scholarly journals A deep learning reconstruction of mass balance series for all glaciers in the French Alps: 1967–2015

2020 ◽  
Vol 12 (3) ◽  
pp. 1973-1983
Author(s):  
Jordi Bolibar ◽  
Antoine Rabatel ◽  
Isabelle Gouttevin ◽  
Clovis Galiez
Keyword(s):  
Deep Learning ◽  
Mass Balance ◽  
Water Cycle ◽  
Regional Analysis ◽  
Average Error ◽  
High Mountain ◽  
Glacier Mass Balance ◽  
French Alps ◽  
Mass Losses ◽  
Regional Area

Abstract. Glacier mass balance (MB) data are crucial to understanding and quantifying the regional effects of climate on glaciers and the high-mountain water cycle, yet observations cover only a small fraction of glaciers in the world. We present a dataset of annual glacier-wide mass balance of all the glaciers in the French Alps for the 1967–2015 period. This dataset has been reconstructed using deep learning (i.e. a deep artificial neural network) based on direct MB observations and remote-sensing annual estimates, meteorological reanalyses and topographical data from glacier inventories. The method's validity was assessed previously through an extensive cross-validation against a dataset of 32 glaciers, with an estimated average error (RMSE) of 0.55 mw.e.a-1, an explained variance (r2) of 75 % and an average bias of −0.021 mw.e.a-1. We estimate an average regional area-weighted glacier-wide MB of −0.69±0.21 (1σ) mw.e.a-1 for the 1967–2015 period with negative mass balances in the 1970s (−0.44 mw.e.a-1), moderately negative in the 1980s (−0.16 mw.e.a-1) and an increasing negative trend from the 1990s onwards, up to −1.26 mw.e.a-1 in the 2010s. Following a topographical and regional analysis, we estimate that the massifs with the highest mass losses for the 1967–2015 period are the Chablais (−0.93 mw.e.a-1), Champsaur (−0.86 mw.e.a-1), and Haute-Maurienne and Ubaye ranges (−0.84 mw.e.a-1 each), and the ones presenting the lowest mass losses are the Mont-Blanc (−0.68 mw.e.a-1), Oisans and Haute-Tarentaise ranges (−0.75 mw.e.a-1 each). This dataset – available at https://doi.org/10.5281/zenodo.3925378 (Bolibar et al., 2020a) – provides relevant and timely data for studies in the fields of glaciology, hydrology and ecology in the French Alps in need of regional or glacier-specific annual net glacier mass changes in glacierized catchments.

scholarly journals A deep learning reconstruction of mass balance series for all glaciers in the French Alps: 1967–2015

2020 ◽  
Author(s):  
Jordi Bolibar ◽  
Antoine Rabatel ◽  
Isabelle Gouttevin ◽  
Clovis Galiez
Keyword(s):  
Deep Learning ◽  
Mass Balance ◽  
Data Science ◽  
Regional Analysis ◽  
Average Error ◽  
High Mountain ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
French Alps ◽  
Mass Losses

Abstract. Glacier surface mass balance (SMB) data are crucial to understand and quantify the regional effects of climate on glaciers and the high-mountain water cycle, yet observations cover only a small fraction of glaciers in the world. We present a dataset of annual glacier-wide surface mass balance of all the glaciers in the French Alps for the 1967–2015 period. This dataset has been reconstructed using deep learning (i.e. a deep artificial neural network), based on direct and remote sensing SMB observations, meteorological reanalyses and topographical data from glacier inventories. This data science reconstruction approach is embedded as a SMB component of the open-source ALpine Parameterized Glacier Model (ALPGM). An extensive cross-validation allowed to assess the method’s validity, with an estimated average error (RMSE) of 0.49 m w.e. a−1, an explained variance (r2) of 79 % and an average bias of +0.017 m w.e. a−1. We estimate an average regional area-weighted glacier-wide SMB of −0.72 ± 0.20 m w.e. a−1 for the 1967–2015 period, with moderately negative mass balances in the 1970s (−0.52 m w.e. a−1) and 1980s (−0.12 m w.e. a−1), and an increasing negative trend from the 1990s onwards, up to −1.39 m w.e. a−1 in the 2010s. Following a topographical and regional analysis, we estimate that the massifs with the highest mass losses for this period are the Chablais (−0.90 m w.e. a−1) and Ubaye and Champsaur ranges (−0.91 m w.e. a−1 both), and the ones presenting the lowest mass losses are the Mont-Blanc (−0.74 m w.e. a−1), Oisans and Haute-Tarentaise ranges (−0.78 m w.e. a−1 both). This dataset (available at: https://doi.org/10.5281/zenodo.3663630) (Bolibar et al., 2020a) – provides relevant and timely data for studies in the fields of glaciology, hydrology and ecology in the French Alps, in need of regional or glacier-specific meltwater contributions in glacierized catchments.

