Elevation change measurement of the East Antarctic Ice Sheet, 1978 to 1988, from 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).

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Long-Term Thinning of the Southeast Greenland Ice Sheet From Seasat, Geosat, and GFO Satellite Radar Altimetry

IEEE Geoscience and Remote Sensing Letters ◽

10.1109/lgrs.2004.824742 ◽

2004 ◽

Vol 1 (2) ◽

pp. 47-50 ◽

Cited By ~ 3

Author(s):

C.H. Davis ◽

S. Sun

Keyword(s):

Ice Sheet ◽

Greenland Ice Sheet ◽

Radar Altimetry ◽

Satellite Radar ◽

Satellite Radar Altimetry

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Analysis of satellite radar-altimeter return wave forms over the East Antarctic ice Sheet

Annals of Glaciology ◽

10.1017/s0260305500016359 ◽

1994 ◽

Vol 20 ◽

pp. 137-142 ◽

Cited By ~ 2

Author(s):

D. Yi ◽

C.R. Bentley

Keyword(s):

Ice Sheet ◽

Temporal Variations ◽

Least Square ◽

Model Parameters ◽

Geographic Variations ◽

Antarctic Ice Sheet ◽

Volume Scattering ◽

Wave Forms ◽

Satellite Radar ◽

East Antarctic Ice Sheet

The precision of satellite-radar altimetry over the Antarctic ice sheet can be improved by using a physically based retracking algorithm on the altimeter returns ("wave forms"). Ridley and Partington (1988) have shown that both surface and volume-scattering affect the shape of the return. Here, we develop a model that is based on a variable combination of surface- and volume-scattering and determine the model parameters through least-square fitting to the observed wave forms. The model parameters include surface roughness, proportion of volume-scattering, extinction coefficient and an amplitude coefficient. Geosat data collected over a test sector of the East Antarctic ice sheet have been analyzed to find quantitative estimates of seasonal and geographic variations of the several parameters. Our results show that the effect of volume-scattering can change the elevation measurement over the inland part of the East Antarctic ice sheet by more than I m and that there are both spatial and temporal variations; temporal variations are less significant than spatial variations.

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