scholarly journals Deriving mass balance and calving variations from reanalysis data and sparse observations, Glaciar San Rafael, northern Patagonia, 1950–2005

2011 ◽  
Vol 5 (3) ◽  
pp. 791-808 ◽  
Author(s):  
M. Koppes ◽  
H. Conway ◽  
L. A. Rasmussen ◽  
M. Chernos
Keyword(s):  
Mass Balance ◽  
Complex Dynamics ◽  
Regional Climate ◽  
Reanalysis Data ◽  
Climate Data ◽  
Glacier Surface ◽  
Total Mass Loss ◽  
Short Period ◽  
San Rafael ◽  
Topographic Constraints

Abstract. Mass balance variations of Glaciar San Rafael, the northernmost tidewater glacier in the Southern Hemisphere, are reconstructed over the period 1950–2005 using NCEP-NCAR reanalysis climate data together with sparse, local historical observations of air temperature, precipitation, accumulation, ablation, thinning, calving, and glacier retreat. The combined observations over the past 50 yr indicate that Glaciar San Rafael has thinned and retreated since 1959, with a total mass loss of ~22 km3 of ice eq. Over that period, except for a short period of cooling from 1998–2003, the climate has become progressively warmer and drier, which has resulted primarily in pervasive thinning of the glacier surface and a decrease in calving rates, with only minor acceleration in retreat of the terminus. A comparison of calving fluxes derived from the mass balance variations and from theoretical calving and sliding laws suggests that calving rates are inversely correlated with retreat rates, and that terminus geometry is more important than balance fluxes to the terminus in driving calving dynamics. For Glaciar San Rafael, regional climate warming has not yet resulted in the significant changes in glacier length seen in other calving glaciers in the region, emphasizing the complex dynamics between climate inputs, topographic constraints and glacier response in calving glacier systems.

scholarly journals Deriving mass balance and calving variations from reanalysis data and sparse observations, Glaciar San Rafael, northern Patagonia, 1950–2005

2011 ◽  
Vol 5 (2) ◽  
pp. 1123-1166
Author(s):  
M. Koppes ◽  
H. Conway ◽  
L. A. Rasmussen ◽  
M. Chernos
Keyword(s):  
Mass Balance ◽  
Complex Dynamics ◽  
Regional Climate ◽  
Reanalysis Data ◽  
Climate Data ◽  
Glacier Surface ◽  
The North ◽  
Total Mass Loss ◽  
Short Period ◽  
San Rafael

Abstract. Mass balance variations of Glaciar San Rafael, the most equatorial tidewater glacier in the North Patagonian Icefield, are reconstructed over the period 1950–2005 using NCEP-NCAR reanalysis climate data together with sparse, local historical observations of air temperature, precipitation, accumulation, ablation, thinning, calving, and glacier retreat. The combined observations over the past 50 yr indicate that Glaciar San Rafael has thinned and retreated since 1959, with a total mass loss of ~22 km3 of ice equivalent. Over that period, except for a short period of cooling from 1998–2003, the climate has become progressively warmer and drier, which has resulted primarily in pervasive thinning of the glacier surface and a decrease in calving rates, with only minor acceleration in retreat of the terminus. A comparison of calving fluxes derived from the mass balance variations and from theoretical calving and sliding laws suggest that calving rates are inversely correlated with retreat rates, and that terminus geometry is more important than changes in balance fluxes to the terminus in driving calving dynamics. For Glaciar San Rafael, regional climate warming has not yet resulted in the significant changes in glacier length seen in other calving glaciers in the region, emphasizing the complex dynamics between climate inputs, topographic constraints and glacier response in calving glacier systems.

scholarly journals Explaining mass balance and retreat dichotomies at Taku and Lemon Creek Glaciers, Alaska

2020 ◽  
Vol 66 (258) ◽  
pp. 530-542 ◽  
Author(s):  
Christopher McNeil ◽  
Shad O'Neel ◽  
Michael Loso ◽  
Mauri Pelto ◽  
Louis Sass ◽  
...  
Keyword(s):  
Mass Balance ◽  
Average Rate ◽  
Regional Climate ◽  
Strong Correlations ◽  
Climate Data ◽  
Negative Mass ◽  
Regional Warming ◽  
Local Climate ◽  
Surface Mass ◽  
Cumulative Mass

