scholarly journals Long-term records of glacier surface velocities in the Ötztal Alps (Austria)

2019 ◽  
Vol 11 (2) ◽  
pp. 705-715 ◽  
Author(s):  
Martin Stocker-Waldhuber ◽  
Andrea Fischer ◽  
Kay Helfricht ◽  
Michael Kuhn
Keyword(s):  
Mass Balance ◽  
Glacier Mass Balance ◽  
Climatic Forcing ◽  
Glacier Surface ◽  
Ice Flow ◽  
Strong Indicator ◽  
Glacier Length ◽  
Length Changes ◽  
Flow Velocities

Abstract. Climatic forcing affects glacier mass balance, which causes changes in ice flow dynamics and glacier length changes on different timescales. Mass balance and length changes are operationally used for glacier monitoring, whereas only a few time series of glacier dynamics have been recorded. Here we present a unique dataset of yearly averaged ice flow velocity measurements at stakes and stone lines covering more than 100 years on Hintereisferner and more than 50 years on Kesselwandferner. Moreover, the dataset contains sub-seasonal variations in ice flow from Gepatschferner and Taschachferner covering almost 10 years. The ice flow velocities on Hintereisferner and (especially) on Kesselwandferner show great variation between advancing and retreating periods, with magnitudes increasing from the stakes at higher elevations to the lower-elevated stakes, making ice flow records at ablation stakes a very sensitive indicator of glacier state. Since the end of the latest glacier advances from the 1970s to the 1980s, the ice flow velocities have decreased continuously, a strong indicator of the negative mass balances of the glaciers in recent decades. The velocity datasets of the four glaciers are available at https://doi.org/10.1594/PANGAEA.896741.

scholarly journals Long-term records of glacier surface velocities in the Ötztal Alps (Austria)

2019 ◽  
Author(s):  
Martin Stocker-Waldhuber ◽  
Andrea Fischer ◽  
Kay Helfricht ◽  
Michael Kuhn
Keyword(s):  
Mass Balance ◽  
Glacier Mass Balance ◽  
Data Sets ◽  
Climatic Forcing ◽  
Glacier Surface ◽  
Ice Flow ◽  
Strong Indicator ◽  
Length Changes ◽  
Flow Velocities

Abstract. Climatic forcing affects glacier mass balance and ice flow dynamics on different time scales, resulting in length changes. Mass Balance and length changes are operationally used for glacier monitoring, whereas only a few time series of glacier dynamics have been recorded. With more than 100 years of measurements of ice flow velocities at stakes and stone lines on Hintereisferner and more than 50 years on Kesselwandferner, annual velocity and glacier fluctuation records have similar lengths. Subseasonal variations of ice flow velocities have been measured on Gepatschferner and Taschachferner for nearly a decade. The ice flow velocities on Hintereisferner and especially on Kesselwandferner show great variations between advancing and retreating periods, with magnitudes increasing from the highest to the lowest stakes, making ice flow records at ablation stakes a very sensitive indicator of glacier state. Since the end of the latest glacier advances from the 1970s to the 1980s, the ice flow velocities have decreased continuously, a strong indicator of the negative mass balances of the glaciers in recent decades. The velocity data sets of the four glaciers are available at https://doi.pangaea.de/10.1594/PANGAEA.896741.

scholarly journals Ice flow velocity as a sensitive indicator of glacier state

2018 ◽  
Author(s):  
Martin Stocker-Waldhuber ◽  
Andrea Fischer ◽  
Kay Helfricht ◽  
Michael Kuhn
Keyword(s):  
Flow Dynamics ◽  
Sensitive Indicator ◽  
Interannual Variations ◽  
Climatic Forcing ◽  
Velocity Change ◽  
Ice Flow ◽  
Glacier Length ◽  
Length Changes ◽  
Flow Velocities

Abstract. Climatic forcing affects glacier length changes, mass balance and ice flow dynamics on different time scales and also dependent on topography. The first two of these parameters are operationally used for glacier monitoring, whereas only a few time series of glacier dynamics exist with the potential to serve as long-term indicators of glacier response to climate change. With more than 100 years of measurements of ice flow velocities at stakes and stone lines on Hintereisferner (HEF) and more than 50 years on Kesselwandferner (KWF), records of annual velocity change are as long as records of glacier fluctuations. Interannual variations of ice flow velocities and shorter supporting interpretations of long-term records have been measured on Gepatschferner (GPF) and Taschachferner (TSF) for nearly 10 years. The ice flow velocities on Hintereisferner and especially on Kesselwandferner show great variations between advancing and retreating periods, with magnitudes increasing from the highest to the lowest stakes, making ice flow records at ablation stakes a very sensitive indicator of glacier state. Since the end of the latest glacier advances from the 1970s to the 1980s, the ice flow velocities have decreased continuously, a strong sign of the severe retreat of the glaciers in recent decades.

