Combination of SAR and Radar Altimeter Data: Lambert Glacier/Amery Ice Shelf

2004 ◽  
pp. 333-340
Author(s):  
Ute Christina Herzfeld
Keyword(s):  
Altimeter Data ◽  
Radar Altimeter ◽  
Ice Shelf ◽  
Amery Ice Shelf ◽  
Lambert Glacier

scholarly journals Geostatistical estimation from radar altimeter data with respect to morphological units outlined by SAR data: application to Lambert Glacier/Amery Ice Shelf, East Antarctica

2004 ◽  
Vol 39 ◽  
pp. 251-255 ◽  
Author(s):  
Ralf Stosius ◽  
Ute C. Herzfeld
Keyword(s):  
Surface Characteristics ◽  
East Antarctica ◽  
Morphological Properties ◽  
Altimeter Data ◽  
Shelf Area ◽  
Radar Altimeter ◽  
Ice Shelf ◽  
Amery Ice Shelf ◽  
Sar Data ◽  
Lambert Glacier

AbstractThe objective of this paper is the comparison of two kriging methods, ordinary kriging and kriging within strata, for calculation of digital elevation models (DEMs) from radar altimeter data, and application to the Lambert Glacier/Amery Ice Shelf system, East Antarctica. Two new DEMs are presented. First, a DEM of the Lambert Glacier/Amery Ice Shelf system is calculated from 1997 European Remote-sensing Satellite-2 (ERS-2) radar altimeter (RA) data using geostatistical interpolation. RA data have high along-track density, but gaps between tracks are several kilometers, depending on the observation mode; this requires interpolation. Because the ice-stream/ice-shelf system is of primary interest in glaciological investigations, in the first approach a variogram characteristic of the Lambert Glacier ice surface is used. The resultant map has low errors for the glacier and the ice shelf. To match the surface characteristics of different morphological units that constitute the Lambert Glacier/Amery Ice Shelf region, a second DEM is constructed as follows: We utilize RADARSAT synthetic aperture radar (SAR) data that were collected in 1997 during the first Antarctic Imaging Campaign and composed into a 125m backscatter-data mosaic by Jezek (1999) and we co-reference the 125m mosaic with the altimetry-derived DEM. The Lambert Glacier/Amery Ice Shelf area is then subdivided into several regions which are homogeneous with respect to characteristic surface-morphological properties identified in the SAR mosaic. For those regions, a problem-oriented complex kriging method known as kriging within strata is performed, and the resulting DEM is compared to the DEM that was derived from kriging without regional subdivision.

scholarly journals Recent advance of the grounding line of Lambert Glacier, Antarctica, deduced from satellite-radar altimetry

1994 ◽  
Vol 20 ◽  
pp. 43-47 ◽  
Author(s):  
Ute C. Herzfeld ◽  
Craig S. Lingle ◽  
Li-Her Lee
Keyword(s):  
Ordinary Kriging ◽  
Altimeter Data ◽  
Fine Scale ◽  
Radar Altimeter ◽  
Ice Shelf ◽  
Amery Ice Shelf ◽  
Grounding Line ◽  
Satellite Radar ◽  
Lambert Glacier ◽  
Satellite Radar Altimetry

Satellite radar-altimeter data from Seasat (1978) and the Geosat Exact Repeat Mission (1987–89) are evaluated to investigate the question of advance or retreat of Lambert Glacier, Amery Ice Shelf, East Antarctica. New maps based on a fine-scale 3 km grid arc calculated using ordinary kriging. The break in slope at the 100 m elevation contour, relative to the WGS 1984 ellipsoid, is taken as a proxy for the grounding line. Measurements indicate that the irregular grounding line, which includes shoals, advanced approximately 10km between 1978 and 1987‐89, corresponding to a mean advance rate of about 1000 m year-1.

scholarly journals Recent advance of the grounding line of Lambert Glacier, Antarctica, deduced from satellite-radar altimetry

