scholarly journals Mass budget of the grounded ice in the Lambert Glacier–Amery Ice Shelf system

2008 ◽  
Vol 48 ◽  
pp. 193-197 ◽  
Author(s):  
Wen Jiahong ◽  
Wang Yafeng ◽  
Liu Jiying ◽  
Kenneth C. Jezek ◽  
Philippe Huybrechts ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Surface Velocity ◽  
Ice Shelf ◽  
Outlet Glacier ◽  
Mass Budget ◽  
Ice Surface ◽  
Amery Ice Shelf ◽  
Lambert Glacier ◽  
Lambert Glacier Basin

AbstractWe used remote-sensing and in situ measurements of surface accumulation rate, ice surface velocity, thickness and elevation to evaluate the mass budgets of grounded ice-flow regimes that form the Lambert Glacier–Amery Ice Shelf system. Three distinct drainage regimes are considered: the western and eastern margins of the ice shelf, and the southern grounding line at the major outlet glacier confluence, which can be identified with drainage zones 9, 11 and 10 respectively of Giovinetto and Zwally (2000). Our findings show the entire grounded portion of the basin is approximately in balance, with a mass budget of –4.2±9.8 Gt a–1. Drainages 9, 10 and 11 are within balance to the level of our measurement uncertainty, with mass budgets of –2.5±2.8 Gt a–1, –2.6±7.8 Gt a–1 and 0.9±2.3 Gt a–1, respectively. The region upstream of the Australian Lambert Glacier basin (LGB) traverse has a net mass budget of 4.4±6.3 Gt a–1, while the downstream region has –8.9±9.9 Gt a–1. These results indicate that glacier drainages 9, 10 and 11, upstream and downstream of the Australian LGB traverse, are in balance to within our measurement error.

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.

Velocities of the Amery Ice Shelf's primary tributary glaciers, 2004–12

2015 ◽  
Vol 27 (5) ◽  
pp. 511-523 ◽  
Author(s):  
M.L. Pittard ◽  
J.L. Roberts ◽  
C.S. Watson ◽  
B.K. Galton-Fenzi ◽  
R.C. Warner ◽  
...  
Keyword(s):  
Surface Velocity ◽  
Ice Shelf ◽  
Ice Flow ◽  
Ice Shelves ◽  
Ice Surface ◽  
Amery Ice Shelf ◽  
Landsat 7 ◽  
One Year ◽  
Shelf Region

AbstractMonitoring the rate of ice flow into ice shelves is vital to understanding how, where and when mass changes occur in Antarctica. Previous observations of ice surface velocity indicate that the Amery Ice Shelf and tributary glaciers have been relatively stable over the period 1968 to 1999. This study measured the displacement of features on the ice surface over a sequence of Landsat 7 images separated by approximately one year and spanning 2004 to 2012 using the surface feature tracking software IMCORR. The focus is on the region surrounding the southern grounding zone of the Amery Ice Shelf and its primary tributary glaciers: the Fisher, Lambert and Mellor glaciers. No significant changes in surface velocity were observed over this period. Accordingly, the velocity fields from each image pair between 2004 and 2012 were used to synthesize an average velocity dataset of the Amery Ice Shelf region and to compare it to previously published velocity datasets and in situ global positioning system velocity observations. No significant change in ice surface velocities was found between 2004 and 2012 in the Amery Ice Shelf region, which suggests that it continues to remain stable.

scholarly journals The Mass Budget of the Lambert Glacier Drainage Basin, Antarctica

1979 ◽  
Vol 24 (90) ◽  
pp. 511
Author(s):  
Ian Allison
Keyword(s):  
Total Mass ◽  
Drainage Basin ◽  
Ice Shelf ◽  
Ice Streams ◽  
Mass Budget ◽  
Glacier System ◽  
Amery Ice Shelf ◽  
Positive Balance ◽  
Lambert Glacier ◽  
Positive State

Abstract Estimates have been made of the mass budget of the total drainage basin of Lambert Glacier. These show a small but significant positive state of balance for the interior basin (the accumulation area up-stream of the major ice streams) and strongly suggest a positive balance for the Lambert Glacier system (the region of major ice streams, between the Amery Ice Shelf and the interior basin). The total mass flux into the interior basin is estimated as 60 Gt a–1. Results are presented from a number of ice movement stations established between 1972 and 1974 around the perimeter of thesouthern Prince Charles Mountains. These results, together with ice thicknesses from radio echo-sounding in the area, give a total mass outflux through the 2000 m contour of 30 Gt a–1, implying a budget excess of a further 30 Gt a–1 over the whole interior basin. Results from velocity and ice-thickness measurements give a mass discharge through a section near the junction of Lambert Glacier and the Amery Ice Shelf of 11 Gt a–1. Losses within the Lambert Glacier system proper account for a further 7 Gt a–1 and an overall mass excess of 12 Gt a–1 is estimated for the Lambert Glacier system. This present positive state of balance contrasts with geomorphological evidence from the southern Prince Charles Mountains of a large drop in ice level in recent geological time, and the ice surface in the area may now be building up after a major recession. This paper has been published in full in Journal of Glaciology, Vol. 22, No. 87,1979, p. 223—35.

