scholarly journals Spatial Heterogeneity in Glacier Mass-Balance Sensitivity across High Mountain Asia

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 776 ◽  
Author(s):  
Rongjun Wang ◽  
Shiyin Liu ◽  
Donghui Shangguan ◽  
Valentina Radić ◽  
Yong Zhang
Keyword(s):  
Climate Change ◽  
Spatial Variability ◽  
Spatial Heterogeneity ◽  
Mass Balance ◽  
High Sensitivity ◽  
High Mountain ◽  
Surface Mass Balance ◽  
Reference Surface ◽  
Surface Mass ◽  
The Relationship

Mass balance of glaciers in High Mountain Asia (HMA) varies substantially across the region. While the spatial variability is attributed to differences in climatic setting and sensitivity of these glaciers to climate change, an assessment of these factors to date has only been performed on a small sample of glaciers and a small set of climate perturbation scenarios. To advance the assessment to larger datasets, we first reconstruct the time series of reference-surface mass balance for 1952–2014 periods using an empirical model calibrated with observed mass balance from 45 glaciers across the HMA. Forcing the model with a set of independent stepwise changes of temperature (±0.5 K to ±6 K) and precipitation (±5% to ±30%), we assess the reference-surface mass balance sensitivity of each glacier in the sample. While the relationship between the change in mass balance and the change in precipitation is linear, the relationship with the change in temperature is non-linear. Spatial heterogeneity in the simulated mass balance sensitivities is attributed to differences in climatic setting, elevation, and the sensitivity of mass-balance profile (gradient) to changes in temperature and precipitation. While maritime and low-lying continental glaciers show high sensitivity to temperature changes and display a uniform mass-balance sensitivity with elevation, the high-lying continental glaciers show high sensitivity to precipitation changes and display a non-uniform mass-balance sensitivity with elevation. Our analysis reveals the dominant drivers of spatial variability in the mass balance sensitivity across the region: temperature as a single driver for maritime glaciers, and a superposition of temperature, precipitation seasonality, and snow/rain differentiation for continental glaciers. Finally, a set of sensitivity tests with perturbed model parameters confirms the robustness of our results. The model’s ability and robustness to resolve spatial patterns in the sensitivities and their drivers implies that simple modeling approaches remain a powerful tool for analyzing glacier response to climate change in HMA.

scholarly journals Influence of Oceanic Boundary Conditions in Simulations of Antarctic Climate and Surface Mass Balance Change during the Coming Century

2008 ◽  
Vol 21 (5) ◽  
pp. 938-962 ◽  
Author(s):  
Gerhard Krinner ◽  
Bérangère Guicherd ◽  
Katia Ox ◽  
Christophe Genthon ◽  
Olivier Magand
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Boundary Conditions ◽  
Mass Balance ◽  
Climate Model ◽  
Sea Surface ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Surface Conditions ◽  
The Antarctic

Abstract This article reports on high-resolution (60 km) atmospheric general circulation model simulations of the Antarctic climate for the periods 1981–2000 and 2081–2100. The analysis focuses on the surface mass balance change, one of the components of the total ice sheet mass balance, and its impact on global eustatic sea level. Contrary to previous simulations, in which the authors directly used sea surface boundary conditions produced by a coupled ocean–atmosphere model for the last decades of both centuries, an anomaly method was applied here in which the present-day simulations use observed sea surface conditions, while the simulations for the end of the twenty-first century use the change in sea surface conditions taken from the coupled simulations superimposed on the present-day observations. It is shown that the use of observed oceanic boundary conditions clearly improves the simulation of the present-day Antarctic climate, compared to model runs using boundary conditions from a coupled climate model. Moreover, although the spatial patterns of the simulated climate change are similar, the two methods yield significantly different estimates of the amplitude of the future climate and surface mass balance change over the Antarctic continent. These differences are of similar magnitude as the intermodel dispersion in the current Intergovernmental Panel on Climate Change (IPCC) exercise: selecting a method for generating boundary conditions for a high-resolution model may be just as important as selecting the climate model itself. Using the anomaly method, the simulated mean surface mass balance change over the grounded ice sheet from 1981–2000 to 2081–2100 is 43-mm water equivalent per year, corresponding to a eustatic sea level decrease of 1.5 mm yr−1. A further result of this work is that future continental-mean surface mass balance changes are dominated by the coastal regions, and that high-resolution models, which better resolve coastal processes, tend to predict stronger precipitation changes than models with lower spatial resolution.

