scholarly journals Climatic drivers of seasonal glacier mass balances: an analysis of 6 decades at Glacier de Sarennes (French Alps)

2013 ◽  
Vol 7 (1) ◽  
pp. 47-66 ◽  
Author(s):  
E. Thibert ◽  
N. Eckert ◽  
C. Vincent
Keyword(s):  
Mass Balance ◽  
Large Scale ◽  
Meteorological Data ◽  
Low Frequency ◽  
Late Winter ◽  
Equilibrium Line Altitude ◽  
French Alps ◽  
Ice Melt ◽  
Main Component ◽  
Snow And Ice

Abstract. Refined temporal signals extracted from a winter and summer mass balance series recorded at Glacier de Sarennes (French Alps) using variance decomposition are related to local meteorological data and large-scale North Atlantic Oscillation (NAO) anomalies in terms of interannual variability, trends of the low-frequency signals, and breaks in the time series. The winter balance has increased by +23% since 1976 due to more precipitation in early and late winter. The summer balance has decreased since 1982 due to a 43% increase in snow and ice melt. A 24-day lengthening of the ablation period – mainly due to longer ice ablation – is the main component in the overall increase in ablation. In addition, the last 25 yr have seen increases in ablation rates of 14 and 10% for snow and ice, respectively. A simple degree-day analysis can account for both the snow/ice melt rate rise and the lengthening of the ablation period as a function of higher air temperatures. From the same analysis, the equilibrium-line altitude of this 45° N latitude south-facing glacier has a sensitivity to temperature of +93 m °C−1 around its mean elevation of 3100 m a.s.l. over 6 decades. The sensitivity of summer balance to temperature is −0.62 m w.e. yr−1 °C−1 for a typical 125-day-long ablation season. Finally, the correlation of winter and summer mass balance terms with NAO anomalies is investigated. Singularly, highest values are obtained between winter NAO anomalies and summer balance. Winter NAO anomalies and winter balance and precipitation are almost disconnected. However, these results strongly depend on how the NAO signal is smoothed, so that the link between Sarennes mass balance seasonal terms and NAO signal remains tenuous and hard to interpret.

scholarly journals Climatic drivers of seasonal glacier mass balances: an analysis of 6 decades at Glacier de Sarennes (French Alps)

2012 ◽  
Vol 6 (3) ◽  
pp. 2115-2160
Author(s):  
E. Thibert ◽  
N. Eckert ◽  
C. Vincent
Keyword(s):  
Mass Balance ◽  
Meteorological Data ◽  
Late Winter ◽  
Equilibrium Line Altitude ◽  
French Alps ◽  
Ice Melt ◽  
Air Temperatures ◽  
Climatic Drivers ◽  
Main Component ◽  
Snow And Ice

Abstract. Refined temporal signals are extracted from a glacier winter and summer mass balance series recorded at Glacier de Sarennes (French Alps) using variance decomposition. They are related to local and synoptic meteorological data in terms of interannual variability and structured trends. The winter balance has increased by +23% since 1976 due to more precipitation in early and late winter. The summer balance has decreased since 1982 due to a 43% increase in snow and ice melt. A 24-day lengthening of the ablation period – mainly due to longer ice ablation – is the main component in the overall increase in ablation. In addition, the last 25 yr have seen increases in ablation rates of 14 and 10% for snow and ice respectively. A simple degree-day analysis can account for both the snow/ice melt rate rise and the lengthening of the ablation period as a function of higher air temperatures. From the same analysis, the equilibrium line altitude of this 45° North latitude south-facing glacier has sensitivity to temperature of +93 m °C−1 around its mean elevation of 3100 m a.s.l. over 6 decades. The sensitivity of summer balance to temperature is −0.62 m w.e. yr−1 °C−1 for a typical 125-day long ablation season. Finally, the time structure of winter and summer mass balance terms are connected to NAO anomalies. Best correlations are obtained with winter NAO anomalies. However, they strongly depend on how the NAO signal is smoothed, so that the link between mass-balance seasonal terms and NAO signal remains tenuous and hard to interpret.

scholarly journals 25 years (1981–2005) of equilibrium-line altitude and mass-balance reconstruction on Glacier Blanc, French Alps, using remote-sensing methods and meteorological data

