scholarly journals Analysis of Alpine glacier length change records with a macroscopic glacier model

2010 ◽  
Vol 65 (2) ◽  
pp. 92-102 ◽  
Author(s):  
M. P. Lüthi ◽  
A. Bauder
Keyword(s):  
Length Change ◽  
Winter Precipitation ◽  
Swiss Alps ◽  
Ice Age ◽  
Equilibrium Line ◽  
Alpine Glacier ◽  
Temperature And Precipitation ◽  
Glacier Length ◽  
Length Changes ◽  
Measured Length

Abstract. The length change record of 91 glaciers in the Swiss Alps was analyzed with a novel macroscopic glacier model (LV-model). Based on a history of equilibrium line variations, synthetic length change data were calculated. From the LV-models matching best the measured length changes, characteristic parameters were obtained. The volume time scale thus determined ranges from 5 to 170 years for glaciers of different slope and length. The analysis shows that the observed glacier length changes cannot be reproduced with an equilibrium line variation based on temperature and precipitation alone. The equilibrium line has to be lowered by 100 to 200 meters during several phases of the Little Ice Age (in the time span 1650 to 1850) to obtain observed glacier responses. Such an effect might be attributable to either higher winter precipitation in the Alps, or to radiation forcing.

scholarly journals Understanding Drivers of Glacier Length Variability Over the Last Millennium

2020 ◽  
Author(s):  
Alan Huston ◽  
Nicholas Siler ◽  
Gerard H. Roe ◽  
Erin Pettit ◽  
Nathan J. Steiger
Keyword(s):  
Climate Variability ◽  
Volcanic Eruptions ◽  
Internal Variability ◽  
Forced Response ◽  
Last Millennium ◽  
External Forcing ◽  
Climate History ◽  
Temperature And Precipitation ◽  
Glacier Length ◽  
Length Changes

Abstract. Changes in glacier length reflect the integrated response to local fluctuations in temperature and precipitation resulting from both external forcing (e.g., volcanic eruptions or anthropogenic CO2) and internal climate variability. In order to interpret the climate history reflected in the glacier moraine record, therefore, the influence of both sources of climate variability must be considered. Here we study the last millennium of glacier length variability across the globe using a simple dynamic glacier model, which we force with temperature and precipitation time series from a 13-member ensemble of simulations from a global climate model. The ensemble allows us to quantify the contributions to glacier length variability from external forcing (given by the ensemble mean) and internal variability (given by the ensemble spread). Within this framework, we find that internal variability drives most length changes in mountain glaciers that have a response timescale of less than a few decades. However, for glaciers with longer response timescales (more than a few decades) external forcing has a greater influence than internal variability. We further find that external forcing also dominates when the response of glaciers from widely separated regions is averaged. Single-forcing simulations indicate that most of the forced response over the last millennium, pre-anthropogenic warming, has been driven by global-scale temperature change associated with volcanic aerosols.

scholarly journals Extension of Glacier de Saint-Sorlin, French Alps, and equilibrium-line altitude during the Little Ice Age

2002 ◽  
Vol 48 (160) ◽  
pp. 118-124 ◽  
Author(s):  
Louis Lliboutry
Keyword(s):  
Little Ice Age ◽  
Meteorological Data ◽  
Vertical Gradient ◽  
Winter Precipitation ◽  
Ice Age ◽  
Equilibrium Line ◽  
Equilibrium Line Altitude ◽  
French Alps ◽  
The Mean ◽  
Accumulation Area Ratio

