Sea-level proxies in Holocene raised beach ridge deposits (Greenland) revealed by ground-penetrating radar.

Science.gov (United States)

Nielsen, Lars; Bendixen, Mette; Kroon, Aart; Hede, Mikkel Ulfeldt; Clemmensen, Lars B; Weβling, Ronny; Elberling, Bo

2017-04-19

Identification of sea-level proxies is important for reconstruction of past sea-level variation. Methods for reconstructing Holocene relative sea-level curves are crucial for quantification of the impact of Greenland ice thickness variation on global sea level and vertical land movement. Arctic beach ridges constitute important potential archives of sea-level variation. However, their surface morphology may have undergone modification since deposition due to freezing/thawing processes and erosion, and their morphology may therefore not be trustworthy for sea-level reconstruction. Therefore, geophysical imaging is used to examine the internal structures of the beach ridges and to define a sea-level proxy unaffected by surface processes. The GPR reflections from study sites in West and South Greenland show deposition of beachface deposits and upper shoreface deposits; the contact between steeply dipping beachface reflections and less-dipping shoreface reflections is used as sea-level proxy. Numerous points are identified along GPR transects facilitating reconstruction of relative sea-level variation of hitherto unprecedented resolution. Erosional events and deformation caused by freezing/thawing processes are clearly delineated. The approach constitutes a solid base for reconstruction of relative sea-level curves affected by a well-defined vertical land movement history since the studied beach ridge systems represent long time intervals and only relatively small spatial extents.

Sea ice and primary production proxies in surface sediments from a High Arctic Greenland fjord

DEFF Research Database (Denmark)

Ribeiro, Sofia; Sejr, Mikael K; Limoges, Audrey

2017-01-01

Monitoring Programme. Clear spatial gradients in organic carbon and biogenic silica contents reflected marine influence, nutrient availability and river-induced turbidity, in good agreement with in situ measurements. The sea ice proxy IP25 was detected at all sites but at low concentrations, indicating...... that IP25 records from fjords need to be carefully considered and not directly compared to marine settings. The sea ice-associated biomarker HBI III revealed an open-water signature, with highest concentrations near the mid-July ice edge. This proxy evaluation is an important step towards reliable......In order to establish a baseline for proxy-based reconstructions for the Young Sound–Tyrolerfjord system (Northeast Greenland), we analysed the spatial distribution of primary production and sea ice proxies in surface sediments from the fjord, against monitoring data from the Greenland Ecosystem...

Greenland climate change

DEFF Research Database (Denmark)

Masson-Delmotte, Valérie; Swingedouw, Didier; Landais, Amaëlle

2012-01-01

Climate archives available from deep-sea and marine shelf sediments, glaciers, lakes and ice cores in and around Greenland allow us to place the current trends in regional climate, ice sheet dynamics, and land surface changes in a broader perspective. We show that during the last decade (2000s......), atmospheric and sea-surface temperatures are reaching levels last encountered millennia ago when northern high latitude summer insolation was higher due to a different orbital configuration. Concurrently, records from lake sediments in southern Greenland document major environmental and climatic conditions...... regional climate and ice sheet dynamics. The magnitude and rate of future changes in Greenland temperature, in response to increasing greenhouse gas emissions, may be faster than any past abrupt events occurring under interglacial conditions. Projections indicate that within one century Greenland may...

Temporal and spatial variations of oceanic pCO2 and air-sea CO2 flux in th Greenland Sea and the Barents Sea

International Nuclear Information System (INIS)

Nakaoka, Shin-Ichiro; Aoki, Shuji; Nakazawa, Takakiyo; Yoshikawa-Inoue, Hisayuki

2006-01-01

In order to elucidate the seasonal and inter annual variations of oceanic CO 2 uptake in the Greenland Sea and the Barents Sea, the partial pressure of CO 2 in the surface ocean (pCO 2 sea ) was measured in all seasons between 1992 and 2001. We derived monthly varying relationships between pCO 2 sea and sea surface temperature (SST) and combined them with the SST data from the NCEP/NCAR reanalysis to determine pCO 2 sea and air-sea CO 2 flux in these seas. The pCO 2 sea values were normalized to the year 1995 by assuming that pCO 2 sea increased at the same growth rate (1.5 μatm/yr) of the pCO 2 in the air (pCO 2 air ) between 1992 and 2001. In 1995, the annual net air-sea CO 2 fluxes were evaluated to be 52 ± 20 gC/m 2 /yr in the Greenland Sea and 46 ± 18 gC/m 2 /yr in the Barents Sea. The CO 2 flux into the ocean reached its maximum in winter and minimum in summer. The wind speed and (delta)pCO 2 (=pCO 2 air -pCO 2 sea ) exerted a greater influence on the seasonal variation than the sea ice coverage. The annual CO 2 uptake examined in this study (70-80 deg N, 20 deg W-40 deg E) was estimated to be 0.050 ± 0.020 GtC/yr in 1995. The inter annual variation in the annual CO 2 uptake was found to be positively correlated with the North Atlantic Oscillation Index (NAOI) via wind strength but negatively correlated with (delta)pCO 2 and the sea ice coverage. The present results indicate that the variability in wind speed and sea ice coverage play a major role, while that in (delta)pCO 2 plays a minor role, in determining the interannual variation of CO 2 uptake in this area

Uranium and plutonium containing particles in a sea sediment sample from Thule, Greenland

DEFF Research Database (Denmark)

Moring, M.; Ikäheimonen, T.K.; Pöllänen, R.

2001-01-01

Particles composed of radioactive materials and probably originating from US nuclear weapons were identified in sea sediment samples collected from Thule, Greenland in 1997. The weapons were destroyed close to the Thule Air Base in 1968 in an aeroplane crash, which dispersed radioactive materials...

Isotopes in Greenland Precipitation

DEFF Research Database (Denmark)

Faber, Anne-Katrine

Greenland ice cores offer a unique opportunity to investigate the climate system behaviour. The objective of this PhD project is to investigate isotope modelling of present- day conditions and conduct model-data comparison using Greenland ice cores. Thus this thesis investigates how the integration...... of model and data can be used to improve the understanding of climate changes. This is done through analysis of isotope modelling, observations and ice core measurements. This dissertation comprises three projects: (1) Modelling the isotopic response to changes in Arctic sea surface conditions, (2......) Constructing a new Greenland database of observations and present-day ice core measurements, and (3) Performance test of isotope-enabled CAM5 for Greenland. The recent decades of rapid Arctic sea ice decline are used as a basis for an observational-based model experiment using the isotope-enabled CAM model 3...

Photobiology of sea ice algae during initial spring growth in Kangerlussuaq, West Greenland

DEFF Research Database (Denmark)

Hawes, Ian; Lund-Hansen, Lars Chresten; Sorrell, Brian Keith

2012-01-01

We undertook a series of measurements of photophysiological parameters of sea ice algae over 12 days of early spring growth in a West Greenland Fjord, by variable chlorophyll fluorescence imaging. Imaging of the ice–water interface showed the development of ice algae in 0.3–0.4 mm wide brine...

Sea-ice thickness from airborne laser altimetry over the Arctic Ocean north of Greenland

DEFF Research Database (Denmark)

Hvidegaard, Sine Munk; Forsberg, René

2002-01-01

We present a new method to measure ice thickness of polar sea-ice freeboard heights, using airborne laser altimetry combined with a precise geoid model, giving estimates of thickness of ice through isostatic equilibrium assumptions. In the paper we analyze a number of flights from the Polar Sea off...... Northern Greenland, and estimate accuracies of the estimated freeboard values to be at a 13 cm level, corresponding to about 1 m in absolute thickness....

Zonal surface wind jets across the Red Sea due to mountain gap forcing along both sides of the Red Sea

KAUST Repository

Jiang, Houshuo

2009-01-01

[1] Mesoscale atmospheric modeling over the Red Sea, validated by in-situ meteorological buoy data, identifies two types of coastal mountain gap wind jets that frequently blow across the longitudinal axis of the Red Sea: (1) an eastward-blowing summer daily wind jet originating from the Tokar Gap on the Sudanese Red Sea coast, and (2) wintertime westward-blowing wind-jet bands along the northwestern Saudi Arabian coast, which occur every 10-20 days and can last for several days when occurring. Both wind jets can attain wind speeds over 15 m s-1 and contribute significantly to monthly mean surface wind stress, especially in the cross-axis components, which could be of importance to ocean eddy formation in the Red Sea. The wintertime wind jets can cause significant evaporation and ocean heat loss along the northeastern Red Sea coast and may potentially drive deep convection in that region. An initial characterization of these wind jets is presented. Copyright 2009 by the American Geophysical Union.

Simulated interannual variability of the Greenland Sea deep water formation and its connection to surface forcing

Science.gov (United States)

Haekkinen, Sirpa

1995-01-01

A fully prognostic Arctic ice-ocean model is used to study the interannual variability of deepwater formation in the Greenland Sea Gyre based on the simulations for the Arctic ice-ocean system for the period 1955 and 1960 - 1985. The model uses monthly climatology for thermodynamic forcing components (such as air temperature and cloudiness), together with constant annual net precipitation and river runoff. The daily wind forcing is derived from analyzed sea level air pressures from the National Center for Atmospheric Research (NCAR). In summary, the model shows that the occurence of deep convection in the Greenland Sea Gyre is controlled by the extensive Fram Strait ice export and/or local wind conditions in the Greenland Sea. In the latter case the weakening of the local wind curl allows the Polar Front to move eastward. The movement of the Polar Front causes adverse ice conditions, often together with much larger than normal ice export from the Arctic, such as in 1968, which can block convection in the gyre. The density difference between upper and lower layers is investigated as an indication of water mass formation through convection, occurring as strong diffusion in the model. The model-simulated density difference between the average top 100 m and deep levels reveals that the period 1960 - 1985 had only a few distinct years with weak stratification, and, especially, the model predicts no deep convection since the nid-1970s. The common factor for the years of the weakest decrease of the model-predicted heat content of the upper 2000 m which can, to a high degree, be explained by local heat loss.

A sea ice model for the marginal ice zone with an application to the Greenland Sea

DEFF Research Database (Denmark)

Pedersen, Leif Toudal; Coon, Max D.

2004-01-01

A model is presented that describes the formation, transport, and desalinization of frazil and pancake ice as it is formed in marginal seas. This model uses as input the total ice concentration evaluated from Special Sensor Microwave Imager and wind speed and direction. The model calculates...... the areal concentration, thickness, volume concentration, and salinity of frazil ice as well as the areal concentration, thickness, and salinity of pancakes. A simple parameterization for the Odden region of the Greenland Sea is presented. The model is run for the winter of 1996-1997. There are direct...... observations of the thickness and salinity of pancakes and the volume concentration of frazil ice to compare with the model. The model results compare very well with the measured data. This new ice model can be tuned to work in marginal seas elsewhere to calculate ice thickness, motion, and brine rejection...

How much can Greenland melt? An upper bound on mass loss from the Greenland Ice Sheet through surface melting

Science.gov (United States)

Liu, X.; Bassis, J. N.

2015-12-01

With observations showing accelerated mass loss from the Greenland Ice Sheet due to surface melt, the Greenland Ice Sheet is becoming one of the most significant contributors to sea level rise. The contribution of the Greenland Ice Sheet o sea level rise is likely to accelerate in the coming decade and centuries as atmospheric temperatures continue to rise, potentially triggering ever larger surface melt rates. However, at present considerable uncertainty remains in projecting the contribution to sea level of the Greenland Ice Sheet both due to uncertainty in atmospheric forcing and the ice sheet response to climate forcing. Here we seek an upper bound on the contribution of surface melt from the Greenland to sea level rise in the coming century using a surface energy balance model coupled to an englacial model. We use IPCC Representative Concentration Pathways (RCP8.5, RCP6, RCP4.5, RCP2.6) climate scenarios from an ensemble of global climate models in our simulations to project the maximum rate of ice volume loss and related sea-level rise associated with surface melting. To estimate the upper bound, we assume the Greenland Ice Sheet is perpetually covered in thick clouds, which maximize longwave radiation to the ice sheet. We further assume that deposition of black carbon darkens the ice substantially turning it nearly black, substantially reducing its albedo. Although assuming that all melt water not stored in the snow/firn is instantaneously transported off the ice sheet increases mass loss in the short term, refreezing of retained water warms the ice and may lead to more melt in the long term. Hence we examine both assumptions and use the scenario that leads to the most surface melt by 2100. Preliminary models results suggest that under the most aggressive climate forcing, surface melt from the Greenland Ice Sheet contributes ~1 m to sea level by the year 2100. This is a significant contribution and ignores dynamic effects. We also examined a lower bound

Greenland plays a large role in the gloomy picture painted of probable future sea-level rise

Science.gov (United States)

Hanna, Edward

2012-12-01

Goelzer et al (2012) paint a portentous picture of what is likely to happen to the global sea-level over the next 1000 years. This worrying assessment is based on our current best understanding of how the world's giant ice sheets of Greenland and Antarctica, as well as a quarter of a million smaller glacial ice masses, and the ocean collectively respond to ongoing climate change. Theirs is a state of the science study that integrates these key contributors of sea-level change based on the latest models and current understanding, and an integrated Earth systems modelling approach termed LOVECLIM. As they point out in their study, only a handful of global climate models to date—i.e. models that are used to make predictions of future climate change—incorporate dynamically (fully) coupled ice-sheet models. According to the scenarios presented by Goelzer et al (2012), we could see between 2.1 and 6.8 m of global sea-level rise by 3000 AD, compared with 'just' 1.1 m if the atmosphere is stabilised at 2000 CO2 levels. Much, up to some 4 m, of this contribution comes from increased melting and mass loss of the Greenland ice sheet, which is several times more sensitive than the Antarctic ice sheet to warming temperatures in these simulations. Interestingly, dynamical ice mass losses through iceberg calving become increasingly less significant for Greenland as the ice sheet retreats further inland during the 1000 yr runs (Sole et al 2008). The latest modelling studies show that around a half, perhaps more, of the recent Greenland mass losses (Barletta et al 2012, Rignot et al 2011) are already through increased melt and runoff (Hanna et al 2008, 2012, van den Broeke et al 2009); note also the recent (summer 2012) record surface melting of the Greenland ice sheet (Nghiem et al 2012) caused by atmospheric forcing (Overland et al 2012) and the potential of such events to impact on ice flow (Bartholomew et al 2011). By contrast, the greatest sea-level rise reported for

Climate variability in West Greenland during the past 1500 years

DEFF Research Database (Denmark)

dos Santos Ribeiro, Sofia Isabel; Moros, Matthias; Ellegaard, Marianne

2012-01-01

-surface temperatures in Disko Bay are out-of-phase with Greenland ice-core reconstructed temperatures and marine proxy data from South and East Greenland. This is probably governed by an NAO-type pattern, which results in warmer sea-surface conditions with less extensive sea ice in the area for the later part....... Sea ice cover and primary productivity were identified as the two main factors driving dinoflagellate cyst community changes through time. Our data provide evidence for an opposite climate trend in West Greenland relative to the NE Atlantic region from c. AD 500 to 1050. For the same period, sea...

