scholarly journals Map-based methods for estimating glacier equilibrium-line altitudes

2003 ◽  
Vol 49 (166) ◽  
pp. 329-336 ◽  
Author(s):  
Katherine C. Leonard ◽  
Andrew G. Fountain
Keyword(s):  
Mass Balance ◽  
Sea Level ◽  
Equilibrium Line ◽  
Topographic Maps ◽  
Kinematic Waves ◽  
The Mean

AbstractWe examine the validity of two methods for estimating glacier equilibrium-line altitudes (ELAs) from topographic maps. The ELA determined by contour inflection (the kinematic ELA) and the mean elevation of the glacier correlate extremely well with the ELA determined from mass-balance data (observed ELA). However, the range in glacier elevations above sea level is much larger than the variation in ELA, making this correlation unhelpful. The data were normalized and a reasonable correlation (r2 = 0.59) was found between observed and kinematic ELA.The average of the normalized kinematic ELAs was consistently located down-glacier from the observed ELA, consistent with theory. The normalized mean elevation of the glacier exhibited no correlation and suggests that the toe–headwall altitude ratio is not a good approximation for the ELA. Kinematic waves had no effect on the position of the kinematic ELA. Therefore, topographic maps of glacier surfaces can be used to infer the position of the ELA and provide a method for estimating past ELAs from historic topographic maps.

scholarly journals Mass-balance estimates on the glacier complex Kongsvegen and Sveabreen, Spitsbergen, Svalbard, using radioactive layers

1994 ◽  
Vol 40 (135) ◽  
pp. 368-376 ◽  
Author(s):  
Bernard Lefauconnier ◽  
Jon Ove Hagen ◽  
Jean Francis Pinglot ◽  
Michel Pourchet
Keyword(s):  
Mass Balance ◽  
Chernobyl Accident ◽  
Ice Cores ◽  
Equilibrium Line ◽  
Novaya Zemlya ◽  
Topographic Data ◽  
Positive Balance ◽  
The Mean ◽  
Nuclear Tests

AbstractAnalyses of total β and γ radioactivity have been carried out on ten shallow ice cores collected in 1989 and 1990 on Kongsvegen and Sveabreen, Spitsbergen. No peak of total β radioactivity, corresponding to the Chernobyl accident (1986), can be identified. Chernobyl layers were identified by 137Cs and 134Cs activities, and a signal from the nuclear tests in Novaya Zemlya (1961–62), was detected at one location by 137Cs activity. The mean net accumulation for the periods 1986–89 and 1962–88 was estimated for both glaciers. Using topographic data, the mean net ablation on Kongsvegen was estimated for the period 1964–90 and the mean net balances were calculated. The results agree with recent direct glaciological balance measurements. For the period 1986–89, the net accumulation was higher on Sveabreen than on Kongsvegen, and the equilibrium-line altitudes (ELA) were around 450 and 520 m a.s.l., respectively. Kongsvegen had a positive balance of 0.11 m w.eq. and Sveabreen was in equilibrium, whereas for the last 26 years the balance of Kongsvegen was slightly negative (−0.10 m w.eq.) and the ELA was around 560 m a.s.l.

scholarly journals Surface mass balance of small glaciers on James Ross Island, north-eastern Antarctic Peninsula, during 2009–2015

2018 ◽  
Vol 64 (245) ◽  
pp. 349-361 ◽  
Author(s):  
ZBYNĚK ENGEL ◽  
KAMIL LÁSKA ◽  
DANIEL NÝVLT ◽  
ZDENĚK STACHOŇ
Keyword(s):  
Mass Balance ◽  
Antarctic Peninsula ◽  
Mass Gain ◽  
Equilibrium Line ◽  
South Shetland Islands ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
North Eastern ◽  
James Ross Island ◽  
The Mean

