scholarly journals Simulation of Run-Off from the Greenland Ice Sheet for Planning Hydro-Electric Power, Ilulissat/Jakobshavn, West Greenland

1989 ◽  
Vol 13 ◽  
pp. 12-15 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Henrik Højmark Thomsen
Keyword(s):  
Electric Power ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Climatic Conditions ◽  
Electric Power Station ◽  
Hydroelectric Power ◽  
Drainage Pattern ◽  
West Greenland ◽  
Run Off ◽  
Hydraulic Conditions

Simulations of run-off from the Greenland ice sheet were made as part of a feasibility study for provision of hydroelectric power for Ilulissat/Jakobshavn, West Greenland. The aims were to see if the available short series of run-off measurements are typical of those under present climatic conditions, and to assess possible changes in run-off likely to be caused by gross changes in drainage pattern on the ice sheet. Specific run-off was calculated from climatological data, whilst run-off volumes were calculated by integrating specific run-off over the area of the ice sheet. There have been substantial year-to-year variations in run-off, but the 6 year measurement period is reasonably representative of present climatic conditions. Run-off could be reduced by 21% as a result of changes in hydraulic conditions on the ice sheet without this having a significant effect on the economy of the planned hydro-electric power station.

scholarly journals Simulation of Run-Off from the Greenland Ice Sheet for Planning Hydro-Electric Power, Ilulissat/Jakobshavn, West Greenland

1989 ◽  
Vol 13 ◽  
pp. 12-15 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Henrik Højmark Thomsen
Keyword(s):  
Electric Power ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Climatic Conditions ◽  
Electric Power Station ◽  
Hydroelectric Power ◽  
Drainage Pattern ◽  
West Greenland ◽  
Run Off ◽  
Hydraulic Conditions

Simulations of run-off from the Greenland ice sheet were made as part of a feasibility study for provision of hydroelectric power for Ilulissat/Jakobshavn, West Greenland. The aims were to see if the available short series of run-off measurements are typical of those under present climatic conditions, and to assess possible changes in run-off likely to be caused by gross changes in drainage pattern on the ice sheet. Specific run-off was calculated from climatological data, whilst run-off volumes were calculated by integrating specific run-off over the area of the ice sheet. There have been substantial year-to-year variations in run-off, but the 6 year measurement period is reasonably representative of present climatic conditions. Run-off could be reduced by 21% as a result of changes in hydraulic conditions on the ice sheet without this having a significant effect on the economy of the planned hydro-electric power station.

scholarly journals Applied Glacier Research for Planning Hydro-Electric Power, Ilulissat/Jakobshavn, West Greenland

1989 ◽  
Vol 13 ◽  
pp. 257-261 ◽  
Author(s):  
H.H. Thomsen ◽  
L. Thorning ◽  
O.B. Olesen
Keyword(s):  
Electric Power ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Hot Water ◽  
Electric Power Station ◽  
Water Drainage ◽  
Drainage Pattern ◽  
Drainage Basins ◽  
Model Calculations ◽  
Radio Echo Sounding

Glaciological investigations were carried out on the Greenland ice sheet to help develop plans for a hydro-electric power station to supply energy to Ilulissat/Jakobshavn. The investigations required research on supraglacial and subglacial melt-water drainage in order to delineate water-drainage basins. This involved repeated detailed photogrammetric mapping, radio echo-sounding, hot-water drilling, and mathematical modelling of subglacial drainage. Repeated mappings combine to show an overall stability in the supraglacial drainage pattern, while model calculations for the subglacial conditions show a limited sensitivity in the predicted drainage areas to changes in hydraulic conditions. The investigations provide the basis for setting safer limits for planning hydro-electric power in the area, and give a general understanding of glacier hydrology for a continuous ice cover such as the Greenland ice sheet.

scholarly journals Applied Glacier Research for Planning Hydro-Electric Power, Ilulissat/Jakobshavn, West Greenland

