scholarly journals Variations of Mass Balance of the Greenland Ice Sheet from 2002 to 2019

2020 ◽  
Vol 12 (16) ◽  
pp. 2609
Author(s):  
Yaqiong Mu ◽  
Yanqiang Wei ◽  
Jinkui Wu ◽  
Yongjian Ding ◽  
Donghui Shangguan ◽  
...  
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
Quantitative Research ◽  
Global Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Rate Of Change ◽  
Ice Caps ◽  
Ice Cap ◽  
Temperature And Precipitation

The melting of the polar ice caps is considered to be an essential factor for global sea-level rise and has received significant attention. Quantitative research on ice cap mass changes is critical in global climate change. In this study, GRACE JPL RL06 data under the Mascon scheme based on the dynamic method were used. Greenland, which is highly sensitive to climate change, was selected as the study area. Greenland was divided into six sub-research regions, according to its watersheds. The spatial–temporal mass changes were compared to corresponding temperature and precipitation statistics to analyze the relationship between changes in ice sheet mass and climate change. The results show that: (i) From February 2002 to September 2019, the rate of change in the Greenland Ice Sheet mass was about −263 ± 13 Gt yr−1 and the areas with the most substantial ice sheet loss and climate changes were concentrated in the western and southern parts of Greenland. (ii) The mass balance of the Greenland Ice Sheet during the study period was at a loss, and this was closely related to increasing trends in temperature and precipitation. (iii) In the coastal areas of western and southern Greenland, the rate of mass change has accelerated significantly, mainly because of climate change.

scholarly journals An efficient regional energy-moisture balance model for simulation of the Greenland ice sheet response to climate change

2009 ◽  
Vol 3 (3) ◽  
pp. 729-764
Author(s):  
A. Robinson ◽  
R. Calov ◽  
A. Ganopolski
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Mass Balance ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Balance Model ◽  
Surface Boundary ◽  
Regional Energy ◽  
Temperature And Precipitation ◽  
Moisture Balance

Abstract. In order to explore the response of the Greenland ice sheet (GIS) to climate change on long (centennial to multi-millennial) time scales, a regional energy-moisture balance model has been developed. This model simulates seasonal variations of temperature and precipitation over Greenland and explicitly accounts for elevation and albedo feedbacks. These fields are used to force a high resolution ice sheet model through the annual mean surface temperature and mass balance. The melt component of the mass balance is computed here using both a conventional positive degree day approach and a more physically-based alternative. As a validation of the model, we first simulated temperature and precipitation over Greenland for the prescribed, present-day topography of Greenland and compared them with empirical data. For the present-day climate, simulated surface boundary conditions for the GIS do not differ significantly from those of a simple parameterization used in many previous simulations. However, for a prescribed, ice-free state, the differences in simulated climatology and surface mass balance between the regional energy-moisture balance model and the conventional approach become significant, with our model showing much stronger summer warming. When coupled to a high resolution, three-dimensional ice sheet model and initialized with present-day conditions, the two melt schemes both allow sufficiently realistic simulations of the present-day GIS. However, when starting from ice-free conditions, two different equilibrium states are achieved, depending on the choice of melt scheme.

scholarly journals Constraining GRACE-derived cryosphere-attributed signal to irregularly shaped ice-covered areas

2013 ◽  
Vol 7 (6) ◽  
pp. 1901-1914 ◽  
Author(s):  
W. Colgan ◽  
S. Luthcke ◽  
W. Abdalati ◽  
M. Citterio
Keyword(s):  
Monte Carlo ◽  
Mass Loss ◽  
Mass Balance ◽  
Spherical Harmonic ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Caps ◽  
Ice Coverage ◽  
Ice Sheet Mass Balance ◽  
Harmonic Representation

