scholarly journals Can the Mass Balance of a Glacier be Estimated from its Equilibrium-Line Altitude?

1984 ◽  
Vol 30 (106) ◽  
pp. 364-368 ◽  
Author(s):  
Roger J. Braithwaite
Keyword(s):  
Mass Balance ◽  
Linear Relationship ◽  
Sufficient Accuracy ◽  
Statistical Analyses ◽  
Equilibrium Line ◽  
Model Parameters ◽  
Equilibrium Line Altitude ◽  
Direct Measurements ◽  
Balanced Budget ◽  
Two Parameters

AbstractThe possibility of replacing or supplementing direct measurements of mass balance by estimates calculated from equilibrium-line altitude (ELA) measurements is investigated by statistical analyses of data from 31 glaciers. A linear relationship between mass balance and ELA in terms of two parameters, the effective balance gradient and the balanced-budget ELA, is tested. It is concluded that existing mass-balance series can be usefully extrapolated by using ELA data for additional years. However, accurate mass balance cannot be calculated for glaciers where no such measurements have been made because of the difficulties in prescribing the two model parameters with sufficient accuracy. For example, the effective balance gradient is of the order of 5 mm water/m so that errors of only a few decametres in the estimation of the balanced-budget ELA can have a great effect upon calculations of mass balance.

scholarly journals Can the Mass Balance of a Glacier be Estimated from its Equilibrium-Line Altitude?

1984 ◽  
Vol 30 (106) ◽  
pp. 364-368 ◽  
Author(s):  
Roger J. Braithwaite
Keyword(s):  
Mass Balance ◽  
Linear Relationship ◽  
Sufficient Accuracy ◽  
Statistical Analyses ◽  
Equilibrium Line ◽  
Model Parameters ◽  
Equilibrium Line Altitude ◽  
Direct Measurements ◽  
Balanced Budget ◽  
Two Parameters

AbstractThe possibility of replacing or supplementing direct measurements of mass balance by estimates calculated from equilibrium-line altitude (ELA) measurements is investigated by statistical analyses of data from 31 glaciers. A linear relationship between mass balance and ELA in terms of two parameters, the effective balance gradient and the balanced-budget ELA, is tested. It is concluded that existing mass-balance series can be usefully extrapolated by using ELA data for additional years. However, accurate mass balance cannot be calculated for glaciers where no such measurements have been made because of the difficulties in prescribing the two model parameters with sufficient accuracy. For example, the effective balance gradient is of the order of 5 mm water/m so that errors of only a few decametres in the estimation of the balanced-budget ELA can have a great effect upon calculations of mass balance.

scholarly journals Estimating equilibrium-line altitude (ELA) from glacier inventory data

2009 ◽  
Vol 50 (53) ◽  
pp. 127-132 ◽  
Author(s):  
R.J. Braithwaite ◽  
S.C.B. Raper
Keyword(s):  
Mass Balance ◽  
Climate Models ◽  
Equilibrium Line ◽  
Strongly Correlated ◽  
Inventory Data ◽  
Equilibrium Line Altitude ◽  
Glacier Inventory ◽  
Geographical Variations ◽  
The World ◽  
Balanced Budget

AbstractA glacier’s most fundamental altitude is the equilibrium-line altitude (ELA) because it divides the glacier into ablation and accumulation areas. The best parameterization of the ELA for glacier inventory is the balanced-budget ELA. We discuss direct estimation of balanced-budget ELA from mass-balance data for individual glaciers, and indirect estimation of balanced-budget ELA from simple topographic parameters available from the World Glacier Inventory (WGI), i.e. the area-median and maximum and minimum altitudes. Mass balance and ELA for individual glaciers are usually strongly correlated and we calculate balanced-budget ELA from the regression equation linking the two. We then compare balanced-budget ELA with area-median and mid-range altitudes for the 94 glaciers for which we have all the necessary data. The different ELA estimates agree well enough (±82 to ±125 m) to describe geographical variations in ELA and for application of glacier–climate models to glacier inventory data. Mid-range and area-median altitudes are already available for tens of thousands of glaciers in the current WGI and should be evaluated in future inventories.

scholarly journals Mass Balance of “Vesper” Glacier, Washington, U.S.A.

