Using a CMIP5 multi-model ensemble to model glacier mass balance on decadal scales

2021 ◽  
Author(s):  
Larissa van der Laan ◽  
Kristian Förster ◽  
Fabien Maussion ◽  
Adam Scaife
Keyword(s):  
Mass Balance ◽  
Sea Level Rise ◽  
Sea Level ◽  
Time Scale ◽  
Water Resource Management ◽  
Glacier Mass Balance ◽  
Spatial And Temporal Scales ◽  
Decadal Scale ◽  
Model Ensembles ◽  
Decadal Climate

<p>Glaciers fulfil several important roles in the earth system, including being clear indicators of climate change and providing essential freshwater storage and downstream runoff to 22% of the global population. In addition, they are the main contributors to sea level rise and are expected to remain so throughout the 21st Century. In order to monitor glacier development, observing and predicting glacier mass balance on different spatial and temporal scales is essential. The current study aims to improve the understanding of glacier mass balance prediction on the decadal scale (5-15 years), a rarely studied time scale in the context of glaciers, but if reliable, highly applicable for glacier related water resource management and sea level rise predictions. This is achieved through the use of CMIP5 decadal climate prediction multi-model ensembles (reforecasts) to force the mass balance component of the Open Global Glacier Model (OGGM). This method is applied to 254 reference glaciers, distributed throughout 17 of the 19 Randolph Glacier Inventory (RGI) regions. The reforecasts are initialized in 1960 and 1980 and bias corrected to the glacier scale. The following statistical analysis then gives a good indication of the skill of climate reforecasts in mass balance modelling on this glacier atypical time scale.</p>

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.

scholarly journals Uncertainties and re-analysis of glacier mass balance measurements

2013 ◽  
Vol 7 (2) ◽  
pp. 789-839 ◽  
Author(s):  
M. Zemp ◽  
E. Thibert ◽  
M. Huss ◽  
D. Stumm ◽  
C. Rolstad Denby ◽  
...  
Keyword(s):  
Climate Change ◽  
Data Quality ◽  
Mass Balance ◽  
Sea Level Rise ◽  
Sea Level ◽  
Error Estimation ◽  
Standard Procedure ◽  
Systematic Errors ◽  
Glacier Mass Balance ◽  
Uncertainty Estimates

Abstract. Glacier-wide mass balance has been measured for more than sixty years and is widely used as an indicator of climate change and to assess the glacier contribution to runoff and sea level rise. Until present, comprehensive uncertainty assessments have rarely been carried out and mass balance data have often been applied using rough error estimation or without error considerations. In this study, we propose a framework for re-analyzing glacier mass balance series including conceptual and statistical toolsets for assessment of random and systematic errors as well as for validation and calibration (if necessary) of the glaciological with the geodetic balance results. We demonstrate the usefulness and limitations of the proposed scheme drawing on an analysis that comprises over 50 recording periods for a dozen glaciers and we make recommendations to investigators and users of glacier mass balance data. Reanalysis of glacier mass balance series needs to become a standard procedure for every monitoring programme to improve data quality and provide thorough uncertainty estimates.

scholarly journals The ‘benchmark glacier’ concept – does it work? Lessons from the North Cascade Range, USA

2009 ◽  
Vol 50 (50) ◽  
pp. 163-168 ◽  
Author(s):  
Andrew G. Fountain ◽  
Matthew J. Hoffman ◽  
Frank Granshaw ◽  
Jon Riedel
Keyword(s):  
Mass Balance ◽  
Sea Level Rise ◽  
Sea Level ◽  
Balance Control ◽  
A Priori ◽  
Glacier Mass Balance ◽  
Alpine Glacier ◽  
Climatic Regions ◽  
The North ◽  
Mass Losses

AbstractBenchmark glaciers were established in many alpine areas during the 1960s as part of the International Hydrological Decade to represent ‘typical’ mass and energy processes on glaciers in different climatic regions around the world. These glaciers have received new interest in the past decade because they are used to infer the contribution of alpine glacier wastage to global sea-level rise. We compare South Cascade Glacier, the benchmark glacier for the northwest contiguous USA, and four other secondary glaciers, against the topographic, area and mass changes of 321 glaciers in the surrounding region. Results show that South Cascade Glacier is unusually large, of lower slope and much larger area and had mass losses greater than most other glaciers in the region. Three of the four secondary glaciers were much more typical. Year-to-year variations in mass balance were highly correlated between all five glaciers, and any of these glaciers, including the benchmark glacier, could be used to infer temporal mass variations in the region. However, the use of South Cascade Glacier to estimate area/mass losses for the region would result in overestimating the area/mass changes by a factor of three. Local differences in the magnitude of annual glacier mass balance control cumulative mass changes and area changes. There appears to be no way to select a representative glacier a priori, and knowledge of changes over the region is required. Therefore, there may be great uncertainty in estimates of sea-level rise from the wastage of alpine glaciers based on the benchmark approach. We recommend re-evaluation of regional glacier mass changes inferred from benchmark glaciers in critical regions.