Environmental radioactivity in Greenland in 1974

International Nuclear Information System (INIS)

Aarkrog, A.; Lippert, J.

1975-07-01

Measurements of fall-out radioactivity in Greenland in 1974 are reported. Strontium 90 (and Caesium-137 in most cases) was determined in samples of precipitation, sea water, vegetation, animals, and drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in the human diet in Greenland in 1974. Three Greenlanders were measured by wholebody counting. (author)

Lead sources in human diet in Greenland

DEFF Research Database (Denmark)

Bjerregaard, Peter; Johansen, Poul; Mulvad, Gert

2004-01-01

Although blood lead levels have declined in Greenland, they are still elevated despite the fact that lead levels in the Greenland environment are very low. Fragments of lead shot in game birds have been suggested as an important source of dietary exposure, and meals of sea birds, particularly eider......, contain high concentrations of lead. In a cross-sectional population survey in Greenland in 1993-1994, blood lead adjusted for age and sex was found to be associated with the reported consumption of sea birds. Participants reporting less than weekly intake of sea birds had blood lead concentrations...... of approximately 75 microg/L, whereas those who reported eating sea birds several times a week had concentrations of approximately 110 microg/L, and those who reported daily intake had concentrations of 170 microg/L (p = 0.01). Blood lead was not associated with dietary exposure to other local or imported food...

Marginal thinning in Northwest Greenland during 2002-2011

DEFF Research Database (Denmark)

Khan, Shfaqat Abbas; Kjær, K. H.; Wahr, J. M.

2012-01-01

Many glaciers along the southeast and northwest coast of Greenland have accelerated, increasing the Greenland ice sheet's (GrIS) contribution to global sea-level rise. Here, we map elevation changes in northwest Greenland during 2003-2009 using high-resolution Ice, Cloud and land Elevation Satell...

Arctic Ocean outflow and glacier-ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

DEFF Research Database (Denmark)

Dmitrenko, Igor A.; Kirillov, Sergey A.; Rudels, Bert

2017-01-01

The first-ever conductivity-temperature-depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April-May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014-2015 drift. The CTD profiles are used to reveal...

Greenland uplift and regional sea level changes from ICESat observations and GIA modelling

DEFF Research Database (Denmark)

Spada, G.; Ruggieri, G.; Sørensen, Louise Sandberg

2012-01-01

‐resolution GrIS mass balance, we study the time‐variations of various geophysical quantities in response to the current mass loss. They include vertical uplift and subsidence, geoid height variations, global patterns of sea level change (or fingerprints), and regional sea level variations along the coasts...... of Greenland. Long‐wavelength uplifts and gravity variations in response to current or past ice thickness variations are obtained solving the sea level equation, which accounts for both the elastic and the viscoelastic components of deformation. To capture the short‐wavelength components of vertical uplift...... in response to current ice mass loss, which is not resolved by satellite gravity observations, we have specifically developed a high‐resolution regional elastic rebound (ER) model. The elastic component of vertical uplift is combined with estimates of the viscoelastic displacement fields associated...

Movements of female polar bears (Usrus maritimus) in the East Greenland pack ice

DEFF Research Database (Denmark)

Wiig, Øystein; Born, Erik W.; Pedersen, Leif Toudal

2003-01-01

The movements of two adult female polar bears (Ursus maritimus) in East Greenland and the Greenland Sea area were studied by use of satellite telemetry between the fall of 1994 and the summer of 1998. One female was tracked for 621 days, the other for 1,415 days. During this time the females used...... for a closer monitoring of the effects of this change on the East Greenland polar bear population....... movement rates varied between 0.32 and 0.76km/h. Both bears had very large home ranges (242,000 and 468,000 km(2)) within the dynamic pack ice of the Greenland Sea. The facts that the bears made extensive use of the offshore sea ice and that there is a marked reduction of the Greenland Sea ice call...

Environmental radioactivity in Greenland 1977

International Nuclear Information System (INIS)

Aarkrog, A.; Lippert, J.

1978-07-01

Measurements of fallout radioactivity in Greenland in 1977 are reported. Strontium-90 (and Cesium-137 in most cases) was determined in samples of precipitation, sea water, vegetation, animals, and drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in the human diet in Greenland in 1977. (author)

Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from JOHAN HJORT in the Barents Sea, North Greenland Sea and Norwegian Sea from 2000-05-27 to 2000-06-20 (NODC Accession 0115683)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0115683 includes biological, chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the Barents Sea, North Greenland Sea...

Frost flowers and sea-salt aerosols over seasonal sea-ice areas in northwestern Greenland during winter–spring

Directory of Open Access Journals (Sweden)

K. Hara

2017-07-01

Full Text Available Sea salts and halogens in aerosols, frost flowers, and brine play an important role in atmospheric chemistry in polar regions. Simultaneous sampling and observations of frost flowers, brine, and aerosol particles were conducted around Siorapaluk in northwestern Greenland during December 2013 to March 2014. Results show that water-soluble frost flower and brine components are sea-salt components (e.g., Na+, Cl−, Mg2+, K+, Ca2+, Br−, and iodine. Concentration factors of sea-salt components of frost flowers and brine relative to seawater were 1.14–3.67. Sea-salt enrichment of Mg2+, K+, Ca2+, and halogens (Cl−, Br−, and iodine in frost flowers is associated with sea-salt fractionation by precipitation of mirabilite and hydrohalite. High aerosol number concentrations correspond to the occurrence of higher abundance of sea-salt particles in both coarse and fine modes, and blowing snow and strong winds. Aerosol number concentrations, particularly in coarse mode, are increased considerably by release from the sea-ice surface under strong wind conditions. Sulfate depletion by sea-salt fractionation was found to be limited in sea-salt aerosols because of the presence of non-sea-salt (NSS SO42−. However, coarse and fine sea-salt particles were found to be rich in Mg. Strong Mg enrichment might be more likely to proceed in fine sea-salt particles. Magnesium-rich sea-salt particles might be released from the surface of snow and slush layer (brine on sea ice and frost flowers. Mirabilite-like and ikaite-like particles were identified only in aerosol samples collected near new sea-ice areas. From the field evidence and results from earlier studies, we propose and describe sea-salt cycles in seasonal sea-ice areas.

Frost flowers and sea-salt aerosols over seasonal sea-ice areas in northwestern Greenland during winter-spring

Science.gov (United States)

Hara, Keiichiro; Matoba, Sumito; Hirabayashi, Motohiro; Yamasaki, Tetsuhide

2017-07-01

Sea salts and halogens in aerosols, frost flowers, and brine play an important role in atmospheric chemistry in polar regions. Simultaneous sampling and observations of frost flowers, brine, and aerosol particles were conducted around Siorapaluk in northwestern Greenland during December 2013 to March 2014. Results show that water-soluble frost flower and brine components are sea-salt components (e.g., Na+, Cl-, Mg2+, K+, Ca2+, Br-, and iodine). Concentration factors of sea-salt components of frost flowers and brine relative to seawater were 1.14-3.67. Sea-salt enrichment of Mg2+, K+, Ca2+, and halogens (Cl-, Br-, and iodine) in frost flowers is associated with sea-salt fractionation by precipitation of mirabilite and hydrohalite. High aerosol number concentrations correspond to the occurrence of higher abundance of sea-salt particles in both coarse and fine modes, and blowing snow and strong winds. Aerosol number concentrations, particularly in coarse mode, are increased considerably by release from the sea-ice surface under strong wind conditions. Sulfate depletion by sea-salt fractionation was found to be limited in sea-salt aerosols because of the presence of non-sea-salt (NSS) SO42-. However, coarse and fine sea-salt particles were found to be rich in Mg. Strong Mg enrichment might be more likely to proceed in fine sea-salt particles. Magnesium-rich sea-salt particles might be released from the surface of snow and slush layer (brine) on sea ice and frost flowers. Mirabilite-like and ikaite-like particles were identified only in aerosol samples collected near new sea-ice areas. From the field evidence and results from earlier studies, we propose and describe sea-salt cycles in seasonal sea-ice areas.

Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the Barents Sea, North Greenland Sea and Norwegian Sea from 1999-06-15 to 1999-07-07 (NODC Accession 0115678)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115678 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the Barents Sea, North Greenland Sea and Norwegian...

Measurement of spectral sea ice albedo at Qaanaaq fjord in northwest Greenland

Science.gov (United States)

Tanikawa, T.

2017-12-01

The spectral albedos of sea ice were measured at Qaanaaq fjord in northwest Greenland. Spectral measurements were conducted for sea ice covered with snow and sea ice without snow where snow was artificially removed around measurement point. Thickness of the sea ice was approximately 1.3 m with 5 cm of snow over the sea ice. The measurements show that the spectral albedos of the sea ice with snow were lower than those of natural pure snow especially in the visible regions though the spectral shapes were similar to each other. This is because the spectral albedos in the visible region have information of not only the snow but also the sea ice under the snow. The spectral albedos of the sea ice without the snow were approximately 0.4 - 0.5 in the visible region, 0.05-0.25 in the near-infrared region and almost constant of approximately 0.05 in the region of 1500 - 2500 nm. In the visible region, it would be due to multiple scattering by an air bubble within the sea ice. In contrast, in the near-infrared and shortwave infrared wavelengths, surface reflection at the sea ice surface would be dominant. Since a light absorption by the ice in these regions is relatively strong comparing to the visible region, the light could not be penetrated deeply within the sea ice, resulting that surface reflection based on Fresnel reflection would be dominant. In this presentation we also show the results of comparison between the radiative transfer calculation and spectral measurement data.

Modelling Greenland icebergs

Science.gov (United States)

Marson, Juliana M.; Myers, Paul G.; Hu, Xianmin

2017-04-01

The Atlantic Meridional Overturning Circulation (AMOC) is well known for carrying heat from low to high latitudes, moderating local temperatures. Numerical studies have examined the AMOC's variability under the influence of freshwater input to subduction and deep convections sites. However, an important source of freshwater has often been overlooked or misrepresented: icebergs. While liquid runoff decreases the ocean salinity near the coast, icebergs are a gradual and remote source of freshwater - a difference that affects sea ice cover, temperature, and salinity distribution in ocean models. Icebergs originated from the Greenland ice sheet, in particular, can affect the subduction process in Labrador Sea by decreasing surface water density. Our study aims to evaluate the distribution of icebergs originated from Greenland and their contribution to freshwater input in the North Atlantic. To do that, we use an interactive iceberg module coupled with the Nucleus for European Modelling of the Ocean (NEMO v3.4), which will calve icebergs from Greenland according to rates established by Bamber et al. (2012). Details on the distribution and trajectory of icebergs within the model may also be of use for understanding potential navigation threats, as shipping increases in northern waters.

East Greenland and Barents Sea polar bears (Ursus maritimus): adaptive variation between two populations using skull morphometrics as an indicator of environmental and genetic differences.

Science.gov (United States)

Pertoldi, Cino; Sonne, Christian; Wiig, Øystein; Baagøe, Hans J; Loeschcke, Volker; Bechshøft, Thea Østergaard

2012-06-01

A morphometric study was conducted on four skull traits of 37 male and 18 female adult East Greenland polar bears (Ursus maritimus) collected 1892-1968, and on 54 male and 44 female adult Barents Sea polar bears collected 1950-1969. The aim was to compare differences in size and shape of the bear skulls using a multivariate approach, characterizing the variation between the two populations using morphometric traits as an indicator of environmental and genetic differences. Mixture analysis testing for geographic differentiation within each population revealed three clusters for Barents Sea males and three clusters for Barents Sea females. East Greenland consisted of one female and one male cluster. A principal component analysis (PCA) conducted on the clusters defined by the mixture analysis, showed that East Greenland and Barents Sea polar bear populations overlapped to a large degree, especially with regards to females. Multivariate analyses of variance (MANOVA) showed no significant differences in morphometric means between the two populations, but differences were detected between clusters from each respective geographic locality. To estimate the importance of genetics and environment in the morphometric differences between the bears, a PCA was performed on the covariance matrix derived from the skull measurements. Skull trait size (PC1) explained approx. 80% of the morphometric variation, whereas shape (PC2) defined approx. 15%, indicating some genetic differentiation. Hence, both environmental and genetic factors seem to have contributed to the observed skull differences between the two populations. Overall, results indicate that many Barents Sea polar bears are morphometrically similar to the East Greenland ones, suggesting an exchange of individuals between the two populations. Furthermore, a subpopulation structure in the Barents Sea population was also indicated from the present analyses, which should be considered with regards to future management

Environmental radioactivity in Greenland in 1976

International Nuclear Information System (INIS)

Aarkrog, A.; Lippert, J.

