scholarly journals Numerical simulation of fluctuations of Hintereisferner, Ötztal Alps, since AD 1850

1997 ◽  
Vol 24 ◽  
pp. 199-202 ◽  
Author(s):  
Elisabeth Schlosser
Keyword(s):  
Mass Balance ◽  
Flow Model ◽  
Grid Point ◽  
Mass Balances ◽  
Specific Mass ◽  
Ice Flow ◽  
One Dimensional ◽  
Temperature And Precipitation ◽  
Forcing Function ◽  
Point Distance

A one-dimensional ice flow model was adapted to reconstruct fluctuations of Hintereisferner, Ötztal Alps, since the last postglacial maximum in the mid-19th century. Both front positions and longitudinal ice thickness profiles were considered.As forcing function the specific mass balance was used. The model was calibrated with the period 1953–91, because since 1953 the mass balance has been determined directly. For the period before 1953, as a first step so-called dendro-mass balances (derived from tree rings) were used. Then the mass balance was also parameterized as a function of temperature and precipitation from adjacent climate stations. With both forcings Hintereisferner could be reconstructed back to about 1850 with an accuracy that lies within the accuracy of the model (200 m grid-point distance).

scholarly journals Numerical simulation of fluctuations of Hintereisferner, Ötztal Alps, since AD 1850

1997 ◽  
Vol 24 ◽  
pp. 199-202 ◽  
Author(s):  
Elisabeth Schlosser
Keyword(s):  
Mass Balance ◽  
Flow Model ◽  
Grid Point ◽  
Mass Balances ◽  
Specific Mass ◽  
Ice Flow ◽  
One Dimensional ◽  
Temperature And Precipitation ◽  
Forcing Function ◽  
Point Distance

A one-dimensional ice flow model was adapted to reconstruct fluctuations of Hintereisferner, Ötztal Alps, since the last postglacial maximum in the mid-19th century. Both front positions and longitudinal ice thickness profiles were considered. As forcing function the specific mass balance was used. The model was calibrated with the period 1953–91, because since 1953 the mass balance has been determined directly. For the period before 1953, as a first step so-called dendro-mass balances (derived from tree rings) were used. Then the mass balance was also parameterized as a function of temperature and precipitation from adjacent climate stations. With both forcings Hintereisferner could be reconstructed back to about 1850 with an accuracy that lies within the accuracy of the model (200 m grid-point distance).

scholarly journals Simulation of the historical variations in length of Unterer Grindelwaldgletscher, Switzerland

1997 ◽  
Vol 43 (143) ◽  
pp. 152-164 ◽  
Author(s):  
M. J. Schmeits ◽  
J. Oerlemans
Keyword(s):  
Mass Balance ◽  
Flow Model ◽  
Balance Model ◽  
Climatic Data ◽  
Seasonal Temperature ◽  
Mass Balance Model ◽  
Ice Flow ◽  
Historical Simulation ◽  
Temperature And Precipitation ◽  
Forcing Functions

AbstractThe historical length variations in Unterer Grindelwaldgletscher have been simulated by coupling a numerical mass-balance model to a dynamic ice-flow model. As forcing functions, we used (partly reconstructed) local climatic records, which were transformed by the mass-balance model into a mass-balance history. The ice-flow model then computes the length variations that have occurred over the course of time.In a model run from AD 1530 to the present, with both seasonal temperature and precipitation variations as forcing functions, the observed maximum length of the glacier around AD 1860 and the subsequent retreat are simulated. The observed AD 1600 maximum, however, does not show up in the simulation. This is probably due to an incorrect reconstruction of the mass balance for this period, as detailed climatic data are available only since 1865. The root-mean-square difference between the simulated and the observed front positions is 0.28 km. The simulated glacier geometry for 1987 fits the observed geometry for that year reasonably well.Because of the success of the historical simulation, an attempt is made to predict future glacier retreat on the basis of two different greenhouse-gas scenarios. For a Business-as-Usual scenario, only 29% of the 1990 volume would remain in AD 2100.

scholarly journals Past and Forecast Fluctuations of Glacier Blanc (French Alps)

1989 ◽  
Vol 13 ◽  
pp. 159-163 ◽  
Author(s):  
Anne Letréguilly ◽  
Louis Reynaud
Keyword(s):  
Mass Balance ◽  
Statistical Method ◽  
Flow Model ◽  
Glacier Retreat ◽  
Water Stream ◽  
Ice Flow ◽  
One Dimensional ◽  
French Alps ◽  
Melt Water ◽  
Glacier Length

In 1980 the new advance of Glacier Blanc covered a trail leading to a mountain hut and threatened the footbridge that crosses its melt-water stream. This event prompted the Laboratoire de Glaciologie et Géophysique de l’Environnement (LGGE) to undertake a new study of the glacier. With the old Eaux et Forêts measurements, and the more recent LGGE ones, it has been possible to forecast the probable fluctuations in glacier length by two different methods: a statistical method based on a correlation between the variations in length and mass balance, and a one-dimensional numerical ice-flow model. Both methods show that a substantial glacier retreat is unlikely during the 1985–90 period.