AbstractWe reanalyzed mass balance records at Taku and Lemon Creek Glaciers to better understand the relative roles of hypsometry, local climate and dynamics as mass balance drivers. Over the 1946–2018 period, the cumulative mass balances diverged. Tidewater Taku Glacier advanced and gained mass at an average rate of +0.25 ± 0.28 m w.e. a–1, contrasting with retreat and mass loss of −0.60 ± 0.15 m w.e. a−1 at land-terminating Lemon Creek Glacier. The uniform influence of regional climate is demonstrated by strong correlations among annual mass balance and climate data. Regional warming trends forced similar statistically significant decreases in surface mass balance after 1989: −0.83 m w.e. a–1 at Taku Glacier and −0.81 m w.e. a–1 at Lemon Creek Glacier. Divergence in cumulative mass balance arises from differences in glacier hypsometry and local climate. Since 2013 negative mass balance and glacier-wide thinning prevailed at Taku Glacier. These changes initiated terminus retreat, which could increase dramatically if calving begins. The future mass balance trajectory of Taku Glacier hinges on dynamics, likely ending the historic dichotomy between these glaciers.

scholarly journals Local topography increasingly influences the mass balance of a retreating cirque glacier

2018 ◽  
Author(s):  
Caitlyn Florentine ◽  
Joel Harper ◽  
Daniel Fagre ◽  
Johnnie Moore ◽  
Erich Peitzsch
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Regional Climate ◽  
Glacier Mass Balance ◽  
Climate Variables ◽  
Climate Data ◽  
Local Effects ◽  
Surface Mass ◽  
Average Mass ◽  
Measured Mass

Abstract. Local topographically driven processes such as wind drifting, avalanching, and shading, are known to alter the relationship between the mass balance of small cirque glaciers and regional climate. Yet partitioning such local effects apart from regional climate influence has proven difficult, creating uncertainty in the climate representativeness of some glaciers. We address this problem for Sperry Glacier in Glacier National Park, USA using field-measured surface mass balance, geodetic constraints on mass balance, and regional climate data recorded at a network of meteorological stations. Geodetically derived mass changes between 1950–1960, 1960–2005, and 2005–2014 document average mass loss rates during each period at −0.22±0.12 m w.e. yr−1, −0.18±0.05 m w.e. yr−1, and −0.10±0.03 m w.e. yr−1. A correlation of field-measured mass balance and regional climate variables closely predicts the geodetically measured mass loss from 2005–2014. However, this correlation overestimates glacier mass balance for 1950–1960 by +1.18±0.92 m w.e. yr−1. This suggests that local effects, not represented in regional climate variables, have become a more dominant driver of the net mass balance as the glacier lost 0.50 km2 and retreated further into its cirque.

Combining distributed glacier mass balance and ice flow models to improve projections of mass change for debris-covered Khumbu Glacier, Nepal

2021 ◽  
Author(s):  
Anya Schlich-Davies ◽  
Ann Rowan ◽  
Duncan Quincey ◽  
Andrew Ross ◽  
David Egholm
Keyword(s):  
Mass Balance ◽  
Climate Models ◽  
Flow Model ◽  
Regional Climate ◽  
Balance Model ◽  
Glacier Mass Balance ◽  
Climate Data ◽  
Ice Flow ◽  
Flow Models ◽  
Distributed Models