1977-07-01

Measurements of fall-out radioactivity in Greenland in 1976 are reported. Strontium-90 (and Caesium-137 in most cases) was determined in samples of precipitation, sea water, vegetation, animals, and drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in the human diet in Greenland in 1976. (author)

Environmental radioactivity in Greenland in 1975

International Nuclear Information System (INIS)

Aarkrog, A.; Lippert, J.

1976-07-01

Measuremtns of fall-out radioactivity in Greenland in 1975 are reported. Strontium-90 (and Caesium-137 in most cases) was determined in samples of precipitation, sea water, vegetation, animals, and drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in the human diet in Greenland in 1975. (author)

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HAKON MOSBY in the Barents Sea, North Greenland Sea and Norwegian Sea from 1999-10-03 to 1999-10-11 (NODC Accession 0113888)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113888 includes chemical, discrete sample, physical and profile data collected from HAKON MOSBY in the Barents Sea, North Greenland Sea and Norwegian...

Environmental radioactivity in the North Atlantic region including the Faroe Islands and Greenland

International Nuclear Information System (INIS)

Aarkrog, A.; Chen, Q.J.; Dahlgaard, H.; Hansen, H.; Nielsen, S.P.; Buch, E.; Christensen, G.C.; Holm, E.

1992-01-01

Measurements of fallout radioactivity in the North Atlantic region including the Faroe Islands and Greenland are reported. Strontium-90, cesium-137 and cesium-134 were determined in samples of precipitation, sea water, vegetation, various foodstuffs (including milk in the Faroes), and drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in human diet in the Faroes and Greenland in 1988 and 1989. 99 Tc data on marine samples, in particular sea water from the Greenland Sea, are reported. (au) (91 taps., 51 ills., 7 refs.)

Classification of new-ice in the Greenland Sea using Satellite SSM/I radiometer and SeaWinds scatterometer data and comparison with ice model

DEFF Research Database (Denmark)

Tonboe, Rasmus; Pedersen, Leif Toudal

2005-01-01

In the ice covered waters of the Greenland Sea the polarisation ratio of QuikSCAT SeaWinds Ku-band (13.4 GHz) scatterometer measurements and the polarisation ratio of DMSP-SSM/I 19 GHz radiometer measurements are used in combination to classify new-ice and mature ice. In particular, the formation...... to the physical transition of the ice cover from pancake ice to a consolidated young-ice sheet. The classification of each pixel into ice or water is done using two scatterometer parameters, namely the polarisation ratio and the daily standard deviation of the backscatter. (C) 2005 Elsevier Inc. All rights...

Environmental radioactivity in Greenland in 1981

International Nuclear Information System (INIS)

Aarkrog, A.; Dahlgaard, H.; Hansen, H.; Lippert, J.; Nilsson, K.; Holm, E.

1982-07-01

Measurements of fallout radioactivity in Greenland in 1981 are reported. Strontium-90 (and Cesium-137 in most cases) was determined in samples of precipitation, sea water, vegetation, animals, and drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in the human diet in Greenland in 1981. Further results of the 239 , 240 Pu and 241 Am measurements on samples from the expedition to Thule in August 1979 are prsented. Brown algae collected in East Greenland in 1969 were analysed for Pu and Am. (author)

MIS-11 duration key to disappearance of the Greenland ice sheet

Science.gov (United States)

Robinson, Alexander; Alvarez-Solas, Jorge; Calov, Reinhard; Ganopolski, Andrey; Montoya, Marisa

2017-07-01

Palaeo data suggest that Greenland must have been largely ice free during Marine Isotope Stage 11 (MIS-11). However, regional summer insolation anomalies were modest during this time compared to MIS-5e, when the Greenland ice sheet likely lost less volume. Thus it remains unclear how such conditions led to an almost complete disappearance of the ice sheet. Here we use transient climate-ice sheet simulations to simultaneously constrain estimates of regional temperature anomalies and Greenland's contribution to the MIS-11 sea-level highstand. We find that Greenland contributed 6.1 m (3.9-7.0 m, 95% credible interval) to sea level, ~7 kyr after the peak in regional summer temperature anomalies of 2.8 °C (2.1-3.4 °C). The moderate warming produced a mean rate of mass loss in sea-level equivalent of only around 0.4 m per kyr, which means the long duration of MIS-11 interglacial conditions around Greenland was a necessary condition for the ice sheet to disappear almost completely.

Environmental radioactivity in Greenland in 1978

International Nuclear Information System (INIS)

Aarkrog, A.; Hansen, H.; Lippert, J.

1979-07-01

Measurements of fallout radioactivity in Greenland in 1978 are reported. Strontium-90 (and Cesium-137 in most cases) was determined in samples of precipitation, sea water, vegetation, animals, and drinking water. Tritium was determined in samples of drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in the human diet in Greenland in 1978. (author)

Geophysical survey of the Eggvin Bank and Logi Ridge - Greenland Sea

Science.gov (United States)

Breivik, A. J.; Mjelde, R.; Rai, A. K.; Frassetto, A.

2012-12-01

The northern Greenland Sea has a number of features associated with excess volcanism. These include the Jan Mayen island, the Jan Mayen Plateau north of, and the Eggvin Bank west of Jan Mayen, and the Vesteris Seamount far to the north. In the summer of 2011, we colleced an Ocean Bottom Seismometer (OBS) profile across the Eggvin Bank, returning four good data sets. We also collected single-channel reflection seismic (SCS) data along the OBS line. The profile crosses the transform part of the West Jan Mayen Fracture Zone (WJMFZ), which connects seafloor spreading between the Kolbeinsey and Mohn ridges. Between the WJMFZ and the Vesteris Seamount there is a narrow ridge 170-180 km long, ending in a few seamounts in the east. It disturbs the magnetic seafloor anomalies, and has no conjugate on the Norwegian margin. It thus appears to be younger than the Eocene seafloor it lies on. Trend and position points to Traill Ø in East Greenland, which had magmatism at ~36 Ma. We name it the Logi Ridge after Norse mythology, where Logi is the master of fire, brother of Aegir, master of the sea. We have collected five SCS profiles across this ridge in order to study the surrounding sedimentation pattern. We also collected gravity and magnetic data along all profiles. Initial results show two flat-topped seamounts on the Eggvin Bank, and a flat-topped Logi Ridge, indicating that these have been at sealevel. The sedimentary strata show recent vertical movement north of the WJMFZ near the Jan Mayen Plateau, and compression around the Logi Ridge. Sailing line of R/V Håkon Mosby of Bergen. Survey lines are in bold, and OBS positions are marked by circles.

Radiocaesium (137Cs) in marine mammals from Svalbard, the Barents Sea and the North Greenland Sea

International Nuclear Information System (INIS)

Andersen, Magnus; Gwynn, Justin P.; Dowdall, Mark; Kovacs, Kit M.; Lydersen, Christian

2006-01-01

Specific activities of the anthropogenic radionuclide, 137 Cs, were determined in marine mammals from Svalbard and the Barents and North Greenland Seas. Muscle samples were collected from 12 polar bears, 15 ringed seals, 10 hooded seals, 7 bearded seals, 14 harp seals, one walrus, one white whale and one blue whale in the period 2000-2003. The mean concentrations (± SD) of 137 Cs were: 0.72 ± 0.62 Bq/kg wet weight (w.w.) for polar bears; 0.49 ± 0.07 Bq/kg w.w. for ringed seals; 0.25 ± 0.10 Bq/kg w.w. for hooded seals; 0.22 ± 0.11 Bq/kg w.w. for bearded seals; 0.36 ± 0.13 Bq/kg w.w. for harp seals; 0.67 Bq/kg w.w. for the white whale sample; 0.24 Bq/kg w.w. for the blue whale; and below detection limit for the walrus. Significant differences in 137 Cs specific activities between some of the species were found. Ringed seals had higher specific activities than the other seal species in the study. Bearded seals and hooded seals had similar values, which were both significantly lower than the harp seal values. The results in the present study are consistent with previous reported results, indicating low specific activities of 137 Cs in Arctic marine mammals in the Barents Sea and Greenland Sea region during the last 20 years. The species specific differences found may be explained by varying diet or movement and distribution patterns between species. No age related patterns were found in specific activities for the two species (polar bears and hooded seals) for which sufficient data was available. Concentration factors (CF) of 137 Cs from seawater were determined for polar bears, ringed, bearded, harp and hooded seals. Mean CF values ranged from 79 ± 32 (SD) for bearded seals sampled in 2002 to 244 ± 36 (SD) for ringed seals sampled in 2003 these CF values are higher than those reported for fish and benthic organisms in the literature, suggesting bioaccumulation of 137 Cs in the marine ecosystem

Greenland, my greenland

DEFF Research Database (Denmark)

Andersen, Astrid

2016-01-01

In 2012, Visit Greenland, the Greenlandic national tourist organisation, conducted a survey on Danish prejudices towards Greenland and Greenlanders. The survey, linked to an ambivalent nation-building strategy that pitched Greenland as ‘the pioneering nation’, was aimed both at challenging...... tourist audience more concerned with preserving whales than with accepting the sustainable visions of indigenous modernity that are currently being articulated by Greenlanders. Contemporary Greenlandic nation branding is a response to these internal and external dichotomies....

Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the Barents Sea, North Greenland Sea and Norwegian Sea from 1993-07-30 to 1993-08-15 (NODC Accession 0113559)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113559 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the Barents Sea, North Greenland Sea and Norwegian...

Stratigraphy and palynology of the Lower Carboniferous Sortebakker Formation, Wandel Sea Basin, eastern North Greenland

Energy Technology Data Exchange (ETDEWEB)

Dalhoff, F.; Stemmerik, L. [Geological Survey of Denmark and Greenland, Copenhagen (Denmark); Vigran, J.O. [IKU Petroleum Research, Trondheim (Norway)

2000-07-01

Two palynological assemblages of Early Carboniferous age have been recorded from the upper parts of the non-marine, fluvial-dominated Sortebakker Formation in the Wandel Sea Basin. The stratigraphically lower assemblage includes poorly preserved Cingulizonates spp., Densosporites spp., Lycospora spp. and Schulzospora spp. whereas the upper assemblage contains a more diversified microflora including the stratigraphically important Tripartites distinctus, Potoniespores delicatus and Savitrisporites spp. The microflora enables correlation and dating of the succession to the late Visean Perotrilites tessellatus - Schulzospora campyloptera (TC) and Raistrickia nigra - Triquitrites marginatus (NM) miospore Biozones of western Europe. The depositional facies correspond to those seen in time equivalent deposits from East Greenland, Svalbard, Bjoernoeya and the Barents Sea. (au)

Microalgal composition and primary production in Arctic sea ice: a seasonal study from Kobbeijord (Kangerluarsunnguaq), West Greenland

DEFF Research Database (Denmark)

Mikkelsen, Ditte Marie; Rysgaard, Søren; Glud, Ronnie N.

2008-01-01

We investigated the microalgal community in sea ice and in the water column of Kobbefjord, west Greenland, through an entire sea ice season, Temporal variation in physical (photosynthetically active radiation [PAR), temperature, brine volume) and chemical (salinity, nutrient concentration......) properties confirmed that sea ice is a very dynamic habitat. Nevertheless, a viable sea ice algal comuunity was present throughout the year, with a species succession from flagellate dominance (dinoflagellates and cryptophytes) in December to February, followed by Chaetoceros simplex (a centric diatom...... (maxima of 1.8 and 2.6 mu g chl](-1) in March and May, respectively). Primary production mirrored biomass dynamic, which had 2 seasonal peaks of ca. 21 and 15 mg Cm-2 d(-1). Integrated primary production over 7 mo was 0.8 g Cm-2 in sea ice and 94.4 g C m(-2) in the water column, with the vast majority...

Microalgal composition and primary production in Arctic sea ice: a seasonal study from Kobbeijord (Kangerluarsunnguaq), West Greenland

DEFF Research Database (Denmark)

Mikkelsen, Ditte Marie; Rysgaard, Søren; Glud, Ronnie N.

2008-01-01

We investigated the microalgal community in sea ice and in the water column of Kobbefjord, west Greenland, through an entire sea ice season, Temporal variation in physical (photosynthetically active radiation [PAR), temperature, brine volume) and chemical (salinity, nutrient concentration...... (maxima of 1.8 and 2.6 mu g chl](-1) in March and May, respectively). Primary production mirrored biomass dynamic, which had 2 seasonal peaks of ca. 21 and 15 mg Cm-2 d(-1). Integrated primary production over 7 mo was 0.8 g Cm-2 in sea ice and 94.4 g C m(-2) in the water column, with the vast majority......) properties confirmed that sea ice is a very dynamic habitat. Nevertheless, a viable sea ice algal comuunity was present throughout the year, with a species succession from flagellate dominance (dinoflagellates and cryptophytes) in December to February, followed by Chaetoceros simplex (a centric diatom...

