scholarly journals Spatio-temporal changes in glacier-wide mass balance quantified by optical remote sensing on 30 glaciers in the French Alps for the period 1983–2014

2016 ◽  
Vol 62 (236) ◽  
pp. 1153-1166 ◽  
Author(s):  
ANTOINE RABATEL ◽  
JEAN PIERRE DEDIEU ◽  
CHRISTIAN VINCENT
Keyword(s):  
Remote Sensing ◽  
Mass Balance ◽  
Satellite Images ◽  
Optical Remote Sensing ◽  
European Alps ◽  
Mass Balances ◽  
Glacier Surface ◽  
Uncertainty Range ◽  
French Alps ◽  
Optical Satellite Images

AbstractRemote sensing is a powerful method to reconstruct annual mass-balance series over past decades by exploiting archives of available images, as well as to study glaciers in inaccessible regions. We present the application of a methodological framework based only on optical satellite images to retrieve glacier-wide annual mass balances for 30 glaciers in the French Alps. The glacier-wide annual mass balance for the period 1983–2014 was reconstructed by combining changes in glacier volumes computed from remote-sensing derived DEMs with annual measurements of the snow line altitude on satellite images. Data from direct observations on two of the glaciers confirmed the accuracy of the annual mass balances quantified by remote sensing with an average difference of ~0.3 m w.e., within the uncertainty range of the methods. Our results confirm the significant increase in mass loss since the early 2000s, with a difference >1 m w.e. a−1 between the periods 1983–2002 and 2003–14. The region-wide mass balance for the French Alps over the period 1979–2011 was −0.66 ± 0.27 m w.e. a−1, close to that of the European Alps. We also show that changes in glacier surface area or length are not representative of changes in mass balance at the scale of a few decades.

scholarly journals Monitoring of seasonal glacier mass balance over the European Alps using low-resolution optical satellite images

2016 ◽  
Vol 62 (235) ◽  
pp. 912-927 ◽  
Author(s):  
VANESSA DROLON ◽  
PHILIPPE MAISONGRANDE ◽  
ETIENNE BERTHIER ◽  
ELSE SWINNEN ◽  
MATTHIAS HUSS
Keyword(s):  
Satellite Images ◽  
Glacier Mass Balance ◽  
Optical Remote Sensing ◽  
European Alps ◽  
Mass Balances ◽  
Low Resolution ◽  
Linear Relationships ◽  
The Alps ◽  
Optical Satellite Images ◽  
Good Agreement

ABSTRACTWe explore a new method to retrieve seasonal glacier mass balances (MBs) from low-resolution optical remote sensing. We derive annual winter and summer snow maps of the Alps during 1998–2014 using SPOT/VEGETATION 1 km resolution imagery. We combine these seasonal snow maps with a DEM to calculate a ‘mean regional’ altitude of snow (Z) in a region surrounding a glacier. Then, we compare the interannual variation of Z with the observed winter/summer glacier MB for 55 Alpine glaciers over 1998–2008, our calibration period. We find strong linear relationships in winter (mean R2 = 0.84) and small errors for the reconstructed winter MB (mean RMSE = 158 mm (w.e.) a−1). This is lower than errors generally assumed for the glaciological MB measurements (200–400 mm w.e. a−1). Results for summer MB are also satisfying (mean R2 and RMSE, respectively, 0.74 and 314 mm w.e. a−1). Comparison with observed seasonal MB available over 2009–2014 (our evaluation period) for 19 glaciers in winter and 13 in summer shows good agreement in winter (RMSE = 405 mm w.e. a−1) and slightly larger errors in summer (RMSE = 561 mm w.e. a−1). These results indicate that our approach might be valuable for remotely determining the seasonal MB of glaciers over large regions.

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 Ship Detection in Optical Satellite Images via Directional Bounding Boxes Based on Ship Center and Orientation Prediction

2019 ◽  
Vol 11 (18) ◽  
pp. 2173 ◽  
Author(s):  
Jinlei Ma ◽  
Zhiqiang Zhou ◽  
Bo Wang ◽  
Hua Zong ◽  
Fei Wu
Keyword(s):  
Remote Sensing ◽  
Satellite Images ◽  
Detection Method ◽  
Semantic Segmentation ◽  
Detection Methods ◽  
Optical Remote Sensing ◽  
Ship Detection ◽  
Bounding Boxes ◽  
Typical Object ◽  
Optical Satellite Images

To accurately detect ships of arbitrary orientation in optical remote sensing images, we propose a two-stage CNN-based ship-detection method based on the ship center and orientation prediction. Center region prediction network and ship orientation classification network are constructed to generate rotated region proposals, and then we can predict rotated bounding boxes from rotated region proposals to locate arbitrary-oriented ships more accurately. The two networks share the same deconvolutional layers to perform semantic segmentation for the prediction of center regions and orientations of ships, respectively. They can provide the potential center points of the ships helping to determine the more confident locations of the region proposals, as well as the ship orientation information, which is beneficial to the more reliable predetermination of rotated region proposals. Classification and regression are then performed for the final ship localization. Compared with other typical object detection methods for natural images and ship-detection methods, our method can more accurately detect multiple ships in the high-resolution remote sensing image, irrespective of the ship orientations and a situation in which the ships are docked very closely. Experiments have demonstrated the promising improvement of ship-detection performance.