ABSTRACTTwo small glaciers on James Ross Island, the north-eastern Antarctic Peninsula, experienced surface mass gain between 2009 and 2015 as revealed by field measurements. A positive cumulative surface mass balance of 0.57 ± 0.67 and 0.11 ± 0.37 m w.e. was observed during the 2009–2015 period on Whisky Glacier and Davies Dome, respectively. The results indicate a change from surface mass loss that prevailed in the region during the first decade of the 21st century to predominantly positive surface mass balance after 2009/10. The spatial pattern of annual surface mass-balance distribution implies snow redistribution by wind on both glaciers. The mean equilibrium line altitudes for Whisky Glacier (311 ± 16 m a.s.l.) and Davies Dome (393 ± 18 m a.s.l.) are in accordance with the regional data indicating 200–300 m higher equilibrium line on James Ross and Vega Islands compared with the South Shetland Islands. The mean accumulation-area ratio of 0.68 ± 0.09 and 0.44 ± 0.09 determined for Whisky Glacier and Davies Dome, respectively, is similar to the value reported for Vega Island and within the range of typical values for high-latitude glaciers.

scholarly journals Climatological and Photogrammetric Speculations on Mass-balance Changes of McCall, Glacier, Brooks Range, Alaska

1976 ◽  
Vol 17 (77) ◽  
pp. 479-490 ◽  
Author(s):  
Egon Dorrer ◽  
Gerd Wendler
Keyword(s):  
Mass Balance ◽  
Northern Hemisphere ◽  
Pressure Level ◽  
Equilibrium Line ◽  
Brooks Range ◽  
Glacier Recession ◽  
The Mean

The mean mass balance of the McCall Glacier, Brooks Range, Alaska, was estimated for the period 1958 to 1971. The three methods used, photogrammetry, mean height of the equilibrium line, and correlation with the height of the synoptic 500 mbar pressure level, all gave negative values, but the amount depended on the method used. This trend of glacier recession is in agreement with most observations of glaciers in the Brooks Range as well as with the majority of the glaciers in the Northern Hemisphere.

scholarly journals The Mass Balance of the Devon Island Ice Cap, Northwest Territories, Canada, 1961-66

1970 ◽  
Vol 9 (57) ◽  
pp. 325-336 ◽  
Author(s):  
R.M. Koerner
Keyword(s):  
Mass Balance ◽  
Equilibrium Line ◽  
Accumulation Pattern ◽  
North West ◽  
Average Value ◽  
Devon Island ◽  
Ice Cap ◽  
The North ◽  
West Part ◽  
The Mean

Methods used in measuring the mass balance of the Devon Island ice cap are described. The use of dyes and melt trays is recommended in the superimposed-ice and firn zones of sub-polar glaciers. The north-west part of the ice cap was studied in most detail and has had a slightly negative net balance for the period 1961-66. An inverse relationship between mean net balance(bn)and elevation of the equilibrium line in the north-west part of the ice cap indicates that the mean net balance there would be zero with an equilibrium line at 920 m (±80 m) elevation. Accumulation on the ice cap is greatest in the south-east but the measurements suggest that the mean net balance there is similar to the mean net balance on the rest of the ice cap. It is concluded that the present accumulation pattern must have existed for several hundreds, and possibly thousands of years. A study of firn stratigraphy and of variations in the elevation of the firn and equilibrium lines indicates that between 1961 and 1966 only 1962 had a more negative mean net balance than the average value for the period 1934-60. During the same 26 year period the net balance at 1 787 m elevation has varied, but summer conditions do not appear to have changed significantly.

scholarly journals Mass-balance estimates on the glacier complex Kongsvegen and Sveabreen, Spitsbergen, Svalbard, using radioactive layers

1994 ◽  
Vol 40 (135) ◽  
pp. 368-376 ◽  
Author(s):  
Bernard Lefauconnier ◽  
Jon Ove Hagen ◽  
Jean Francis Pinglot ◽  
Michel Pourchet
Keyword(s):  
Mass Balance ◽  
Chernobyl Accident ◽  
Ice Cores ◽  
Equilibrium Line ◽  
Novaya Zemlya ◽  
Topographic Data ◽  
Positive Balance ◽  
The Mean ◽  
Nuclear Tests