Abstract. We use a Monte Carlo approach to invert a spherical harmonic representation of cryosphere-attributed mass change in order to infer the most likely underlying mass changes within irregularly shaped ice-covered areas at nominal 26 km resolution. By inverting a spherical harmonic representation through the incorporation of additional fractional ice coverage information, this approach seeks to eliminate signal leakage between non-ice-covered and ice-covered areas. The spherical harmonic representation suggests a Greenland mass loss of 251 ± 25 Gt a−1 over the December 2003 to December 2010 period. The inversion suggests 218 ± 20 Gt a−1 was due to the ice sheet proper, and 34 ± 5 Gt a−1 (or ~14%) was due to Greenland peripheral glaciers and ice caps (GrPGICs). This mass loss from GrPGICs exceeds that inferred from all ice masses on both Ellesmere and Devon islands combined. This partition therefore highlights that GRACE-derived "Greenland" mass loss cannot be taken as synonymous with "Greenland ice sheet" mass loss when making comparisons with estimates of ice sheet mass balance derived from techniques that sample only the ice sheet proper.

scholarly journals A daily, 1 km resolution data set of downscaled Greenland ice sheet surface mass balance (1958–2015)

2016 ◽  
Vol 10 (5) ◽  
pp. 2361-2377 ◽  
Author(s):  
Brice Noël ◽  
Willem Jan van de Berg ◽  
Horst Machguth ◽  
Stef Lhermitte ◽  
Ian Howat ◽  
...  
Keyword(s):  
Mass Balance ◽  
Climate Model ◽  
Regional Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Surface Mass Balance ◽  
Data Set ◽  
Surface Mass ◽  
Ice Caps ◽  
Elevation Model

Abstract. This study presents a data set of daily, 1 km resolution Greenland ice sheet (GrIS) surface mass balance (SMB) covering the period 1958–2015. Applying corrections for elevation, bare ice albedo and accumulation bias, the high-resolution product is statistically downscaled from the native daily output of the polar regional climate model RACMO2.3 at 11 km. The data set includes all individual SMB components projected to a down-sampled version of the Greenland Ice Mapping Project (GIMP) digital elevation model and ice mask. The 1 km mask better resolves narrow ablation zones, valley glaciers, fjords and disconnected ice caps. Relative to the 11 km product, the more detailed representation of isolated glaciated areas leads to increased precipitation over the southeastern GrIS. In addition, the downscaled product shows a significant increase in runoff owing to better resolved low-lying marginal glaciated regions. The combined corrections for elevation and bare ice albedo markedly improve model agreement with a newly compiled data set of ablation measurements.

scholarly journals Positive mass balance during the late 20th century on Austfonna, Svalbard, revealed using satellite radar interferometry

2007 ◽  
Vol 46 ◽  
pp. 117-122 ◽  
Author(s):  
Suzanne Bevan ◽  
Adrian Luckman ◽  
Tavi Murray ◽  
Helena Sykes ◽  
Jack Kohler
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
Radar Interferometry ◽  
The Arctic ◽  
Late 20Th Century ◽  
Ice Caps ◽  
Ice Cap ◽  
Radio Echo Sounding ◽  
Satellite Radar ◽  
Increasing Temperature

AbstractDetermining whether increasing temperature or precipitation will dominate the cryospheric response to climate change is key to forecasting future sea-level rise. The volume of ice contained in the ice caps and glaciers of the Arctic archipelago of Svalbard is small compared with that of the Greenland or Antarctic ice sheets, but is likely to be affected much more rapidly in the short term by climate change. This study investigates the mass balance of Austfonna, Svalbard’s largest ice cap. Equilibrium-line fluxes for the whole ice cap, and for individual drainage basins, were estimated by combining surface velocities measured using satellite radar interferometry with ice thicknesses derived from radio-echo sounding. These fluxes were compared with balance fluxes to reveal that during the 1990s the total mass balance of the accumulation zone was (5.6±2.0)×108m3 a–1. Three basins in the quiescent phase of their surge cycles contributed 75% of this accumulation. The remaining volume may be attributable either to as yet unidentified surge-type glaciers, or to increased precipitation. This result emphasizes the importance of considering the surge dynamics of glaciers when attempting to draw any conclusions on climate change based on snapshot observations of the cryosphere.