1994 ◽  
Vol 20 ◽  
pp. 43-47 ◽  
Author(s):  
Ute C. Herzfeld ◽  
Craig S. Lingle ◽  
Li-Her Lee
Keyword(s):  
Ordinary Kriging ◽  
Altimeter Data ◽  
Fine Scale ◽  
Radar Altimeter ◽  
Ice Shelf ◽  
Amery Ice Shelf ◽  
Grounding Line ◽  
Satellite Radar ◽  
Lambert Glacier ◽  
Satellite Radar Altimetry

Satellite radar-altimeter data from Seasat (1978) and the Geosat Exact Repeat Mission (1987–89) are evaluated to investigate the question of advance or retreat of Lambert Glacier, Amery Ice Shelf, East Antarctica. New maps based on a fine-scale 3 km grid arc calculated using ordinary kriging. The break in slope at the 100 m elevation contour, relative to the WGS 1984 ellipsoid, is taken as a proxy for the grounding line. Measurements indicate that the irregular grounding line, which includes shoals, advanced approximately 10km between 1978 and 1987‐89, corresponding to a mean advance rate of about 1000 m year-1.

scholarly journals Mass balance of the Lambert Glacier–Amery Ice Shelf system, East Antarctica: a comparison of computed balance fluxes and measured fluxes

2000 ◽  
Vol 46 (155) ◽  
pp. 561-570 ◽  
Author(s):  
Helen A. Fricker ◽  
Roland C. Warner ◽  
Ian Allison
Keyword(s):  
Mass Balance ◽  
Drainage System ◽  
Radar Altimeter ◽  
Drainage Basins ◽  
Ice Shelf ◽  
Amery Ice Shelf ◽  
Ice Sheet Mass Balance ◽  
Lambert Glacier ◽  
Lambert Glacier Basin

AbstractWe combine European Remote-sensing Satellite (ERS-1) radar altimeter surface elevations (Fricker and others, 2000) with six different accumulation distributions to compute balance fluxes for the Lambert Glacier–Amery Ice Shelf drainage system. These interpolated balance fluxes are compared with fluxes derived from in situ measurements of ice thickness and velocity at 73 stations of the Lambert Glacier basin traverse and at 11 stations further downstream, to assess the system’s state of balance. For the upstream line we obtain a range of imbalance estimates, from −23.8% to +19.9% of the observed flux, reflecting the sensitivity to the accumulation distributions. For some of the accumulation distributions the imbalance estimates vary significantly between different parts of the line. Imbalance estimates for the downstream line range from −17.7% to +70.2%, with four of the estimates exceeding +30%, again reflecting the sensitivity of the result to input accumulation, and strongly suggesting that the mass balance of the region between the two lines is positive. Our results confirm the importance of accurate estimates of accumulation in ice-sheet mass-balance studies. Furthermore, they suggest that it is not possible to accurately determine the state of balance of large Antarctic drainage basins on the basis of currently available accumulation distributions.

scholarly journals Digital elevation models for the Lambert Glacier–Amery Ice Shelf system, East Antarctica, from ERS-1 satellite radar altimetry

2000 ◽  
Vol 46 (155) ◽  
pp. 553-560 ◽  
Author(s):  
Helen A. Fricker ◽  
Glenn Hyland ◽  
Richard Coleman ◽  
Neal W. Young
Keyword(s):  
Digital Elevation Models ◽  
Radar Altimeter ◽  
Ice Shelf ◽  
Waveform Data ◽  
Amery Ice Shelf ◽  
Digital Elevation ◽  
Satellite Radar ◽  
Lambert Glacier ◽  
Satellite Radar Altimetry ◽  
Insight Into