1989 ◽  
Vol 13 ◽  
pp. 257-261 ◽  
Author(s):  
H.H. Thomsen ◽  
L. Thorning ◽  
O.B. Olesen
Keyword(s):  
Electric Power ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Hot Water ◽  
Electric Power Station ◽  
Water Drainage ◽  
Drainage Pattern ◽  
Drainage Basins ◽  
Model Calculations ◽  
Radio Echo Sounding

Glaciological investigations were carried out on the Greenland ice sheet to help develop plans for a hydro-electric power station to supply energy to Ilulissat/Jakobshavn. The investigations required research on supraglacial and subglacial melt-water drainage in order to delineate water-drainage basins. This involved repeated detailed photogrammetric mapping, radio echo-sounding, hot-water drilling, and mathematical modelling of subglacial drainage. Repeated mappings combine to show an overall stability in the supraglacial drainage pattern, while model calculations for the subglacial conditions show a limited sensitivity in the predicted drainage areas to changes in hydraulic conditions. The investigations provide the basis for setting safer limits for planning hydro-electric power in the area, and give a general understanding of glacier hydrology for a continuous ice cover such as the Greenland ice sheet.

scholarly journals Mapping of a hydrological ice-sheet drainage basin on the West Greenland ice-sheet margin from ERS-1/-2 SAR interferometry, ice-radar measurement and modelling

2002 ◽  
Vol 34 ◽  
pp. 309-314 ◽  
Author(s):  
A. P. Ahlstrøm ◽  
C. Egede Bøggild ◽  
J. J. Mohr ◽  
N. Reeh ◽  
E. Lintz Christensen ◽  
...  
Keyword(s):  
High Resolution ◽  
Water Pressure ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Sar Interferometry ◽  
Overburden Pressure ◽  
West Greenland ◽  
Sheet Surface ◽  
Bedrock Topography ◽  
Run Off

AbstractThe hydrological ice-sheet basin draining into the Tasersiaq lake, West Greenland (66°13’ N, 50°30’W), was delineated, first using standard digital elevation models (DEMs) for ice-sheet surface and bedrock, and subsequently using a new high-resolution dataset, with a surface DEM derived from repeat-track interferometric synthetic aperture radar (SAR) and a bedrock topography derived from an airborne 60 MHz ice-penetrating radar. The extent of the delineation was calculated from a water-pressure potential as a function of the ice-sheet surface and bedrock elevations and a hydraulic factor k describing the relative importance of the potential of the ice overburden pressure compared to the bedrock topography. Themeltwater run-off for the basin delineations was modelled with an energy-balance model calibrated with observed ice-sheet ablation and compared to a 25 year time series of measured basin run-off. The standard DEMs were found to be inadequate for delineation purposes, whereas delineations from high-resolution data were found to be very sensitive to changes in k in a non-linear way, causing a factor 5 change of basin area, corresponding to a doubling of the modelled runoff. The 50% standard deviation of the measured basin run-off could thus be explained by small year-to-year variations of the k-factor.

scholarly journals Variations of near-surface firn density in the lower accumulation area of the Greenland ice sheet, Pâkitsoq, West Greenland

1994 ◽  
Vol 40 (136) ◽  
pp. 477-485 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Martin Laternser ◽  
W. Tad Pfeffer
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Low Density ◽  
Near Surface ◽  
West Greenland ◽  
Climate Monitoring ◽  
Run Off ◽  
The Mean ◽  
Satellite Radar ◽  
Satellite Radar Altimetry

AbstractFirn-density variations have been studied in the lower accumulation area of the Greenland ice sheet (1440-1620 m a.s.l.) near Pâkitsoq, West Greenland. The main control on density in the near-surface firn layer (of 5-10 m thickness) is the formation of ice layers by the refreezing of meltwater that reaches depths of 2-4 m below the surface. The density variations are described by the ratio of annual surface melt M to the annual accumulation C. The ratio M/C is about 0.6 at the run-off limit (at about 1400 m a.s.l. in the study area) where refreezing of meltwater transforms snow into impermeable ice. The mean density of near-surface firn decreases with elevation, reflecting a decrease in melt with elevation. There is a surprising decrease in firn density at depths of more than about 4 m below the 1991 summer surface, which reflects lower melt rates and/or higher accumulation in the early 1980s and late 1970s when this firn was passing through the surface layer. The formation of such low-density firn may have partially contributed to the 1978-85 thickening of the ice sheet observed by satellite-radar altimetry. Near-surface firn density is therefore very sensitive to climate change and might be an attractive target for climate monitoring.