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.

Early 21st-century glacier surface mass balance across High Mountain Asia derived from remote sensing

2020 ◽  
Author(s):  
Evan Miles ◽  
Michael McCarthy ◽  
Amaury Dehecq ◽  
Marin Kneib ◽  
Stefan Fugger ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Mass Balance ◽  
Surface Velocity ◽  
High Mountain ◽  
Surface Mass Balance ◽  
Equilibrium Line Altitude ◽  
Glacier Surface ◽  
Surface Mass ◽  
Early 21St Century ◽  
Debris Cover

<p>Glaciers in High Mountain Asia have experienced intense scientific scrutiny in the past decade due to their hydrological and societal importance. The explosion of freely-available satellite observations has greatly advanced our understanding of their thinning, motion, and overall mass losses, and it has become clear that they exhibit both local and regional variations due to debris cover, surging and climatic regime. However, our understanding of glacier accumulation and ablation rates is limited to a few individual sites, and altitudinal surface mass balance is essentially unknown across the vast region.</p><p>Here we combine recent assessments of ice thickness and surface velocity to correct observed glacier thinning rates for mass redistribution in a flowband framework to derive the first estimates of altitudinal glacier surface mass balance across the region. We first evaluate our results at the glacier scale with all available glaciological field measurements (27 glaciers), then analyze 4665 glaciers (we exclude surging and other anomalous glaciers) comprising 43% of area and 36% of mass for glaciers larger than 2 km<sup>2</sup> in the region. The surface mass balance results allow us to determine the equilibrium line altitude for each glacier for the period 2000-2016.  We then aggregate our altitudinal and hypsometric surface mass balance results to produce idealised profiles for distinct subregions, enabling us to consider the subregional heterogeneity of mass balance and the importance of debris-covered ice for the region’s overall ablation.</p><p>We find clear patterns of ELA variability across the region.  9% of glaciers accumulate mass over less than 10% of their area on average for the study period. These doomed  glaciers are concentrated in Nyainqentanglha, which also has the most negative mass balance of the subregions, whereas accumulation area ratios of 0.7-0.9 are common for glaciers in the neutral-balance Karakoram and Kunlun Shan. We find that surface debris extent is negatively correlated with ELA, explaining up to 1000 m of variability across the region and reflecting the importance of avalanching as a mass input for debris-covered glaciers at lower elevations. However, in contrast with studies of thinning rates alone, we find a clear melt reduction for low-elevation debris-covered glacier areas, consistent across regions, largely resolving the ‘debris cover anomaly’.  </p><p>Our results provide a comprehensive baseline for the health of the High Asian ice reservoirs in the early 21<sup>st</sup> Century. The estimates of altitudinal surface mass balance and ELAs will additionally enable novel strategies for the calibration of glacier and hydrological models. Finally, our results emphasize the potential of combined remote-sensing observations to understand the environmental factors and physical processes responsible for High Asia’s heterogeneous patterns of recent glacier evolution.</p>

scholarly journals Modeling the evolution of the Juneau Icefield between 1971 and 2100 using the Parallel Ice Sheet Model (PISM)

2016 ◽  
Vol 62 (231) ◽  
pp. 199-214 ◽  
Author(s):  
FLORIAN A. ZIEMEN ◽  
REGINE HOCK ◽  
ANDY ASCHWANDEN ◽  
CONSTANTINE KHROULEV ◽  
CHRISTIAN KIENHOLZ ◽  
...  
Keyword(s):  
Mass Balance ◽  
Spatial Interpolation ◽  
Ice Sheet ◽  
Weather Research And Forecasting ◽  
High Mountain ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Orographic Effects ◽  
Ice Volume ◽  
Good Agreement

ABSTRACTWe study the evolution of the Juneau Icefield, one of the largest icefields in North America (>3700 km2), using the Parallel Ice Sheet Model (PISM). We test two climate datasets: 20 km Weather Research and Forecasting Model (WRF) output, and data from the Scenarios Network for Alaska Planning (SNAP), derived from spatial interpolation of observations. Good agreement between simulated and observed surface mass balance was achieved only after substantially adjusting WRF precipitation to account for unresolved orographic effects, while SNAP's climate pattern is incompatible with observations of surface mass balance. Using the WRF data forced with the RCP6.0 emission scenario, the model projects a decrease in ice volume by 58–68% and a 57–63% area loss by 2099 compared with 2010. If the modeled 2070–99 climate is held constant beyond 2099, the icefield is eliminated by 2200. With constant 1971–2010 climate, the icefield stabilizes at 86% of its present-day volume. Experiments started from an ice-free state indicate that steady-state volumes are largely independent of the initial ice volume when forced by identical scenarios of climate stabilization. Despite large projected volume losses, the complex high-mountain topography makes the Juneau Icefield less susceptible to climate warming than low-lying Alaskan icefields.