1981 ◽  
Vol 27 (96) ◽  
pp. 271-282 ◽  
Author(s):  
David P. Dethier ◽  
Jan E. Frederick
Keyword(s):  
Nineteenth Century ◽  
Mass Balance ◽  
Cascade Range ◽  
Equilibrium Line ◽  
Equilibrium Line Altitude ◽  
Climatic Fluctuations ◽  
The North ◽  
Snow Line ◽  
The Relationship ◽  
Geologic Data

AbstractDuring 1974–75 glaciologic and geologic studies were conducted on a small (0.17 km2) avalanche-nourished glacier in the North Cascade Range of Washington. The approximate equilibrium-line altitude (ELA) for this ice body, informally called “Vesper” glacier, lies at 1475 m, some 300 m below the regional ELA value. Estimated annual accumulation was 6 100±675 mm during the two years of study; 15 to 30% of this flux resulted from avalanche and wind–transported snow. Average annual ablation during the period was 5 350 mm, giving a total net balance of + 1 600 mm for the two-year study period. “Vesper” glacier persists well below the regional snow-line because of excessive local precipitation, substantial avalanche contributions, and a favourable north-facing aspect.Neoglacial moraines indicate that maximum ELA lowering in this period was approximately 165 m and occurred prior to a.d. 1670. Minor re-advances occurred during the nineteenth century. These reconnaissance measurements are consistent with the sparse geologic data reported from other glaciers in the Cascade Range. While the relationship between regional lowering of snow-line and avalanche activity is uncertain at present, these data suggest that avalanche-nourished glaciers provide a useful record of climatic fluctuations.

scholarly journals Mass Balance of Four Cirque Glaciers in the Torngat Mountains of Northern Labrador, Canada

1986 ◽  
Vol 32 (111) ◽  
pp. 208-218
Author(s):  
Robert J. Rogerson
Keyword(s):  
Mass Balance ◽  
Temporal Pattern ◽  
Climatic Conditions ◽  
Spatial Variations ◽  
Equilibrium Line ◽  
Positive Mass ◽  
Negative Mass ◽  
Equilibrium Line Altitude ◽  
Ice Surface ◽  
Debris Cover

AbstractThe net mass balance of four small cirque glaciers (0.7–1.4 km2) in the Torngat Mountains of northern Labrador was measured for 1981–84, allowing three complete mass-balance years to be calculated. The two largest glaciers experienced positive mass-balance conditions in 1982 while all the glaciers were negative in 1983. The temporal pattern relates directly to general climatic conditions, in particular winter snowfall. Spatial variations of mass balance on the glaciers are the result of several factors including altitude, extent of supraglacial debris cover, slope, proximity to side and backwalls of the enclosing cirque, and the height of the backwall above the ice surface. Abraham Glacier, the smallest studied and with consistently the largest negative mass balance (–1.28 m in 1983), re-advanced an average of 1.2 m each year between 1981 and 1984. Mean equilibrium-line altitude (ELA) for the four glaciers is 1050 m, varying substantially from one glacier to another (+240 to –140 m) and from year to year (+60 to –30 m).

scholarly journals Modelled glacier equilibrium line altitudes during the mid-Holocene in the southern mid-latitudes

2015 ◽  
Vol 11 (2) ◽  
pp. 603-636 ◽  
Author(s):  
C. Bravo ◽  
M. Rojas ◽  
B. M. Anderson ◽  
A. N. Mackintosh ◽  
E. Sagredo ◽  
...  
Keyword(s):  
New Zealand ◽  
Mass Balance ◽  
Southern Hemisphere ◽  
Equilibrium Line ◽  
Balance Model ◽  
Glacier Mass Balance ◽  
Equilibrium Line Altitude ◽  
Climate Conditions ◽  
Precipitation Changes ◽  
Autumn And Winter

Abstract. Glacier behaviour during the mid-Holocene (MH, 6000 year BP) in the Southern Hemisphere provides observational data to constrain our understanding of the origin and propagation of palaeo-climatic signals. We examine the climatic forcing of glacier expansion in the MH by evaluating modelled glacier equilibrium line altitude (ELA) and climate conditions during the MH compared with pre-industrial time (PI, year 1750) in the mid latitudes of the Southern Hemisphere, specifically in Patagonia and the South Island of New Zealand. Climate conditions for the MH are obtained from PMIP2 models simulations, which in turn force a simple glacier mass balance model to simulate changes in equilibrium-line altitude during this period. Climate conditions during the MH show significantly (p ≤ 0.05) colder temperatures in summer, autumn and winter, and significantly (p ≤ 0.05) warmer temperatures in spring. These changes are a consequence of insolation differences between the two periods. Precipitation does not show significant changes, but exhibits a temporal pattern with less precipitation from August to September and more precipitation from October to April during the MH. In response to these climatic changes, glaciers in both analysed regions have an ELA that is 15–33 m lower than PI during the MH. The main causes of this difference are the colder temperature during the MH, reinforcing previous results that mid-latitude glaciers are more sensitive to temperature change compared to precipitation changes. Differences in temperature have a dual effect on mass balance. First, during summer and early autumn less energy is available for melting. Second in late autumn and winter, lower temperatures cause more precipitation to fall as snow rather than rain, resulting in more accumulation and higher surface albedo. For these reasons, we postulate that the modelled ELA changes, although small, may help to explain larger glacier extents observed in the mid Holocene in both South America and New Zealand.

