Isolation basins, sea-level changes and the Holocene history of the Greenland Ice Sheet

The Greenland ice sheet presently accounts for ~70% of global ice sheet mass loss. Because this mass loss is associated with sea-level rise at a rate of 0.7 mm/year, the development of improved monitoring techniques to observe ongoing changes in ice sheet mass balance is of paramount concern. Spaceborne mass balance techniques are commonly used; however, they are inadequate for many purposes because of their low spatial and/or temporal resolution. We demonstrate that small variations in seismic wave speed in Earth’s crust, as measured with the correlation of seismic noise, may be used to infer seasonal ice sheet mass balance. Seasonal loading and unloading of glacial mass induces strain in the crust, and these strains then result in seismic velocity changes due to poroelastic processes. Our method provides a new and independent way of monitoring (in near real time) ice sheet mass balance, yielding new constraints on ice sheet evolution and its contribution to global sea-level changes. An increased number of seismic stations in the vicinity of ice sheets will enhance our ability to create detailed space-time records of ice mass variations.

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Measurements of firn density in the lower accumulation area of the Greenland ice sheet: EPOCH 1992

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v159.8210 ◽

1993 ◽

Vol 159 ◽

pp. 62-65

Author(s):

R.J Braithwaite ◽

M Laternser

Keyword(s):

Sea Level ◽

Natural Hazards ◽

European Community ◽

Present Note ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Field Work ◽

Sea Level Changes ◽

Work Done ◽

European Programme

Groups from several countries are studying Greenland glaciers in connection with the 'greenhouse effect' (Braithwaite et al., 1992a). In particular, GGU is the Danish partner in a IO-nation two-year project (March 1991 to February 1993) on causes and effects of sea level changes which is funded by the European Community through the European Programme on Climatology and Natural Hazards (EPOCH). As its contribution to EPOCH, GGU is studying the effects of meltwater refreezing in the lower accumulation area of the Greenland ice sheet which may reduce, or at least delay, the expected sea level rise under warmer climate. Work done under EPOCH in 1991 was described by Braithwaite et al. (1992b) while the present note describes the most important results of the 1992 field work.

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Firn temperature and meltwater refreezing in the lower accumulation area of the Greenland ice sheet, Pâkitsoq, West Greenland

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v159.8218 ◽

1993 ◽

Vol 159 ◽

pp. 109-114

Author(s):

R.J Braithwaite

Keyword(s):

Sea Level ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

International Project ◽

Sea Level Changes ◽

West Greenland ◽

Degree Day ◽

Air Temperatures ◽

Surface Melt ◽

High Degree

Firn temperatures and meltwater refreezing are studied in the lower accumulation area of the Greenland ice sheet as part of an international project on sea level changes. In the study area, 1440–1620 m a.s.l., meltwater penetrates several metres into the firn and refreezes, warming the firn by 5–7°C compared with annual air temperatures. This firn warming is closely related to surface melt which can be estimated by several methods. A relatively high degree-day factor is needed to account for the melt rates found.

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Data products from the ESA CCI Sea Level Budget Closure project

10.5194/egusphere-egu2020-12811 ◽

2020 ◽

Author(s):

Martin Horwath ◽

Keyword(s):

Sea Level ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Sea Level Changes ◽

