scholarly journals Surface mass-balance observations and automatic weather station data along a transect near Kangerlussuaq, West Greenland

2005 ◽  
Vol 42 ◽  
pp. 311-316 ◽  
Author(s):  
R.S.W. van de Wal ◽  
W. Greuell ◽  
M.R. van den Broeke ◽  
C.H. Reijmer ◽  
J. Oerlemans
Keyword(s):  
Mass Balance ◽  
Interannual Variability ◽  
Annual Cycle ◽  
Surface Mass Balance ◽  
Weather Station ◽  
Automatic Weather Station ◽  
Net Radiation ◽  
Surface Mass ◽  
Station Data ◽  
The Mean

AbstractSurface mass-balance data from the Kangerlussuaq transect (K-transect) located on the western part of the Greenland ice sheet near 67° N are presented. The series covers the period 1990-2003 and is the longest series of surface mass-balance measurements in Greenland. The surface mass-balance measurements cover an altitude range of 390-1850 m and show a linear increase of the specific mass balance, with a mass-balance gradient of 3.7 × 10–3 m m–1 and a mean equilibrium-line altitude of 1535 ma.s.l. Interannual variability shows a weak 4 yearly periodicity. In addition to the surface mass-balance data, automatic weather station data at an elevation of approximately 1010m are available for the period 1997-2002. These data are used to explain observed surface mass-balance anomalies over the same 5 years. It is shown that variations in shortwave radiation dominate interannual variability. The mean annual cycle of temperature is characterized by a maximum in summer around the melting point, leading to a mean summer outgoing longwave radiation of approximately 314 W–2. The mean annual cycle in wind speed shows a maximum in winter (on average around 8 m s–1) and a minimum in summer (on average around around 5 m s–1), which is characteristic for a katabatic forcing. During summer the net radiation is on average about 61 Wm–2, which is used for ice melting at a rate of typically 2 cm w.e.d-1. Net radiation contributes 84% of the total energy used for summer melting averaged over the 5 years.

scholarly journals Climate sensitivity and mass-balance evolution of Gran Campo Nevado ice cap, southwest Patagonia

2008 ◽  
Vol 48 ◽  
pp. 32-42 ◽  
Author(s):  
Marco Möller ◽  
Christoph Schneider
Keyword(s):  
Mass Balance ◽  
20Th Century ◽  
Climate Model ◽  
Surface Mass Balance ◽  
Weather Station ◽  
Surface Mass ◽  
Ice Cap ◽  
Temperature And Precipitation ◽  
Station Data ◽  
Weather Station Data

AbstractA degree-day model extended for surface mass-balance calculations has been applied to derive the sensitivity of Gran Campo Nevado ice cap (GCN), southwest Patagonia, to climate change. Seasonal sensitivity characteristics were computed using automatic weather station data gathered in the period 2000–05. Results indicate pronounced mass-balance sensitivity to temperature during the summer, with monthly values of –0.27±0.01mw.e. K–1. Monthly sensitivity to a 10% precipitation perturbation fluctuates around +0.03mw.e The sensitivity characteristics obtained were used to model the surface mass-balance evolution of GCN during the 20th and 21 st centuries based on monthly means of air temperature and precipitation derived from bias-corrected weather station data and statistically downscaled re-analysis and general climate model data. Surface mass balance shows a persistently negative trend ranging from around +1mw.e. a–1 at the beginning of the 20th century down to almost –1.5mw.e. a–1 during the first years of the 21st century, with only a few positive years occurring occasionally during the second half of the 20th century. The scenario for the end of the 21 st century totals approximately –4.5mw.e. a–1, i.e. an estimated ice volume loss for GCN of 59 km3 during 1900–2099.

scholarly journals Twenty-one years of mass balance observations along the K-transect, West Greenland

2012 ◽  
Vol 4 (1) ◽  
pp. 31-35 ◽  
Author(s):  
R. S. W. van de Wal ◽  
W. Boot ◽  
C. J. P. P. Smeets ◽  
H. Snellen ◽  
M. R. van den Broeke ◽  
...  
Keyword(s):  
Mass Balance ◽  
Entire Period ◽  
Surface Mass Balance ◽  
Altitude Range ◽  
Equilibrium Line Altitude ◽  
Surface Mass ◽  
West Greenland ◽  
Increasing Trend ◽  
Period Data ◽  
The Mean

Abstract. A 21-yr record is presented of surface mass balance measurements along the K-transect. The series covers the period 1990–2011. Data are available at eight sites along a transect over an altitude range of 380–1850 m at approximately 67° N in West Greenland. The surface mass balance gradient is on average 3.8 × 10−3 m w.e. m−1, and the mean equilibrium line altitude is 1553 m a.s.l. Only the lower three sites within 10 km of the margin up to an elevation of 700 m experience a significant increasing trend in the ablation over the entire period. Data are available at: doi:10.1594/PANGAEA.779181.

scholarly journals Surface mass balance of small glaciers on James Ross Island, north-eastern Antarctic Peninsula, during 2009–2015