scholarly journals Hintereisferner, Austria: mass-balance reconstruction and numerical modelling of the historical length variations

1992 ◽  
Vol 38 (129) ◽  
pp. 233-244 ◽  
Author(s):  
W. Greuell
Keyword(s):  
Regression Analysis ◽  
Mass Balance ◽  
Flow Model ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Temperature Series ◽  
Ice Flow ◽  
Local Climate ◽  
One Dimensional ◽  
Climate Fluctuations

AbstractIn this study, an attempt is made to simulate the historical length variations of Hintereisferner (Austria). Key elements in the model are: (1) reconstruction of the local climate (Vent); (2) multiple linear regression analysis between measured climate and mass-balance variations; (3) reconstruction of the mass balance with (1) and (2); (4) a one-dimensional numerical ice-flow model forced by the mass-balance history. Progress relative to the previous, similar studies can be summarized as two points: (1) the mass balance is reconstructed more carefully, and (2) sensitivity experiments show that uncertainties and assumptions in the flow model hardly affect the response of the glacier to climate fluctuations with a time-scale of the order of (or larger than) the response time of the glacier (around 100 year).In the regression equation, mass-balance fluctuations are determined by the temperature during the ablation season and the annual precipitation. Cloudiness has no effect. The local temperature can be reconstructed as far back as 1755 with the temperature series from Basel, but the reconstruction of precipitation is unreliable prior to 1900. Mainly due to this point, a simulation starting in 1755 failed completely. However, in a run starting in 1894, the total retreat since then (2.2 km) was reproduced within 10%.

scholarly journals Simulation of the historical variations in length of Unterer Grindelwaldgletscher, Switzerland

1997 ◽  
Vol 43 (143) ◽  
pp. 152-164 ◽  
Author(s):  
M. J. Schmeits ◽  
J. Oerlemans
Keyword(s):  
Mass Balance ◽  
Flow Model ◽  
Balance Model ◽  
Climatic Data ◽  
Seasonal Temperature ◽  
Mass Balance Model ◽  
Ice Flow ◽  
Historical Simulation ◽  
Temperature And Precipitation ◽  
Forcing Functions

AbstractThe historical length variations in Unterer Grindelwaldgletscher have been simulated by coupling a numerical mass-balance model to a dynamic ice-flow model. As forcing functions, we used (partly reconstructed) local climatic records, which were transformed by the mass-balance model into a mass-balance history. The ice-flow model then computes the length variations that have occurred over the course of time.In a model run from AD 1530 to the present, with both seasonal temperature and precipitation variations as forcing functions, the observed maximum length of the glacier around AD 1860 and the subsequent retreat are simulated. The observed AD 1600 maximum, however, does not show up in the simulation. This is probably due to an incorrect reconstruction of the mass balance for this period, as detailed climatic data are available only since 1865. The root-mean-square difference between the simulated and the observed front positions is 0.28 km. The simulated glacier geometry for 1987 fits the observed geometry for that year reasonably well.Because of the success of the historical simulation, an attempt is made to predict future glacier retreat on the basis of two different greenhouse-gas scenarios. For a Business-as-Usual scenario, only 29% of the 1990 volume would remain in AD 2100.

scholarly journals Past and Forecast Fluctuations of Glacier Blanc (French Alps)

1989 ◽  
Vol 13 ◽  
pp. 159-163 ◽  
Author(s):  
Anne Letréguilly ◽  
Louis Reynaud
Keyword(s):  
Mass Balance ◽  
Statistical Method ◽  
Flow Model ◽  
Glacier Retreat ◽  
Water Stream ◽  
Ice Flow ◽  
One Dimensional ◽  
French Alps ◽  
Melt Water ◽  
Glacier Length

In 1980 the new advance of Glacier Blanc covered a trail leading to a mountain hut and threatened the footbridge that crosses its melt-water stream. This event prompted the Laboratoire de Glaciologie et Géophysique de l’Environnement (LGGE) to undertake a new study of the glacier. With the old Eaux et Forêts measurements, and the more recent LGGE ones, it has been possible to forecast the probable fluctuations in glacier length by two different methods: a statistical method based on a correlation between the variations in length and mass balance, and a one-dimensional numerical ice-flow model. Both methods show that a substantial glacier retreat is unlikely during the 1985–90 period.

scholarly journals Hintereisferner, Austria: mass-balance reconstruction and numerical modelling of the historical length variations

1992 ◽  
Vol 38 (129) ◽  
pp. 233-244 ◽  
Author(s):  
W. Greuell
Keyword(s):  
Regression Analysis ◽  
Mass Balance ◽  
Flow Model ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Temperature Series ◽  
Ice Flow ◽  
Local Climate ◽  
One Dimensional ◽  
Climate Fluctuations