Greenland ice-sheet contribution to sea-level rise buffered by meltwater storage in firn.

Science.gov (United States)

Harper, J; Humphrey, N; Pfeffer, W T; Brown, J; Fettweis, X

2012-11-08

Surface melt on the Greenland ice sheet has shown increasing trends in areal extent and duration since the beginning of the satellite era. Records for melt were broken in 2005, 2007, 2010 and 2012. Much of the increased surface melt is occurring in the percolation zone, a region of the accumulation area that is perennially covered by snow and firn (partly compacted snow). The fate of melt water in the percolation zone is poorly constrained: some may travel away from its point of origin and eventually influence the ice sheet's flow dynamics and mass balance and the global sea level, whereas some may simply infiltrate into cold snow or firn and refreeze with none of these effects. Here we quantify the existing water storage capacity of the percolation zone of the Greenland ice sheet and show the potential for hundreds of gigatonnes of meltwater storage. We collected in situ observations of firn structure and meltwater retention along a roughly 85-kilometre-long transect of the melting accumulation area. Our data show that repeated infiltration events in which melt water penetrates deeply (more than 10 metres) eventually fill all pore space with water. As future surface melt intensifies under Arctic warming, a fraction of melt water that would otherwise contribute to sea-level rise will fill existing pore space of the percolation zone. We estimate the lower and upper bounds of this storage sink to be 322 ± 44 gigatonnes and  1,289(+388)(-252) gigatonnes, respectively. Furthermore, we find that decades are required to fill this pore space under a range of plausible future climate conditions. Hence, routing of surface melt water into filling the pore space of the firn column will delay expansion of the area contributing to sea-level rise, although once the pore space is filled it cannot quickly be regenerated.

Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Greenland Sea and Norwegian Sea from 1993-11-06 to 1993-12-02 (NODC Accession 0115679)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115679 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Greenland Sea and Norwegian Sea from...

Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Greenland Sea and Norwegian Sea from 1992-11-05 to 1992-12-01 (NODC Accession 0115403)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115403 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Greenland Sea and Norwegian Sea from...

Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Greenland Sea and Norwegian Sea from 1991-11-05 to 1991-11-27 (NODC Accession 0115685)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115685 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Greenland Sea and Norwegian Sea from...

Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Greenland Sea and Norwegian Sea from 1996-10-30 to 1996-11-10 (NODC Accession 0115680)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115680 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Greenland Sea and Norwegian Sea from...

Storm-induced water dynamics and thermohaline structure at the tidewater Flade Isblink Glacier outlet to theWandel Sea (NE Greenland)

DEFF Research Database (Denmark)

Kirillov, Sergei; Dmitrenko, Igor; Rysgaard, Soren

2017-01-01

In April 2015, an ice-tethered conductivity-temperature-depth (CTD) profiler and a down-looking acoustic Doppler current profiler (ADCP) were deployed from the landfast ice near the tidewater glacier terminus of the Flade Isblink Glacier in the Wandel Sea, NE Greenland. The 3-week time series...

Radiocaesium ({sup 137}Cs) in marine mammals from Svalbard, the Barents Sea and the North Greenland Sea

Energy Technology Data Exchange (ETDEWEB)

Andersen, Magnus; Kovacs, Kit M.; Lydersen, Christian [Norwegian Polar Institute, N-9296, Tromsoe (Norway); Gwynn, Justin P.; Dowdall, Mark [Norwegian Radiation Protection Authority, N-9296, Tromsoe (Norway)

2006-06-15

Specific activities of the anthropogenic radionuclide, {sup 137}Cs, were determined in marine mammals from Svalbard and the Barents and North Greenland Seas. Muscle samples were collected from 12 polar bears, 15 ringed seals, 10 hooded seals, 7 bearded seals, 14 harp seals, one walrus, one white whale and one blue whale in the period 2000-2003. The mean concentrations (+/-SD) of {sup 137}Cs were: 0.72+/-0.62 Bq/kg wet weight (w.w.) for polar bears; 0.49+/-0.07 Bq/kg w.w. for ringed seals; 0.25+/-0.10 Bq/kg w.w. for hooded seals; 0.22+/-0.11 Bq/kg w.w. for bearded seals; 0.36+/-0.13 Bq/kg w.w. for harp seals; 0.67 Bq/kg w.w. for the white whale sample; 0.24 Bq/kg w.w. for the blue whale; and below detection limit for the walrus. Significant differences in {sup 137}Cs specific activities between some of the species were found. Ringed seals had higher specific activities than the other seal species in the study. Bearded seals and hooded seals had similar values, which were both significantly lower than the harp seal values. The results in the present study are consistent with previous reported results, indicating low specific activities of {sup 137}Cs in Arctic marine mammals in the Barents Sea and Greenland Sea region during the last 20 years. The species specific differences found may be explained by varying diet or movement and distribution patterns between species. No age related patterns were found in specific activities for the two species (polar bears and hooded seals) for which sufficient data was available. Concentration factors (CF) of {sup 137}Cs from seawater were determined for polar bears, ringed, bearded, harp and hooded seals. Mean CF values ranged from 79+/-32 (SD) for bearded seals sampled in 2002 to 244+/-36 (SD) for ringed seals sampled in 2003 these CF values are higher than those reported for fish and benthic organisms in the literature, suggesting bioaccumulation of {sup 137}Cs in the marine ecosystem. (author)

Environmental radioactivity in the North Atlantic region. The Faroe Islands and Greenland included. 1983

International Nuclear Information System (INIS)

Aarkrog, A.; Boelskifte, S.; Buch, E.; Christensen, G.C.; Dahlgaard, H.; Hallstadius, L.; Hansen, H.; Holm, E.; Mattsson, S.; Meide, A.

1984-12-01

Measurements of fallout radioactivity in the North Atlantic region including the Faroe Islands and Greenland are reported. Strontium-90 and cesium-137 was determined in samples of precipitation, sea water, vegetation, various foodstuffs (including milk in the Faroes) and drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in human diet in the Faroes and Greenland in 1983. Results from samplings of surface sea water and seaweed in the Norwegian and Greenland Seas and along the Norwegian and Greenland west coasts are reported. Beside radiocesium and 90 Sr some of these samples have also been anlysed for tritium,plutonium and americium. Finally technetium-99 data on seaweed samples collected in the North Atlantic region since the beginning of the sixties are presented. (author)

Environmental radioactivity in the North Atlantic region. The Faroe Islands and Greenland included. 1984

International Nuclear Information System (INIS)

Aarkrog, A.; Boelskifte, S.; Buch, E.; Christensen, G.C.; Dahlgaard, H.; Hallstadius, L.; Hansen, H.; Holm, E.

1985-12-01

Measurements of fallout radioactivity in the North Atlantic region including the Faroe Islands and Greenland are reported. Strontium-90 and cesium-137 was determined in samples of precipitation, sea water, vegetation, various foodstuffs (including milk in the Faroes) and drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in human diet in the Faroes and Greenland in 1984. Results from samplings of surface sea water and seaweed in the Norwegian and Greenland Seas and along the Norwegian and Greenland west coasts are reported. Beside radiocesium and 90 Sr some of these samples have also been anlysed for tritium, polonium, plutonium and americium. Finally technetium-99 data on seaweed samples collected in the North Atlantic region since the beginning of the sixties are presented. (author)

Wintertime re-ventilation of the East Greenland Current's Atlantic-origin Overflow Water in the western Iceland Sea

Science.gov (United States)

Våge, Kjetil; Håvik, Lisbeth; Papritz, Lukas; Spall, Michael; Moore, Kent

2017-04-01

The Deep Western Boundary Current constitutes the lower limb of the Atlantic Meridional Overturning Circulation, and, as such, is a crucial component of the Earth's climate system. The largest and densest contribution to the current stems from the overflow plume that passes through Denmark Strait. A main source of Denmark Strait Overflow Water (DSOW) is the East Greenland Current (EGC). The DSOW transported by the EGC originates from the Atlantic inflow into the Nordic Seas. This is then transformed into Atlantic-origin Overflow Water while progressing northward through the eastern part of the Nordic Seas. Here we show, using measurements from autonomous gliders deployed from fall 2015 to spring 2016, that the Atlantic-origin Overflow Water transported toward Denmark Strait by the EGC was re-ventilated while transiting the western Iceland Sea in winter. In summer, this region is characterized by an upper layer of cold, fresh Polar Surface Water that is thought to prevent convection. But in fall and winter this fresh water mass is diverted toward the Greenland shelf by enhanced northerly winds, which results in a water column that is preconditioned for convection. Severe heat loss from the ocean to the atmosphere offshore of the ice edge subsequently causes the formation of deep mixed layers. This further transforms the Atlantic-origin Overflow Water and impacts the properties of the DSOW, and hence the deepest and densest component of the lower limb of the Atlantic Meridional Overturning Circulation.

Past sea-level data from Lakse Bugt, Disko Island, West Greenland from ground-penetrating radar data

DEFF Research Database (Denmark)

Emerich Souza, Priscila; Nielsen, Lars; Kroon, Aart

Beach-ridge deposits have been used as sea-level indicators in numerous studies from temperate coastal regions. However, their present surface morphology in artic regions may not accurately correspond to past sea-level, because subsequent surface erosion, solifluction processes and/or later...... sediment deposition may have altered the surface significantly. The internal structure of these beach ridges, however, is often well-preserved and thus constitutes an important key to reconstruction of past sea levels as seen elsewhere. In the present study, high-resolution reflection GPR data and high......-precision topographic data were collected at Lakse Bugt (Disko Island, West Greenland) using a shielded 250 MHz antennae system and a RTK-Trimble R8 DGPS, respectively. Three transects were collected across a sequence of fossil, raised beach ridge deposits, and two transects were obtained across modern beach deposits...

QUANTIFYING REGIONAL SEA LEVEL RISE CONTRIBUTIONS FROM THE GREENLAND ICE SHEET

Directory of Open Access Journals (Sweden)

Diandong Ren

2013-01-01

Full Text Available This study projects the sea level contribution from the Greenland ice sheet (GrIS through to 2100, using a recently developed ice dynamics model forced by atmospheric parameters derived from three different climate models (CGCMs. The geographical pattern of the near-surface ice warming imposes a divergent flow field favoring mass loss through enhanced ice flow. The calculated average mass loss rate during the latter half of the 21st century is ~0.64±0.06 mm/year eustatic sea level rise, which is significantly larger than the IPCC AR4 estimate from surface mass balance. The difference is due largely to the positive feedbacks from reduced ice viscosity and the basal sliding mechanism present in the ice dynamics model. This inter-model, inter-scenario spread adds approximately a 20% uncertainty to the IPCC ice model estimates. The sea level rise is geographically non-uniform and reaches 1.69±0.24 mm/year by 2100 for the northeast coastal region of the United States, amplified by the expected weakening of the Atlantic meridional overturning circulation (AMOC. In contrast to previous estimates, which neglected the GrIS fresh water input, both sides of the North Atlantic Gyre are projected to experience sea level rises. The impacts on a selection of major cities on both sides of the Atlantic and in the Pacific and southern oceans also are assessed. The other ocean basins are found to be less affected than the Atlantic Ocean.

Zonal surface wind jets across the Red Sea due to mountain gap forcing along both sides of the Red Sea

KAUST Repository

Jiang, Houshuo; Farrar, J. Thomas; Beardsley, Robert C.; Chen, Ru; Chen, Changsheng

2009-01-01

[1] Mesoscale atmospheric modeling over the Red Sea, validated by in-situ meteorological buoy data, identifies two types of coastal mountain gap wind jets that frequently blow across the longitudinal axis of the Red Sea: (1) an eastward

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the USCGC POLAR SEA in the North Greenland Sea from 1992-07-15 to 1992-08-14 (NODC Accession 0115687)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115687 includes biological, chemical, discrete sample, physical and profile data collected from USCGC POLAR SEA in the North Greenland Sea from...

Abrupt Greenland Ice Sheet runoff and sea water temperature changes since 1821, recorded by coralline algae

Science.gov (United States)

Kamenos, N.; Hoey, T.; Bedford, J.; Claverie, T.; Fallick, A. E.; Lamb, C. M.; Nienow, P. W.; O'Neill, S.; Shepherd, I.; Thormar, J.