scholarly journals From Doktor Kurowski's Schneegrenze to our modern glacier equilibrium line altitude (ELA)

2015 ◽  
Vol 9 (3) ◽  
pp. 3165-3204 ◽  
Author(s):  
R. J. Braithwaite
Keyword(s):  
Close Agreement ◽  
Equilibrium Line ◽  
Surface Mass Balance ◽  
Equilibrium Line Altitude ◽  
Surface Mass ◽  
Inappropriate Use ◽  
Mountain Glaciers ◽  
Precipitation Increase ◽  
The Mean ◽  
Balanced Budget

Abstract. Translated into modern terminology, Kurowski suggested in 1891 that the equilibrium line altitude (ELA) of a glacier is equal to the mean altitude of the glacier when the whole glacier is in balance between accumulation and ablation. Kurowski's method has been widely misunderstood, partly due to inappropriate use of statistical terminology by later workers, and has been little tested except by Braithwaite and Müller in a 1980 paper (for 32 glaciers). I now compare Kurowski's mean altitude with balanced-budget ELA calculated for 103 modern glaciers with measured surface mass balance data. Kurowski's mean altitude is significantly higher (at 95% level) than balanced-budget ELA for 19 outlet and 42 valley glaciers, but not significantly higher for 34 mountain glaciers. The error in Kurowski mean altitude as a predictor of balanced-budget ELA might be due to generally lower balance gradients in accumulation area compared with ablation areas for many glaciers, as suggested by several workers, but some glaciers have higher gradients, presumably due to precipitation increase with altitude. The relatively close agreement between balanced-budget ELA and mean altitude for mountain glaciers (mean error −8 m with standard deviation 59 m) may reflect smaller altitude ranges for these glaciers such that there is less room for effects of different balance gradients to manifest themselves.

scholarly journals Mass Balance of “Vesper” Glacier, Washington, U.S.A.

1981 ◽  
Vol 27 (96) ◽  
pp. 271-282
Author(s):  
David P. Dethier ◽  
Jan E. Frederick
Keyword(s):  
Nineteenth Century ◽  
Mass Balance ◽  
Cascade Range ◽  
Equilibrium Line ◽  
Equilibrium Line Altitude ◽  
Climatic Fluctuations ◽  
The North ◽  
Snow Line ◽  
The Relationship ◽  
Geologic Data

AbstractDuring 1974–75 glaciologic and geologic studies were conducted on a small (0.17 km2) avalanche-nourished glacier in the North Cascade Range of Washington. The approximate equilibrium-line altitude (ELA) for this ice body, informally called “Vesper” glacier, lies at 1475 m, some 300 m below the regional ELA value. Estimated annual accumulation was 6 100±675 mm during the two years of study; 15 to 30% of this flux resulted from avalanche and wind–transported snow. Average annual ablation during the period was 5 350 mm, giving a total net balance of + 1 600 mm for the two-year study period. “Vesper” glacier persists well below the regional snow-line because of excessive local precipitation, substantial avalanche contributions, and a favourable north-facing aspect.Neoglacial moraines indicate that maximum ELA lowering in this period was approximately 165 m and occurred prior to a.d. 1670. Minor re-advances occurred during the nineteenth century. These reconnaissance measurements are consistent with the sparse geologic data reported from other glaciers in the Cascade Range. While the relationship between regional lowering of snow-line and avalanche activity is uncertain at present, these data suggest that avalanche-nourished glaciers provide a useful record of climatic fluctuations.

scholarly journals Mass balance of White Glacier, Axel Heiberg Island, N.W.T., Canada, 1960–91

1996 ◽  
Vol 42 (142) ◽  
pp. 548-563 ◽  
Author(s):  
J.Graham Cogley ◽  
W. P. Adams ◽  
M. A. Ecclestone ◽  
F. Jung-Rothenhäusler ◽  
C. S. L. Ommanney
Keyword(s):  
Mass Balance ◽  
Satellite Images ◽  
Equilibrium Line ◽  
Glacier Mass Balance ◽  
Equilibrium Line Altitude ◽  
Fold Reduction ◽  
Random Samples ◽  
Measurements Errors ◽  
Standard Techniques