AbstractThe Lambert Glacier–Amery Ice Shelf system is a major component of the East Antarctic ice sheet. This paper presents two digital elevation models (DEMs) that have been generated for the Lambert–Amery system from validated European Remote-sensing Satellite (ERS-1) radar altimeter waveform data. The first DEM covers the Amery Ice Shelf only, and was produced using kriging on a 1 km grid. The second is a coarser (5 km) DEM of the entire Lambert–Amery system, generated via simple averaging procedures. The DEMs provide unprecedented surface elevation information for the Lambert–Amery system and allow new insight into the glaciology of the region.

scholarly journals Surface meltstreams on the Amery Ice Shelf, East Antarctica

1998 ◽  
Vol 27 ◽  
pp. 177-181 ◽  
Author(s):  
Helen A. Phillips
Keyword(s):  
Synthetic Aperture Radar Image ◽  
East Antarctica ◽  
Altimeter Data ◽  
Topographic Map ◽  
Ice Shelf ◽  
Brightness Temperatures ◽  
Amery Ice Shelf ◽  
Microwave Imager ◽  
Shelf Region ◽  
Lambert Glacier

A topographic map of a 120 km by 20 km section of the Amery Ice Shelf, East Antarctica, mapped with the global positioning system (GPS) in the spring of 1995, revealed two long, shallow troughs in the ice-shelf surface. Smooth features coinciding with these troughs appeared in a synthetic aperture radar image acquired 18 months earlier. ERS-1 altimeter waveform sequences and backscatter measurements along repeat satellite ground tracks across the same section of the Amery Ice Shelf, for the 1993-94 summer, exhibited a dramatic change over a 2 km sector between 30 January and 2 February 1994. The change is consistent with the presence of liquid water on the ice-shelf surface, located in the deeper of the two troughs. A time series of special sensor microwave/ imager brightness temperatures over the Lambert Glacier-Amery Ice Shelf region for the same period has sharp maxima on 5 January and 21 January 1994. These maxima are interpreted as the melting events leading to the meltstream observed in the altimeter data 25 days later.

scholarly journals Modelling the response of the Lambert Glacier–Amery Ice Shelf system, East Antarctica, to uncertain climate forcing over the 21st and 22nd centuries

2014 ◽  
Vol 8 (3) ◽  
pp. 1057-1068 ◽  
Author(s):  
Y. Gong ◽  
S. L. Cornford ◽  
A. J. Payne
Keyword(s):  
Climate Model ◽  
Global Environmental Change ◽  
Ice Sheet ◽  
Adaptive Mesh ◽  
Ocean Model ◽  
East Antarctica ◽  
Ice Shelf ◽  
Amery Ice Shelf ◽  
Grounding Line ◽  
Lambert Glacier

Abstract. The interaction between the climate system and the large polar ice sheet regions is a key process in global environmental change. We carried out dynamic ice simulations of one of the largest drainage systems in East Antarctica: the Lambert Glacier–Amery Ice Shelf system, with an adaptive mesh ice sheet model. The ice sheet model is driven by surface accumulation and basal melt rates computed by the FESOM (Finite-Element Sea-Ice Ocean Model) ocean model and the RACMO2 (Regional Atmospheric Climate Model) and LMDZ4 (Laboratoire de Météorologie Dynamique Zoom) atmosphere models. The change of ice thickness and velocity in the ice shelf is mainly influenced by the basal melt distribution, but, although the ice shelf thins in most of the simulations, there is little grounding line retreat. We find that the Lambert Glacier grounding line can retreat as much as 40 km if there is sufficient thinning of the ice shelf south of Clemence Massif, but the ocean model does not provide sufficiently high melt rates in that region. Overall, the increased accumulation computed by the atmosphere models outweighs ice stream acceleration so that the net contribution to sea level rise is negative.

scholarly journals Radio-echo sounding of the lambert glacier basin

1975 ◽  
Vol 15 (73) ◽  
pp. 103-111 ◽  
Author(s):  
V. I. Morgan ◽  
W. F. Budd
Keyword(s):  
Surface Topography ◽  
Sea Level ◽  
Drainage Basin ◽  
Ice Thickness ◽  
Ice Shelf ◽  
Deep Trench ◽  
Glacier System ◽  
Amery Ice Shelf ◽  
Lambert Glacier ◽  
Echo Sounding