AbstractIn this study, an attempt is made to simulate the historical length variations of Hintereisferner (Austria). Key elements in the model are: (1) reconstruction of the local climate (Vent); (2) multiple linear regression analysis between measured climate and mass-balance variations; (3) reconstruction of the mass balance with (1) and (2); (4) a one-dimensional numerical ice-flow model forced by the mass-balance history. Progress relative to the previous, similar studies can be summarized as two points: (1) the mass balance is reconstructed more carefully, and (2) sensitivity experiments show that uncertainties and assumptions in the flow model hardly affect the response of the glacier to climate fluctuations with a time-scale of the order of (or larger than) the response time of the glacier (around 100 year).In the regression equation, mass-balance fluctuations are determined by the temperature during the ablation season and the annual precipitation. Cloudiness has no effect. The local temperature can be reconstructed as far back as 1755 with the temperature series from Basel, but the reconstruction of precipitation is unreliable prior to 1900. Mainly due to this point, a simulation starting in 1755 failed completely. However, in a run starting in 1894, the total retreat since then (2.2 km) was reproduced within 10%.

scholarly journals Application of a mass-balance model to a Himalayan glacier

1999 ◽  
Vol 45 (151) ◽  
pp. 559-567 ◽  
Author(s):  
Rijan Bhakta Kayastha ◽  
Tetsuo Ohata ◽  
Yutaka Ageta
Keyword(s):  
Mass Balance ◽  
Surface Albedo ◽  
Balance Model ◽  
Mass Balance Model ◽  
Mass Balances ◽  
Climatic Parameters ◽  
Glacier Surface ◽  
Temperature And Precipitation ◽  
Ice Surface ◽  
Good Agreement

AbstractA mass-balance model based on the energy balance at the snow or ice surface is formulated, with particular attention paid to processes affecting absorption of radiation. The model is applied to a small glacier, Glacier AX010 in the Nepalese Himalaya, and tests of its mass-balance sensitivity to input and climatic parameters are carried out. Calculated and observed area-averaged mass balances of the glacier during summer 1978 (June-September) show good agreement, namely -0.44 and -0.46 m w.e., respectively.Results show the mass balance is strongly sensitive to snow or ice albedo, to the effects of screening by surrounding mountain walls, to areal variations in multiple reflection between clouds and the glacier surface, and to thin snow covers which alter the surface albedo. In tests of the sensitivity of the mass balance to seasonal values of climatic parameters, the mass balance is found to be strongly sensitive to summer air temperature and precipitation but only weakly sensitive to relative humidity.

scholarly journals Climate sensitivity of glaciers in southern Norway: application of an energy-balance model to Nigardsbreen, Hellstugubreen and Alfotbreen

1992 ◽  
Vol 38 (129) ◽  
pp. 223-232 ◽  
Author(s):  
J. Oerlemans
Keyword(s):  
Energy Balance ◽  
Mass Balance ◽  
Climate Sensitivity ◽  
Flow Model ◽  
Energy Balance Model ◽  
Balance Model ◽  
Equilibrium Line Altitude ◽  
Ice Flow ◽  
Calculated Mass ◽  
Southern Norway

AbstractThree glaciers in southern Norway, with very different mass-balance characteristics, are studied with an energy-balance model of the ice/snow surface. The model simulates the observed mass-balance profiles in a satisfactory way, and can thus be used with some confidence in a study of climate sensitivity. Calculated changes in equilibrium-line altitude for a 1 K temperature increase are 110, 108 and 135 m for Nigardsbreen, Hellstugubreen and Alfotbreen, respectively. The corresponding changes in mass balance, averaged over the entire glacier area, are −0.88, −0.715 and −1.11 m year−1 (water equivalent).Runs with an ice-flow model for Nigardsbreen, to which calculated mass-balance profiles arc imposed, predict that the front will advance by 3 km for a 1 K cooling, and will retreat by as much as 6.5 km for a 1 K warming. The response to a 10% increase in precipitation would be a 2 km advance of the snout, whereas a 4 km retreat is predicted for a 10% decrease. This large sensitivity (as compared to many other glaciers) is to a large extent due to the geometry of Nigardsbreen.

scholarly journals Wave Ogives

1986 ◽  
Vol 32 (112) ◽  
pp. 325-334 ◽  
Author(s):  
E.D. Waddington
Keyword(s):  
Mass Balance ◽  
Method Of Characteristics ◽  
Wave Pattern ◽  
Wave Excitation ◽  
Ice Flow ◽  
Forcing Function ◽  
Excitation Potential ◽  
Ice Velocity ◽  
Balance Functions ◽  
Velocity Channel

AbstractWave ogives arise in a solution of the continuity equation by the method of characteristics. Steady ice flow is assumed. Ice velocity, channel width, and mass-balance functions combine to form a wave-excitation potential that yields the forcing function for wave ogives. This linear-systems formulation extends the ogive theory of Nye. Convolution of the temporal cumulative mass balance and spatial forcing functions gives the total wave pattern below an ice fall. Many ice falls do not generate ogives because the wave amplitude is modulated by a factor related to ice-fall length. The wave ogives at Austerdalsbreen, Norway, are due almost entirely to ice acceleration at the top of the ice-fall, i.e. the same zone that King and Lewis showed was responsible for forming Forbes bands.

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