scholarly journals Accumulation variability and mass budgets of the Lambert Glacier-Amery Ice Shelf system, East Antarctica, at high elevations

2006 ◽  
Vol 43 ◽  
pp. 351-360 ◽  
Author(s):  
Jiahong Wen ◽  
Kenneth C. Jezek ◽  
Andrew J. Monaghan ◽  
Bo Sun ◽  
Jiawen Ren ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Accumulation Rate ◽  
Temporal Variations ◽  
High Elevation ◽  
East Antarctica ◽  
Ice Shelf ◽  
Surface Mass ◽  
Amery Ice Shelf ◽  
High Elevations ◽  
Lambert Glacier

AbstractThe temporal and spatial variability of the annual accumulation rate and the mass budgets of five sub-basins of the Lambert Glacier-Amery Ice Shelf system (LAS), East Antarctica, at high elevations are assessed using a variety of datasets derived from field measurements and modeling. The annual temporal variations of the accumulation rate for four cores from the west and east sides of the LAS are around ±34%. Decadal fluctuation of the accumulation from the DT001 firn core drops to ±10%, and the 30 year fluctuation to ±5%, which is assumed to contain the information about the regional and long-term trend in accumulation. The 15-point running mean of the annual accumulation rate derived from stake measurements can remove most of the high-frequency spatial variation so as to better represent the local accumulation. Model simulations show that the spatial variability of erosion/ deposition of snow by the wind has a noticeable impact on the surface mass balance at the higher parts of the LAS. Mass-budget estimates at high-elevation sub-basins of the LAS suggest drainage 9 has a negative imbalance of −0.7 ± 0.4 Gta-1, Lambert and Mellor Glaciers have a positive imbalance of 3.9 ± 2.1 and 2.1 ±2.4 Gta-1 respectively, and Fisher Glacier and drainage 11 are approximately in balance. The higher-elevation region as a whole has a positive mass imbalance of 4.4 ± 6.3 Gta-1, which is consistent with the most recent radar altimetry assessment that shows an overall thickening over this region.

scholarly journals The Mass Budget of the Lambert Glacier Drainage Basin, Antarctica

1979 ◽  
Vol 24 (90) ◽  
pp. 511-511
Author(s):  
Ian Allison
Keyword(s):  
Total Mass ◽  
Drainage Basin ◽  
Ice Shelf ◽  
Ice Streams ◽  
Mass Budget ◽  
Glacier System ◽  
Amery Ice Shelf ◽  
Positive Balance ◽  
Lambert Glacier ◽  
Positive State

AbstractEstimates have been made of the mass budget of the total drainage basin of Lambert Glacier. These show a small but significant positive state of balance for the interior basin (the accumulation area up-stream of the major ice streams) and strongly suggest a positive balance for the Lambert Glacier system (the region of major ice streams, between the Amery Ice Shelf and the interior basin). The total mass flux into the interior basin is estimated as 60 Gt a–1. Results are presented from a number of ice movement stations established between 1972 and 1974 around the perimeter of thesouthern Prince Charles Mountains. These results, together with ice thicknesses from radio echo-sounding in the area, give a total mass outflux through the 2000 m contour of 30 Gt a–1, implying a budget excess of a further 30 Gt a–1 over the whole interior basin. Results from velocity and ice-thickness measurements give a mass discharge through a section near the junction of Lambert Glacier and the Amery Ice Shelf of 11 Gt a–1. Losses within the Lambert Glacier system proper account for a further 7 Gt a–1 and an overall mass excess of 12 Gt a–1 is estimated for the Lambert Glacier system. This present positive state of balance contrasts with geomorphological evidence from the southern Prince Charles Mountains of a large drop in ice level in recent geological time, and the ice surface in the area may now be building up after a major recession.This paper has been published in full in Journal of Glaciology, Vol. 22, No. 87,1979, p. 223—35.

scholarly journals The Mass Budget of the Lambert Glacier Drainage Basin, Antarctica

1979 ◽  
Vol 22 (87) ◽  
pp. 223-235 ◽  
Author(s):  
Ian Allison
Keyword(s):  
Total Mass ◽  
Drainage Basin ◽  
Ice Shelf ◽  
Ice Streams ◽  
Mass Budget ◽  
Glacier System ◽  
Amery Ice Shelf ◽  
Positive Balance ◽  
Lambert Glacier ◽  
Positive State