2012-12-01

The Greenland Ice Sheet (GrIS) contains the largest store of fresh water in the northern hemisphere, equivalent to ~7.4m of eustatic sea level rise, but its impacts on current, past and future sea level, ocean circulation and European climate are poorly understood. Previous estimates of GrIS melt, from 26 years of satellite observations and temperature driven melt-models over 48 years, show a trend of increasing melt. There are however no runoff data of comparable duration with which to validate temperature-based runoff models, or relationships between the spatial extent of melt and runoff. Further, longer runoff records that extend GrIS melt records to centennial timescales will enable recently observed trends to be put into a better historical context. We measured Mg/Ca, δ18O and structural cell size in annual growth bands of red coralline algae to reconstruct: (1) near surface sea water temperature; and, (2) melt/runoff from the GrIS. (1) Temperature: we reconstructed the longest (1821-2009) sub-annual resolution record of water temperature in Disko Bugt (western Greenland) showing an abrupt change in temperature oscillation patterns during the 1920s which may be attributable to the interaction between atmospheric temperature and mass loss from Jakobshavn Isbrae glacier. (2) GrIS runoff: using samples from distal parts of Søndre Strømfjord we produced the first reconstruction of decadal (1939-2002) GrIS runoff. We observed significant negative relationships between historic runoff, relative salinity and marine summer temperature. Our reconstruction shows a trend of increasing reconstructed runoff since the mid 1980s. In situ summer marine temperatures followed a similar trend. We suggest that since 1939 atmospheric temperatures have been important in forcing runoff. Subject to locating in situ coralline algae samples, these methods can be applied across hundreds to thousands of years. These results show that our technique has significant potential to enhance

Migration and breeding biology of arctic terns in Greenland

DEFF Research Database (Denmark)

Egevang, Carsten

(Sandøen) in high-Arctic Northeast Greenland. The level of knowledge of the Arctic tern in Greenland before 2002 was to a large extent poor, with aspects of its biology being completely unknown in the Greenland population. This thesis presents novel findings for the Arctic tern, both on an international...... scale and on a national scale. The study on Arctic tern migration (Manus I) – the longest annual migration ever recorded in any animal – is a study with an international appeal. The study documented how Greenland and Iceland breeding terns conduct the roundtrip migration to the Weddell Sea in Antarctica...

Environmental radioactivity in the North Atlantic region including the Faroe Islands and Greenland. 1990 and 1991

International Nuclear Information System (INIS)

Aarkrog, A.; Chen, Q.J.; Dahlgaard, H.; Hansen, H.; Nielsen, S.P.; Strandberg, M.; Buch, E.; Christensen, G.C.; Holm, E.

1994-01-01

Measurements of fallout radioactivity in the North Atlantic region including Faroe Islands and Greenland are reported. Strontium-90, cesium-137 and cesium-134 were determined in samples of precipitation, sea water, vegetation, various foodstuffs (including milk in the Faroes), and drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in human diet in the Faroes and Greenland in 1990 and 1991. 99 Tc data on marine samples, in particular sea water from the Greenland Sea, are reported. (au) (77 tabs., 46 ills., 8 refs.)

Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the YMER in the Arctic Ocean, Barents Sea and North Greenland Sea from 1980-08-11 to 1980-09-19 (NODC Accession 0113607)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113607 includes chemical, discrete sample, physical and profile data collected from YMER in the Arctic Ocean, Barents Sea and North Greenland Sea...

Environmental radioactivity in Greenland in 1979

International Nuclear Information System (INIS)

Aarkrog, A.; Dahlgaard, H.; Lippert, J.; Nilsson, K.; Holm, E.

1980-07-01

Measurements of fallout radioactivity in Greenland in 1979 are reported. Strontium-90 (and Cesium-137 in most cases) was determined in samples of precipitation, sea water, vegetation, animals, and drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in the human diet in Greenland in 1979. Provisional results of the 239 , 240 Pu and 241 Am measurements on samples from the expedition to Thule in August 1979 are presented. (author)

Evidence for ephemeral middle Eocene to early Oligocene Greenland glacial ice and pan-Arctic sea ice.

Science.gov (United States)

Tripati, Aradhna; Darby, Dennis

2018-03-12

Earth's modern climate is defined by the presence of ice at both poles, but that ice is now disappearing. Therefore understanding the origin and causes of polar ice stability is more critical than ever. Here we provide novel geochemical data that constrain past dynamics of glacial ice on Greenland and Arctic sea ice. Based on accurate source determinations of individual ice-rafted Fe-oxide grains, we find evidence for episodic glaciation of distinct source regions on Greenland as far-ranging as ~68°N and ~80°N synchronous with ice-rafting from circum-Arctic sources, beginning in the middle Eocene. Glacial intervals broadly coincide with reduced CO 2 , with a potential threshold for glacial ice stability near ~500 p.p.m.v. The middle Eocene represents the Cenozoic onset of a dynamic cryosphere, with ice in both hemispheres during transient glacials and substantial regional climate heterogeneity. A more stable cryosphere developed at the Eocene-Oligocene transition, and is now threatened by anthropogenic emissions.

Cloud amount/frequency, TRANSMISSIVITY and other data from BARTLETT in the Greenland Sea from 1989-09-07 to 1989-09-20 (NODC Accession 9200159)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD) and other data were collected in Greenland Sea. Data was collected from Ship BARTLETT. The data was collected over a...

Cloud amount/frequency, TRANSMISSIVITY and other data from BARTLETT in the Greenland Sea from 1990-08-02 to 1990-08-20 (NODC Accession 9200158)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD) and other data were collected in Greenland Sea. Data was collected from Ship BARTLETT. The data was collected over a...

Coral by-catch in shrimp bottom trawl surveys in West Greenland waters (2010 – 2012)

DEFF Research Database (Denmark)

Jørgensbye, Helle; Arboe, Nanette Hammeken

There have been zoological expeditions in Greenland waters since the 19th century documenting the sea life, including cold water corals. Coral trees (vernacular name for Paragorgia arborea) are mentioned as early as 1741 in the first natural history book about Greenland (Egede 1741). Due to the m......There have been zoological expeditions in Greenland waters since the 19th century documenting the sea life, including cold water corals. Coral trees (vernacular name for Paragorgia arborea) are mentioned as early as 1741 in the first natural history book about Greenland (Egede 1741). Due....... The identification of the corals is based on Kenchington et al. (2009). The identification of many specimens has further been verified by Ole Tendal (Zoological Museum, Copenhagen) on the basis of frozen samples. Few corals, mainly soft corals (Alcyonacea) and sea pens (Pennatulacea), were found in the depth range...

Destabilization of the Northeast Greenland Ice Stream

DEFF Research Database (Denmark)

Korsgaard, N. J.; Khan, Shfaqat Abbas; Kjaer, K. H.

. Here, we reveal that the Northeast Greenland Ice Stream (NEGIS), which extends more than 600 km into the interior of the ice sheet, is now undergoing dynamic thinning after more than a quarter of a century of stability. This sector of the GrIS is of particular interest in sea level projections, because...... the glacier flows into a large submarine basin with a negative bed slope near the grounding line. Our findings unfold the next step in mass loss of the GrIS as we show a heightened risk of rapid sustained loss from Northeast Greenland on top of the thinning in Southeast and Northwestern Greenland....

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Greenland Sea and Norwegian Sea from 1994-05-25 to 1994-06-06 (NODC Accession 0113954)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113954 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Greenland Sea and Norwegian Sea from...

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HAKON MOSBY in the North Greenland Sea and Norwegian Sea from 1998-03-08 to 1998-03-24 (NODC Accession 0113546)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113546 includes chemical, discrete sample, physical and profile data collected from HAKON MOSBY in the North Greenland Sea and Norwegian Sea from...

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HAKON MOSBY in the North Greenland Sea and Norwegian Sea from 1997-02-25 to 1997-03-24 (NODC Accession 0113545)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113545 includes chemical, discrete sample, physical and profile data collected from HAKON MOSBY in the North Greenland Sea and Norwegian Sea from...

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HAKON MOSBY in the North Greenland Sea and Norwegian Sea from 1994-02-24 to 1994-03-17 (NODC Accession 0113541)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113541 includes chemical, discrete sample, physical and profile data collected from HAKON MOSBY in the North Greenland Sea and Norwegian Sea from...

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HAKON MOSBY in the North Greenland Sea and Norwegian Sea from 1994-08-26 to 1994-09-10 (NODC Accession 0113542)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113542 includes chemical, discrete sample, physical and profile data collected from HAKON MOSBY in the North Greenland Sea and Norwegian Sea from...

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Greenland Sea and Norwegian Sea from 1995-04-27 to 1995-05-23 (NODC Accession 0113561)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113561 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Greenland Sea and Norwegian Sea from...

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Greenland Sea and Norwegian Sea from 1995-11-08 to 1995-11-26 (NODC Accession 0113562)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113562 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Greenland Sea and Norwegian Sea from...

Hunting and fishing settlements in Upernavik district of Northern Greenland

DEFF Research Database (Denmark)

Hendriksen, Kåre; Jørgensen, Ulrik

2015-01-01

Inuit in the Upernavik district of Northern Greenland has in generations used the winter sea ice as the basis for the essential hunting of seals, white- and narwhales. Since the late 1980’ies hunting has been combined with increasing fishery of Greenland halibut during summer from dinghies and in...

Estimating the Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR

NARCIS (Netherlands)

Fettweis, X.; Franco, B.; Tedesco, M.; van Angelen, J.H.; Lenaerts, J.T.M.; van den Broeke, M.R.; Gallée, H.

2013-01-01

To estimate the sea level rise (SLR) originating from changes in surface mass balance (SMB) of the Greenland ice sheet (GrIS), we present 21st century climate projections obtained with the regional climate model MAR (Mod`ele Atmosph´erique R´egional), forced by output of three CMIP5 (Coupled Model

Description of Pyramimonas diskoicola sp. nov. and the importance of the flagellate Pyramimonas (Prasinophyceae) in Greenland sea ice during the winter–spring transition

DEFF Research Database (Denmark)

Harðardóttir, Sara; Lundholm, Nina; Moestrup, Øjvind

2014-01-01

Pyramimonas Schmarda is a genus of unicellular green flagellates, recorded in marine water and sea ice samples. Pyramimonas is within the prey size range of the most important protozoan grazers in Disko Bay, West Greenland, where this study took place. Despite the potential ecological importance...

Correlation between sea surface temperature and wind speed in Greenland Sea and their relationships with NAO variability

Directory of Open Access Journals (Sweden)

Bo Qu

2012-09-01

Full Text Available The North Atlantic Oscillation (NAO is one of the major causes of many recent changes in the Arctic Ocean. Generally, it is related to wind speed, sea surface temperature (SST, and sea ice cover. In this study, we analyzed the distributions of and correlations between SST, wind speed, NAO, and sea ice cover from 2003 to 2009 in the Greenland Sea at 10°W to 10°E, 65°N to 80°N. SST reached its peak in July, while wind speed reached its minimum in July. Seasonal variability of SST and wind speed was different for different regions. SST and wind speed mainly had negative correlations. Detailed correlation research was focused on the 75°N to 80°N band. Regression analysis shows that in this band, the variation of SST lagged three months behind that of wind speed. Ice cover and NAO had a positive correlation, and the correlation coefficient between ice cover and NAO in the year 2007 was 0.61. SST and NAO also had a positive correlation, and SST influenced NAO one month in advance. The correlation coefficients between SST and NAO reached 0.944 for the year 2005, 0.7 for the year 2008, and 0.74 for the year 2009 after shifting SST one month later. NAO also had a positive correlation with wind speed, and it also influenced wind speed one month in advance. The correlation coefficients between NAO and wind speed reached 0.783, 0.813, and 0.818 for the years 2004, 2005, and 2008, respectively, after shifting wind speed one month earlier.

Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Greenland Sea and Norwegian Sea from 1997-04-14 to 1997-05-22 (NODC Accession 0113563)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113563 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Greenland Sea and Norwegian Sea from...

Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HAKON MOSBY in the North Greenland Sea and Norwegian Sea from 1995-02-17 to 1995-03-18 (NODC Accession 0113543)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113543 includes chemical, discrete sample, physical and profile data collected from HAKON MOSBY in the North Greenland Sea and Norwegian Sea from...

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JAMES CLARK ROSS in the North Greenland Sea and Norwegian Sea from 1996-07-20 to 1996-08-22 (NODC Accession 0113757)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113757 includes chemical, discrete sample, physical and profile data collected from JAMES CLARK ROSS in the North Greenland Sea and Norwegian Sea...

Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Greenland Sea and Norwegian Sea from 1998-08-01 to 1998-08-23 (NODC Accession 0113758)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113758 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Greenland Sea and Norwegian Sea from...

Fueling Plankton Production by a Meandering Frontal Jet: A Case Study for the Alboran Sea (Western Mediterranean)

Science.gov (United States)

Oguz, Temel; Macias, Diego; Garcia-Lafuente, Jesus; Pascual, Ananda; Tintore, Joaquin

2014-01-01

A three dimensional biophysical model was employed to illustrate the biological impacts of a meandering frontal jet, in terms of efficiency and persistency of the autotrophic frontal production, in marginal and semi-enclosed seas. We used the Alboran Sea of the Western Mediterranean as a case study. Here, a frontal jet with a width of 15–20 km, characterized by the relatively low density Atlantic water mass, flows eastward within the upper 100 m as a marked meandering current around the western and the eastern anticyclonic gyres prior to its attachment to the North African shelf/slope topography of the Algerian basin. Its inherent nonlinearity leads to the development of a strong ageostrophic cross-frontal circulation that supplies nutrients into the nutrient-starved euphotic layer and stimulates phytoplankton growth along the jet. Biological production is larger in the western part of the basin and decreases eastwards with the gradual weakening of the jet. The higher production at the subsurface levels suggests that the Alboran Sea is likely more productive than predicted by the satellite chlorophyll data. The Mediterranean water mass away from the jet and the interiors of the western and eastern anticyclonic gyres remain unproductive. PMID:25372789

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from the G.O. SARS in the North Greenland Sea and Norwegian Sea from 2006-07-21 to 2006-08-05 (NODC Accession 0105859)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0105859 includes chemical, discrete sample, physical and profile data collected from G.O. SARS in the North Greenland Sea and Norwegian Sea from...

Environmental radioactivity in the North Atlantic region. The Faroe Islands and Greenland included. 1985

International Nuclear Information System (INIS)

Aarkrog, A.; Boelskifte, S.; Dahlgaard, H.; Hansen, H.; Buch, E.; Christensen, G.C.; Hallstadius, L.; Rioseco, J.; Holm, E.