2018 ◽  
Vol 64 (245) ◽  
pp. 349-361 ◽  
Author(s):  
ZBYNĚK ENGEL ◽  
KAMIL LÁSKA ◽  
DANIEL NÝVLT ◽  
ZDENĚK STACHOŇ
Keyword(s):  
Mass Balance ◽  
Antarctic Peninsula ◽  
Mass Gain ◽  
Equilibrium Line ◽  
South Shetland Islands ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
North Eastern ◽  
James Ross Island ◽  
The Mean

ABSTRACTTwo small glaciers on James Ross Island, the north-eastern Antarctic Peninsula, experienced surface mass gain between 2009 and 2015 as revealed by field measurements. A positive cumulative surface mass balance of 0.57 ± 0.67 and 0.11 ± 0.37 m w.e. was observed during the 2009–2015 period on Whisky Glacier and Davies Dome, respectively. The results indicate a change from surface mass loss that prevailed in the region during the first decade of the 21st century to predominantly positive surface mass balance after 2009/10. The spatial pattern of annual surface mass-balance distribution implies snow redistribution by wind on both glaciers. The mean equilibrium line altitudes for Whisky Glacier (311 ± 16 m a.s.l.) and Davies Dome (393 ± 18 m a.s.l.) are in accordance with the regional data indicating 200–300 m higher equilibrium line on James Ross and Vega Islands compared with the South Shetland Islands. The mean accumulation-area ratio of 0.68 ± 0.09 and 0.44 ± 0.09 determined for Whisky Glacier and Davies Dome, respectively, is similar to the value reported for Vega Island and within the range of typical values for high-latitude glaciers.

scholarly journals Reduced melt on debris-covered glaciers: investigations from Changri Nup Glacier, Nepal

2016 ◽  
Author(s):  
C. Vincent ◽  
P. Wagnon ◽  
J. M. Shea ◽  
W. W. Immerzel ◽  
P. D. A. Kraaijenbrink ◽  
...  
Keyword(s):  
Mass Balance ◽  
Surface Mass Balance ◽  
Mass Balances ◽  
Elevation Change ◽  
Surface Mass ◽  
Future Evolution ◽  
Debris Cover ◽  
Aerial Vehicle ◽  
The Mean ◽  
Terrestrial Photogrammetry

Abstract. Debris-covered glaciers occupy more than 1/4 of the total glacierized area in the Everest region of Nepal, yet the surface mass balance of these glaciers has not been measured directly. In this study, ground-based measurements of surface elevation and ice depth are combined with terrestrial photogrammetry and unmanned aerial vehicle (UAV) elevation models to derive the surface mass balance of the debris-covered Changri Nup Glacier, located in the Everest region. Over the debris-covered tongue, the mean elevation change between 2011 and 2015 is −0.93 m ice/year or −0.84 m water equivalent per year (w.e. a−1). The mean emergence velocity over this region, estimated from the total ice flux through a cross-section immediately above the debris-covered zone, is +0.37 m w.e. a−1. The debris-covered portion of the glacier thus has an area-averaged mass balance of −1.21 ± 0.2 m w.e. a−1 between 5240 and 5525 m above sea level (m a.s.l.). The surface mass balances observed on nearby debris-free glaciers suggest that the ablation is strongly reduced (by ca. 1.8 m w.e. a−1) by the debris cover. The insulating effect of the debris cover largely dominates the enhanced ice ablation due to the supra-glacial ponds and exposed ice cliffs. This finding has major implications for modeling the future evolution of debris-covered glaciers.

scholarly journals Interannual Variability of Summer Surface Mass Balance and Surface Melting in the Amundsen Sector, West Antarctica

2019 ◽  
Author(s):  
Marion Donat-Magnin ◽  
Nicolas C. Jourdain ◽  
Hubert Gallée ◽  
Charles Amory ◽  
Christoph Kittel ◽  
...  
Keyword(s):  
Mass Balance ◽  
Interannual Variability ◽  
Climate Models ◽  
Surface Wind ◽  
Surface Melting ◽  
Surface Mass Balance ◽  
Climate Trends ◽  
West Antarctica ◽  
Near Surface ◽  
Surface Mass

Abstract. Understanding the interannual variability of Surface Mass Balance (SMB) and surface melting in Antarctica is key to quantify the signal to noise ratio in climate trends, identify opportunities for multi-year climate predictions, and to assess the ability of climate models to respond to climate variability. Here we simulate summer SMB and surface melting from 1979 to 2017 using the regional atmospheric model MAR at 10 km resolution over the drainage basins of the Amundsen glaciers in West Antarctica. Our simulations reproduce the mean present-day climate in terms of near-surface temperature (mean overestimation of 0.10 °C), near-surface wind speed (mean underestimation of 0.42 m s-1), and SMB (relative bias

scholarly journals Assessment of the surface mass balance along the K-transect (Greenland ice sheet) from satellite-derived albedos