scholarly journals Aspect controls the survival of ice cliffs on debris-covered glaciers

2018 ◽  
Vol 115 (17) ◽  
pp. 4369-4374 ◽  
Author(s):  
Pascal Buri ◽  
Francesca Pellicciotti
Keyword(s):  
Solar Radiation ◽  
Mass Balance ◽  
Hot Spots ◽  
3D Model ◽  
Vertical Gradient ◽  
High Mass ◽  
View Factor ◽  
High Mountain ◽  
Mass Losses ◽  
Very High

Supraglacial ice cliffs exist on debris-covered glaciers worldwide, but despite their importance as melt hot spots, their life cycle is little understood. Early field observations had advanced a hypothesis of survival of north-facing and disappearance of south-facing cliffs, which is central for predicting the contribution of cliffs to total glacier mass losses. Their role as windows of energy transfer suggests they may explain the anomalously high mass losses of debris-covered glaciers in High Mountain Asia (HMA) despite the insulating debris, currently at the center of a debated controversy. We use a 3D model of cliff evolution coupled to very high-resolution topographic data to demonstrate that ice cliffs facing south (in the Northern Hemisphere) disappear within a few months due to enhanced solar radiation receipts and that aspect is the key control on cliffs evolution. We reproduce continuous flattening of south-facing cliffs, a result of their vertical gradient of incoming solar radiation and sky view factor. Our results establish that only north-facing cliffs are recurrent features and thus stable contributors to the melting of debris-covered glaciers. Satellite observations and mass balance modeling confirms that few south-facing cliffs of small size exist on the glaciers of Langtang, and their contribution to the glacier volume losses is very small (∼1%). This has major implications for the mass balance of HMA debris-covered glaciers as it provides the basis for new parameterizations of cliff evolution and distribution to constrain volume losses in a region where glaciers are highly relevant as water sources for millions of people.

scholarly journals Examining geodetic glacier mass balance in the eastern Pamir transition zone

2020 ◽  
Vol 66 (260) ◽  
pp. 927-937
Author(s):  
Mingyang Lv ◽  
Duncan J. Quincey ◽  
Huadong Guo ◽  
Owen King ◽  
Guang Liu ◽  
...  
Keyword(s):  
Mass Balance ◽  
Statistical Difference ◽  
Mass Gain ◽  
High Mountain ◽  
Glacier Mass Balance ◽  
Negative Mass ◽  
Glacier Surface ◽  
Digital Elevation ◽  
Elevation Changes ◽  
Individual Scale

AbstractGlaciers in the eastern Pamir have reportedly been gaining mass during recent decades, even though glaciers in most other regions in High Mountain Asia have been in recession. Questions still remain about whether the trend is strengthening or weakening, and how far the positive balances extend into the eastern Pamir. To address these gaps, we use three different digital elevation models to reconstruct glacier surface elevation changes over two periods (2000–09 and 2000–15/16). We characterize the eastern Pamir as a zone of transition from positive to negative mass balance with the boundary lying at the northern end of Kongur Tagh, and find that glaciers situated at higher elevations are those with the most positive balances. Most (67% of 55) glaciers displayed a net mass gain since the 21st century. This led to an increasing regional geodetic glacier mass balance from −0.06 ± 0.16 m w.e. a−1 in 2000–09 to 0.06 ± 0.04 m w.e. a−1 in 2000–15/16. Surge-type glaciers, which are prevalent in the eastern Pamir, showed fluctuations in mass balance on an individual scale during and after surges, but no statistical difference compared to non-surge-type glaciers when aggregated across the region.

