,et al.  Backscattering Characteristics of Sea Ice in Lützow-Holm Bay, Antarctica, by ERS-2 , 2006 .

[3]  M. Nakawo,et al.  Growth Rate and Salinity Profile of First-Year Sea Ice in the High Arctic , 1981 .

[4]  D. Thomas,et al.  Sea ice : an introduction to its physics, chemistry, biology, and geology , 2003 .

[5]  Hiroyuki Wakabayashi,et al.  Sea-Ice thickness retrieval in the Sea of Okhotsk using dual-polarization SAR data , 2006, Annals of Glaciology.

[6]  Takeshi Matsuoka,et al.  Polarimetric Characteristics of sea ice in the sea of Okhotsk observed by airborne L-band SAR , 2004, IEEE Transactions on Geoscience and Remote Sensing.

[7]  Frank D. Carsey,et al.  Microwave Remote Sensing of Sea Ice , 1992 .

[8]  Shotaro Uto,et al.  Ship-borne electromagnetic induction Sounding of Sea-ice thickness in the Southern Sea of Okhotsk , 2006, Annals of Glaciology.

[9]  Eric Rignot,et al.  Winter Sea-ice mapping from multi-parameter synthetic-aperture radar data , 1994, Journal of Glaciology.

[10]  Sivaprasad Gogineni,et al.  Search for proxy indicators of young sea ice thickness , 1996 .

[11]  Ron Kwok,et al.  ICESat observations of Arctic sea ice: A first look , 2004 .

[12]  Martin Gade,et al.  Retrieval of thin-ice thickness using the L-band polarization ratio measured by the helicopter-borne scatterometer Heliscat , 2006, Annals of Glaciology.

[13]  Wilford F. Weeks,et al.  Salinity Variations in Sea Ice , 1974, Journal of Glaciology.

[14]  Ron Kwok,et al.  Analysis of SAR Data of the Polar Oceans: Recent Advances , 2011 .

[15]  Seiho Uratsuka,et al.  Observation of sea-ice thickness in the sea of Okhotsk by using dual-frequency and fully polarimetric airborne SAR (pi-SAR) data , 2005, IEEE Transactions on Geoscience and Remote Sensing.

[16]  Shotaro Uto,et al.  Characteristics of Sea-ice thickness and Snow-depth distributions of the Summer landfast ice in Lützow-Holm Bay, East Antarctica , 2006, Annals of Glaciology.

[17]  G. Jackson,et al.  Concurrent remote sensing of Arctic sea ice from submarine and aircraft , 1991 .

[18]  Simon Yueh,et al.  Retrieval of thin ice thickness from multifrequency polarimetric SAR data , 1995 .

[19]  Pieter Hoekstra,et al.  Dielectric properties of sea and sodium chloride ice at UHF and microwave frequencies , 1971 .

[20]  Ian Joughin,et al.  On the response of polarimetric synthetic aperture radar signatures at 24-cm wavelength to sea ice thickness in Arctic leads , 1995 .

[21]  Seiho Uratsuka,et al.  Deriving sea-ice thickness and ice types in the Sea of Okhotsk using dual-frequency airborne SAR (Pi-SAR) data , 2002, Annals of Glaciology.