scholarly journals Influence of albedo parameterization on surface mass balance in the perspective of Greenland ice sheet modelling in EC-Earth

2016 ◽  
Author(s):  
Michiel Helsen ◽  
Roderik Van de Wal ◽  
Thomas Reerink ◽  
Richard Bintanja ◽  
Marianne Sloth Madsen ◽  
...  
Keyword(s):  
Mass Balance ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Surface Mass Balance ◽  
Surface Mass

Abstract. The albedo of the surface of ice sheets changes as a function of time, due to the effects of deposition of new snow, ageing of dry snow, melting and runoff. Currently, the calculation of the albedo of ice sheets is highly parameterized within the Earth System Model EC-Earth, by taking a constant value for areas with thick perennial snow cover. This is one of the reasons that the surface mass balance (SMB) of the Greenland ice sheet (GrIS) is poorly resolved in the model. To improve this, eight snow albedo schemes are evaluated here. The resulting SMB is downscaled from the lower resolution global climate model topography to the higher resolution ice sheet topography of the GrIS, such that the influence of these different SMB climatologies on the long-term evolution of the GrIS is tested by ice sheet model simulations. This results in an optimised albedo parameterization that can be used in future EC-Earth simulations with an interactive ice sheet component.

scholarly journals Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change

2017 ◽  
Vol 11 (1) ◽  
pp. 281-302 ◽  
Author(s):  
Henning Åkesson ◽  
Kerim H. Nisancioglu ◽  
Rianne H. Giesen ◽  
Mathieu Morlighem
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
Ice Age ◽  
Ice Flow ◽  
Outlet Glacier ◽  
Surface Mass ◽  
Ice Caps ◽  
Ice Cap ◽  
Length Changes

Abstract. Understanding of long-term dynamics of glaciers and ice caps is vital to assess their recent and future changes, yet few long-term reconstructions using ice flow models exist. Here we present simulations of the maritime Hardangerjøkulen ice cap in Norway from the mid-Holocene through the Little Ice Age (LIA) to the present day, using a numerical ice flow model combined with glacier and climate reconstructions. In our simulation, under a linear climate forcing, we find that Hardangerjøkulen grows from ice-free conditions in the mid-Holocene to its maximum extent during the LIA in a nonlinear, spatially asynchronous fashion. During its fastest stage of growth (2300–1300 BP), the ice cap triples its volume in less than 1000 years. The modeled ice cap extent and outlet glacier length changes from the LIA until today agree well with available observations. Volume and area for Hardangerjøkulen and several of its outlet glaciers vary out-of-phase for several centuries during the Holocene. This volume–area disequilibrium varies in time and from one outlet glacier to the next, illustrating that linear relations between ice extent, volume and glacier proxy records, as generally used in paleoclimatic reconstructions, have only limited validity. We also show that the present-day ice cap is highly sensitive to surface mass balance changes and that the effect of the ice cap hypsometry on the mass balance–altitude feedback is essential to this sensitivity. A mass balance shift by +0.5 m w.e. relative to the mass balance from the last decades almost doubles ice volume, while a decrease of 0.2 m w.e. or more induces a strong mass balance–altitude feedback and makes Hardangerjøkulen disappear entirely. Furthermore, once disappeared, an additional +0.1 m w.e. relative to the present mass balance is needed to regrow the ice cap to its present-day extent. We expect that other ice caps with comparable geometry in, for example, Norway, Iceland, Patagonia and peripheral Greenland may behave similarly, making them particularly vulnerable to climate change.

scholarly journals On the importance of the albedo parameterization for the mass balance of the Greenland ice sheet in EC-Earth