Gaussian Process emulation of multi-model ice sheet and glacier projections

2021 ◽  
Author(s):  
Tamsin Edwards ◽  
Keyword(s):  
Gaussian Process ◽  
Sea Level Rise ◽  
Sea Level ◽  
Climate Models ◽  
Ice Sheet ◽  
Surface Air Temperature ◽  
Model Parameters ◽  
Gaussian Process Emulation ◽  
Model Ensembles ◽  
Global Mean

<p><strong>The land ice contribution to global mean sea level rise has not yet been predicted with ice sheet and glacier models for the latest set of socio-economic scenarios (SSPs), nor with coordinated exploration of uncertainties arising from the various computer models involved. Two recent international projects (ISMIP6 and GlacierMIP) generated a large suite of projections using multiple models, but mostly used previous generation scenarios and climate models, and could not fully explore known uncertainties. </strong></p><p><strong>Here we estimate probability distributions for these projections for the SSPs using Gaussian Process emulation of the ice sheet and glacier model ensembles. We model the sea level contribution as a function of global mean surface air temperature forcing and (for the ice sheets) model parameters, with the 'nugget' allowing for multi-model structural uncertainty. Approximate independence of ice sheet and glacier models is assumed, because a given model responds very differently under different setups (such as initialisation). </strong></p><p><strong>We find that limiting global warming to 1.5</strong>°<strong>C </strong><strong>would halve the land ice contribution to 21<sup>st</sup> century </strong><strong>sea level rise</strong><strong>, relative to current emissions pledges: t</strong><strong>he median decreases from 25 to 13 cm sea level equivalent (SLE) by 2100. However, the Antarctic contribution does not show a clear response to emissions scenario, due to competing processes of increasing ice loss and snowfall accumulation in a warming climate. </strong></p><p><strong>However, under risk-averse (pessimistic) assumptions for climate and Antarctic ice sheet model selection and ice sheet model parameter values, Antarctic ice loss could be five times higher, increasing the median land ice contribution to 42 cm SLE under current policies and pledges, with the 95<sup>th</sup> percentile exceeding half a metre even under 1.5</strong>°<strong>C warming. </strong></p><p><strong>Gaussian Process emulation can therefore be a powerful tool for estimating probability density functions from multi-model ensembles and testing the sensitivity of the results to assumptions.</strong></p>

scholarly journals Simulation of the future sea level contribution of Greenland with a new glacial system model

2018 ◽  
Vol 12 (10) ◽  
pp. 3097-3121 ◽  
Author(s):  
Reinhard Calov ◽  
Sebastian Beyer ◽  
Ralf Greve ◽  
Johanna Beckmann ◽  
Matteo Willeit ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Surface Temperature ◽  
Mass Balance ◽  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
System Model ◽  
Surface Mass Balance ◽  
Surface Mass

Abstract. We introduce the coupled model of the Greenland glacial system IGLOO 1.0, including the polythermal ice sheet model SICOPOLIS (version 3.3) with hybrid dynamics, the model of basal hydrology HYDRO and a parameterization of submarine melt for marine-terminated outlet glaciers. The aim of this glacial system model is to gain a better understanding of the processes important for the future contribution of the Greenland ice sheet to sea level rise under future climate change scenarios. The ice sheet is initialized via a relaxation towards observed surface elevation, imposing the palaeo-surface temperature over the last glacial cycle. As a present-day reference, we use the 1961–1990 standard climatology derived from simulations of the regional atmosphere model MAR with ERA reanalysis boundary conditions. For the palaeo-part of the spin-up, we add the temperature anomaly derived from the GRIP ice core to the years 1961–1990 average surface temperature field. For our projections, we apply surface temperature and surface mass balance anomalies derived from RCP 4.5 and RCP 8.5 scenarios created by MAR with boundary conditions from simulations with three CMIP5 models. The hybrid ice sheet model is fully coupled with the model of basal hydrology. With this model and the MAR scenarios, we perform simulations to estimate the contribution of the Greenland ice sheet to future sea level rise until the end of the 21st and 23rd centuries. Further on, the impact of elevation–surface mass balance feedback, introduced via the MAR data, on future sea level rise is inspected. In our projections, we found the Greenland ice sheet to contribute between 1.9 and 13.0 cm to global sea level rise until the year 2100 and between 3.5 and 76.4 cm until the year 2300, including our simulated additional sea level rise due to elevation–surface mass balance feedback. Translated into additional sea level rise, the strength of this feedback in the year 2100 varies from 0.4 to 1.7 cm, and in the year 2300 it ranges from 1.7 to 21.8 cm. Additionally, taking the Helheim and Store glaciers as examples, we investigate the role of ocean warming and surface runoff change for the melting of outlet glaciers. It shows that ocean temperature and subglacial discharge are about equally important for the melting of the examined outlet glaciers.

