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Radar backscattering from snow facies of the Greenland ice sheet: Results from the AIRSAR 1991 campaignIn June 1991, the NASA/JPL airborne SAR (AIRSAR) acquired C- (lambda = 5.6cm), L- (lambda = 24cm), and P- (lambda = 68m) band polarimetric SAR data over the Greenland ice sheet. These data are processed using version 3.55 of the AIRSAR processor which provides radiometrically and polarimetrically calibrated images. The internal calibration of the AIRSAR data is cross-checked using the radar response from corner reflectors deployed prior to flight in one of the scenes. In addition, a quantitative assessment of the noise power level at various frequencies and polarizations is made in all the scenes. Synoptic SAR data corresponding to a swath width of about 12 by 50 km in length (compared to the standard 12 x 12 km size of high-resolution scenes) are also processed and calibrated to study transitions in radar backscatter as a function of snow facies at selected frequencies and polarizations. The snow facies on the Greenland ice sheet are traditionally categorized based on differences in melting regime during the summer months. The interior of Greenland corresponds to the dry snow zone where terrain elevation is the highest and no snow melt occurs. The lowest elevation boundary of the dry snow zone is known traditionally as the dry snow line. Beneath it is the percolation zone where melting occurs in the summer and water percolates through the snow freezing at depth to form massive ice lenses and ice pipes. At the downslope margin of this zone is the wet snow line. Below it, the wet snow zone corresponds to the lowest elevations where snow remains at the end of the summer. Ablation produces enough meltwater to create areas of snow saturated with water, together with ponds and lakes. The lowest altitude zone of ablation sees enough summer melt to remove all traces of seasonal snow accumulation, such that the surface comprises bare glacier ice.
Document ID
19940015961
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Rignot, Eric
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Jezek, K.
(Ohio State Univ. Columbus., United States)
Vanzyl, J. J.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Drinkwater, Mark R.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Lou, Y. L.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1993
Publication Information
Publication: gress In Electromagnetics Research Symposium (PIERS)
Subject Category
Oceanography
Accession Number
94N20434
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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