2017 ◽  
Vol 11 (4) ◽  
pp. 1949-1965 ◽  
Author(s):  
Michiel M. Helsen ◽  
Roderik S. W. van de Wal ◽  
Thomas J. Reerink ◽  
Richard Bintanja ◽  
Marianne S. Madsen ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Mass Balance ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Albedo

Abstract. The albedo of the surface of ice sheets changes as a function of time due to the effects of deposition of new snow, ageing of dry snow, bare ice exposure, melting and run-off. Currently, the calculation of the albedo of ice sheets is highly parameterized within the earth system model EC-Earth by taking a constant value for areas with thick perennial snow cover. This is an important reason why the surface mass balance (SMB) of the Greenland ice sheet (GrIS) is poorly resolved in the model. The purpose of this study is to improve the SMB forcing of the GrIS by evaluating different parameter settings within a snow albedo scheme. By allowing ice-sheet albedo to vary as a function of wet and dry conditions, the spatial distribution of albedo and melt rate improves. Nevertheless, the spatial distribution of SMB in EC-Earth is not significantly improved. As a reason for this, we identify omissions in the current snow albedo scheme, such as separate treatment of snow and ice and the effect of refreezing. The resulting SMB is downscaled from the lower-resolution global climate model topography to the higher-resolution ice-sheet topography of the GrIS, such that the influence of these different SMB climatologies on the long-term evolution of the GrIS is tested by ice-sheet model simulations. From these ice-sheet simulations we conclude that an albedo scheme with a short response time of decaying albedo during wet conditions performs best with respect to long-term simulated ice-sheet volume. This results in an optimized albedo parameterization that can be used in future EC-Earth simulations with an interactive ice-sheet component.

scholarly journals Greenland glaciers and the 'greenhouse effect', status 1991

1992 ◽  
Vol 155 ◽  
pp. 9-13
Author(s):  
R.J Braithwaite ◽  
N Reeh ◽  
A Weidick
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Global Climate Change ◽  
Greenhouse Effect ◽  
Global Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Potential Hazard ◽  
High Latitudes ◽  
Public Concern

Possible global climate change caused by increased 'greenhouse effect' continues to be a matter of international public concern. In particular, a warmer climate is expected to cause increased melting of the Greenland ice sheet, and a rise in world sea level. The Greenland ice sheet is therefore a potential hazard for low-Iying countries. Climate warming may be apparent first, and with greatest magnitude, at high latitudes so that increased melting of the Greenland ice sheet could give early warning of global climate change. For these reasons, GGU and foreign organisations are studying Greenland glaciers in connection with the 'greenhouse effect' (Fig. 1). The present review updates the note by Braithwaite (1990).

scholarly journals A daily, 1-km resolution dataset of downscaled Greenland ice sheet surface mass balance (1958–2015)

2016 ◽  
Author(s):  
Brice Noël ◽  
Willem Jan van de Berg ◽  
Horst Machguth ◽  
Stef Lhermitte ◽  
Ian Howat ◽  
...  
Keyword(s):  
Mass Balance ◽  
Climate Model ◽  
Regional Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Ice Caps ◽  
Improve Model ◽  
Elevation Model

Abstract. This study presents a dataset of daily, 1-km resolution Greenland ice sheet (GrIS) surface mass balance (SMB) covering the period 1958–2015. Using elevation dependence, the high-resolution product is statistically downscaled from the native daily output of the polar regional climate model RACMO2.3 at 11-km. The dataset includes all individual SMB components projected to a down-sampled version of the Greenland Ice Mapping Project (GIMP) digital elevation model and ice mask. The 1-km mask better resolves narrow ablation zones, valley glaciers, fjords and disconnected ice caps. Relative to the 11-km product, the more detailed representation of confined glaciated areas leads to increased precipitation over the southeastern GrIS. In addition, the downscaled product shows a significant increase in runoff owing to better resolved low-lying marginal glaciated regions. The combined corrections for elevation and bare ice albedo markedly improve model agreement with a newly compiled dataset of ablation measurements.

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