scholarly journals Ice-flow and mass changes of Lewis Glacier, Mount Kenya, East Africa, 1986–90: observations and modeling

1992 ◽  
Vol 38 (128) ◽  
pp. 36-42
Author(s):  
Stefan Hastenrath
Keyword(s):  
Time Interval ◽  
Volume Loss ◽  
Climatic Forcing ◽  
Ice Flow ◽  
Mass Budget ◽  
Modeling And Prediction ◽  
Mass Redistribution ◽  
Glacier Changes ◽  
Flow Velocities

AbstractThe long-term monitoring of Lewis Glacier on Mount Kenya serves as a basis for the study of glacier evolution in response to climatic forcing through modeling of its ice flow and mass budget. Following up on an earlier modeling and prediction study to 1990, this paper examines the ice-mass and flow changes in relation to the net-balance conditions over 1986–90. A model experiment using as climatic forcing the observed 1978–86 vertical net-balance profile yielded a volume loss and slow down of ice flow more drastic than observed during 1986–90. The causes of this discrepancy were examined in successive model experiments. Realistic simulations of mass-budget and thickness changes over 1986–90 are obtained using as input the net-balance forcing for the same period rather than for the preceding 1978–86 interval, and approximate flow velocities. With the same net-balance forcing and a completely stagnant Lewis Glacier, the elimination of mass redistribution by ice flow acts to mitigate the loss of volume and thickness in the upper glacier, and to accentuate it in the lower glacier. Accordingly, the observed 1986–90 net-balance profile along with the 1990 ice-flow velocities provide suitable input for the modeling of Lewis Glacier changes to 1994. Under continuation of the 1986–90 climatic forcing, ice thinning ranging from less than 1 m in the upper glacier to more than 7 m in the lower glacier, and a total volume loss of order 57 × 104 m3, are anticipated over the 1990–94 time interval.

scholarly journals Ice-flow and mass changes of Lewis Glacier, Mount Kenya, East Africa, 1986–90: observations and modeling

1992 ◽  
Vol 38 (128) ◽  
pp. 36-42 ◽  
Author(s):  
Stefan Hastenrath
Keyword(s):  
Time Interval ◽  
Volume Loss ◽  
Climatic Forcing ◽  
Ice Flow ◽  
Mass Budget ◽  
Modeling And Prediction ◽  
Mass Redistribution ◽  
Glacier Changes ◽  
Flow Velocities

AbstractThe long-term monitoring of Lewis Glacier on Mount Kenya serves as a basis for the study of glacier evolution in response to climatic forcing through modeling of its ice flow and mass budget. Following up on an earlier modeling and prediction study to 1990, this paper examines the ice-mass and flow changes in relation to the net-balance conditions over 1986–90. A model experiment using as climatic forcing the observed 1978–86 vertical net-balance profile yielded a volume loss and slow down of ice flow more drastic than observed during 1986–90. The causes of this discrepancy were examined in successive model experiments. Realistic simulations of mass-budget and thickness changes over 1986–90 are obtained using as input the net-balance forcing for the same period rather than for the preceding 1978–86 interval, and approximate flow velocities. With the same net-balance forcing and a completely stagnant Lewis Glacier, the elimination of mass redistribution by ice flow acts to mitigate the loss of volume and thickness in the upper glacier, and to accentuate it in the lower glacier. Accordingly, the observed 1986–90 net-balance profile along with the 1990 ice-flow velocities provide suitable input for the modeling of Lewis Glacier changes to 1994. Under continuation of the 1986–90 climatic forcing, ice thinning ranging from less than 1 m in the upper glacier to more than 7 m in the lower glacier, and a total volume loss of order 57 × 104m3, are anticipated over the 1990–94 time interval.

scholarly journals Meteorological controls on glacier mass balance: empirical relations suggested by measurements on glacier de Sarennes, France

1997 ◽  
Vol 43 (143) ◽  
pp. 131-137 ◽  
Author(s):  
C. Vincent ◽  
M. Vallon
Keyword(s):  
Mass Balance ◽  
Time Scale ◽  
Meteorological Data ◽  
Empirical Relation ◽  
Glacier Mass Balance ◽  
Glacier Surface ◽  
Surface Conditions ◽  
The Past ◽  
Empirical Relations