AbstractEstimates have been made of the mass budget of the total drainage basin of Lambert Glacier. These show a small but significant positive state of balance for the interior basin (the accumulation area up-stream of the major ice streams), and strongly suggest a positive balance for the Lambert Glacier system (the region of major ice streams, between the Amery Ice Shelf and the interior basin). The total mass flux into the interior basin is estimated as 60 Gt a−1. Results are presented from a number of ice movement stations established between 1972 and 1974 around the perimeter of the southern Prince Charles Mountains. These results, together with ice thicknesses from radio echo-sounding in the area, give a total mass outflux through the 2 000 m contour of 30 Gt a−1, implying a budget excess of a further 30 Gt a−1over the whole interior basin. Results from velocity and ice thickness measurements give a mass discharge through a section near the junction of Lambert Glacier and the Amery Ice Shelf of 11 Gt a−1. Losses within the Lambert Glacier system proper account for a further 7 Gt a−1and an overall mass excess of 12 Gt a−1is estimated for the Lambert Glacier system. This present positive state of balance contrasts with geomorphological evidence from the southern Prince Charles Mountains of a large drop in ice level in recent geological time, and the ice surface in the area may now be building up after a major recession.

The Mass Budget of the Lambert Glacier Drainage Basin, Antarctica

1979 ◽  
Vol 22 (87) ◽  
pp. 223-235 ◽  
Author(s):  
Ian Allison
Keyword(s):  
Total Mass ◽  
Drainage Basin ◽  
Ice Shelf ◽  
Ice Streams ◽  
Mass Budget ◽  
Glacier System ◽  
Amery Ice Shelf ◽  
Positive Balance ◽  
Lambert Glacier ◽  
Positive State

AbstractEstimates have been made of the mass budget of the total drainage basin of Lambert Glacier. These show a small but significant positive state of balance for the interior basin (the accumulation area up-stream of the major ice streams), and strongly suggest a positive balance for the Lambert Glacier system (the region of major ice streams, between the Amery Ice Shelf and the interior basin). The total mass flux into the interior basin is estimated as 60 Gt a−1. Results are presented from a number of ice movement stations established between 1972 and 1974 around the perimeter of the southern Prince Charles Mountains. These results, together with ice thicknesses from radio echo-sounding in the area, give a total mass outflux through the 2 000 m contour of 30 Gt a−1, implying a budget excess of a further 30 Gt a−1 over the whole interior basin. Results from velocity and ice thickness measurements give a mass discharge through a section near the junction of Lambert Glacier and the Amery Ice Shelf of 11 Gt a−1. Losses within the Lambert Glacier system proper account for a further 7 Gt a−1 and an overall mass excess of 12 Gt a−1 is estimated for the Lambert Glacier system. This present positive state of balance contrasts with geomorphological evidence from the southern Prince Charles Mountains of a large drop in ice level in recent geological time, and the ice surface in the area may now be building up after a major recession.

scholarly journals Supraglacial lake drainage at a fast-flowing Greenlandic outlet glacier

2019 ◽  
Vol 116 (51) ◽  
pp. 25468-25477 ◽  
Author(s):  
Thomas R. Chudley ◽  
Poul Christoffersen ◽  
Samuel H. Doyle ◽  
Marion Bougamont ◽  
Charlotte M. Schoonman ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Dynamic Responses ◽  
Surface Velocity ◽  
Outlet Glacier ◽  
Direct Observations ◽  
Ice Surface ◽  
Ice Sheet Dynamics ◽  
Lake Drainage

Supraglacial lake drainage events influence Greenland Ice Sheet dynamics on hourly to interannual timescales. However, direct observations are rare, and, to date, no in situ studies exist from fast-flowing sectors of the ice sheet. Here, we present observations of a rapid lake drainage event at Store Glacier, west Greenland, in 2018. The drainage event transported 4.8 × 106m3of meltwater to the glacier bed in ∼5 h, reducing the lake to a third of its original volume. During drainage, the local ice surface rose by 0.55 m, and surface velocity increased from 2.0 m⋅d−1to 5.3 m⋅d−1. Dynamic responses were greatest ∼4 km downstream from the lake, which we interpret as an area of transient water storage constrained by basal topography. Drainage initiated, without any precursory trigger, when the lake expanded and reactivated a preexisting fracture that had been responsible for a drainage event 1 y earlier. Since formation, this fracture had advected ∼500 m from the lake’s deepest point, meaning the lake did not fully drain. Partial drainage events have previously been assumed to occur slowly via lake overtopping, with a comparatively small dynamic influence. In contrast, our findings show that partial drainage events can be caused by hydrofracture, producing new hydrological connections that continue to concentrate the supply of surface meltwater to the bed of the ice sheet throughout the melt season. Our findings therefore indicate that the quantity and resultant dynamic influence of rapid lake drainages are likely being underestimated.

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