Ocean Mass ◽

Data Products ◽

Global Mean Sea Level ◽

The Individual ◽

Land Water ◽

Global Mean

Studies of the sea-level budget are a means of assessing our ability to quantify and understand sea-level changes and their causes. ESA's Climate Change Initiative (CCI) projects include Sea Level CCI, Greenland Ice Sheet CCI, Antarctic Ice Sheet CCI, Glaciers CCI and the Sea Surface Temperature CCI, all addressing Essential Climate Variables (ECVs) related to sea level. The cross-ECV project CCI Sea Level Budget Closure used different products for the sea level and its components, based on the above CCI projects in conjunction with in situ data for ocean thermal expansion (e.g., Argo), GRACE-based assessments of ocean mass change, land water and land ice mass change, and model-based data for glaciers and land hydrology. The involvement of the authors of the individual data products facilitated consistency and enabled a unified treatment of uncertainties and their propagation to the overall budget closure.&#160;After conclusion of the project, the developed data products are now available for science users and the public. This poster summarizes the project results with a focus on presenting these data products. They include time series (for the periods 1993-2016 and 2003-2016) of global mean sea level changes and global mean sea level contributions from the steric component, from the ocean mass component and from the individual mass contributions by glaciers, the Greenland Ice Sheet, the Antarctic Ice Sheet and changes in land water storage. They are designed and documented in the consistent framework of ESA SLBC_cci and include uncertainty measures per datum. Additional more comprehensive information, such as geographic grids underlying the global means, are available for some components.For the long-term trend, the budget is closed within uncertainties on the order of 0.3 mm/yr (1 sigma). Moreover, the budget is also closed within uncertainties for interannual variations.

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PISM paleo simulations of the Antarctic Ice Sheet over the last two glacial cycles

10.5194/egusphere-egu2020-15081 ◽

2020 ◽

Author(s):

Torsten Albrecht ◽

Ricarda Winkelmann ◽

Anders Levermann

Keyword(s):

Boundary Conditions ◽

Sea Level ◽

Ice Sheet ◽

Sea Level Changes ◽

Glacial Cycles ◽

Antarctic Ice Sheet ◽

History Of ◽

Global Sea Level ◽

Glacial Time ◽

The Antarctic

Simulations of the glacial-interglacial history of the Antarctic Ice Sheet provide insights into dynamic threshold behavior and estimates of the ice sheet's contributions to global sea-level changes, for the past, present and future. However, boundary conditions are weakly constrained, in particular at the interface of the ice-sheet and the bedrock. We use the Parallel Ice Sheet Model (PISM) to investigate the dynamic effects of different choices of input data and of various parameterizations on the sea-level relevant ice volume. We evaluate the model's transient sensitivity to corresponding parameter choices and to different boundary conditions over the last two glacial cycles and provide estimates of involved uncertainties. We also present isolated and combined effects of climate and sea-level forcing on glacial time scales.&#160;

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Sea level in Thule measured with tide gauge, GNSS-IR and Satellite Altimetry

10.5194/egusphere-egu2020-5077 ◽

2020 ◽

Author(s):

Trine S. Dahl-Jensen ◽

Shfaqat Abbas Khan ◽

Simon D.P. Williams ◽

Ole B. Andersen ◽

Carsten A. Ludwigsen

Keyword(s):

Sea Level ◽

Satellite Altimetry ◽

Tide Gauge ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Sea Level Changes ◽

Level Measurement ◽

Time Period ◽

The Right ◽

Gps Station

Recent studies show that under the right conditions relative sea level can be measured using GNSS interferometric reflectometry (GNSS-IR). We test the possibility of using an existing GNET GPS station in Thule, Greenland, to measure inter annual changes in sea level by comparing sea level measurements from GNSS-IR with tide gauge observations and satellite altimetry data. GNET is a network of 56 permanent GPS stations positioned on the bedrock around the edge fo the Greenland ice sheet with the main purpose of monitoring ice mass changes. Currently, Thule is the only location in Greenland where we have both a tide gauge and a GPS station that is suitable for sea level measurement covering the same time period for more than a couple of years. If successful a number of other GPS stations are also expected to be suitable for GNSS-IR measurements of sea level. However, they lack the tide gauge station for testing. We compare the measured sea level with uplift measured using the GPS and modeled from height changes of the Greenland ice sheet as well as sea surface temperatures and modeled sea level changes from gravimetry, in order to investigate the origin of sea level changes in the region. &#160; &#160;

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Appraisal of the Future Climate of the Holocene in the Rocky Mountains

Quaternary Research ◽

10.1016/0033-5894(72)90051-8 ◽

1972 ◽

Vol 2 (3) ◽

pp. 315-322 ◽

Cited By ~ 7

Author(s):

Gerald M. Richmond

Keyword(s):