AbstractWhite Glacier is a valley glacier at 79.5°N with an area of 38.7 km2. Its mass balance has been measured, over 32 years with a 3 year gap, by standard techniques using the stratigraphic system with a stake density of the order of one stake per km2. Errors in stake mass balance are about ±(200–250) mm, due largely to the local unrepresentativeness of measurements. Errors in the whole-glacier mass balanceBare of the same order as single-slake errors. However, the lag-1 autocorrelation in the time series ofBis effectively zero, so it consists of independent random samples, and the error in the long-term “balance normal”〈B〉is noticeably less.〈B〉is −100 ± 48 mm. The equilibrium-line altitude (ELA) averages 970 m. with a range of 470–1400 m. Mass balance is well correlated with ELA, but detailed modelling shows that the equilibrium line is undetectable on visible-band satellite images. A reduced network of a few stakes could give acceptable but less accurate estimates of the mass balance, as could estimates based on data from a weather station 120 km away. There is no evidence of a trend in the mass balance of White Glacier. To detect a climatologically plausible trend will require a ten-fold reduction of measurement error, a conclusion which may well apply to most estimates of mass balance based on similar stake densities.

scholarly journals Relation between the Mass Balance of Western Canadian Mountain Glaciers and Meteorological Data

1988 ◽  
Vol 34 (116) ◽  
pp. 11-18 ◽  
Author(s):  
Anne Letréguilly
Keyword(s):  
Mass Balance ◽  
Meteorological Data ◽  
Winter Precipitation ◽  
Summer Temperature ◽  
Equilibrium Line ◽  
Regression Equations ◽  
Equilibrium Line Altitude ◽  
Mountain Glaciers

AbstractThe mass balance, summer balance, winter balance, and equilibrium-line altitude of three Canadian glaciers (Peyto, Place, and Sentinel Glaciers) are compared with the meteorological records of neighbouring stations for the period 1966—84. While Peyto Glacier’s mass balance is almost entirely related to summer temperature, Sentinel Glacier’s mass balance is mostly controlled by winter precipitation. Place Glacier is influenced by both elements. Statistical reconstructions are presented for the three glaciers, using the best regression equations with the meteorological records since 1938.

Surface mass balance of Davies Dome and Whisky Glacier on James Ross Island, north-eastern Antarctic Peninsula, based on different volume-mass conversion approaches

2019 ◽  
Vol 9 (1) ◽  
pp. 1-12
Author(s):  
Zbyněk Engel ◽  
Filip Hrbáček ◽  
Kamil Láska ◽  
Daniel Nývlt ◽  
Zdeněk Stachoň
Keyword(s):  
Mass Balance ◽  
Mass Gain ◽  
Equilibrium Line ◽  
South Shetland Islands ◽  
Surface Mass Balance ◽  
Equilibrium Line Altitude ◽  
Surface Mass ◽  
Shetland Islands ◽  
James Ross Island ◽  
Accumulation Area Ratio

This study presents surface mass balance of two small glaciers on James Ross Island calculated using constant and zonally-variable conversion factors. The density of 500 and 900 kg·m–3 adopted for snow in the accumulation area and ice in the ablation area, respectively, provides lower mass balance values that better fit to the glaciological records from glaciers on Vega Island and South Shetland Islands. The difference between the cumulative surface mass balance values based on constant (1.23 ± 0.44 m w.e.) and zonally-variable density (0.57 ± 0.67 m w.e.) is higher for Whisky Glacier where a total mass gain was observed over the period 2009–2015. The cumulative surface mass balance values are 0.46 ± 0.36 and 0.11 ± 0.37 m w.e. for Davies Dome, which experienced lower mass gain over the same period. The conversion approach does not affect much the spatial distribution of surface mass balance on glaciers, equilibrium line altitude and accumulation-area ratio. The pattern of the surface mass balance is almost identical in the ablation zone and very similar in the accumulation zone, where the constant conversion factor yields higher surface mass balance values. The equilibrium line altitude and accumulation-area ratio determined for the investigated glaciers differ by less than 2m and 0.01, respectively. The annual changes of equilibrium line altitude and the mean values determined over the period 2009–2015 for Whisky Glacier (311 ± 16 m a.s.l.) and Davies Dome (393 ± 18 m a.s.l.) coincide with the values reported from Bahía del Diablo Glacier on Vega Island but differ from the glaciological records on South Shetland Islands.

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