AbstractGlacial mass-balance reconstruction for a long-term time-scale requires knowledge of the relation between climate change and mass-balance fluctuations. A large number of mass-balance reconstructions since the beginning of the century are based on statistical relations between monthly meteorological data and mass balance. The question examined in this paper is: are these relationships reliable enough for long-term time-scale extrapolation? From the glacier de Sarennes long mass-balance observations series, we were surprised to discover large discrepancies between relations resulting from different time periods. The importance of the albedo in relation to ablation and mass balance is highlighted, and it is shown that it is impossible to ignore glacier-surface conditions in establishing the empirical relation between mass-balance fluctuations and climatic variation; to omit this parameter leads to incorrect results for mass-balance reconstruction in the past based on meteorological data.

scholarly journals Modelling mass balance using photogrammetric and geophysical data: a pilot study at Griesgletscher, Swiss Alps

1999 ◽  
Vol 45 (151) ◽  
pp. 575-583 ◽  
Author(s):  
Andreas Kääb ◽  
Martin Funk
Keyword(s):  
Pilot Study ◽  
Mass Balance ◽  
Surface Strain ◽  
Swiss Alps ◽  
Surface Velocity ◽  
Glacier Mass Balance ◽  
Glacier Surface ◽  
Ice Flow ◽  
Applied Model ◽  
Ice Velocity

AbstractThe kinematic boundary condition al the glacier surface can be used to give glacier mass balance at a point as a function of changes in the surface elevation, and of the horizontal and vertical velocities. Vertical velocity can in turn be estimated from basal slope, basal ice velocity and surface strain. In a pilot study on the tongue of Griesgletscher, Swiss Alps, the applicability of the relation for modelling area-wide ice flow and mass-balance distribution is tested. The key input of the calculations, i.e. the area-wide surface velocity field, is obtained using a newly developed photogrammetric technique. Ice thickness is derived from radar-echo soundings. Error estimates and comparisons with stake measurements show an average accuracy of approximately ±0.3 ma-1for the calculated vertical ice velocity at the surface and ±0.7 ma-1for the calculated mass balance. Due to photogrammetric restrictions and model-inherent sensitivities the applied model appeared to be most suitable for determining area-wide mass balance and ice flow on flat-lying ablation areas, but is so far not very well suited for steep ablation areas and most parts of accumulation areas. Nevertheless, the study on Griesgletscher opens a new and promising perspective for the monitoring of spatial and temporal glacier mass-balance variations.

scholarly journals Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change

2017 ◽  
Vol 11 (1) ◽  
pp. 281-302 ◽  
Author(s):  
Henning Åkesson ◽  
Kerim H. Nisancioglu ◽  
Rianne H. Giesen ◽  
Mathieu Morlighem
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
Ice Age ◽  
Ice Flow ◽  
Outlet Glacier ◽  
Surface Mass ◽  
Ice Caps ◽  
Ice Cap ◽  
Length Changes

Abstract. Understanding of long-term dynamics of glaciers and ice caps is vital to assess their recent and future changes, yet few long-term reconstructions using ice flow models exist. Here we present simulations of the maritime Hardangerjøkulen ice cap in Norway from the mid-Holocene through the Little Ice Age (LIA) to the present day, using a numerical ice flow model combined with glacier and climate reconstructions. In our simulation, under a linear climate forcing, we find that Hardangerjøkulen grows from ice-free conditions in the mid-Holocene to its maximum extent during the LIA in a nonlinear, spatially asynchronous fashion. During its fastest stage of growth (2300–1300 BP), the ice cap triples its volume in less than 1000 years. The modeled ice cap extent and outlet glacier length changes from the LIA until today agree well with available observations. Volume and area for Hardangerjøkulen and several of its outlet glaciers vary out-of-phase for several centuries during the Holocene. This volume–area disequilibrium varies in time and from one outlet glacier to the next, illustrating that linear relations between ice extent, volume and glacier proxy records, as generally used in paleoclimatic reconstructions, have only limited validity. We also show that the present-day ice cap is highly sensitive to surface mass balance changes and that the effect of the ice cap hypsometry on the mass balance–altitude feedback is essential to this sensitivity. A mass balance shift by +0.5 m w.e. relative to the mass balance from the last decades almost doubles ice volume, while a decrease of 0.2 m w.e. or more induces a strong mass balance–altitude feedback and makes Hardangerjøkulen disappear entirely. Furthermore, once disappeared, an additional +0.1 m w.e. relative to the present mass balance is needed to regrow the ice cap to its present-day extent. We expect that other ice caps with comparable geometry in, for example, Norway, Iceland, Patagonia and peripheral Greenland may behave similarly, making them particularly vulnerable to climate change.