AbstractAnalyses of total β and γ radioactivity have been carried out on ten shallow ice cores collected in 1989 and 1990 on Kongsvegen and Sveabreen, Spitsbergen. No peak of total β radioactivity, corresponding to the Chernobyl accident (1986), can be identified. Chernobyl layers were identified by137Cs and134Cs activities, and a signal from the nuclear tests in Novaya Zemlya (1961–62), was detected at one location by137Cs activity. The mean net accumulation for the periods 1986–89 and 1962–88 was estimated for both glaciers. Using topographic data, the mean net ablation on Kongsvegen was estimated for the period 1964–90 and the mean net balances were calculated. The results agree with recent direct glaciological balance measurements. For the period 1986–89, the net accumulation was higher on Sveabreen than on Kongsvegen, and the equilibrium-line altitudes (ELA) were around 450 and 520 m a.s.l., respectively. Kongsvegen had a positive balance of 0.11 m w.eq. and Sveabreen was in equilibrium, whereas for the last 26 years the balance of Kongsvegen was slightly negative (−0.10 m w.eq.) and the ELA was around 560 m a.s.l.

scholarly journals The transfer of mass-balance profiles to unmeasured glaciers

2009 ◽  
Vol 50 (50) ◽  
pp. 185-190 ◽  
Author(s):  
Michael Kuhn ◽  
Jakob Abermann ◽  
Michael Bacher ◽  
Marc Olefs
Keyword(s):  
Mass Balance ◽  
Digital Elevation Models ◽  
Quantitative Information ◽  
Equilibrium Line ◽  
Equilibrium Line Altitude ◽  
Altitude Exposure ◽  
Digital Elevation ◽  
Area Distribution ◽  
Elevation Changes ◽  
The Mean

AbstractFor estimation of the mass balance of an unmeasured glacier, its area distribution with altitude, s (h), generally is the only available quantitative information. The appropriate specific balance profile, b (h), needs to be transferred from a measured glacier, where transfer means modification and adaptation to the topographic and climatic situation of the unmeasured glacier, such as altitude, exposure to sun and wind, or temperature. This study proposes the area median elevation, M, as a parameter of prime importance for the transfer. Using as an example ten Alpine glaciers, the similarity of M and equilibrium-line altitude is quantified and the effect of aspect and surrounding topography is qualitatively suggested. The transfer of b (h) between well-measured glaciers yielded differences in the mean specific balance of 150 mm in the mean of a 10 year period, which corresponds to a change in median altitude by 30 m. Transfer of b (h) with a shift according to median glacier elevation to a basin with 27 glaciers and 23 km2 ice cover agreed to within 10% with elevation changes converted from digital elevation models of 1969 and 1997.

scholarly journals The Mass Balance of the Devon Island Ice Cap, Northwest Territories, Canada, 1961-66

1970 ◽  
Vol 9 (57) ◽  
pp. 325-336 ◽  
Author(s):  
R.M. Koerner
Keyword(s):  
Mass Balance ◽  
Equilibrium Line ◽  
Accumulation Pattern ◽  
North West ◽  
Average Value ◽  
Devon Island ◽  
Ice Cap ◽  
The North ◽  
West Part ◽  
The Mean

Methods used in measuring the mass balance of the Devon Island ice cap are described. The use of dyes and melt trays is recommended in the superimposed-ice and firn zones of sub-polar glaciers. The north-west part of the ice cap was studied in most detail and has had a slightly negative net balance for the period 1961-66. An inverse relationship between mean net balance (bn) and elevation of the equilibrium line in the north-west part of the ice cap indicates that the mean net balance there would be zero with an equilibrium line at 920 m (±80 m) elevation. Accumulation on the ice cap is greatest in the south-east but the measurements suggest that the mean net balance there is similar to the mean net balance on the rest of the ice cap. It is concluded that the present accumulation pattern must have existed for several hundreds, and possibly thousands of years. A study of firn stratigraphy and of variations in the elevation of the firn and equilibrium lines indicates that between 1961 and 1966 only 1962 had a more negative mean net balance than the average value for the period 1934-60. During the same 26 year period the net balance at 1 787 m elevation has varied, but summer conditions do not appear to have changed significantly.

scholarly journals A mean net accumulation pattern derived from radioactive layers and radar soundings on Austfonna, Nordaustlandet, Svalbard