scholarly journals A Systematic, Regional Assessment of High Mountain Asia Glacier Mass Balance

2020 ◽  
Vol 7 ◽  
Author(s):  
David E. Shean ◽  
Shashank Bhushan ◽  
Paul Montesano ◽  
David R. Rounce ◽  
Anthony Arendt ◽  
...  
Keyword(s):  
Mass Balance ◽  
High Mountain ◽  
Glacier Mass Balance ◽  
Regional Assessment

scholarly journals Glacier evolution in high-mountain Asia under stratospheric sulfate aerosol injection geoengineering

2017 ◽  
Vol 17 (11) ◽  
pp. 6547-6564 ◽  
Author(s):  
Liyun Zhao ◽  
Yi Yang ◽  
Wei Cheng ◽  
Duoying Ji ◽  
John C. Moore
Keyword(s):  
Mass Balance ◽  
Radiative Forcing ◽  
Sulfate Aerosol ◽  
Balance Model ◽  
Climate Projections ◽  
High Mountain ◽  
Glacier Mass Balance ◽  
Volume Loss ◽  
Surface Mass ◽  
Glacier Shrinkage

Abstract. Geoengineering by stratospheric sulfate aerosol injection may help preserve mountain glaciers by reducing summer temperatures. We examine this hypothesis for the glaciers in high-mountain Asia using a glacier mass balance model driven by climate simulations from the Geoengineering Model Intercomparison Project (GeoMIP). The G3 and G4 schemes specify use of stratospheric sulfate aerosols to reduce the radiative forcing under the Representative Concentration Pathway (RCP) 4.5 scenario for the 50 years between 2020 and 2069, and for a further 20 years after termination of geoengineering. We estimate and compare glacier volume loss for every glacier in the region using a glacier model based on surface mass balance parameterization under climate projections from three Earth system models under G3, five models under G4, and six models under RCP4.5 and RCP8.5. The ensemble projections suggest that glacier shrinkage over the period 2010–2069 is equivalent to sea-level rise of 9.0 ± 1.6 mm (G3), 9.8 ± 4.3 mm (G4), 15.5 ± 2.3 mm (RCP4.5), and 18.5 ± 1.7 mm (RCP8.5). Although G3 keeps the average temperature from increasing in the geoengineering period, G3 only slows glacier shrinkage by about 50 % relative to losses from RCP8.5. Approximately 72 % of glaciated area remains at 2069 under G3, as compared with about 30 % for RCP8.5. The widely reported reduction in mean precipitation expected for solar geoengineering is unlikely to be as important as the temperature-driven shift from solid to liquid precipitation for forcing Himalayan glacier change. The termination of geoengineering at 2069 under G3 leads to temperature rise of about 1.3 °C over the period 2070–2089 relative to the period 2050-2069 and corresponding increase in annual mean glacier volume loss rate from 0.17 to 1.1 % yr−1, which is higher than the 0.66 % yr−1 under RCP8.5 during 2070–2089.

scholarly journals The High Mountain Asia glacier contribution to sea-level rise from 2000 to 2050

2016 ◽  
Vol 57 (71) ◽  
pp. 223-231 ◽  
Author(s):  
Liyun Zhao ◽  
Ran Ding ◽  
John C. Moore
Keyword(s):  
Mass Balance ◽  
Sea Level Rise ◽  
Sea Level ◽  
Radiative Forcing ◽  
Climate Model ◽  
Meteorological Data ◽  
High Mountain ◽  
Glacier Mass Balance ◽  
Equilibrium Line Altitude ◽  
Summer Temperatures