AbstractGlacier de Saint-Sorlin, French Alps, left terminal moraines at 1.3, 2.9 and 3.7 km ahead of the present terminus. According to proxy data and to historical maps, these were formed in the 19th, 18th and 17th centuries, respectively. A plateau at 2700–2625 m was then surrounded by ice but never became an accumulation area. This fact shows that the equilibrium-line altitude (ELA) on the glacier never dropped below 2300 m. The following simple models apply sufficiently to yield reliable estimations of past ELA: (1) a uniform and constant vertical gradient of the mass balance, down to the terminus; and (2) a plane bed, with a slope of 8.5° and a uniform width. Then in a steady situation the accumulation–area ratio is 1/2. Compared to the mean for 1956–72, at the onset of the Little Ice Age the balances were higher by 3.75 m ice a−1, and the ELA was 400 m lower. Correlations between 1956–72 balances and meteorological data suggest that during the melting season the 0°C isotherm was about 800 m lower, while the winter precipitation at low altitudes did not change. These correlations may have been different in the past, but an equal lowering of the ELA and of the 0°C isotherm, as assumed by several authors, seems excluded.

scholarly journals A model study of Abrahamsenbreen, a surging glacier in northern Spitsbergen

2014 ◽  
Vol 8 (6) ◽  
pp. 5687-5726
Author(s):  
J. Oerlemans ◽  
W. J. J. van Pelt
Keyword(s):  
Ice Core ◽  
Climatic Conditions ◽  
Ice Age ◽  
Equilibrium Line ◽  
Change Scenario ◽  
Equilibrium Line Altitude ◽  
Mass Budget ◽  
Model Study ◽  
Glacier Length ◽  
Bed Slope

Abstract. The climate sensitivity of Abrahamsenbreen, a 20 km long surge-type glacier in northern Spitsbergen, is studied with a simple glacier model. A scheme to describe the surges is included, which makes it possible to account for the effect of surges on the total mass budget of the glacier. A climate reconstruction back to AD 1300, based on ice-core data from Lomonosovfonna and climate records from Longyearbyen, is used to drive the model. The model is calibrated by requesting that it produces the correct Little Ice Age maximum glacier length and simulates the observed magnitude of the 1978-surge. Abrahamsenbreen is strongly out of balance with the current climate. If climatic conditions will remain as they were for the period 1989–2010, the glacier will ultimately shrink to a length of about 4 km (but this will take hundreds of years). For a climate change scenario involving a 2 m yr−1 rise of the equilibrium line from now onwards, we predict that in the year 2100 Abrahamsenbreen will be about 12 km long. The main effect of a surge is to lower the mean surface elevation and to increase the ablation area, thereby causing a negative perturbation of the mass budget. We found that the occurrence of surges leads to a somewhat stronger retreat of the glacier in a warming climate. Because of the very small bed slope, Abrahamsenbreen is sensitive to small perturbations in the equilibrium-line altitude E. For a decrease of E of only 160 m, the glacier would steadily grow into the Woodfjorddalen until after 2000 years it would reach the Woodfjord and calving could slow down the advance.

scholarly journals Modern and Little Ice Age glaciers in “humid” and “arid” areas of the Tien Shan, Central Asia: two different patterns of fluctuation

1997 ◽  
Vol 24 ◽  
pp. 142-147 ◽  
Author(s):  
O. S. Savoskul
Keyword(s):  
Central Asia ◽  
Little Ice Age ◽  
Tien Shan ◽  
Ice Age ◽  
Equilibrium Line ◽  
Arid Areas ◽  
Glacier Length ◽  
Climate Signals ◽  
Length And Area ◽  
Inner Parts

Patterns of retreat from maximum Little Ice Age (LIA) to present limits are studied at 20 glaciers in the relatively humid northwestern front ranges and arid inner areas of the Tien Shan, Central Asia. The depression of equilibrium-line altitudes has been calculated using several approaches. Data on changes of elevation ranges, glacier length and area are used to compare the patterns of glacier fluctuation. It is found that the large LIA glaciers in the warm and humid northwestern frontal ranges were 1.5–1.9 times larger in area than the modern glaciers; and the LIA glaciers in cold and arid inner parts of the Tien Shan were only 1.03–1.07 times larger. The changes in terminus-to-headwall elevation ranges are about 1.3–1.6 and 1.02–1.10, respectively. The largest LIA glaciers were 1.4–1.9 times longer than modern glaciers in “humid” ranges and only 1.02–1.12 times longer in “arid” areas. The maximum equilibrium-line depressions are approximately 100–200 m in “humid”areas and 20–50 m in “arid”areas. These results suggest that the glaciers in the “humid” areas are likely to be more variable than those in “arid” areas. The differences may be explained either by differences in the sensitivity of glaciers to climate change or by variability of climate signals from one area to another.