2001 ◽  
Vol 47 (159) ◽  
pp. 555-566 ◽  
Author(s):  
Jean Francis Pinglot ◽  
Jon Ove Hagen ◽  
Kjetil Melvold ◽  
Trond Eiken ◽  
Christian Vincent
Keyword(s):  
Mass Balance ◽  
Ice Cores ◽  
Snow Accumulation ◽  
Equilibrium Line ◽  
Accumulation Pattern ◽  
Ice Cap ◽  
The Mean ◽  
Nuclear Tests ◽  
Ground Penetrating ◽  
High Degree

AbstractWe present the snow-accumulation distribution over Austfonna, Nordaustlandet, Svalbard, based on 29 shallow ice cores that were retrieved from this ice cap during 1998 and 1999. Mean annual net accumulation is deduced from radioactive layers resulting from the 1954–74 atmospheric nuclear tests (maximum in 1963) and the Chernobyl accident (1986). The Chernobyl layer was located in 19 ice cores in the accumulation area, and the nuclear test layer was located in two deeper ice cores. In addition, the spatial variation of the depth of winter 1998/99 snowpack was mapped using snow probing, ground-penetrating radar methods and pit studies. The altitudinal gradient of the mean annual net mass balance and the altitude of the mean equilibrium line are determined along five transects ending at the top of the ice cap. The mean annual net mass balance and the equilibrium-line altitudes show a high degree of asymmetry between the western and eastern parts of Austfonna, in accordance with the distribution of winter accumulation. Large interannual variations of the accumulation exist. However, the study of the mean annual net mass balance shows no trend for two different time periods, 1963–86 and 1986 to the date of the drillings (1998/99).

scholarly journals Climatological and Photogrammetric Speculations on Mass-balance Changes of McCall, Glacier, Brooks Range, Alaska

1976 ◽  
Vol 17 (77) ◽  
pp. 479-490 ◽  
Author(s):  
Egon Dorrer ◽  
Gerd Wendler
Keyword(s):  
Mass Balance ◽  
Northern Hemisphere ◽  
Pressure Level ◽  
Equilibrium Line ◽  
Brooks Range ◽  
Glacier Recession ◽  
The Mean

The mean mass balance of the McCall Glacier, Brooks Range, Alaska, was estimated for the period 1958 to 1971. The three methods used, photogrammetry, mean height of the equilibrium line, and correlation with the height of the synoptic 500 mbar pressure level, all gave negative values, but the amount depended on the method used. This trend of glacier recession is in agreement with most observations of glaciers in the Brooks Range as well as with the majority of the glaciers in the Northern Hemisphere.

A method for monitoring glacier mass balance using satellite albedo measurements: application to Vatnajökull, Iceland

2002 ◽  
Vol 48 (161) ◽  
pp. 267-278 ◽  
Author(s):  
Martijn S. De Ruyter De Wildt ◽  
Johannes Oerlemans ◽  
Helgi Björnsson
Keyword(s):  
Mass Balance ◽  
Surface Albedo ◽  
Global Radiation ◽  
Winter Precipitation ◽  
Equilibrium Line ◽  
Gradual Transition ◽  
Glacier Mass Balance ◽  
Ice Cap ◽  
The Mean ◽  
Melting Season

AbstractWe compare satellite albedo images of Vatnajökull, Iceland, with mass-balance measurements for the years 1991–99. We find that the equilibrium line is mostly not visible when it is located above its position of the previous year(s). Equilibrium-line detection is further hindered by clouds and a gradual transition between ice and firn or snow. Consequently, firn-line elevation at the end of the melting season is not particularly useful for estimating the annual mass balance. Instead, we propose to study the mean albedo of the entire ice cap throughout the melting season so that all available information about the surface albedo is taken into account. The mean net potential global radiation, which can be estimated from the mean surface albedo alone, both depends on and influences summer melt. It also depends on winter precipitation and, integrated over the melting season, is found to relate linearly to the specific mass balance B (r = 0.87 and 0.94 for different outlets of Vatnajökull). B can be estimated quantitatively when this relation is known and qualitatively when it is not. The uncertainty in the satellite-derived value of B is 0.5–0.8 m w.e., which for Vatnajökull corresponds to about 27% of the interannual variability of B.

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