scholarly journals Reanalysing glacier mass balance measurement series

2013 ◽  
Vol 7 (4) ◽  
pp. 1227-1245 ◽  
Author(s):  
M. Zemp ◽  
E. Thibert ◽  
M. Huss ◽  
D. Stumm ◽  
C. Rolstad Denby ◽  
...  
Keyword(s):  
Climate Change ◽  
Data Quality ◽  
Mass Balance ◽  
Sea Level ◽  
Error Estimation ◽  
Standard Procedure ◽  
Systematic Errors ◽  
Glacier Mass Balance ◽  
Uncertainty Estimates ◽  
Measurement Series

Abstract. Glacier-wide mass balance has been measured for more than sixty years and is widely used as an indicator of climate change and to assess the glacier contribution to runoff and sea level rise. Until recently, comprehensive uncertainty assessments have rarely been carried out and mass balance data have often been applied using rough error estimation or without consideration of errors. In this study, we propose a framework for reanalysing glacier mass balance series that includes conceptual and statistical toolsets for assessment of random and systematic errors, as well as for validation and calibration (if necessary) of the glaciological with the geodetic balance results. We demonstrate the usefulness and limitations of the proposed scheme, drawing on an analysis that comprises over 50 recording periods for a dozen glaciers, and we make recommendations to investigators and users of glacier mass balance data. Reanalysing glacier mass balance series needs to become a standard procedure for every monitoring programme to improve data quality, including reliable uncertainty estimates.

scholarly journals Decadal-scale onset and termination of Antarctic ice-mass loss during the last deglaciation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael E. Weber ◽  
Nicholas R. Golledge ◽  
Chris J. Fogwill ◽  
Chris S. M. Turney ◽  
Zoë A. Thomas
Keyword(s):  
Mass Loss ◽  
Sea Level Rise ◽  
Sea Level ◽  
Ross Sea ◽  
Ice Sheet ◽  
Rate Of Change ◽  
Last Deglaciation ◽  
Decadal Scale ◽  
Ice Sheet Modeling ◽  
Global Sea Level

AbstractEmerging ice-sheet modeling suggests once initiated, retreat of the Antarctic Ice Sheet (AIS) can continue for centuries. Unfortunately, the short observational record cannot resolve the tipping points, rate of change, and timescale of responses. Iceberg-rafted debris data from Iceberg Alley identify eight retreat phases after the Last Glacial Maximum that each destabilized the AIS within a decade, contributing to global sea-level rise for centuries to a millennium, which subsequently re-stabilized equally rapidly. This dynamic response of the AIS is supported by (i) a West Antarctic blue ice record of ice-elevation drawdown >600 m during three such retreat events related to globally recognized deglacial meltwater pulses, (ii) step-wise retreat up to 400 km across the Ross Sea shelf, (iii) independent ice sheet modeling, and (iv) tipping point analysis. Our findings are consistent with a growing body of evidence suggesting the recent acceleration of AIS mass loss may mark the beginning of a prolonged period of ice sheet retreat and substantial global sea level rise.

scholarly journals An estimate of glacier mass balance for the Chandra basin, western Himalaya, for the period 1984–2012

2017 ◽  
Vol 58 (75pt2) ◽  
pp. 99-109 ◽  
Author(s):  
Sayli Atul Tawde ◽  
Anil V. Kulkarni ◽  
Govindasamy Bala
Keyword(s):  
Mass Balance ◽  
Water Resource Management ◽  
Western Himalaya ◽  
Ratio Method ◽  
Glacier Mass Balance ◽  
Equilibrium Line Altitude ◽  
Temperature Index ◽  
Field Investigations ◽  
Basin Scale ◽  
Accumulation Area Ratio

ABSTRACTAn improved understanding of fresh water stored in the Himalaya is crucial for water resource management in South Asia and can be inferred from glacier mass-balance estimates. However, field investigations in the rugged Himalaya are limited to a few individual glaciers and short duration. Therefore, we have recently developed an approach that combines satellite-derived snowlines, a temperature-index melt model and the accumulation-area ratio method to estimate annual mass balance of glaciers at basin scale and for a long period. In this investigation, the mass balance of 146 glaciers in the Chandra basin, western Himalaya, is estimated from 1984 to 2012. We estimate the trend in equilibrium line altitude of the basin as +113 m decade−1and the mean mass balance as −0.61 ± 0.46 m w.e. a−1. Our basin-wide mass-balance estimates are in agreement with the geodetic method during 1999–2012. Sensitivity analysis suggests that a 20% increase in precipitation can offset changes in mass balance for a 1 °C temperature rise. A water loss of 18% of the total basin volume is estimated, and 67% for small and low-altitude glaciers during 1984–2012, indicating a looming water scarcity crisis for villages in this valley.

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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