scholarly journals Variations of near-surface firn density in the lower accumulation area of the Greenland ice sheet, Pâkitsoq, West Greenland

1994 ◽  
Vol 40 (136) ◽  
pp. 477-485 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Martin Laternser ◽  
W. Tad Pfeffer
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Low Density ◽  
Near Surface ◽  
West Greenland ◽  
Climate Monitoring ◽  
Run Off ◽  
The Mean ◽  
Satellite Radar ◽  
Satellite Radar Altimetry

AbstractFirn-density variations have been studied in the lower accumulation area of the Greenland ice sheet (1440-1620 m a.s.l.) near Pâkitsoq, West Greenland. The main control on density in the near-surface firn layer (of 5-10 m thickness) is the formation of ice layers by the refreezing of meltwater that reaches depths of 2-4 m below the surface. The density variations are described by the ratio of annual surface meltMto the annual accumulationC. The ratioM/Cis about 0.6 at the run-off limit (at about 1400 m a.s.l. in the study area) where refreezing of meltwater transforms snow into impermeable ice. The mean density of near-surface firn decreases with elevation, reflecting a decrease in melt with elevation. There is a surprising decrease in firn density at depths of more than about 4 m below the 1991 summer surface, which reflects lower melt rates and/or higher accumulation in the early 1980s and late 1970s when this firn was passing through the surface layer. The formation of such low-density firn may have partially contributed to the 1978-85 thickening of the ice sheet observed by satellite-radar altimetry. Near-surface firn density is therefore very sensitive to climate change and might be an attractive target for climate monitoring.

scholarly journals Topographic and Glaciological Controls on Holocene Ice-Sheet Margin Dynamics. Central West Greenland

1990 ◽  
Vol 14 ◽  
pp. 307-310 ◽  
Author(s):  
C.R. Warren ◽  
N.R.J. Hulton
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Glacial Maximum ◽  
Warm Climate ◽  
Short Term ◽  
The West ◽  
West Greenland ◽  
The Past

The retreat of the West Greenland ice sheet from its Sisimiut (Wisconsinan) glacial maximum, was punctuated by a series of Stillstands or small readvances that formed numerous moraines. These landforms have been interpreted in the past as the result of short-term, regional falls in ablation-season temperatures. However, mapping of the geomorphological evidence south of Ilulissat (Jakobshavn) suggests that retreat behaviour was not primarily governed by climate, and therefore that the former ice margins are not palaeoclimatically significant. During warm climate ice-sheet wastage, the successive quasi-stable positions adopted by the ice margin were largely governed by topography. The retreat of the inherently unstable calving glaciers was arrested only at topographically-determined locations where stability could be achieved.

scholarly journals Brief communication: Glacier run-off estimation using altimetry derived basin volume change: case study at Humboldt Glacier, Northwest Greenland

2020 ◽  
Author(s):  
Laurence Gray
Keyword(s):  
Volume Change ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Run Off ◽  
Height Change ◽  
North Western

Abstract. CryoSat can provide temporal height change around the Greenland Ice Sheet including that close to the terminus of many glaciers. Height change from the northern outlet of the Humboldt Glacier in north-western Greenland is combined with ice flux into and out of sections of the glacier basin to derive the water run-off each year from 2011 to 2019. The cumulative nine-year run-off for this part of the Humboldt basin is 9.6 ± 2.9 km3 and is predominantly sub-glacial at the terminus with large run-offs occurring in 2012, 2015 and 2019, and much smaller ones in 2013, 2016, 2017 and 2018.

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