1987-06-01

Measurements of fallout radioactivity in the North Atlantic region including the Faroe Islands and Greenland are reported. Strontium-90 and cesium-137 was determined in samples of precipitation, sea water vegetation, various foodstuffs (including milk in the Faroes) and drinking water. Estimates are given of the mean contents of 90 Sr a 137 Cs in human diet in the Faroes and Greenland in 1985. Results from samplings of surface sea water and seaweed in the English Channel, the Fram Strait and along the Norwegian and Greenland coast are reported. Beside radiocesium and 90 Sr some of these samples have also been analysed for tritium, plutonium and americium. Finally technetium-99 data on seaweed and sea water samples collected in the North Atlantic region are presented. 14 refs. (author)

The relationship between sea surface temperature and population change of Great Cormorants Phalacrocorax carbo breeding near Disko Bay, Greenland

DEFF Research Database (Denmark)

White, C.R.; Boertmann, David; Gremillet, D.

2011-01-01

waters. We show that rates of population change of Cormorant colonies around Disko Bay, Greenland, are positively correlated with sea surface temperature, suggesting that they may benefit from a warming Arctic. However, although Cormorant populations may increase in response to Arctic warming, the extent...... of expansion of their winter range may ultimately be limited by other factors, such as sensory constraints on foraging behaviour during long Arctic nights....

History of the Greenland Ice Sheet: paleoclimatic insights

DEFF Research Database (Denmark)

Alley, Richard B.; Andrews, John Thomas; Brigham-Grette, Julia

2010-01-01

Paleoclimatic records show that the Greenland Ice Sheet consistently has lost mass in response to warming, and grown in response to cooling. Such changes have occurred even at times of slow or zero sea-level change, so changing sea level cannot have been the cause of at least some of the ice-shee...

Contemporary Arctic Sea Level

Science.gov (United States)

Cazenave, A. A.

2017-12-01

During recent decades, the Arctic region has warmed at a rate about twice the rest of the globe. Sea ice melting is increasing and the Greenland ice sheet is losing mass at an accelerated rate. Arctic warming, decrease in the sea ice cover and fresh water input to the Arctic ocean may eventually impact the Arctic sea level. In this presentation, we review our current knowledge of contemporary Arctic sea level changes. Until the beginning of the 1990s, Arctic sea level variations were essentially deduced from tide gauges located along the Russian and Norwegian coastlines. Since then, high inclination satellite altimetry missions have allowed measuring sea level over a large portion of the Arctic Ocean (up to 80 degree north). Measuring sea level in the Arctic by satellite altimetry is challenging because the presence of sea ice cover limits the full capacity of this technique. However adapted processing of raw altimetric measurements significantly increases the number of valid data, hence the data coverage, from which regional sea level variations can be extracted. Over the altimetry era, positive trend patterns are observed over the Beaufort Gyre and along the east coast of Greenland, while negative trends are reported along the Siberian shelf. On average over the Arctic region covered by satellite altimetry, the rate of sea level rise since 1992 is slightly less than the global mea sea level rate (of about 3 mm per year). On the other hand, the interannual variability is quite significant. Space gravimetry data from the GRACE mission and ocean reanalyses provide information on the mass and steric contributions to sea level, hence on the sea level budget. Budget studies show that regional sea level trends over the Beaufort Gyre and along the eastern coast of Greenland, are essentially due to salinity changes. However, in terms of regional average, the net steric component contributes little to the observed sea level trend. The sea level budget in the Arctic

Cloud amount/frequency, NITRATE and other data from KNORR, ENDEAVOR and OCEANUS in the Greenland Sea from 1988-09-11 to 1991-03-22 (NODC Accession 9100241)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD), Bathythermograph (XBT) and Sound Velocity data (XSV) were collected from fifty seven stations in Greenland Sea using...

Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the USCGC POLAR SEA in the North Greenland Sea from 1993-07-18 to 1993-08-20 (NODC Accession 0114447)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0114447 includes biological, chemical, discrete sample, physical and profile data collected from USCGC POLAR SEA in the North Greenland Sea from...

Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from G.O. SARS in the North Greenland Sea, North Sea and Norwegian Sea from 2011-04-29 to 2011-11-01 (NCEI Accession 0157278)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157278 includes Surface underway, chemical, meteorological and physical data collected from G.O. SARS in the North Greenland Sea, North Sea and...

The response of the Red Sea to a strong wind jet near the Tokar Gap in summer

KAUST Repository

Zhai, Ping

2013-01-01

[1] Remote sensing and in situ observations are used to investigate the ocean response to the Tokar Wind Jet in the Red Sea. The wind jet blows down the atmospheric pressure gradient through the Tokar Gap on the Sudanese coast, at about 19°N, during the summer monsoon season. It disturbs the prevailing along-sea (southeastward) winds with strong cross-sea (northeastward) winds that can last from days to weeks and reach amplitudes of 20-25 m/s. By comparing scatterometer winds with along-track and gridded sea level anomaly observations, it is observed that an intense dipolar eddy spins up in response to the wind jet. The eddy pair has a horizontal scale of 140 km. Maximum ocean surface velocities can reach 1 m/s and eddy currents extend more than 100 m into the water column. The eddy currents appear to cover the width of the sea, providing a pathway for rapid transport of marine organisms and other drifting material from one coast to the other. Interannual variability in the strength of the dipole is closely matched with variability in the strength of the wind jet. The dipole is observed to be quasi-stationary, although there is some evidence for slow eastward propagation in an idealized numerical model. Simulation of the dipole in an idealized high-resolution numerical model suggests that this is the result of self-advection. © 2012. American Geophysical Union. All Rights Reserved.

From the chlorophyll a in the surface layer to its vertical profile: a Greenland Sea relationship for satellite applications

Directory of Open Access Journals (Sweden)

A. Cherkasheva

2013-04-01

Full Text Available Current estimates of global marine primary production range over a factor of two. Improving these estimates requires an accurate knowledge of the chlorophyll vertical profiles, since they are the basis for most primary production models. At high latitudes, the uncertainty in primary production estimates is larger than globally, because here phytoplankton absorption shows specific characteristics due to the low-light adaptation, and in situ data and ocean colour observations are scarce. To date, studies describing the typical chlorophyll profile based on the chlorophyll in the surface layer have not included the Arctic region, or, if it was included, the dependence of the profile shape on surface concentration was neglected. The goal of our study was to derive and describe the typical Greenland Sea chlorophyll profiles, categorized according to the chlorophyll concentration in the surface layer and further monthly resolved profiles. The Greenland Sea was chosen because it is known to be one of the most productive regions of the Arctic and is among the regions in the Arctic where most chlorophyll field data are available. Our database contained 1199 chlorophyll profiles from R/Vs Polarstern and Maria S. Merian cruises combined with data from the ARCSS-PP database (Arctic primary production in situ database for the years 1957–2010. The profiles were categorized according to their mean concentration in the surface layer, and then monthly median profiles within each category were calculated. The category with the surface layer chlorophyll (CHL exceeding 0.7 mg C m−3 showed values gradually decreasing from April to August. A similar seasonal pattern was observed when monthly profiles were averaged over all the surface CHL concentrations. The maxima of all chlorophyll profiles moved from the greater depths to the surface from spring to late summer respectively. The profiles with the smallest surface values always showed a subsurface chlorophyll

Rapid dynamic thinning on Upernavik Icestream, West Greenland

DEFF Research Database (Denmark)

Khan, Shfaqat Abbas; Kjær, Kurt H.; Korsgaard, Niels Jákup

2011-01-01

The main outlet glaciers in Greenland have more than doubled their contribution to global sea level rise over the last decade. Several studies have shown increase in ice discharge from the main outlet glaciers (notably Kangerdlugssuaq (KG) and Helheim glaciers (HG) in Southeast Greenland, and Jak......) laser altimetry data supplemented with altimeter surveys from NASA’s Airborne Topographic Mapper (ATM). To assess thinning prior to 2003, we analyze 1985 aerial photos and derived a 2x2 m grid digital elevation model (DEM)....

Greenland Ice Sheet: High-Elevation Balance and Peripheral Thinning.

Science.gov (United States)

Krabill; Abdalati; Frederick; Manizade; Martin; Sonntag; Swift; Thomas; Wright; Yungel

2000-07-21

Aircraft laser-altimeter surveys over northern Greenland in 1994 and 1999 have been coupled with previously reported data from southern Greenland to analyze the recent mass-balance of the Greenland Ice Sheet. Above 2000 meters elevation, the ice sheet is in balance on average but has some regions of local thickening or thinning. Thinning predominates at lower elevations, with rates exceeding 1 meter per year close to the coast. Interpolation of our results between flight lines indicates a net loss of about 51 cubic kilometers of ice per year from the entire ice sheet, sufficient to raise sea level by 0.13 millimeter per year-approximately 7% of the observed rise.

Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Greenland Sea and Norwegian Sea from 1996-07-20 to 1996-08-05 (NODC Accession 0115688)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115688 includes biological, chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Greenland Sea and Norwegian...

Sustained mass loss of the northeast Greenland ice sheet triggered by regional warming

DEFF Research Database (Denmark)

Khan, Shfaqat Abbas; Kjaer, Kurt H.; Bevis, Michael

2014-01-01

The Greenland ice sheet has been one of the largest contributors to global sea-level rise over the past 20 years, accounting for 0.5 mm yr(-1) of a total of 3.2 mm yr(-1). A significant portion of this contribution is associated with the speed-up of an increased number of glaciers in southeast...... and northwest Greenland. Here, we show that the northeast Greenland ice stream, which extends more than 600 km into the interior of the ice sheet, is now undergoing sustained dynamic thinning, linked to regional warming, after more than a quarter of a century of stability. This sector of the Greenland ice sheet...... is of particular interest, because the drainage basin area covers 16% of the ice sheet (twice that of Jakobshavn Isbrae) and numerical model predictions suggest no significant mass loss for this sector, leading to an under-estimation of future global sea-level rise. The geometry of the bedrock and monotonic trend...

Plankton data collected from instrumented tower and net casts in the Greenland Sea from the POLARSTERN from 09 June 1991 to 16 June 1991 (NODC Accession 0000772)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Plankton data were collected using instrumented tower and net casts from the POLARSTERN in the Greenland Sea. Data were collected from 09 June 1991 to 16 June 1991....

Aerial photographs reveal late-20th-century dynamic ice loss in northwestern greenland

DEFF Research Database (Denmark)

Kjær, Kurt H.; Khan, Shfaqat Abbas; Korsgaard, Niels J

2012-01-01

Global warming is predicted to have a profound impact on the Greenland Ice Sheet and its contribution to global sea-level rise. Recent mass loss in the northwest of Greenland has been substantial. Using aerial photographs, we produced digital elevation models and extended the time record of recent...

Ecosystem variability in west Greenland waters

DEFF Research Database (Denmark)

Buch, E.; Pedersen, Søren Anker; Ribergaard, M. H.

2004-01-01

A review of the climate conditions off West Greenland during the past 50 years shows large variability in the atmospheric, oceanographic and sea-ice variables, as well as in fish stocks. A positive relationship is found between water temperature and the recruitment of cod and redfish, whereas the...

Greenland's balance of Payments and Self-governance

DEFF Research Database (Denmark)

Aage, Hans

Why is the current account of Greenland a topical issue, while those of Denmark and of the island of Bornholm in the Baltic Sea are not? Has the current account anything to do with future inde­pendence? It is ar­gued that balance of payments and foreign debt are closely connected to political and...... of produc­tion and living standards and large current account deficits. It is possible to remove the trade balance deficit and the need for Danish transfers simultaneously, but this would require higher tax rates and huge increases of exports.......Why is the current account of Greenland a topical issue, while those of Denmark and of the island of Bornholm in the Baltic Sea are not? Has the current account anything to do with future inde­pendence? It is ar­gued that balance of payments and foreign debt are closely connected to political...... and eco­nomic national identi­ty. Until recently Greenland's current account was positive by large amounts, which were unex­plained, as it proved impos­sible to uncover corresponding capital account defi­cits. However, im­proved balance of payments statistics together with sim­ple compu...

Rapid dynamic thinning events during 1985-2010 on Upernavik Isstrøm, West Greenland

DEFF Research Database (Denmark)

Khan, Shfaqat Abbas; Kjær, Kurt H.; Korsgaard, Niels Jákup

Many glaciers along the southeast and northwest coast of Greenland have accelerated, increasing the ice sheet's contribution to global sea-level rise. Here, we map elevation changes on Upernavik Isstrøm (UI), West Greenland, during 2003-2009 using high-resolution Ice, Cloud and land Elevation...

Regions of open water and melting sea ice drive new particle formation in North East Greenland.

Science.gov (United States)

Dall Osto, M; Geels, C; Beddows, D C S; Boertmann, D; Lange, R; Nøjgaard, J K; Harrison, Roy M; Simo, R; Skov, H; Massling, A

2018-04-17

Atmospheric new particle formation (NPF) and growth significantly influences the indirect aerosol-cloud effect within the polar climate system. In this work, the aerosol population is categorised via cluster analysis of aerosol number size distributions (9-915 nm, 65 bins) taken at Villum Research Station, Station Nord (VRS) in North Greenland during a 7 year record (2010-2016). Data are clustered at daily averaged resolution; in total, we classified six categories, five of which clearly describe the ultrafine aerosol population, one of which is linked to nucleation events (up to 39% during summer). Air mass trajectory analyses tie these frequent nucleation events to biogenic precursors released by open water and melting sea ice regions. NPF events in the studied regions seem not to be related to bird colonies from coastal zones. Our results show a negative correlation (r = -0.89) between NPF events and sea ice extent, suggesting the impact of ultrafine Arctic aerosols is likely to increase in the future, given the likely increased sea ice melting. Understanding the composition and the sources of Arctic aerosols requires further integrated studies with joint multi-component ocean-atmosphere observation and modelling.