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 The AntSMB dataset: a comprehensive compilation of surface mass balance field observations over the Antarctic Ice Sheet

2021 ◽  
Vol 13 (6) ◽  
pp. 3057-3074
Author(s):  
Yetang Wang ◽  
Minghu Ding ◽  
Carleen H. Reijmer ◽  
Paul C. J. P. Smeets ◽  
Shugui Hou ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Mass Balance ◽  
Ice Sheet ◽  
Ice Cores ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Temporal And Spatial Variability ◽  
Temporal And Spatial ◽  
The Antarctic ◽  
Comprehensive Compilation

Abstract. A comprehensive compilation of observed records is needed for accurate quantification of surface mass balance (SMB) over Antarctica, which is a key challenge for calculation of Antarctic contribution to global sea level change. Here, we present the AntSMB dataset: a new quality-controlled dataset of a variety of published field measurements of the Antarctic Ice Sheet SMB by means of stakes, snow pits, ice cores, ultrasonic sounders, and ground-penetrating radar (GPR). The dataset collects 3579 individual multi-year-averaged observations, 687 annually resolved time series from 675 sites extending back over the past 1000 years, and daily resolved records covering 245 years from 32 sites across the whole ice sheet. These records are derived from ice cores, snow pits, stakes/stake farms, and ultrasonic sounders. Furthermore, GPR multi-year-averaged measurements are included in the dataset, covering an area of 22 025 km2. This is the first ice-sheet-scale compilation of SMB records at different temporal (daily, annual, and multi-year) resolutions from multiple types of measurement and is available at https://doi.org/10.11888/Glacio.tpdc.271148 (Wang et al., 2021). The database has potentially wide applications such as the investigation of temporal and spatial variability in SMB, model validation, assessment of remote sensing retrievals, and data assimilation. As a case of model estimation, records of the AntSMB dataset are used to assess the performance of ERA5 for temporal and spatial variability in SMB over Antarctica.

scholarly journals Implications for the dynamic health of a glacier from comparison of conventional and reference-surface balances

2009 ◽  
Vol 50 (50) ◽  
pp. 25-30 ◽  
Author(s):  
W.D. Harrison ◽  
L.H Cox ◽  
R. Hock ◽  
R.S. March ◽  
E.C. Pettit
Keyword(s):  
Response Time ◽  
Mass Balance ◽  
Linear Theory ◽  
Present State ◽  
Climate Changes ◽  
Surface Mass Balance ◽  
Reference Surface ◽  
Surface Mass ◽  
Non Linear

AbstractConventional and reference-surface mass-balance data from Gulkana and Wolverine Glaciers, Alaska, USA, are used to address the questions of how rapidly these glaciers are adjusting (or ‘responding’) to climate, whether their responses are stable, and whether the glaciers are likely to survive in today’s climate. Instability means that a glacier will eventually vanish, or at least become greatly reduced in volume, if the climate stabilizes at its present state. A simple non-linear theory of response is presented for the analysis. The response of Gulkana Glacier is characterized by a timescale of several decades, but its stability and therefore its survival in today’s climate are uncertain. Wolverine seems to be responding to climate more slowly, on the timescale of one to several centuries. Its stability is also uncertain, but a slower response time would make it more susceptible to climate changes.

scholarly journals Greenland Ice Sheet model parameters constrained using simulations of the Eemian Interglacial

2010 ◽  
Vol 6 (4) ◽  
pp. 1551-1588 ◽  
Author(s):  
A. Robinson ◽  
R. Calov ◽  
A. Ganopolski
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
Regional Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Interglacial Period ◽  
Model Parameters ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Eemian Interglacial