scholarly journals Modern and Little Ice Age glaciers in “humid” and “arid” areas of the Tien Shan, Central Asia: two different patterns of fluctuation

1997 ◽  
Vol 24 ◽  
pp. 142-147 ◽  
Author(s):  
O. S. Savoskul
Keyword(s):  
Central Asia ◽  
Little Ice Age ◽  
Tien Shan ◽  
Ice Age ◽  
Equilibrium Line ◽  
Arid Areas ◽  
Glacier Length ◽  
Climate Signals ◽  
Length And Area ◽  
Inner Parts

Patterns of retreat from maximum Little Ice Age (LIA) to present limits are studied at 20 glaciers in the relatively humid northwestern front ranges and arid inner areas of the Tien Shan, Central Asia. The depression of equilibrium-line altitudes has been calculated using several approaches. Data on changes of elevation ranges, glacier length and area are used to compare the patterns of glacier fluctuation. It is found that the large LIA glaciers in the warm and humid northwestern frontal ranges were 1.5–1.9 times larger in area than the modern glaciers; and the LIA glaciers in cold and arid inner parts of the Tien Shan were only 1.03–1.07 times larger. The changes in terminus-to-headwall elevation ranges are about 1.3–1.6 and 1.02–1.10, respectively. The largest LIA glaciers were 1.4–1.9 times longer than modern glaciers in “humid” ranges and only 1.02–1.12 times longer in “arid” areas. The maximum equilibrium-line depressions are approximately 100–200 m in “humid”areas and 20–50 m in “arid”areas. These results suggest that the glaciers in the “humid” areas are likely to be more variable than those in “arid” areas. The differences may be explained either by differences in the sensitivity of glaciers to climate change or by variability of climate signals from one area to another.

scholarly journals Eastern Alpine glacier activity and climatic records since 1860

1997 ◽  
Vol 24 ◽  
pp. 164-168 ◽  
Author(s):  
M. Kuhn ◽  
E. Schlosser ◽  
N. Span
Keyword(s):  
Mass Balance ◽  
Winter Precipitation ◽  
Winter Temperature ◽  
Precipitation Data ◽  
Mass Balances ◽  
Positive Mass ◽  
Alpine Glacier ◽  
Temperature And Precipitation ◽  
Glacier Front ◽  
The Difference

We have analyzed records of glacier-front variations, mass-balance reconstructions, temperature and precipitation data of Alpine stations, and found that the difference between summer and winter temperature in connection with winter precipitation is a useful indicator of glacier activity. Application of this parameter to the records of six stations since 1860 indicated the advance around 1920 had been preceded by a decade with frequent positive mass balances, while the period 1928–64 was characterized by increased climatic continentality and strong, uniform glacier retreats.

scholarly journals Alpine glacier resilience and Neoglacial fluctuations linked to Holocene snowfall trends in the western United States

2020 ◽  
Vol 6 (47) ◽  
pp. eabc7661
Author(s):  
Darren J. Larsen ◽  
Sarah E. Crump ◽  
Aria Blumm
Keyword(s):  
United States ◽  
Winter Precipitation ◽  
Environmental Indicators ◽  
Western United States ◽  
Geological Evidence ◽  
Alpine Glacier ◽  
Temperature And Precipitation ◽  
Rock Glaciers ◽  
Teton Range ◽  
Paleoclimate Records