<p>Debris-covered glaciers in the Himalaya are losing mass more rapidly than expected. Quantifying and understanding the behaviour of these glaciers under climate change requires the use of numerical glacier models that represent the important feedbacks between debris transport, ice flow, and mass balance. However, these approaches have, so far, lacked a robust representation of the distributed mass balance forcing that is critical for making accurate simulations of ice volume change. This study forces a 3D higher-order ice flow model, with the outputs from an ensemble of distributed models of present day and future mass balance of Khumbu Glacier, Nepal. Distributed mass balance modelling, using the open access COupled Snowpack and Ice surface energy and mass balance model in PYthon (COSIPY) model (Sauter et al., 2020), was forced by three statistically downscaled climate models from the Coordinated Regional Climate Downscaling Experiment (CORDEX) project.</p><p>Climate models were selected based on their ability to reproduce observed present-day seasonality and to account for several future climate and monsoon scenarios, the latter being of particular importance for these summer-accumulation type glaciers. Two emission scenarios, RCP4.5 and RCP8.5, were also chosen to simulate glacier change to 2100. Statistical downscaling involved Quantile Mapping and Generalized Analog Regression Downscaling, and the efficacy of these approaches was informed by present day mass balance sensitivity studies. Downscaled daily climate data were trained with data from two weather stations to aid disaggregation to an hourly resolution.</p><p>The integration of the mass balance and ice flow models posed some interesting challenges. The COSIPY model was run as if Khumbu Glacier were a clean-ice glacier (with no supraglacial debris) with sub-debris ablation resolved in the ice flow model. The value of using distributed mass balance forcing is seen in the simulated present-day velocities in the Khumbu icefall, which give a better fit to remote-sensing observations than previous simulations using a simple elevation-dependent mass balance forcing. The simulated present-day glacier extent is considerably smaller than the existing glacier outline. The debris-covered tongue, known to be losing mass at an accelerating rate, is virtually absent from these results, and is indicative of a stagnant tongue that is now or very soon to be dynamically disconnected from the active upper reaches of Khumbu Glacier.</p>

scholarly journals Local topography increasingly influences the mass balance of a retreating cirque glacier

2018 ◽  
Vol 12 (6) ◽  
pp. 2109-2122 ◽  
Author(s):  
Caitlyn Florentine ◽  
Joel Harper ◽  
Daniel Fagre ◽  
Johnnie Moore ◽  
Erich Peitzsch
Keyword(s):  
Mass Balance ◽  
Regional Climate ◽  
Glacier Mass Balance ◽  
Climate Variables ◽  
Climate Data ◽  
Local Effects ◽  
Surface Mass ◽  
Average Mass ◽  
The Relationship ◽  
Measured Mass

Abstract. Local topographically driven processes – such as wind drifting, avalanching, and shading – are known to alter the relationship between the mass balance of small cirque glaciers and regional climate. Yet partitioning such local effects from regional climate influence has proven difficult, creating uncertainty in the climate representativeness of some glaciers. We address this problem for Sperry Glacier in Glacier National Park, USA, using field-measured surface mass balance, geodetic constraints on mass balance, and regional climate data recorded at a network of meteorological and snow stations. Geodetically derived mass changes during 1950–1960, 1960–2005, and 2005–2014 document average mass change rates during each period at −0.22 ± 0.12, −0.18 ± 0.05, and −0.10 ± 0.03 m w.e. yr−1, respectively. A correlation of field-measured mass balance and regional climate variables closely (i.e., within 0.08 m w.e. yr−1) predicts the geodetically measured mass loss from 2005 to 2014. However, this correlation overestimates glacier mass balance for 1950–1960 by +1.20 ± 0.95 m w.e. yr−1. Our analysis suggests that local effects, not represented in regional climate variables, have become a more dominant driver of the net mass balance as the glacier lost 0.50 km2 and retreated further into its cirque.

scholarly journals Glaciers, snow and ski tourism in Austria’s changing climate

2011 ◽  
Vol 52 (58) ◽  
pp. 89-96 ◽  
Author(s):  
Andrea Fischer ◽  
Marc Olefs ◽  
Jakob Abermann
Keyword(s):  
Mass Balance ◽  
Snow Cover ◽  
Climate Data ◽  
Adaptation Measures ◽  
Glacier Surface ◽  
Ski Resort ◽  
Ski Resorts ◽  
Before And After ◽  
Natural Snow

