Estimates of glacier equilibrium line altitudes by the Area×Altitude, the Area×Altitude Balance Ratio and the Area×Altitude Balance Index methods and their validation

Osmaston, Henry

doi:10.1016/j.quaint.2005.02.004

Cited by 214 publications

(207 citation statements)

References 6 publications

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“…Previous works highlighted that the AABR method creates better reconstructions than the other methods and is the only one that can be applied to current glaciers and paleoglaciers [75,81]. On the other hand, the paleoELA 2 (4993 m) reconstructed in this work can be a representative reconstruction of the maximum extension of all the paleoglaciers towards the Nevado Coropuna northeast (Figure 7), including the ice masses located in sites isolated topographically from the surrounding peaks.…”

Section: Paleoelamentioning

confidence: 76%

“…The mapping of paleoglaciers ( Figure 7), based on the geomorphological map, led to the ELA and paleoELA reconstruction by the AABR method [75], because where good topographic maps and air photograph coverage are available, this method is more rigorous than any other [81]. The application of the same method for current ELAs and paleoELAs is almost a novelty in the Tropical Andes because, with few exceptions [77,82], previous works in Coropuna [47] and other mountains [83] used different procedures for the present and the past.…”

Section: Ela and Paleoela Reconstructionmentioning

confidence: 99%

“…They are the only current ice tongues to the northeastward of Coropuna. Following the method proposed by Osmaston [75]: first, the ELAs were tabulated in series with the BR values used for their estimation. Then, the averages and standard deviations of the statistical series were calculated.…”

Section: Ela Paleoelas Climate Cooling and Paleoprecipitationmentioning

confidence: 99%

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Prospecting Glacial Ages and Paleoclimatic Reconstructions Northeastward of Nevado Coropuna (16° S, 73° W, 6377 m), Arid Tropical Andes

et al. 2018

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This work investigates the timing, paleoclimatic framework and inter-hemispheric teleconnections inferred from the glaciers last maximum extension and the deglaciation onset in the Arid Tropical Andes. A study area was selected to the northeastward of the Nevado Coropuna, the volcano currently covered by the largest tropical glacier on Earth. The current glacier extent, the moraines deposited in the past and paleoglaciers at their maximum extension have been mapped. The present and past Equilibrium Line Altitudes (ELA and paleoELA) have been reconstructed and the chlorine-36 ages have been calculated, for preliminary absolute dating of glacial and volcanic processes. The paleoELA depression, the thermometers installed in the study area and the accumulation data previously published allowed development of paleotemperature and paleoprecipitation models. The Coropuna glaciers were in maximum extension (or glacial standstill) 20-12 ka ago (and maybe earlier). This last maximum extension was contemporary to the Heinrich 2-1 and Younger Dryas events and the Tauca and Coipasa paleolake transgressions on Bolivian Altiplano. The maximum paleoELA depression (991 m) shows a colder (−6.4 • C) and moister climate with precipitation ×1.2-×2.8 higher than the present. The deglaciation onset in the Arid Tropical Andes was 15-11 ka ago, earlier in the most southern, arid, and low mountains and later in the northernmost, less arid, and higher mountains.

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Section: Paleoelamentioning

confidence: 76%

Section: Ela and Paleoela Reconstructionmentioning

confidence: 99%

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Prospecting Glacial Ages and Paleoclimatic Reconstructions Northeastward of Nevado Coropuna (16° S, 73° W, 6377 m), Arid Tropical Andes

et al. 2018

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“…Despite the fact that ELA estimates depend largely on choice of method, reconstruction of ELAs remains a powerful tool for providing paleoclimatic information from either presently or past glacierized regions [Osmaston, 2005].…”

Section: A Closer Look At Surging Glaciers Moraines and Equilibriummentioning

confidence: 99%

Reconstructing Climate Change: Not All Glaciers Suitable

Yde

Paasche

2010

EoS Transactions

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Glaciers are among the most trusted indicators of climate change, not just because they retreat due to the current rise in global temperatures but also because of their central role in reconstructing past climates. Glaciers come in many forms, and their sensitivity to climate change depends partly on the physics governing the individual glacier, implying that a response can be fast or slow, straightforward or complex, which in sum suggests that not all glaciers are equally suitable for reconstructing past and present climate conditions. In particular, surging and debris‐covered glaciers may especially yield misleading results (Figure 1).

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“…Meierding, 1982;Porter, 2001;Kaser and Osmaston, 2002;Benn et al 2005;Osmaston, 2005). It is recognised, for instance, that a glaciologically-sensible method should account for the elevation dependence of glacier area, i.e., glacier hypsometry (Benn and Gemmell, 1997;Porter, 2001; Kaser and Osmaston, 2002;Osmaston, 2005) and that this consideration is missing from the classic Accumulation-Area-Ratio method (Meier and Post, 1962) adopted by some studies (e.g. Balascio et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Using the surface profiles of modern ice masses to inform palaeo-glacier reconstructions

Barr

Clark

2010

Quaternary Science Reviews

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Morphometric study of modern ice masses is useful because many reconstructions of glaciers traditionally draw on their shape for guidance. Here we analyse data derived from the surface profiles of 200 modern ice masses-valley glaciers, icefields, ice caps, and ice sheets with length scales from 10 0 to 10 3 km-from different parts of the world.Four profile-attributes are investigated: relief, span, and two parameters C * and C that result from using Nye's (1952) theoretical parabola as a profile descriptor. C * and C respectively measure each profile's aspect ratio and steepness, and are found to decrease in size and variability with span. This dependence quantifies the competing influences of unconstrained spreading behaviour of ice flow and bed topography on the profile shape of ice masses, which becomes more parabolic as span increases (with C * and C tending to low values of 2.5-3.3 m 1/2 ). The same data reveal coherent minimum bounds in C * and C for modern ice masses that we develop into two new methods of palaeo-glacier reconstruction. In the first method, glacial limits are known from moraines, and the bounds are used to constrain the lowest palaeo ice surface consistent with modern profiles. We give an example of applying this method over a three-dimensional glacial landscape in Kamchatka. In the second method, we test the plausibility of existing reconstructions by comparing their C * and C against the modern minimum bounds. Of the 86 published palaeo ice masses that we put to this test, 88% are found to be plausible.The search for other morphometric constraints will help us formalise glacier reconstructions and reduce their uncertainty and subjectiveness.

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Estimates of glacier equilibrium line altitudes by the Area×Altitude, the Area×Altitude Balance Ratio and the Area×Altitude Balance Index methods and their validation

Cited by 214 publications

References 6 publications

Prospecting Glacial Ages and Paleoclimatic Reconstructions Northeastward of Nevado Coropuna (16° S, 73° W, 6377 m), Arid Tropical Andes

Prospecting Glacial Ages and Paleoclimatic Reconstructions Northeastward of Nevado Coropuna (16° S, 73° W, 6377 m), Arid Tropical Andes

Reconstructing Climate Change: Not All Glaciers Suitable

Using the surface profiles of modern ice masses to inform palaeo-glacier reconstructions

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