Geological evidence indicates that glaciers in the western United States fluctuated in response to Holocene changes in temperature and precipitation. However, because moraine chronologies are characteristically discontinuous, Holocene glacier fluctuations and their climatic drivers remain ambiguous, and future glacier changes are uncertain. Here, we construct a continuous 10-thousand-year (ka) record of glacier activity in the Teton Range, Wyoming, using glacial and environmental indicators in alpine lake sediments. We show that Teton glaciers persisted in some form through early Holocene warmth, likely as small debris-covered glaciers or rock glaciers. Subsequent Neoglacial ice expansion began ~6.3 ka, with two prominent glacier maxima at ~2.8 and 0.1 ka that were separated by a multicentennial phase of ice retreat. Comparison with regional paleoclimate records suggests that glacier activity was dominantly controlled by winter precipitation variability superposed on long-term Holocene temperature trends, offering key insights into western U.S. glacier resilience and vulnerability to future warming.

scholarly journals Eastern Alpine glacier activity and climatic records since 1860

1997 ◽  
Vol 24 ◽  
pp. 164-168 ◽  
Author(s):  
M. Kuhn ◽  
E. Schlosser ◽  
N. Span
Keyword(s):  
Mass Balance ◽  
Winter Precipitation ◽  
Winter Temperature ◽  
Precipitation Data ◽  
Mass Balances ◽  
Positive Mass ◽  
Alpine Glacier ◽  
Temperature And Precipitation ◽  
Glacier Front ◽  
The Difference

We have analyzed records of glacier-front variations, mass-balance reconstructions, temperature and precipitation data of Alpine stations, and found that the difference between summer and winter temperature in connection with winter precipitation is a useful indicator of glacier activity. Application of this parameter to the records of six stations since 1860 indicated the advance around 1920 had been preceded by a decade with frequent positive mass balances, while the period 1928–64 was characterized by increased climatic continentality and strong, uniform glacier retreats.

Equilibrium line altitudes along the Andes during the Last millennium: Paleoclimatic implications

The Holocene ◽  
2016 ◽  
Vol 27 (7) ◽  
pp. 1019-1033 ◽  
Author(s):  
Esteban A Sagredo ◽  
Thomas V Lowell ◽  
Meredith A Kelly ◽  
Summer Rupper ◽  
Juan Carlos Aravena ◽  
...  
Keyword(s):  
Climatic Conditions ◽  
Equilibrium Line ◽  
Last Millennium ◽  
Spatial And Temporal Patterns ◽  
Climate Conditions ◽  
Alpine Glacier ◽  
Climate Anomalies ◽  
Temperature And Precipitation ◽  
The Andes ◽  
Precipitation Anomalies

Deciphering the climate changes that influenced the glacial fluctuations of the last millennium requires documenting the spatial and temporal patterns of these glacial events. Here, we estimate the change in equilibrium line altitudes (ELAs) between the most prominent glacial advance of the last millennium and the present for four alpine glaciers located in different climatic regimes along the Andes. For each glacier, we reconstruct scenarios of climatic conditions (temperature and precipitation anomalies) that accommodate the observed ELA changes. We focus on the following glaciers: an alpine glacier in the Cordillera Vilcanota (13°S), Tapado glacier (30°S), Cipreses glacier (34°S), and Tranquilo glacier (47°S). Our results show that the range of possible temperature and precipitation anomalies that accommodate the observed ELA changes overlap significantly at three of the four sites (i.e. Vilcanota, Cipreses, and Tranquilo). Only Tapado glacier exhibits a set of climate anomalies that differs from the other three sites. Assuming no change in precipitation, the estimated ELA changes require a cooling of at least 0.7°C in the Cordillera Vilcanota, 1.0°C at Tapado glacier, 0.6°C at Cipreses glacier, and 0.7°C at Tranquilo glacier. Conversely, assuming no change in temperature, the estimated ELA changes are explained by increases in precipitation exceeding 0.52 m yr−1 (64% of the annual precipitation) in the Cordillera Vilcanota, 0.31 m yr−1 (89%) at Tapado glacier, 0.22 m yr−1 (27%) at Cipreses glacier, and 0.3 m yr−1 (27%) at Tranquilo glacier. By mapping the ELA changes and modeling the potential climate forcing across diverse climate settings, we aim to contribute toward documenting the spatial variability of climate conditions during the last millennium, a key step to decipher the mechanisms underlying the glacial fluctuation that occurred during this period.

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