Abstract. Using a new approach to force an ice sheet model, we performed an ensemble of simulations of the Greenland Ice Sheet evolution during the last two glacial cycles, with emphasis on the Eemian Interglacial. This ensemble was generated by perturbing four key parameters in the coupled regional climate – ice sheet model and by introducing additional uncertainty in the prescribed "background" climate change. Sensitivity of the surface melt model to climate change was determined to be the dominant driver of ice sheet instability, as reflected by simulated ice sheet loss during the Eemian Interglacial period. To eliminate unrealistic parameter combinations, constraints from present-day and paleo information were applied. The constraints include (i) the diagnosed present-day surface mass balance partition between surface melting and calving, (ii) the modeled present-day elevation at GRIP; and (iii) the modeled elevation reduction at GRIP during the Eemian. Using these three constraints, a total of 270 simulations with 90 different model realizations were filtered down to 47 simulations and 20 model realizations considered valid. The paleo constraint eliminated more sensitive melt parameter values, in agreement with the surface mass balance partition assumption. The constrained simulations result in a range of Eemian ice loss of 0.4–4.1 m sea level (m.s.l.) equivalent, with a more likely value of about 4.1 m.s.l. if the GRIP δ18O isotope record can be considered an accurate proxy for the precipitation-weighted annual mean temperatures.

scholarly journals Reply to the Comment of Leclercq et al. on "100-year mass changes in the Swiss Alps linked to the Atlantic Multidecadal Oscillation"

2010 ◽  
Vol 4 (4) ◽  
pp. 2587-2592 ◽  
Author(s):  
M. Huss ◽  
R. Hock ◽  
A. Bauder ◽  
M. Funk
Keyword(s):  
Time Series ◽  
Mass Balance ◽  
Atlantic Multidecadal Oscillation ◽  
Swiss Alps ◽  
Surface Mass Balance ◽  
Reference Surface ◽  
Surface Mass ◽  
The Difference ◽  
Opposing Effects

Abstract. In their comment, Leclercq et al. argue that Huss et al. (2010) overestimate the effect of the Atlantic Multidecadal Oscillation (AMO) on the 100-year mass balance variations in the Swiss Alps because time series of conventional balances instead of reference-surface balances were used. Applying the same model as in Huss et al. we calculate time series of reference-surface mass balance, and show that the difference between conventional and reference-surface mass balance is significantly smaller than stated in the comment. Both series exhibit very similar multidecadal variations. The opposing effects of retreat and surface lowering on mass balance partly cancel each other.

scholarly journals Multi-decadal mass balance series of three Kyrgyz glaciers inferred from modelling constrained with repeated snow line observations

2018 ◽  
Vol 12 (6) ◽  
pp. 1899-1919 ◽  
Author(s):  
Martina Barandun ◽  
Matthias Huss ◽  
Ryskul Usubaliev ◽  
Erlan Azisov ◽  
Etienne Berthier ◽  
...  
Keyword(s):  
Mass Balance ◽  
Tien Shan ◽  
High Mountain ◽  
Surface Mass Balance ◽  
Glacier Surface ◽  
Surface Mass ◽  
Temperature And Precipitation ◽  
Snow Line ◽  
Digital Elevation ◽  
Continuous Surface

Abstract. Glacier surface mass balance observations in the Tien Shan and Pamir are relatively sparse and often discontinuous. Nevertheless, glaciers are one of the most important components of the high-mountain cryosphere in the region as they strongly influence water availability in the arid, continental and intensely populated downstream areas. This study provides reliable and continuous surface mass balance series for selected glaciers located in the Tien Shan and Pamir-Alay. By cross-validating the results of three independent methods, we reconstructed the mass balance of the three benchmark glaciers, Abramov, Golubin and Glacier no. 354 for the past 2 decades. By applying different approaches, it was possible to compensate for the limitations and shortcomings of each individual method. This study proposes the use of transient snow line observations throughout the melt season obtained from satellite optical imagery and terrestrial automatic cameras. By combining modelling with remotely acquired information on summer snow depletion, it was possible to infer glacier mass changes for unmeasured years. The model is initialized with daily temperature and precipitation data collected at automatic weather stations in the vicinity of the glacier or with adjusted data from climate reanalysis products. Multi-annual mass changes based on high-resolution digital elevation models and in situ glaciological surveys were used to validate the results for the investigated glaciers. Substantial surface mass loss was confirmed for the three studied glaciers by all three methods, ranging from −0.30 ± 0.19 to −0.41 ± 0.33 m w.e. yr−1 over the 2004–2016 period. Our results indicate that integration of snow line observations into mass balance modelling significantly narrows the uncertainty ranges of the estimates. Hence, this highlights the potential of the methodology for application to unmonitored glaciers at larger scales for which no direct measurements are available.

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