AbstractWe estimate all the individual glacier area and volume changes in High Mountain Asia (HMA) by 2050 based on Randolph Glacier Inventory (RGI) version 4.0, using different methods of assessing sensitivity to summer temperatures driven by a regional climate model and the IPCC A1B radiative forcing scenario. A large range of sea-level rise variation comes from varying equilibrium-line altitude (ELA) sensitivity to summer temperatures. This sensitivity and also the glacier mass-balance gradients with elevation have the largest coefficients of variability (amounting to ~50%) among factors examined. Prescribing ELA sensitivities from energy-balance models produces the highest sea-level rise (9.2 mm, or 0.76% of glacier volume a–1), while the ELA sensitivities estimated from summer temperatures at Chinese meteorological stations and also from 1°x1° gridded temperatures in the Berkeley Earth database produce 3.6 and 3.8 mm, respectively. Different choices of the initial ELA or summer precipitation lead to 15% uncertainties in modelled glacier volume loss. RGI version 4.0 produces 20% lower sea-level rise than version 2.0. More surface mass-balance observations, meteorological data from the glaciated areas, and detailed satellite altimetry data can provide better estimates of sea-level rise in the future.

Glacier mass balance in High Mountain Asia inferred from a GRACE release-6 gravity solution for the period 2002–2016

2021 ◽  
Vol 13 (3) ◽  
pp. 224-238
Author(s):  
Longwei Xiang ◽  
Hansheng Wang ◽  
Liming Jiang ◽  
Qiang Shen ◽  
Holger Steffen ◽  
...  
Keyword(s):  
Mass Balance ◽  
High Mountain ◽  
Glacier Mass Balance

scholarly journals The Rofental: a high Alpine research basin (1890 m – 3770 m a.s.l.) in the Ötztal Alps (Austria) with over 150 years of hydro-meteorological and glaciological observations

2017 ◽  
Author(s):  
Ulrich Strasser ◽  
Thomas Marke ◽  
Ludwig Braun ◽  
Heidi Escher-Vetter ◽  
Irmgard Juen ◽  
...  
Keyword(s):  
Mass Balance ◽  
Laser Scanner ◽  
Longwave Radiation ◽  
Water Levels ◽  
Original Research ◽  
High Mountain ◽  
Glacier Mass Balance ◽  
Data Sets ◽  
Data Set ◽  
Entire Area

Abstract. A comprehensive hydrometeorological and glaciological data set is presented, originating from a multitude of recordings at several intensively operated research sites in the Rofental (1891–3772 m a.s.l., Ötztal Alps, Austria). The data sets are spanning a period of 150 years and hence represent a unique, worldwide unprecedented pool of high mountain observations. Their collection has originally been initiated to support the scientific investigation of the glaciers Hintereis-, Kesselwand- and Vernagtferner. Later, additional measurements of meteorological and hydrological variables have been undertaken; data now comprise records of temperature, relative humidity, short- and longwave radiation, wind speed and direction, air pressure, precipitation and water levels. For the glaciers, annual mass balance, glacier front variation and flow velocities as well as photographic images of the glacier status have been recorded. Since 2001, a series of distributed (airborne and terrestrial) laserscans has been processed. Most recently, a permanent terrestrial laser scanner installed on "Im hintern Eis" (3244 m a.s.l.) enables to continuously observe almost the entire area of Hintereisferner. The data and research undertaken at the sites of investigation enable combined research of atmospheric, cryospheric and hydrological processes in complex terrain, and support the development of several state-of-the art hydroclimatological and glacier mass balance models. The institutions taking part in the Rofental research framework have joined to a cooperation consortium and promote their site in several international research initiatives. In the framework of INARCH, all original research data sets are now provided to the scientific community according to the Creative Commons Attribution License by means of the PANGAEA repository (https://doi.org/doi:10.1594/PANGAEA.876120).

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