AbstractSeveral seasons of aerial ice-thickness soundings over the region of the Prince Charles Mountains, the Lambert Glacier system, the Amery Ice Shelf, and their drainage basin in east Antarctica have now been completed. The measurements provide detailed maps of surface topography and ice thickness over an area of about 2 X 105 km2. The equipment used consisted of a 100 MHz echo sounder designed and constructed by Antarctic Division and carried in a Pilatus Porter aircraft. ERTS imagery provides a valuable background for portraying the echo-sounding results. These results show that an extensive, deep subglacial valley system forms the basis of the large drainage basin with concave ice surface topography which channels the ice flow into the Amery Ice Shelf. Deep glacial streams penetrate a long way into the ice-sheet basin. The rock relief is considerable, varying from 3 000 m above (present) sea-level to 2 000 m below sea-level. A very deep subglacial trench exists in the region of the confluence of the Fisher, Mellor, and Lambert Glaciers where the ice thickness reaches 2 500 m. The low surface slope and high ice velocity are suggestive of high melt production in this region. The strong echo, together with the high bedrock back-slope, suggests that the deep trench may contain a basal melt lake.

scholarly journals Surging of Fisher Glacier, Eastern Antarctica: Evidence From Geomorphology

1982 ◽  
Vol 28 (98) ◽  
pp. 23-28 ◽  
Author(s):  
Peter Wellman
Keyword(s):  
Climatic Change ◽  
The Other ◽  
Present Level ◽  
Altitude Range ◽  
Ice Shelf ◽  
Amery Ice Shelf ◽  
Lambert Glacier

AbstractA study of the geomorphology of the Prince Charles Mountains using colour vertical air photographs shows well–preserved old moraines throughout much of the outcrop area. Along Fisher Glacier, lower Lambert Glacier and the Amery Ice Shelf, within the altitude range 50–2 000 m, the old moraines show that the ice level had risen 150–200 m above the present level at least three times. Old moraines elsewhere show that none of the other glaciers had risen significantly in their upper parts; the rise of their lower parts was caused by the rise of lower Lambert Glacier and the Amery Ice Shelf. The changes in ice level are unlikely to be due to climatic change because this would not repeatedly affect only one glacier draining central Antarctica. It is thought that the changes in ice level are caused by repeated surges of Fisher Glacier.

The Amery Ice Shelf and its hinterland

Polar Record ◽  
1960 ◽  
Vol 10 (64) ◽  
pp. 30-34 ◽  
Author(s):  
Malcolm Mellor ◽  
Graeme McKinnon
Keyword(s):  
Prydz Bay ◽  
Ice Shelf ◽  
Amery Ice Shelf ◽  
Antarctic Research ◽  
Lambert Glacier ◽  
The Antarctic

During the thirty years since the Amery Ice Shelf was first sighted there has been a steady accumulation of information, first on the ice shelf itself and later on the interesting mountains and glacier systems which lie to its south. The ice shelf occupies the head of a large embayment consisting of Prydz Bay and Mackenzie Bay, which deeply indents the coastline of the Antarctic mainland near the borders of MacRobertson Land and Princess Elizabeth Land. An associated valley runs south from the bay, between the Prince Charles Mountains and the Mawson Escarpment, and it is occupied by one of the world's largest valley glaciers, the Lambert Glacier. (In fact, recent findings by Soviet parties suggest that the Lambert Glacier is considerably longer than the Beardmore Glacier.) The exploration, survey and subsequent mapping of the ice shelf, and the mountains and glaciers of its hinterland, by Australian National Antarctic Research Expeditions in recent years has been a major contribution to Antarctic geography.

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