2005 ◽  
Vol 42 ◽  
pp. 107-117 ◽  
Author(s):  
Wouter Greuell ◽  
Johannes Oerlemans
Keyword(s):  
Mass Balance ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Radar Data ◽  
Detection Algorithm ◽  
Surface Mass Balance ◽  
Cloud Detection ◽  
Equilibrium Line Altitude ◽  
Surface Mass ◽  
The Mean

AbstractThis paper explores the potential of using satellite-derived albedos to estimate the surface mass balance of the Kangerlussuaq transect (K-transect; Greenland ice sheet). We first retrieved surface albedos from Advanced Very High Resolution Radar data by using, among other techniques, a new cloud detection algorithm based on the relation between brightness temperature and surface elevation. We then computed the ‘satellite-derived mass balance’ (bsat) from the mean albedo for the transect, by taking fixed values for atmospheric transmissivity and the longwave and turbulent fluxes. We found that bsat explains 7 1% of the variance in 13 years of stake mass-balance measurements (bm). Our method also provides good estimates of the magnitude of the interannual variability in bm. The performance of the method degrades considerably without correction for anisotropic reflection at the surface and recalibration of the satellite sensors with dry snow at the top of the ice sheet. Sensitivity tests indicate that the method’s performance is hardly sensitive to uncertainties in parameters. Therefore, we expect that the method could be successfully applied on other glaciers and parts of ice sheets and ice caps, especially where accumulation rates are relatively small. We show that the investigated method performs best just below the mean equilibrium-line altitude.

scholarly journals Twenty-one years of mass balance observations along the K-transect, West Greenland

2012 ◽  
Vol 5 (1) ◽  
pp. 351-363 ◽  
Author(s):  
R. S. W. van de Wal ◽  
W. Boot ◽  
C. J. P. P. Smeets ◽  
H. Snellen ◽  
M. R. van den Broeke ◽  
...  
Keyword(s):  
Mass Balance ◽  
Entire Period ◽  
Surface Mass Balance ◽  
Altitude Range ◽  
Equilibrium Line Altitude ◽  
Surface Mass ◽  
West Greenland ◽  
Increasing Trend ◽  
Period Data ◽  
The Mean

Abstract. A 21-yr record is presented of surface mass balance measurements along the K-transect. The series covers the period 1990–2011. Data are available at 8 sites along a transect over an altitude range of 390–1850 m at approximately 67° N in West Greenland. The surface mass balance gradient is on average 3.8 × 10−3 m w.e. m−1, and the mean equilibrium line altitude is 1553 m a.s.l. Only the lower 3 sites within 10 km of the margin experience a significant increasing trend in the ablation over the entire period. Data are available at: http://doi.pangaea.de/10.1594/PANGAEA.779181.

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 Uncertainties in projected surface mass balance over the polar ice sheets from downscaled EC-Earth models

2021 ◽  
Author(s):  
Fredrik Boberg ◽  
Ruth Mottram ◽  
Nicolaj Hansen ◽  
Shuting Yang ◽  
Peter L. Langen
Keyword(s):  
Mass Balance ◽  
Climate Model ◽  
Global Climate ◽  
Ice Sheet ◽  
Coupled Model ◽  
Surface Mass Balance ◽  
Model Intercomparison ◽  
Surface Mass ◽  
Intercomparison Project ◽  
The Mean

Abstract. The future rates of ice sheet melt in Greenland and Antarctica are an important factor when making estimates of the likely rate of sea level rise. Global climate models that took part in the fifth Coupled Model Intercomparison Project (CMIP5) have generally been unable to replicate observed rates of ice sheet melt. With the advent of the sixth Coupled Model Intercomparison Project (CMIP6), with a general increase in the equilibrium climate sensitivity, we here compare two versions of the global climate model EC-Earth using the regional climate model HIRHAM5 downscaling EC-Earth for Greenland and Antarctica. One version (v2) of EC-Earth is taken from CMIP5 for the high-emissions Representative Concentration Pathways (RCP8.5) scenario and the other (v3) from CMIP6 for the comparable high-emissions Shared Socioeconomic Pathways (SSP5-8.5) scenario). For Greenland, we downscale the two versions of EC-Earth for the historical period 1991–2010 and for the scenario period 2081–2100. For Antarctica, the periods are 1971–2000 and 2071–2100, respectively. For the Greenland Ice Sheet, we find that the mean change in temperature is 5.9 °C when downscaling EC-Earth v2 and 6.8 °C when downscaling EC-Earth v3. Corresponding values for Antarctica are 4.1 °C for v2 and 4.8 °C for v3. The mean change in surface mass balance at the end of the century under these high emissions scenarios is found to be −210 Gt yr−1 (v2) and −1150 Gt yr−1 (v3) for Greenland and 420 Gt yr−1 (v2) and 80 Gt yr−1 (v3) for Antarctica. These distinct differences in temperature change and particularly surface mass balance change are a result of the higher equilibrium climate sensitivity in EC-Earth v3 (4.3 K) compared with 3.3 K in EC-Earth v2 and the differences in greenhouse gas concentrations between the RCP8.5 and the SSP5-8.5 scenarios.

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