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 Geodetic point surface mass balances: A new approach to determine point surface mass balances on glaciers from remote sensing measurements

2021 ◽  
Author(s):  
Christian Vincent ◽  
Diego Cusicanqui ◽  
Bruno Jourdain ◽  
Olivier Laarman ◽  
Delphine Six ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Mass Balance ◽  
Mass Balances ◽  
New Approach ◽  
Surface Mass ◽  
Assess Climate Change ◽  
Satellite Sensors ◽  
Aerial Vehicle ◽  
Velocity Changes ◽  
One Year

&lt;p&gt;Mass balance observations are very useful to assess climate change in different regions of the world. As opposed to glacier-wide mass balances, which are influenced by the dynamic response of each glacier, point mass-balances provide a direct climatic signal that depends on surface accumulation and ablation only. Unfortunately, major efforts are required to conduct in situ measurements on glaciers. Here, we propose a new approach that determines point surface mass balances from remote sensing observations. We call this balance the geodetic point surface mass balance. From observations and modelling performed on Argenti&amp;#232;re and Mer de Glace glaciers over the last decade, we show that the vertical ice flow velocity changes are small in areas of low bedrock slope. Therefore, assuming constant vertical velocities in time for such areas and provided that the vertical velocities have been measured for at least one year in the past, our method can be used to reconstruct annual point surface mass balances from surface elevations and horizontal velocities alone. We demonstrate that the annual point surface mass balances can be reconstructed with an accuracy of about 0.3 m w.e. a&lt;sup&gt;-1&lt;/sup&gt; using the vertical velocities observed over the previous years and data from Unmanned Aerial Vehicle images. Given the recent improvements of satellite sensors, it should be possible to apply this method to high spatial resolution satellite images as well.&lt;/p&gt;

scholarly journals Geodetic point surface mass balances: a new approach to determine point surface mass balances on glaciers from remote sensing measurements

2021 ◽  
Vol 15 (3) ◽  
pp. 1259-1276
Author(s):  
Christian Vincent ◽  
Diego Cusicanqui ◽  
Bruno Jourdain ◽  
Olivier Laarman ◽  
Delphine Six ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Mass Balance ◽  
Mass Balances ◽  
New Approach ◽  
Surface Mass ◽  
Assess Climate Change ◽  
Satellite Sensors ◽  
Aerial Vehicle ◽  
Velocity Changes

Abstract. Mass balance observations are very useful to assess climate change in different regions of the world. As opposed to glacier-wide mass balances which are influenced by the dynamic response of each glacier, point mass balances provide a direct climatic signal that depends on surface accumulation and ablation only. Unfortunately, major efforts are required to conduct in situ measurements on glaciers. Here, we propose a new approach that determines point surface mass balances from remote sensing observations. We call this balance the geodetic point surface mass balance. From observations and modelling performed on the Argentière and Mer de Glace glaciers over the last decade, we show that the vertical ice flow velocity changes are small in areas of low bedrock slope. Therefore, assuming constant vertical velocities in time for such areas and provided that the vertical velocities have been measured for at least 1 year in the past, our method can be used to reconstruct annual point surface mass balances from surface elevations and horizontal velocities alone. We demonstrate that the annual point surface mass balances can be reconstructed with an accuracy of about 0.3 m of water equivalent per year (m w.e. a−1) using the vertical velocities observed over the previous years and data from unmanned aerial vehicle images. Given the recent improvements of satellite sensors, it should be possible to apply this method to high-spatial-resolution satellite images as well.

scholarly journals Spatial patterns of North Atlantic Oscillation influence on mass balance variability of European Glaciers

2012 ◽  
Vol 6 (1) ◽  
pp. 1-35 ◽  
Author(s):  
B. Marzeion ◽  
A. Nesje
Keyword(s):  
North Atlantic Oscillation ◽  
Mass Balance ◽  
North Atlantic ◽  
Winter Season ◽  
Winter Precipitation ◽  
Glacier Mass Balance ◽  
European Alps ◽  
Mass Balances ◽  
Minimal Models ◽  
Temperature Anomalies

Abstract. We present and validate a set of minimal models of glacier mass balance variability. The most skillful model is then applied to reconstruct 7735 individual time series of mass balance variability for all glaciers in the European Alps and Scandinavia. Subsequently, we investigate the influence of atmospheric variability associated with the North Atlantic Oscillation (NAO) on the glaciers' mass balances. We find a spatial coherence in the glaciers' sensitivity to NAO forcing which is caused by regionally similar mechanisms relating the NAO forcing to the mass balance: In Southwestern Scandinavia, winter precipitation causes a correlation of mass balances with the NAO. In Northern Scandinavia, temperature anomalies outside the core winter season cause an anti-correlation between NAO and mass balances. In the Western Alps, both temperature and winter precipitation anomalies lead to a weak anti-correlation of mass balances with the NAO, while in the Eastern Alps, the influences of winter precipitation and temperature anomalies tend to cancel each other, and only on the southern side a slight anti-correlation of mass balances with the NAO prevails.

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