2008 ◽  
Vol 54 (185) ◽  
pp. 307-314 ◽  
Author(s):  
Antoine Rabatel ◽  
Jean-Pierre Dedieu ◽  
Emmanuel Thibert ◽  
Anne Letréguilly ◽  
Christian Vincent
Keyword(s):  
Remote Sensing ◽  
Mass Balance ◽  
Satellite Images ◽  
Meteorological Data ◽  
Equilibrium Line ◽  
Surface Mass Balance ◽  
Mass Balances ◽  
Equilibrium Line Altitude ◽  
Surface Mass ◽  
French Alps

AbstractAnnual equilibrium-line altitude (ELA) and surface mass balance of Glacier Blanc, Ecrins region, French Alps, were reconstructed from a 25 year time series of satellite images (1981–2005). The remote-sensing method used was based on identification of the snowline, which is easy to discern on optical satellite images taken at the end of the ablation season. In addition, surface mass balances at the ELA were reconstructed for the same period using meteorological data from three nearby weather stations. A comparison of the two types of series reveals a correlation of r > 0.67 at the 0.01 level of significance. Furthermore, the surface mass balances obtained from remote-sensing data are consistent with those obtained from field measurements on five other French glaciers (r = 0.76, p < 0.01). Also consistent for Glacier Blanc is the total mass loss (10.8 m w.e.) over the studied period. However, the surface mass balances obtained with the remote-sensing method show lower interannual variability. Given that the remote-sensing method is based on changes in the ELA, this difference probably results from the lower sensitivity of the surface mass balance to climate parameters at the ELA.

scholarly journals The Northeast Asia mountain glaciers in the near future by AOGCM scenarios

2010 ◽  
Vol 4 (4) ◽  
pp. 435-445 ◽  
Author(s):  
M. D. Ananicheva ◽  
A. N. Krenke ◽  
R. G. Barry
Keyword(s):  
Mass Balance ◽  
Meteorological Data ◽  
Northeast Asia ◽  
Morphological Structure ◽  
Kamchatka Peninsula ◽  
Baseline Period ◽  
Equilibrium Line Altitude ◽  
Mountain Glaciers ◽  
Glacier System ◽  
Glacier Terminus

Abstract. We studied contrasting glacier systems in continental (Orulgan, Suntar-Khayata and Chersky) mountain ranges, located in the region of the lowest temperatures in the Northern Hemisphere at the boundary of Atlantic and Pacific influences – and maritime ones (Kamchatka Peninsula) – under Pacific influence. Our purpose is to present a simple projection method to assess the main parameters of these glacier regions under climate change. To achieve this, constructed vertical profiles of mass balance (accumulation and ablation) based both on meteorological data for the 1950–1990s (baseline period) and ECHAM4 for 2049–2060 (projected period) are used, the latter – as a climatic scenario. The observations and scenarios were used to define the recent and future equilibrium line altitude and glacier terminus altitude level for each glacier system as well as areas and balance components. The altitudinal distributions of ice areas were determined for present and future, and they were used for prediction of glacier extent versus altitude in the system taking into account the correlation between the ELA and glacier-terminus level change. We tested two hypotheses of ice distribution versus altitude in mountain (valley) glaciers – "linear" and "non-linear". The results are estimates of the possible changes of the areas and morphological structure of northeastern Asia glacier systems and their mass balance characteristics for 2049–2060. Glaciers in the southern parts of northeastern Siberia and those covering small ranges in Kamchatka will likely disappear under the ECHAM4 scenario; the best preservation of glaciers will be on the highest volcanic peaks of Kamchatka. Finally, we compare characteristics of the stability of continental and maritime glacier systems under global warming.

scholarly journals Evaluating the impact of climate on snow- and ice-melt dynamics in the Taillon basin, French Pyrénées

1997 ◽  
Vol 43 (145) ◽  
pp. 563-568 ◽  
Author(s):  
David M. Hannah ◽  
Glenn R. McGregor
Keyword(s):  
Large Scale ◽  
Energy Budgets ◽  
Computer Assisted ◽  
Air Masses ◽  
Atmospheric Circulation Patterns ◽  
Ice Melt ◽  
Circulation Types ◽  
The Impact ◽  
Snow And Ice Melt ◽  
Snow And Ice