AbstarctThis study illustrates the relevance of cryospheric changes for, and their impact on, ski tourism in Austria. The results of several case studies on snow reliability, snow production and mass balance in glacier ski resorts in the Ötz and Stubai valleys are summarized. Climate data from Obergurgl (1936ma.s.l.) in the Ötz valley are analyzed with respect to the amount and duration of natural snow cover and the possibility of snow production. A case study on Mittelbergferner focuses on the impacts of glacial recession on a ski resort and possible adaptation measures. From long-term glacier inventory and short-term mass-balance data, the effect of operating ski resorts on glaciers is investigated. At Obergurgl, the probability of both snow cover and snow production is >80% from December to March and decreases significantly in the months before and after this peak season. The interannual variability of snow cover and production is low during the main season and higher in other months. Year-to-year differences are larger than any long-term trend. Glacier ski resorts must adapt to shrinking glacial area and falling glacier surface. Covering the glacier with textiles reduces ablation by 60% and results in significantly less volume loss than on uncovered parts of the glacier. Neither the mass-balance comparison between groomed and ungroomed areas nor the comparison of long-term volume changes between 10 ski resort glaciers and 100 surrounding glaciers showed evidence for an impact of the operation of ski resorts on the glaciers.

scholarly journals A model study of the energy and mass balance of Chhota Shigri glacier in the Western Himalaya, India

2011 ◽  
Vol 5 (1) ◽  
pp. 95-129 ◽  
Author(s):  
F. Pithan
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
Climate Model ◽  
Monsoon Season ◽  
Regional Climate ◽  
Western Himalaya ◽  
Reanalysis Data ◽  
Balance Model ◽  
Mass Balances ◽  
The Impact

Abstract. The impact of climate change on Himalaya mountain glaciers is increasingly subject of public and scientific debate. However, observational data are sparse and important knowledge gaps remain in the understanding of what drives changes in these glaciers' mass balances. The present study investigates the glacier regime on Chhota Shigri, a benchmark glacier for the observation of climate change in the monsoon-arid transition zone of Western Himalaya. Results of an energy-balance model driven by reanalysis data and the observed mass balances from three years on 50 m altitude intervals across the glacier display a correlation coefficient of 0.974. Contrary to prior assumptions, monsoon precipitation accounts for a quarter to a third of total accumulation. It has an additional importance because it lowers the surface albedo during the ablation season. Results confirm radiation as the main energy source for melt on Himalaya glaciers. Latent heat flux acts as an important energy sink in the pre-monsoon season. Mass balance is most sensitive to changes in atmospheric humidity, changing by 900 mm w.e. per 10% change in humidity. Temperature sensitivity is 220 mm w.e.K−1. Model results using 21st century anomalies from a regional climate model based on the SRES A2 scenario suggest that a monsoon increase might offset the effect of warming.

scholarly journals Evidence and analysis of 2012 Greenland records from spaceborne observations, a regional climate model and reanalysis data

2012 ◽  
Vol 6 (6) ◽  
pp. 4939-4976 ◽  
Author(s):  
M. Tedesco ◽  
X. Fettweis ◽  
T. Mote ◽  
J. Wahr ◽  
P. Alexander ◽  
...  
Keyword(s):  
Regional Climate Model ◽  
Mass Balance ◽  
Climate Model ◽  
Regional Climate ◽  
Ice Sheet ◽  
Reanalysis Data ◽  
Surface Mass Balance ◽  
Near Surface ◽  
Surface Mass ◽  
The Mean

Abstract. A combined analysis of remote sensing observations, regional climate model (RCM) outputs and reanalysis data over the Greenland ice sheet provides evidence that multiple records were set during summer 2012. Melt extent was the largest in the satellite era (extending up to ~ 97% of the ice sheet) and melting lasted up to ~ two months longer than the 1979–2011 mean. Model results indicate that near surface temperature was ~ 3 standard deviations (σ) above the 1958–2011 mean, while surface mass balance was ~ 3σ below the mean and runoff was 3.9σ above the mean over the same period. Albedo, exposure of bare ice and surface mass balance also set new records, as did the total mass balance with summer and annual mass changes of, respectively, −627 Gt and −574 Gt, 2σ below the 2003–2012 mean. We identify persistent anticyclonic conditions over Greenland associated with anomalies in the North Atlantic Oscillation (NAO), changes in surface conditions (e.g. albedo) and pre-conditioning of surface properties from recent extreme melting as major driving mechanisms for the 2012 records. Because of self-amplifying positive feedbacks, less positive if not increasingly negative SMB will likely occur should large-scale atmospheric circulation and induced surface characteristics observed over the past decade persist. Since the general circulation models of the Coupled Model Intercomparison Project Phase 5 (CMIP5) do not simulate the abnormal anticyclonic circulation resulting from extremely negative NAO conditions as observed over recent years, contribution to sea level rise projected under different warming scenarios will be underestimated should the trend in NAO summer values continue.

