A comparison of Geosat altimeter and synthetic aperture radar measurements over east Greenland pack ice

Fetterer, F.; Laxon, Seymour W.; Johnson, Donald R.

doi:10.1080/01431169108929673

Cited by 5 publications

(2 citation statements)

References 14 publications

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“…Airborne measurements of the radar backscatter at 13.3 GHz made during March 1970 show the strongest returns at nadir (σ 0 = 15 dB) originating from open water within the pack ice, with backscatter decreasing from 6 to 0 dB as the ice thickness increased from 5 to 360 cm [ Parashar et al , 1974]. Comparisons of Seasat and Geosat altimetry with SAR revealed peaked waveforms with a backscatter of between 25 and 40 dB over new ice and leads [ Fetterer et al , 1991; Ulander , 1987]. By comparing Ku band airborne radar altimeter observations with coincident aerial photography, Drinkwater [1991] concluded that these strong peaked echoes originate from open water between ice floes.…”

Section: Radar Altimetry Over Sea Icementioning

confidence: 99%

Sea surface height determination in the Arctic Ocean from ERS altimetry

2004

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[1] Accurate sea surface height measurements have been extracted from ERS altimeter data in sea ice-covered regions for the first time. The data have been used to construct a mean sea surface of the Arctic Ocean between the latitudes of 60°N and 81.5°N based on 4 years of ERS-2 data. An RMS value for the crossover differences of mean sea surface profiles of 4.2 cm was observed in the ice-covered Canada Basin, compared with 3.8 cm in the ice-free Greenland-Iceland-Norwegian Seas. Comparisons are made with an existing global mean sea surface (OSUMSS95), highlighting significant differences between the two surfaces in permanently ice-covered seas. In addition, we present the first altimeter-derived sea surface height variability map of the Arctic Ocean. Comparisons with a high-resolution coupled ocean-sea ice general circulation model reveal a good qualitative agreement in the spatial distribution of variability. Quantitatively, we found that the observed variability was on average a factor of 3-4 greater than model predictions.

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Section: Radar Altimetry Over Sea Icementioning

confidence: 99%

Sea surface height determination in the Arctic Ocean from ERS altimetry

2004

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“…Near-coincidental SAR imagery has proven a valuable source for verification of lead detection algorithms in altimeter data processing, e.g., [13,14]. In the late 1980s, two studies have been undertaken with data from Seasat and Geosat to relate SAR backscatter and altimetric data over sea ice, but both were limited to one SAR image as a reference [15,16]. Presently however, Copernicus' Sentinel-1 and Sentinel-3 two satellite constellations in addition to Radarsat-2/Radarsat-Constellation and CryoSat-2 provide an increasing and long term (Copernicus program) data availability especially at lower latitudes (below 81.5 • ).…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of Radar Altimeter Waveform to Changes in Sea Ice Type at Resolution of Synthetic Aperture Radar

2019

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Radar altimetry in the context of sea ice has mostly been exploited to retrieve basin-scale information about sea ice thickness. In this paper, we investigate the sensitivity of altimetric waveforms to small-scale changes (a few hundred meters to about 10 km) of the sea ice surface. Near-coincidental synthetic aperture radar (SAR) imagery and CryoSat-2 altimetric data in the Beaufort Sea are used to identify and study the spatial evolution of altimeter waveforms over these features. Open water and thin ice features are easily identified because of their high peak power waveforms. Thicker ice features such as ridges and multiyear ice floes of a few hundred meters cause a response in the waveform. However, these changes are not reflected in freeboard estimates. Retrieval of robust freeboard estimates requires homogeneous floes in the order of 10 km along-track and a few kilometers to both sides across-track. We conclude that the combination of SAR imagery and altimeter data could improve the local sea ice picture by extending spatially scarce freeboard estimates to regions of similar SAR signature.

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