Improving AVHRR Resolution Through Data Cumulation for Mapping Polar Ice Sheets

Scambos, Ted; Kvaran, Geir; Fahnestock, M. A.

doi:10.1016/s0034-4257(99)00009-7

Cited by 21 publications

(14 citation statements)

References 11 publications

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“…The products (a visible-band image mosaic and a surface snow grain size map) were derived from MODIS bands 1 and 2 using orbit swath data. Multiple images of all areas were combined in a data cumulation scheme (Scambos et al 1999) to improve spatial resolution Table II. Details of SAR tandem pairs used to construct the two DSIs presented in this paper (see Fig.…”

Section: Visible Satellite Imagerymentioning

confidence: 99%

Mapping the grounding zone of the Amery Ice Shelf, East Antarctica using InSAR, MODIS and ICESat

et al. 2009

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Abstract:We use a combination of satellite techniques (interferometric synthetic aperture radar (InSAR), visible-band imagery, and repeat-track laser altimetry) to develop a benchmark map for the Amery Ice Shelf (AIS) grounding zone (GZ), including its islands and ice rises. The break-in-slope, as an indirect estimate of grounding line location, was mapped for the entire AIS. We have also mapped ,55% of the landward edge and ,30% of the seaward edge of the ice shelf flexure boundary for the AIS perimeter. Vertical ice motion from Global Positioning System receivers confirms the location of the satellite-derived GZ in two regions. Our map redefines the extent of floating ice in the south-western AIS and identifies several previously unmapped grounded regions, improving our understanding of the stresses supporting the current dynamical state of the ice shelf. Finally, we identify three along-flow channels in the ice shelf basal topography, approximately 10 km apart, 1.5 km wide and 300-500 m deep, near the southern GZ. These channels, which form at the suture zones between ice streams, may represent zones of potential weakness in the ice shelf and may influence sub-ice-shelf ocean circulation.

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Section: Visible Satellite Imagerymentioning

confidence: 99%

Mapping the grounding zone of the Amery Ice Shelf, East Antarctica using InSAR, MODIS and ICESat

et al. 2009

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“…A second iteration, refined by the initial estimate of the surface normal, is run to yield the final best-fit surface normal for the cell. The use of several images, accurately co-registered to less than one sensor pixel precision, also results in some improvement in spatial resolution beyond what is present in a single image (see Scambos and others, 1999).…”

Section: Photoclinometric Methodsmentioning

confidence: 99%

An image-enhanced DEM of the Greenland ice sheet

Scambos

Haran

2002

Ann. Glaciol.

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We have assembled an elevation grid for the Greenland ice sheet using a combination of the best current digital elevation model (DEM) (Bamber and others, 2000a, 2001) and 44 Advanced Very High Resolution Radiometer satellite images acquired in spring 1997. The images are used to quantitatively enhance the representation of surface undulations through photoclinometry. Gridcell spacing of the new DEM is 625 m. To validate the new DEM, we compared profiles extracted from it and the Bamber and others DEM with airborne laser altimetry profiles collected in the 1990s by the Airborne Topographic Mapper (Krabill and others, 1995). The image-enhanced DEM has a greatly improved representation of decameter-relief surface features <15 km in lateral extent, and reduces the mean elevation error in regions having these features by 20–50%. Root-mean-squared errors are typically 7–15m in the Bamber DEM, and 4–10m after image enhancement. However, the photoclinometry process adds some noise. In very smooth portions of the ice sheet where decameter undulationsare absent, the photoclinometry process caused a slight increase in the rms error, from ~1 min the Bamber and others DEM to ∼2.5 min the image-enhanced DEM. The image-enhanced DEM will be useful for inferring accumulation-rate variations over the undulation field, or for improving maps of bedrock elevation through inversion of surface elevation, for example. We briefly explore the preliminary steps of this latter application.

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“…and Allebach [25] study the relation of mean squared error to the spacing of irreg ular samples. Scambos et al [35] use a linear technique called data cumulation to increase the resolution of AVHRR data by averaging multiple images onto a finer sampling grid. Like other resolution enhancement algorithms, accurate coregistration, or alignment, of the images is required; data cumulation requires coregistration accuracy of better than 0.2 pixels.…”

Section: Interpolative Image Resolution Enhancementmentioning

confidence: 99%

“…past that point).Figures 4.32 and 4.34 show the six-frame HR estimates for the two images using 6 = 0°, 5°, 10°, 15°, 20°, 25°; Figs. 4.33 and 4 35. show the corresponding ISNR curves with AO = 5° up to a maximum off-nadir angle oi 9 = 45°.…”

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confidence: 99%

Resolution Enhancement of Multilook Imagery

Galbraith¹

2004

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Improving AVHRR Resolution Through Data Cumulation for Mapping Polar Ice Sheets

Cited by 21 publications

References 11 publications

Mapping the grounding zone of the Amery Ice Shelf, East Antarctica using InSAR, MODIS and ICESat

Mapping the grounding zone of the Amery Ice Shelf, East Antarctica using InSAR, MODIS and ICESat

An image-enhanced DEM of the Greenland ice sheet

Resolution Enhancement of Multilook Imagery

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