Sea Level ◽

Rocky Mountains ◽

Future Climate ◽

Sea Level Changes ◽

Holocene Climate ◽

The Holocene ◽

The Past ◽

The Future ◽

History Of ◽

Climatic History

Consideration of the history of Holocene climate in the Rocky Mountains indicates that the over-all trend during the past 2500 yr has been toward increasing warmth, interrupted by cooler times of minor advances of cirque glaciers. Comparison of Holocene climatic history with the record of past interglacials in the region suggests that the present interglacial is not complete and that the climate may become first warmer and subsequently wetter before it is completed. Correlation of the timing of the regional glacial-interglacial record for the past 140,000 yr with the record of major sea level changes and with the calculated changes in the earth's insolation suggest that the present interglacial may be completed within a few millenia and that it may be followed by a significant cooling of the climate.

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Regional Sea Level Changes for the Twentieth and the Twenty-First Centuries Induced by the Regional Variability in Greenland Ice Sheet Surface Mass Loss

Journal of Climate ◽

10.1175/jcli-d-16-0337.1 ◽

2017 ◽

Vol 30 (6) ◽

pp. 2011-2028 ◽

Cited By ~ 10

Author(s):

B. Meyssignac ◽

X. Fettweis ◽

R. Chevrier ◽

G. Spada

Keyword(s):

Sea Level ◽

Climate Model ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Northern Coast ◽

Sea Level Changes ◽

Regional Variability ◽

Relative Sea Level ◽

Surface Mass ◽

Regional Sea Level

Abstract Surface mass balance (SMB) variations of the Greenland ice sheet (GrIS) have been identified as an important contributor to contemporary and projected global mean sea level variations, but their impact on the regional sea level change pattern is still poorly known. This study proposes estimates of GrIS SMB over 1900–2100 based on the output of 32 atmosphere–ocean general circulation models and Earth system models involved in phase 5 of the Climate Model Intercomparison Project (CMIP5). It is based on a downscaling technique calibrated against the Modèle Atmosphérique Régional (MAR) regional climate model and it provides an ensemble of 32 Greenland SMB estimates for each Greenland major drainage basin. Because the GrIS SMB does not respond uniformly to greenhouse gas (GHG) emissions, the southern part of the GrIS is more sensitive to climate warming. This study shows that this part should be in imbalance in the twenty-first century sooner than the northern part. This regional variability significantly affects the associated relative sea level pattern over the entire ocean and particularly along the U.S. East Coast and the northern coast of Europe. This highlights the necessity of taking into account GrIS regional SMB changes to evaluate accurately relative sea level changes in future projections.

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Late Holocene relative sea level rise and the Neoglacial history of the Greenland ice sheet

Journal of Quaternary Science ◽

10.1002/jqs.1235 ◽

2009 ◽

Vol 24 (4) ◽

pp. 345-359 ◽

Cited By ~ 30

Author(s):

Antony J. Long ◽

Sarah A. Woodroffe ◽

Sue Dawson ◽

David H. Roberts ◽

Charlotte L. Bryant

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Late Holocene ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Relative Sea Level ◽

Relative Sea Level Rise ◽

History Of

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Evidence for a Former Large Ice Sheet in the Orville Coast–Ronne Ice Shelf Area, Antarctica

Journal of Glaciology ◽

10.3189/s0022143000011527 ◽

1981 ◽

Vol 27 (97) ◽

pp. 487-491

Author(s):

Paul Carrara

Keyword(s):

Sea Level ◽

Ross Sea ◽

Ice Sheet ◽

Shelf Area ◽

Sea Level Changes ◽

Ice Shelf ◽

The Past ◽

The World ◽

History Of ◽

The Antarctic

AbstractThe Orville Coast area of the Antarctic Peninsula was extensively glacierized in the past. Striations, polished rock surfaces, and erratics on nunatak summits indicate that this area was covered by a broad regional ice sheet whose grounded ice margin was on the continental shelf, in the present-day Ronne Ice Shelf area. If the glacial history of Antarctica has been controlled by eustatic sea-level changes, the destruction of this ice sheet would have been contemporaneous with that of the Ross Sea ice sheet due to the world-wide rise of eustatic sea-level at the end of the Wisconsin glaciation.

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