20th-century climate change inferred from four long-term point observations of seasonal mass balance

2009 ◽  
Vol 50 (50) ◽  
pp. 207-214 ◽  
Author(s):  
Matthias Huss ◽  
Andreas Bauder
Keyword(s):  
Time Series ◽  
Mass Balance ◽  
20Th Century ◽  
Heat Budget ◽  
Balance Model ◽  
Climatic Forcing ◽  
Glacier Surface ◽  
Temperature Index ◽  
Air Temperatures

AbstractFour long-term time series of seasonal mass-balance observations, all starting in 1914, have been compiled for two stakes on Claridenfirn and one stake on Grosser Aletschgletscher and Silvrettagletscher, Switzerland. These data represent the longest records of mass balance worldwide. A mass-balance model based on the temperature-index approach is used to correct field data for varying observation dates and data gaps and to separate accumulation and ablation. The homogenized continuous 93 year time series cover most of the 20th century and enable us to investigate temporal, regional and altitudinal variability in mass balance and changes in the climatic forcing on glaciers. A high-altitude site shows summer balance trends opposite to those at three stakes located near the equilibrium line. Since 1975, melt rates have increased by 10%(10 a)−1 periods of enhanced climatic forcing are detected: 1943–53 and 1987–2007. The energy consumed for melt was higher in the 1940s despite lower air temperatures compared to the years since 1987. We find evidence for a change in the glacier surface heat budget, which has important implications for the long-term stability of degree-day factors in empirical temperature-index modelling.

scholarly journals Basal melting beneath a fast-flowing temperate tidewater glacier

2013 ◽  
Vol 54 (63) ◽  
pp. 265-271 ◽  
Author(s):  
D.J. Alexander ◽  
T.R.H. Davies ◽  
J. Shulmeister
Keyword(s):  
Mass Balance ◽  
Published Data ◽  
Glacier Mass Balance ◽  
Glacier Surface ◽  
Ice Flow ◽  
Tidewater Glaciers ◽  
Tidewater Glacier ◽  
Order Of Magnitude ◽  
Basal Melting

AbstractThe role of melting at the base of temperate tidewater glaciers is rarely discussed, and its potential importance for total glacier mass balance and subglacial dynamics is often overlooked. We use Columbia Glacier, Alaska, USA, as an example of a temperate tidewater glacier to estimate the spatial distribution of basal melt due to friction both before and during the glacier’s well-documented retreat since the early 1980s. Published data on glacier surface and bed profiles, ice-flow velocities and surface melt were collated and used as input data for a two-dimensional basal melt model. We estimate that before the retreat of Columbia Glacier (pre-1980s), mean basal melt amounted to 61 mm a–1, increasing to 129 mma–1 during retreat (post-1980s). According to our calculations, basal melt accounts for 3% and 5% of total glacier melt for the pre-retreat and syn-retreat (i.e. during retreat) glacier profiles, respectively. These calculations of basal melt are an order of magnitude greater than those typically reported in polar glacier settings. Basal melting in temperate tidewater settings may be a non-negligible process affecting glacier mass balance and subglacial dynamics.

scholarly journals Meteorological controls on glacier mass balance: empirical relations suggested by measurements on glacier de Sarennes, France

1997 ◽  
Vol 43 (143) ◽  
pp. 131-137 ◽  
Author(s):  
C. Vincent ◽  
M. Vallon
Keyword(s):  
Mass Balance ◽  
Time Scale ◽  
Meteorological Data ◽  
Empirical Relation ◽  
Glacier Mass Balance ◽  
Glacier Surface ◽  
Surface Conditions ◽  
The Past ◽  
Empirical Relations

AbstractGlacial mass-balance reconstruction for a long-term time-scale requires knowledge of the relation between climate change and mass-balance fluctuations. A large number of mass-balance reconstructions since the beginning of the century are based on statistical relations between monthly meteorological data and mass balance. The question examined in this paper is: are these relationships reliable enough for long-term time-scale extrapolation? From the glacier de Sarennes long mass-balance observations series, we were surprised to discover large discrepancies between relations resulting from different time periods. The importance of the albedo in relation to ablation and mass balance is highlighted, and it is shown that it is impossible to ignore glacier-surface conditions in establishing the empirical relation between mass-balance fluctuations and climatic variation; to omit this parameter leads to incorrect results for mass-balance reconstruction in the past based on meteorological data.

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