AbstractThis pilot study adopts a computer-assisted synoptic typing methodology to evaluate the totality of climatic influences on snow- and ice-melt dynamics within a small cirque basin in the French Pyrénées. The synoptic categories identified possess contrasting large-scale atmospheric circulation patterns and surface energy budgets which generate differential ablation responses. Continental air masses yield consistently high melt. Advection of moist maritime air also produces elevated but more variable ablation due to air-mass transitions. The two observed local valley circulation types show melt to be higher under nocturnal katabatic drainage than for anabatic wind flows associated with development of daytime ridge-top cumulus.

scholarly journals Surface mass balance of glaciers in the French Alps: distributed modeling and sensitivity to climate change

2005 ◽  
Vol 51 (175) ◽  
pp. 561-572 ◽  
Author(s):  
M. Gerbaux ◽  
C. Genthon ◽  
P. Etchevers ◽  
C. Vincent ◽  
J.P. Dedieu
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
Full Range ◽  
Balance Model ◽  
Surface Mass Balance ◽  
Equilibrium Line Altitude ◽  
Time Step ◽  
Meteorological Model ◽  
Surface Mass ◽  
French Alps

AbstractA new physically based distributed surface mass-balance model is presented for Alpine glaciers. Based on the Crocus prognostic snow model, it resolves both the temporal (1 hour time-step) and spatial (200 m grid-step) variability of the energy and mass balance of glaciers. Mass-balance reconstructions for the period 1981–2004 are produced using meteorological reconstruction from the SAFRAN meteorological model for Glacier de Saint-Sorlin and Glacier d’Argentière, French Alps. Both glaciers lost mass at an accelerated rate in the last 23 years. The spatial distribution of precipitation within the model grid is adjusted using field mass-balance measurements. This is the only correction made to the SAFRAN meteorological input to the glacier model, which also includes surface atmospheric temperature, moisture, wind and all components of downward radiation. Independent data from satellite imagery and geodetic measurements are used for model validation. With this model, glacier sensitivity to climate change can be separately evaluated with respect to a full range of meteorological parameters, whereas simpler models, such as degree-day models, only account for temperature and precipitation. We provide results for both mass balance and equilibrium-line altitude (ELA) using a generic Alpine glacier. The sensitivity of the ELA to air temperature alone is found to be 125 m °C–1, or 160 m °C¯1 if concurrent (Stefan–Boltzmann) longwave radiation change is taken into account.

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 The spectacular cluster chain Abell 781 as observed with LOFAR, GMRT, and XMM-Newton

2019 ◽  
Vol 622 ◽  
pp. A19 ◽  
Author(s):  
A. Botteon ◽  
T. W. Shimwell ◽  
A. Bonafede ◽  
D. Dallacasa ◽  
F. Gastaldello ◽  
...  
Keyword(s):  
Radio Emission ◽  
Large Scale ◽  
Thermal Emission ◽  
Low Frequency ◽  
Current Data ◽  
Mass Relation ◽  
Radio Halo ◽  
Main Cluster ◽  
Upper Limit ◽  
Main Component

Context. A number of merging galaxy clusters show the presence of large-scale radio emission associated with the intra-cluster medium (ICM). These synchrotron sources are generally classified as radio haloes and radio relics. Aims. Whilst it is commonly accepted that mergers play a crucial role in the formation of radio haloes and relics, not all the merging clusters show the presence of giant diffuse radio sources and this provides important information concerning current models. The Abell 781 complex is a spectacular system composed of an apparent chain of clusters on the sky. Its main component is undergoing a merger and hosts peripheral emission that is classified as a candidate radio relic and a disputed radio halo. Methods. We used new LOw Frequency ARay (LOFAR) observations at 143 MHz and archival Giant Metrewave Radio Telescope (GMRT) observations at 325 and 610 MHz to study radio emission from non-thermal components in the ICM of Abell 781. Complementary information came from XMM-Newton data, which allowed us to investigate the connection with the thermal emission and its complex morphology. Results. The origin of the peripheral emission is still uncertain. We speculate that it is related to the interaction between a head tail radio galaxy and shock. However, the current data allow us only to set an upper limit of ℳ <  1.4 on the Mach number of this putative shock. Instead, we successfully characterise the surface brightness and temperature jumps of a shock and two cold fronts in the main cluster component of Abell 781. Their positions suggest that the merger is involving three substructures. We do not find any evidence for a radio halo either at the centre of this system or in the other clusters of the chain. We place an upper limit to the diffuse radio emission in the main cluster of Abell 781 that is a factor of 2 below the current radio power-mass relation for giant radio haloes.

scholarly journals A century reconstruction of the mass balance of Glacier de Sarennes, French Alps

