Improved resolution ice sheet mapping with satellite radar altimeters

Eos ◽  
1993 ◽  
Vol 74 (10) ◽  
pp. 113-116 ◽  
Author(s):  
C. G. Rapley ◽  
J. G. Morley ◽  
D. J. Wingham
Keyword(s):  
Ice Sheet ◽  
Satellite Radar ◽  
Ice Sheet Mapping

scholarly journals GNSS Profile from the Greenland Korth Expeditions in the Context of Satellite Data

2021 ◽  
Vol 11 (3) ◽  
pp. 1115
Author(s):  
Aleš Bezděk ◽  
Jakub Kostelecký ◽  
Josef Sebera ◽  
Thomas Hitziger
Keyword(s):  
Ice Sheet ◽  
Satellite Observations ◽  
Elevation Change ◽  
Gradual Decline ◽  
Satellite Gravimetry ◽  
Surface Elevation Change ◽  
Satellite Radar ◽  
Gnss Measurements ◽  
Gnss Data ◽  
Satellite Radar Altimetry

Over the last two decades, a small group of researchers repeatedly crossed the Greenland interior skiing along a 700-km long route from east to west, acquiring precise GNSS measurements at exactly the same locations. Four such elevation profiles of the ice sheet measured in 2002, 2006, 2010 and 2015 were differenced and used to analyze the surface elevation change. Our goal is to compare such locally measured GNSS data with independent satellite observations. First, we show an agreement in the rate of elevation change between the GNSS data and satellite radar altimetry (ERS, Envisat, CryoSat-2). Both datasets agree well (2002–2015), and both correctly display local features such as an elevation increase in the central part of the ice sheet and a sharp gradual decline in the surface heights above Jakobshavn Glacier. Second, we processed satellite gravimetry data (GRACE) in order for them to be comparable with local GNSS measurements. The agreement is demonstrated by a time series at one of the measurement sites. Finally, we provide our own satellite gravimetry (GRACE, GRACE-FO, Swarm) estimate of the Greenland mass balance: first a mild decrease (2002–2007: −210 ± 29 Gt/yr), then an accelerated mass loss (2007–2012: −335 ± 29 Gt/yr), which was noticeably reduced afterwards (2012–2017: −178 ± 72 Gt/yr), and nowadays it seems to increase again (2018–2019: −278 ± 67 Gt/yr).

scholarly journals Measurement of ice-sheet topography using satellite-radar interferometry

1996 ◽  
Vol 42 (140) ◽  
pp. 10-22 ◽  
Author(s):  
Ian Joughin ◽  
Dale Winebrenner ◽  
Mark Fahnestock ◽  
Ron Kwok ◽  
William Krabill
Keyword(s):  
Ice Sheets ◽  
Ice Sheet ◽  
Surface Displacement ◽  
Horizontal Resolution ◽  
Radar Interferometry ◽  
Altimeter Data ◽  
Laser Altimeter ◽  
Digital Elevation ◽  
Satellite Radar ◽  
Ice Sheet Topography

AbstractDetailed digital elevation models (DEMs) do not exist for much of the Greenland and Antartic ice sheets. Radar altimetry is at present the primary, in many cases the only, source of topographic data over the ice sheets, but the horizontal resolution of such data is coarse. Satellite-radar interferometry uses the phase difference between pairs of synthetic aperture radar (SAR) images to measure both ice-sheet topography and surface displacement. We have applied this technique using ERS-1 SAR data to make detailed (i.e. 80 m horizontal resolution) maps of surface topography in a 100 km by 300 km strip in West Greenland, extending northward from just above Jakobshavns Isbræ. Comparison with а 76 km long line of airborne laser-altimeter data shows that We have achieved a relative accuracy of 2.5 m along the profile. These observations provide a detailed view of dynamically Supported topography near the margin of an ice sheet. In the final section We compare our estimate of topography with phase contours due to motion, and confirm our earlier analysis concerning vertical ice-sheet motion and complexity in ERS-1 SAR interferograms.