scholarly journals Evidence and analysis of 2012 Greenland records from spaceborne observations, a regional climate model and reanalysis data

2013 ◽  
Vol 7 (2) ◽  
pp. 615-630 ◽  
Author(s):  
M. Tedesco ◽  
X. Fettweis ◽  
T. Mote ◽  
J. Wahr ◽  
P. Alexander ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Regional Climate Model ◽  
Mass Balance ◽  
Climate Model ◽  
Regional Climate ◽  
Ice Sheet ◽  
Reanalysis Data ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
The Mean

Abstract. A combined analysis of remote sensing observations, regional climate model (RCM) outputs and reanalysis data over the Greenland ice sheet provides evidence that multiple records were set during summer 2012. Melt extent was the largest in the satellite era (extending up to ∼97% of the ice sheet) and melting lasted up to ∼2 months longer than the 1979–2011 mean. Model results indicate that near surface temperature was ∼3 standard deviations (σ) above the 1958–2011 mean, while surface mass balance (SMB) was ∼3σ below the mean and runoff was 3.9σ above the mean over the same period. Albedo, exposure of bare ice and surface mass balance also set new records, as did the total mass balance with summer and annual mass changes of, respectively, −627 Gt and −574 Gt, 2σ below the 2003–2012 mean. We identify persistent anticyclonic conditions over Greenland associated with anomalies in the North Atlantic Oscillation (NAO), changes in surface conditions (e.g., albedo, surface temperature) and preconditioning of surface properties from recent extreme melting as major driving mechanisms for the 2012 records. Less positive if not increasingly negative SMB will likely occur should these characteristics persist.

scholarly journals Glaciological Measurements and Mass Balances from Sperry Glacier, Montana, USA Years 2005–2015

2016 ◽  
Author(s):  
Adam M. Clark ◽  
Daniel B. Fagre ◽  
Erich H. Peitzsch ◽  
Blase A. Reardon ◽  
Joel T. Harper
Keyword(s):  
Mass Balance ◽  
Regional Climate ◽  
Monitoring Program ◽  
The United States ◽  
United States Geological Survey ◽  
Glacier Mass Balance ◽  
Mass Balances ◽  
Glacier Surface ◽  
Entire Area ◽  
Surface Mass

Abstract. Glacier mass balance measurements help to provide an understanding of the behavior of glaciers and their response to local and regional climate influences. In 2005, the United States Geological Survey established a surface mass balance monitoring program on Sperry Glacier, Montana, USA. This program is the first quantitative study of mass changes of a glacier in this region and continues to the present. This paper describes the methods used during the first eleven years of measurements and reports the associated results. Between years 2005–2015, we estimate Sperry Glacier lost approximately 4.37 m of water equivalent averaged over its entire area. The mean winter, summer, and annual glacier-wide mass balances were 2.92 m per year, −3.41 m per year, and −0.40 m per year respectively. We derive these cumulative and mean results from an expansive dataset of snow depth, snow density, and ablation measurements taken at selected points on the glacier, the resultant mass balance point values for these measurement sites, and a time series of seasonal and annual glacier-wide mass balances for all eleven measurement years. We also provide measurements of total glacier surface and accumulation areas for select years. All data have been submitted to the World Glacier Monitoring Service and are available at http://dx.doi.org/10.5904/wgms-fog-2016-08. This foundational data enhances our basic understanding of mass balance of Sperry Glacier, and future work will focus on the processes that control accumulation and ablation patterns across the glacier.

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