2002 ◽  
Vol 48 (160) ◽  
pp. 142-148 ◽  
Author(s):  
Olivier Torinesi ◽  
Anne Letréguilly ◽  
François Valla
Keyword(s):  
Time Series ◽  
Mass Balance ◽  
Classical Method ◽  
Meteorological Data ◽  
New Method ◽  
Calibration Period ◽  
French Alps ◽  
Long Period ◽  
Albedo Change

AbstractThe 50 year time series of mass balance on Glacier de Sarennes is one of the longest in the French Alps, and so is often used as a reference for glacier variations in the French Alps. Meteorological data can be used to extend the series backwards in time. Martin (1978) proposed such a reconstruction for the 1882–1977 period. With 50 years of observations, we show that the classical method used by Martin is too dependent on the calibration period. We therefore try to improve the accuracy of this reconstruction using the Vincent and Vallon (1997) method which takes into account the albedo change of the surface during the ablation period (this is called the daily method). This new method appears to be stable in time. Once calibrated, the daily method is applied to reconstruct the 1881–1949 period. The new reconstruction is compared to a volumetric balance between two maps from 1906 and 1981. It appears that both reconstructions (classical and daily) fail to render the trend correctly over a long period of time. The cumulative centred mass balance correlates well (r2 = 0.62) with the hydrological mass-balance series of Aletschgletscher, Switzerland.

scholarly journals Relation between the Mass Balance of Western Canadian Mountain Glaciers and Meteorological Data

1988 ◽  
Vol 34 (116) ◽  
pp. 11-18 ◽  
Author(s):  
Anne Letréguilly
Keyword(s):  
Mass Balance ◽  
Meteorological Data ◽  
Winter Precipitation ◽  
Summer Temperature ◽  
Equilibrium Line ◽  
Regression Equations ◽  
Equilibrium Line Altitude ◽  
Mountain Glaciers

AbstractThe mass balance, summer balance, winter balance, and equilibrium-line altitude of three Canadian glaciers (Peyto, Place, and Sentinel Glaciers) are compared with the meteorological records of neighbouring stations for the period 1966—84. While Peyto Glacier’s mass balance is almost entirely related to summer temperature, Sentinel Glacier’s mass balance is mostly controlled by winter precipitation. Place Glacier is influenced by both elements. Statistical reconstructions are presented for the three glaciers, using the best regression equations with the meteorological records since 1938.

scholarly journals Relative performance of empirical and physical models in assessing the seasonal and annual glacier surface mass balance of Saint-Sorlin Glacier (French Alps)

2018 ◽  
Vol 12 (4) ◽  
pp. 1367-1386 ◽  
Author(s):  
Marion Réveillet ◽  
Delphine Six ◽  
Christian Vincent ◽  
Antoine Rabatel ◽  
Marie Dumont ◽  
...  
Keyword(s):  
Energy Balance ◽  
Mass Balance ◽  
Meteorological Data ◽  
Model Performance ◽  
Surface Mass Balance ◽  
Glacier Surface ◽  
Meteorological Forcing ◽  
Surface Mass ◽  
French Alps

Abstract. This study focuses on simulations of the seasonal and annual surface mass balance (SMB) of Saint-Sorlin Glacier (French Alps) for the period 1996–2015 using the detailed SURFEX/ISBA-Crocus snowpack model. The model is forced by SAFRAN meteorological reanalysis data, adjusted with automatic weather station (AWS) measurements to ensure that simulations of all the energy balance components, in particular turbulent fluxes, are accurately represented with respect to the measured energy balance. Results indicate good model performance for the simulation of summer SMB when using meteorological forcing adjusted with in situ measurements. Model performance however strongly decreases without in situ meteorological measurements. The sensitivity of the model to meteorological forcing indicates a strong sensitivity to wind speed, higher than the sensitivity to ice albedo. Compared to an empirical approach, the model exhibited better performance for simulations of snow and firn melting in the accumulation area and similar performance in the ablation area when forced with meteorological data adjusted with nearby AWS measurements. When such measurements were not available close to the glacier, the empirical model performed better. Our results suggest that simulations of the evolution of future mass balance using an energy balance model require very accurate meteorological data. Given the uncertainties in the temporal evolution of the relevant meteorological variables and glacier surface properties in the future, empirical approaches based on temperature and precipitation could be more appropriate for simulations of glaciers in the future.

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