Satellite Radar Interferometry for Monitoring Ice Sheet Motion: Application to an Antarctic Ice Stream

Science ◽  
1993 ◽  
Vol 262 (5139) ◽  
pp. 1525-1530 ◽  
Author(s):  
R. M. Goldstein ◽  
H. Engelhardt ◽  
B. Kamb ◽  
R. M. Frolich
Keyword(s):  
Ice Sheet ◽  
Radar Interferometry ◽  
Ice Stream ◽  
Satellite Radar

scholarly journals Using the temporal variability of satellite radar altimetric observations to map surface properties of the Antarctic ice sheet

1998 ◽  
Vol 44 (147) ◽  
pp. 197-206 ◽  
Author(s):  
Benoît Legrésy ◽  
Frédérique Rémy
Keyword(s):  
Ice Sheet ◽  
Temporal Variations ◽  
Radar Altimeter ◽  
Height Measurement ◽  
Radar Echoes ◽  
Measuring Surface ◽  
Antarctic Continent ◽  
Ice Sheet Mass Balance ◽  
Satellite Radar ◽  
The Antarctic

AbstractThe problem of measuring surface height and snowpack characteristics from satellite radar altimeter echoes is investigated. In this paper, we perform an analysis of the ERS1 altimeter dataset acquired during a 3 day repeat orbit. The analysis reveals that there are temporal variations in shapes of the radar altimeter echo and that these variations are linked to meteorological phenomena. The time- and space-scales over which these variations apply are a few to tens of days and a few hundred kilometres, respectively. This phenomenon, if not accounted for, can create error in the height measurement. A numerical echo model is used to recover snowpack characteristics by taking advantage of the temporal variations of the radar echoes. A map of penetration depth of the radar waves in the Ku band over the Antarctic continent is obtained and suggests that grain-size produces the dominant effect on radar extinction in the snowpack at this frequency. Finally, a procedure is proposed to correct the height measurement within the context of ice-sheet mass-balance survey.

scholarly journals Ice-Sheet Topography From Geosat Radar Altimetry (Abstract)

1988 ◽  
Vol 11 ◽  
pp. 213 ◽  
Author(s):  
H. Jay Zwally ◽  
R. A. Bindschadler
Keyword(s):  
Standard Deviation ◽  
Ice Sheet ◽  
Satellite Orbit ◽  
Mean Value ◽  
Surface Elevation ◽  
Data Set ◽  
Radar Altimetry ◽  
Fitting Procedure ◽  
Optimal Spacing ◽  
Satellite Radar

Ice-sheet surface topography is the principal ice parameter obtainable from satellite radar altimetry. Surface-elevation maps of the East Antarctic ice sheet north of 72°S from Seasat data, collected between July and October 1978, and preliminary maps from Geosat data, collected between March 1985 and September 1986, are described. The Geosat data, obtained from the U.S. Navy as an unclassified data set, have greatly increased the density of elevation measurements. A principal correction to the altimeter measurements is obtained by applying a computer curve-fitting procedure to each radar waveform to correct for errors in the automatic range-tracking circuitry of the altimeter. The errors are caused by slow response to range variations due to undulations of the ice surface between successive measurements made at intervals of 662 m along track. The retracking correction for Geosat data has a standard deviation of 2.4 m and a mean value of 1.1m, values which are about 20% smaller than the corresponding values for Seasat. The positive mean correction indicates a common tendency of the altimeters' automatic tracking to give an excessive range to the surface. The precision of the measurements, given by the standard deviation of the range differences at cross-over points, is about 1.6 m before adjustment for errors in the radial position of the satellite orbit. The preliminary surface-elevation maps from Geosat data are improved over those produced from Seasat, mainly due to optimal spacing of successive ground tracks. The locations of ice divides and drainage basins along the East Antarctic coast are delineated by several methods, including vector plots of surface slope.

Observations of ice-sheet motion in Greenland using satellite radar interferometry

1995 ◽  
Vol 22 (5) ◽  
pp. 571-574 ◽  
Author(s):  
Ian R. Joughin ◽  
Dale P. Winebrenner ◽  
Mark A. Fahnestock
Keyword(s):  
Ice Sheet ◽  
Radar Interferometry ◽  
Satellite Radar

Global Ice Sheet Mapping Observatory: Airborne experiments

2009 ◽  
Author(s):  
Kenneth Jezek ◽  
Prasad Gogineni ◽  
Xiaoqing Wu ◽  
Ernesto Rodriguez ◽  
Fernando Rodriguez ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Ice Sheet Mapping
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