Mass loss of the Greenland Ice Sheet since the Little Ice Age, implications on sea level

DEFF Research Database (Denmark)

Kjeldsen, K. K.; Bjork, A. A.; Khan, Shfaqat Abbas

The impact of mass loss from the Greenland Ice Sheet (GrIS) on 20th Century sea level rise (SLR) has long been subject to intense discussions. While globally distributed tide gauges suggest a global mean SLR of 15-20 cm, quantifying the separate components is of great concern - in particular...... for modeling sea level projections into the 21st Century. Estimates of the past GrIS contribution to SLR have been derived using a number of different approaches, e.g. surface mass balance (SMB) calculations combined with estimates of ice discharge found by in correlating SMB anomalies and calving rates. Here......-2010, NASA's Ice, Cloud, and land Elevation Satellite (ICESat) from 2003-2009, and NASA's Land, Vegetation, and Ice Sensor (LVIS) from 2010, to estimate mass loss throughout the 20th and early 21st Century. We present mass balance estimates of the GrIS since retreat commence from the maximum extent...

Development of ice floe tracker algorithm to measure Lagrangian statistics in the eastern Greenland coast

Science.gov (United States)

Lopez, Rosalinda; Wilhelmus, Monica M.; Schodlok, Michael; Klein, Patrice

2017-11-01

Sea ice export through Fram Strait is a key component of the Arctic climate system. The East Greenland Current (EGC) carries most of the sea ice southwards until it melts. Lagrangian methods using sea ice buoys have been used to map ice features in polar regions. However, their spatial and temporal coverage is limited. Satellite data can provide a better tool to map sea ice flow and its variability. Here, an automated sea ice floe detection algorithm uses ice floes as tracers for surface ocean currents. We process Moderate Resolution Imaging Spectroradiometer satellite images to track ice floes (length scale 5-10 km) in the north-eastern Greenland Sea region. Our matlab-based routines effectively filter out clouds and adaptively modify the images to segment and identify ice floes. Ice floes were tracked based on persistent surface features common in successive images throughout 2016. Their daily centroid locations were extracted and its resulting trajectories are used to describe surface circulation and its variability using differential kinematic parameters. We will discuss the application of this method to a longer time series and larger spatial coverage. This enables us to derive the inter-annual variability of mesoscale features along the eastern coast of Greenland. Supported by UCR Mechanical Engineering Departmental Fellowship.

The response of the Red Sea to a strong wind jet near the Tokar Gap in summer

KAUST Repository

Zhai, Ping; Bower, Amy

2013-01-01

[1] Remote sensing and in situ observations are used to investigate the ocean response to the Tokar Wind Jet in the Red Sea. The wind jet blows down the atmospheric pressure gradient through the Tokar Gap on the Sudanese coast, at about 19°N, during

Extreme Low Light Requirement for Algae Growth Underneath Sea Ice: A Case Study From Station Nord, NE Greenland

Science.gov (United States)

Hancke, Kasper; Lund-Hansen, Lars C.; Lamare, Maxim L.; Højlund Pedersen, Stine; King, Martin D.; Andersen, Per; Sorrell, Brian K.

2018-02-01

Microalgae colonizing the underside of sea ice in spring are a key component of the Arctic foodweb as they drive early primary production and transport of carbon from the atmosphere to the ocean interior. Onset of the spring bloom of ice algae is typically limited by the availability of light, and the current consensus is that a few tens-of-centimeters of snow is enough to prevent sufficient solar radiation to reach underneath the sea ice. We challenge this consensus, and investigated the onset and the light requirement of an ice algae spring bloom, and the importance of snow optical properties for light penetration. Colonization by ice algae began in May under >1 m of first-year sea ice with ˜1 m thick snow cover on top, in NE Greenland. The initial growth of ice algae began at extremely low irradiance (automated high-frequency temperature profiles. We propose that changes in snow optical properties, caused by temperature-driven snow metamorphosis, was the primary driver for allowing sufficient light to penetrate through the thick snow and initiate algae growth below the sea ice. This was supported by radiative-transfer modeling of light attenuation. Implications are an earlier productivity by ice algae in Arctic sea ice than recognized previously.

Late Quaternary glaciation history of northernmost Greenland - Evidence of shelf-based ice

DEFF Research Database (Denmark)

Larsen, Nicolaj K.; Kjær, Kurt H.; Funder, Svend Visby

2010-01-01

We present the mapping of glacial landforms and sediments from northernmost Greenland bordering 100 km of the Arctic Ocean coast. One of the most important discoveries is that glacial landforms, sediments, including till fabric measurements, striae and stoss-lee boulders suggest eastward ice......-flow along the coastal plain. Volcanic erratic boulders document ice-transport from 80 to 100 km west of the study area. We argue that these findings are best explained by local outlet glaciers from the Greenland Ice Sheet and local ice caps that merged to form a shelf-based ice in the Arctic Ocean...... and possibly confirming an extensive ice shelf in the Lincoln Sea between Greenland and Ellesmere Island. It is speculated that the shelf-based ice was largely affected by the presence of thick multiyear sea ice in the Arctic Ocean that prevented it from breaking up and forced the outlet glaciers to flow...

Palaeogene tectono-stratigraphic evolution of the Western Barents Sea, Svalbard and Northeast Greenland

DEFF Research Database (Denmark)

Petersen, Thomas Guldborg

This thesis contains a detailed interpretation of seismic facies of the Paleogene sedimentary succession on the Northeast Greenland Shelf. Based on this, a model for the depostional environment and its interplay with the large scale plate tectonic evolution is produced. The model suggests...... is similar and by using the dated volcanic events onshore Greenland temporal constraints of the deposition on the Northeast Greenland Shelf are much improved. Based on this correlation, the succession can be subdivided into pre-, syn- and post- volcanic intervals. The provenance of the sedimentary succession...

High air-sea CO 2 uptake rates in nearshore and shelf areas of Southern Greenland: Temporal and spatial variability

DEFF Research Database (Denmark)

Rysgaard, Søren; Mortensen, J.; Juul-Pedersen, T.

2012-01-01

significant correlation between average annual gross primary production and annual air-sea flux during 2005-2010, which suggests that regulation of pCO 2 in the fjord is more complex. Despite three confined periods with supersaturated pCO 2 conditions in surface waters during 2005-2010, Godthåbsfjord can......The present study is based on hourly samplings of wind speed, monthly sampling sessions of temperature, salinity, dissolved inorganic carbon, alkalinity, nutrients, primary productivity and vertical export in the outer sill region (station GF3) of a sub-arctic SW Greenland fjord (Godthåbsfjord......) through 2005-2010. Air-sea CO 2 fluxes varied at GF3 from c. -20gCm -2month -1 (uptake from the atmosphere) to 25gCm -2month -1 (release to the atmosphere) during 2005-10. The average annual air-sea CO 2 flux of -83 to -108gCm -2yr -1 was within the range of the local gross annual primary productivity...

Surface Energy and Mass Balance Model for Greenland Ice Sheet and Future Projections

Science.gov (United States)

Liu, Xiaojian

The Greenland Ice Sheet contains nearly 3 million cubic kilometers of glacial ice. If the entire ice sheet completely melted, sea level would raise by nearly 7 meters. There is thus considerable interest in monitoring the mass balance of the Greenland Ice Sheet. Each year, the ice sheet gains ice from snowfall and loses ice through iceberg calving and surface melting. In this thesis, we develop, validate and apply a physics based numerical model to estimate current and future surface mass balance of the Greenland Ice Sheet. The numerical model consists of a coupled surface energy balance and englacial model that is simple enough that it can be used for long time scale model runs, but unlike previous empirical parameterizations, has a physical basis. The surface energy balance model predicts ice sheet surface temperature and melt production. The englacial model predicts the evolution of temperature and meltwater within the ice sheet. These two models can be combined with estimates of precipitation (snowfall) to estimate the mass balance over the Greenland Ice Sheet. We first compare model performance with in-situ observations to demonstrate that the model works well. We next evaluate how predictions are degraded when we statistically downscale global climate data. We find that a simple, nearest neighbor interpolation scheme with a lapse rate correction is able to adequately reproduce melt patterns on the Greenland Ice Sheet. These results are comparable to those obtained using empirical Positive Degree Day (PDD) methods. Having validated the model, we next drove the ice sheet model using the suite of atmospheric model runs available through the CMIP5 atmospheric model inter-comparison, which in turn built upon the RCP 8.5 (business as usual) scenarios. From this exercise we predict how much surface melt production will increase in the coming century. This results in 4-10 cm sea level equivalent, depending on the CMIP5 models. Finally, we try to bound melt water

Greenland Ice Sheet Surface Temperature, Melt, and Mass Loss: 2000-2006

Science.gov (United States)

Hall, Dorothy K.; Williams, Richard S., Jr.; Luthcke, Scott B.; DiGirolamo, Nocolo

2007-01-01

Extensive melt on the Greenland Ice Sheet has been documented by a variety of ground and satellite measurements in recent years. If the well-documented warming continues in the Arctic, melting of the Greenland Ice Sheet will likely accelerate, contributing to sea-level rise. Modeling studies indicate that an annual or summer temperature rise of 1 C on the ice sheet will increase melt by 20-50% therefore, surface temperature is one of the most important ice-sheet parameters to study for analysis of changes in the mass balance of the ice-sheet. The Greenland Ice Sheet contains enough water to produce a rise in eustatic sea level of up to 7.0 m if the ice were to melt completely. However, even small changes (centimeters) in sea level would cause important economic and societal consequences in the world's major coastal cities thus it is extremely important to monitor changes in the ice-sheet surface temperature and to ultimately quantify these changes in terms of amount of sea-level rise. We have compiled a high-resolution, daily time series of surface temperature of the Greenland Ice Sheet, using the I-km resolution, clear-sky land-surface temperature (LST) standard product from the Moderate-Resolution Imaging Spectroradiometer (MODIS), from 2000 - 2006. We also use Gravity Recovery and Climate Experiment (GRACE) data, averaged over 10-day periods, to measure change in mass of the ice sheet as it melt and snow accumulates. Surface temperature can be used to determine frequency of surface melt, timing of the start and the end of the melt season, and duration of melt. In conjunction with GRACE data, it can also be used to analyze timing of ice-sheet mass loss and gain.

Accelerated mass loss from Greenland ice sheet : Links to atmospheric circulation in the North Atlantic

NARCIS (Netherlands)

Seo, Ki-Weon; Waliser, Duane E.; Lee, Choon-Ki; Tian, Baijun; Scambos, Ted; Kim, Baek-Min; van Angelen, Jan H.; van den Broeke, Michiel R.

Understanding the mechanisms that drive the mass imbalance of the Greenland ice sheet (GrIS) is critical to the accurate projection of its contribution to future sea level rise. Greenland's ice mass loss has been accelerating recently. Using satellite Earth-gravity and regional climate model data,

Greenland ice sheet surface mass balance: evaluating simulations and making projections with regional climate models

NARCIS (Netherlands)

Rae, J.G.L.; Aðalgeirsdóttir, G.; Edwards, T.L.; Fettweis, X.; Gregory, J.M.; Hewitt, H.T.; Lowe, J.A.; Lucas-Picher, P.; Mottram, R.H.; Payne, A.J.; Ridley, J.K.; Shannon, S.R.; van de Berg, W.J.; van de Wal, R.S.W.; van den Broeke, M.R.

2012-01-01

Four high-resolution regional climate models (RCMs) have been set up for the area of Greenland, with the aim of providing future projections of Greenland ice sheet surface mass balance (SMB), and its contribution to sea level rise, with greater accuracy than is possible from coarser-resolution

Oceanic Transport of Surface Meltwater from the Southern Greenland Ice Sheet

Science.gov (United States)

Luo, Hao; Castelao, Renato M.; Rennermalm, Asa K.; Tedesco, Marco; Bracco, Annalisa; Yager, Patricia L.; Mote, Thomas L.

2016-01-01

The Greenland ice sheet has undergone accelerating mass losses during recent decades. Freshwater runoff from ice melt can influence fjord circulation and dynamic1 and the delivery of bioavailable micronutrients to the ocean. It can also have climate implications, because stratification in the adjacent Labrador Sea may influence deep convection and the strength of the Atlantic meridional overturning circulation. Yet, the fate of the meltwater in the ocean remains unclear. Here, we use a high-resolution ocean model to show that only 1-15% of the surface meltwater runoff originating from southwest Greenland is transported westwards. In contrast, up to 50-60% of the meltwater runoff originating from southeast Greenland is transported westwards into the northern Labrador Sea, leading to significant salinity and stratification anomalies far from the coast. Doubling meltwater runoff, as predicted in future climate scenarios, results in a more-than-double increase in anomalies offshore that persists further into the winter. Interannual variability in offshore export of meltwater is tightly related to variability in wind forcing. The new insight that meltwaters originating from the west and east coasts have different fates indicates that future changes in mass loss rates and surface runoff will probably impact the ocean differently, depending on their Greenland origins.

Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus)

DEFF Research Database (Denmark)

Nielsen, Julius; Hedeholm, Rasmus B.; Heinemeier, Jan

2016-01-01

The Greenland shark (Somniosus microcephalus), an iconic species of the Arctic Seas, grows slowly and reaches >500 centimeters (cm) in total length, suggesting a life span well beyond those of other vertebrates. Radiocarbon dating of eye lens nuclei from 28 female Greenland sharks (81 to 502 cm i...

Spatial variation in energy exchange across coastal environments in Greenland

Science.gov (United States)

Lund, M.; Abermann, J.; Citterio, M.; Hansen, B. U.; Larsen, S. H.; Stiegler, C.; Sørensen, L. L.; van As, D.

2015-12-01

The surface energy partitioning in Arctic terrestrial and marine areas is a crucial process, regulating snow, glacier ice and sea ice melt, and permafrost thaw, as well as modulating Earth's climate on both local, regional, and eventually, global scales. The Arctic region has warmed approximately twice as much as the global average, due to a number of feedback mechanisms related to energy partitioning, most importantly the snow and ice-albedo feedback. However, direct measurements of surface energy budgets in the Arctic are scarce, especially for the cold and dark winter period and over transects going from the ice sheet and glaciers to the sea. This study aims to describe annual cycles of the surface energy budget from various surface types in Arctic Greenland; e.g. glacier, snow, wet and dry tundra and sea ice, based on data from a number of measurement locations across coastal Greenland related to the Greenland Ecosystem Monitoring (GEM) program, including Station Nord/Kronprins Christians Land, Zackenberg/Daneborg, Disko, Qaanaq, Nuuk/Kobbefjord and Upernaviarsuk. Based on the available time series, we will analyze the sensitivity of the energy balance partitioning to variations in meteorological conditions (temperature, cloudiness, precipitation). Such analysis would allow for a quantification of the spatial variation in the energy exchange in aforementioned Arctic environments. Furthermore, this study will identify uncertainties and knowledge gaps in Arctic energy budgets and related climate feedback effects.

Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Atlantic Ocean, North Greenland Sea and Norwegian Sea from 1994-10-29 to 1994-11-23 (NODC Accession 0115681)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115681 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Atlantic Ocean, North Greenland Sea and...

Lime stabilization of fine-grained sediments in western Greenland

DEFF Research Database (Denmark)

Jørgensen, Anders Stuhr; Ingeman-Nielsen, Thomas; Skels, Peteris

2011-01-01

Thick deposits of fine-grained marine sediments exist in large areas of western Greenland. Many places these sediments are located above sea-level, and now complicate construction projects in urban areas. The mineralogy of the fine-grained sediments is very different from European sediments, mainly...... due to the cold climate, and it is therefore of great interest to study possible methods to improve the stability and strength properties. This project includes laboratory studies of lime stabilization on fine-grained marine sediments from Kangerlussuaq, western Greenland. The results have included...

North and northeast Greenland ice discharge from satellite radar interferometry

DEFF Research Database (Denmark)

Rignot, E.J.; Gogineni, S.P.; Krabill, W.B.

1997-01-01

Ice discharge from north and northeast Greenland calculated from satellite radar interferometry data of 14 outlet glaciers is 3.5 times that estimated from iceberg production. The satellite estimates, obtained at the grounding line of the outlet glaciers, differ from those obtained at the glacier...... front, because basal melting is extensive at the underside of the floating glacier sections. The results suggest that the north and northeast parts of the Greenland ice sheet may be thinning and contributing positively to sea-level rise....

Greenland ice sheet mass balance: a review

DEFF Research Database (Denmark)

Khan, Shfaqat Abbas; Aschwanden, Andy; Bjørk, Anders A.

2015-01-01

Over the past quarter of a century the Arctic has warmed more than any other region on Earth, causing a profound impact on the Greenland ice sheet (GrIS) and its contribution to the rise in global sea level. The loss of ice can be partitioned into processes related to surface mass balance...

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from HUDSON in the North Atlantic Ocean, North Greenland Sea and Norwegian Sea from 1982-02-28 to 1982-04-04 (NODC Accession 0113889)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0113889 includes chemical, discrete sample, physical and profile data collected from HUDSON in the North Atlantic Ocean, North Greenland Sea and...

Biogeochemical cycling in a subarctic fjord adjacent to the Greenland Ice Sheet

NARCIS (Netherlands)

Meire, L.

2016-01-01

Temperatures in the Arctic have increased rapidly in recent years resulting in the melting of sea ice and glaciers at unprecedented rates. In 2012, sea ice extent across the Arctic reached a record minimum and the melt extent of Greenland Ice Sheet reached a record maximum. The accelerated mass loss

Strategic environmental assessment (SEA) as a means to include environmental knowledge in decision making in the case of an aluminium reduction plant in Greenland

DEFF Research Database (Denmark)

Hansen, Anne Merrild

2011-01-01

The purpose and means of strategic environmental assessment (SEA) can vary depending on the case investigated and interests of actors involved. Based on the objective for the SEA of a proposed aluminium reduction plant (ARP) in Greenland, this paper evaluates the SEA’s effectiveness in securing...... environmental knowledge in a decision-making process. It is concluded that the SEA secured inclusion of environmental knowledge in three out of four key decision arenas, which determined the direction and outcome of the process. The results from the SEA did not oppose the recommendations based on the economic...... assessments. As there was no conflict between economic and environmental recommendations, and hence no visible proof of SEA’s influence on the outcome of the decision, it is discussed whether environmental knowledge, in this decision making process, equals influence. The investigation was carried out...

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JAN MAYEN in the Arctic Ocean, Barents Sea and North Greenland Sea from 2005-05-20 to 2005-06-02 (NODC Accession 0113564)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113564 includes chemical, discrete sample, physical and profile data collected from JAN MAYEN in the Arctic Ocean, Barents Sea and North Greenland...

Linkages between Icelandic Low position and SE Greenland winter precipitation

Science.gov (United States)

Berdahl, M.; Rennermalm, A. K.; Hammann, A. C.; Mioduszewski, J.; Hameed, S.; Tedesco, M.; Stroeve, J. C.; Mote, T. L.

2015-12-01

Greenland's largest flux of precipitation occurs in its Southeast (SE) region. An understanding of the mechanisms controlling precipitation in this region is lacking despite its disproportionate importance in the mass balance of Greenland and the consequent contributions to sea level rise. We use weather station data from the Danish Meteorological Institute to reveal the governing influences on precipitation in SE Greenland during the winter and fall. We find that precipitation in the fall is significantly correlated to the longitude of the Icelandic Low and the NAO. Winter precipitation is correlated with the strength and longitude of the Icelandic Low, as well as the NAO. We show that in years of extreme high precipitation, onshore winds dominate, thereby advecting more moisture inland. In low precipitation years, winds are more westerly, approaching the stations from land. Understanding the controls of SE Greenland precipitation will help us predict how future precipitation in this key region may change in a warming climate.

Younger Dryas cooling and the Greenland climate response to CO2.

Science.gov (United States)

Liu, Zhengyu; Carlson, Anders E; He, Feng; Brady, Esther C; Otto-Bliesner, Bette L; Briegleb, Bruce P; Wehrenberg, Mark; Clark, Peter U; Wu, Shu; Cheng, Jun; Zhang, Jiaxu; Noone, David; Zhu, Jiang

2012-07-10

Greenland ice-core δ(18)O-temperature reconstructions suggest a dramatic cooling during the Younger Dryas (YD; 12.9-11.7 ka), with temperatures being as cold as the earlier Oldest Dryas (OD; 18.0-14.6 ka) despite an approximately 50 ppm rise in atmospheric CO(2). Such YD cooling implies a muted Greenland climate response to atmospheric CO(2), contrary to physical predictions of an enhanced high-latitude response to future increases in CO(2). Here we show that North Atlantic sea surface temperature reconstructions as well as transient climate model simulations suggest that the YD over Greenland should be substantially warmer than the OD by approximately 5 °C in response to increased atmospheric CO(2). Additional experiments with an isotope-enabled model suggest that the apparent YD temperature reconstruction derived from the ice-core δ(18)O record is likely an artifact of an altered temperature-δ(18)O relationship due to changing deglacial atmospheric circulation. Our results thus suggest that Greenland climate was warmer during the YD relative to the OD in response to rising atmospheric CO(2), consistent with sea surface temperature reconstructions and physical predictions, and has a sensitivity approximately twice that found in climate models for current climate due to an enhanced albedo feedback during the last deglaciation.

The role of the meridional sea surface temperature gradient in controlling the Caribbean low-level jet

Science.gov (United States)

Maldonado, Tito; Rutgersson, Anna; Caballero, Rodrigo; Pausata, Francesco S. R.; Alfaro, Eric; Amador, Jorge

2017-06-01

The Caribbean low-level jet (CLLJ) is an important modulator of regional climate, especially precipitation, in the Caribbean and Central America. Previous work has inferred, due to their semiannual cycle, an association between CLLJ strength and meridional sea surface temperature (SST) gradients in the Caribbean Sea, suggesting that the SST gradients may control the intensity and vertical shear of the CLLJ. In addition, both the horizontal and vertical structure of the jet have been related to topographic effects via interaction with the mountains in Northern South America (NSA), including funneling effects and changes in the meridional geopotential gradient. Here we test these hypotheses, using an atmospheric general circulation model to perform a set of sensitivity experiments to examine the impact of both SST gradients and topography on the CLLJ. In one sensitivity experiment, we remove the meridional SST gradient over the Caribbean Sea and in the other, we flatten the mountains over NSA. Our results show that the SST gradient and topography have little or no impact on the jet intensity, vertical, and horizontal wind shears, contrary to previous works. However, our findings do not discount a possible one-way coupling between the SST and the wind over the Caribbean Sea through friction force. We also examined an alternative approach based on barotropic instability to understand the CLLJ intensity, vertical, and horizontal wind shears. Our results show that the current hypothesis about the CLLJ must be reviewed in order to fully understand the atmospheric dynamics governing the Caribbean region.

Levels and trends of radioactive contaminants in the Greenland environment

DEFF Research Database (Denmark)

Dahlgaard, H.; Eriksson, M.; Nielsen, S.P.

2004-01-01

. The concentrations are expected to increase in the future, especially in East Greenland. The Bylot Sound at the Thule Airbase (Pituffik) in North-West Greenland was contaminated with plutonium and enriched uranium in a weapons accident in 1968. Biological activity has mixed accident plutonium efficiently...... into the new sediments resulting in continued high surface sediment concentrations three decades after the accident. Transfer of plutonium to benthic biota is low-and lower than observed in the Irish Sea. This is supposed to be caused by the physico-chemical form of the accident plutonium. A recent study...

Design and results of the ice sheet model initialisation initMIP-Greenland: an ISMIP6 intercomparison

Directory of Open Access Journals (Sweden)

H. Goelzer

2018-04-01

Full Text Available Earlier large-scale Greenland ice sheet sea-level projections (e.g. those run during the ice2sea and SeaRISE initiatives have shown that ice sheet initial conditions have a large effect on the projections and give rise to important uncertainties. The goal of this initMIP-Greenland intercomparison exercise is to compare, evaluate, and improve the initialisation techniques used in the ice sheet modelling community and to estimate the associated uncertainties in modelled mass changes. initMIP-Greenland is the first in a series of ice sheet model intercomparison activities within ISMIP6 (the Ice Sheet Model Intercomparison Project for CMIP6, which is the primary activity within the Coupled Model Intercomparison Project Phase 6 (CMIP6 focusing on the ice sheets. Two experiments for the large-scale Greenland ice sheet have been designed to allow intercomparison between participating models of (1 the initial present-day state of the ice sheet and (2 the response in two idealised forward experiments. The forward experiments serve to evaluate the initialisation in terms of model drift (forward run without additional forcing and in response to a large perturbation (prescribed surface mass balance anomaly; they should not be interpreted as sea-level projections. We present and discuss results that highlight the diversity of data sets, boundary conditions, and initialisation techniques used in the community to generate initial states of the Greenland ice sheet. We find good agreement across the ensemble for the dynamic response to surface mass balance changes in areas where the simulated ice sheets overlap but differences arising from the initial size of the ice sheet. The model drift in the control experiment is reduced for models that participated in earlier intercomparison exercises.

Exploring the Potential Impact of Greenland Meltwater on Stratification, Photosynthetically Active Radiation, and Primary Production in the Labrador Sea

Science.gov (United States)

Oliver, Hilde; Luo, Hao; Castelao, Renato M.; van Dijken, Gert L.; Mattingly, Kyle S.; Rosen, Joshua J.; Mote, Thomas L.; Arrigo, Kevin R.; Rennermalm, Åsa K.; Tedesco, Marco; Yager, Patricia L.

2018-04-01

In July 2012, the surface of the Greenland Ice Sheet (GrIS) melted to an extent unprecedented over the last 100 years; we questioned the potential for such an extreme melt event to impact marine phytoplankton offshore. We hypothesized that stratification from meltwater could reduce light limitation for phytoplankton, and used a suite of numerical models to quantify the impact for 2003-2012. Because much of the 2012 meltwater discharged from southern Greenland, our study focused on the southwestern and southeastern coasts of Greenland, and the Labrador Sea. A 1-D phytoplankton model used output from a Regional Ocean Modeling System (ROMS) coupled with a Regional Climate Model and a hydrological model of meltwater from runoff sources on the ice sheet, peripheral glaciers, and tundra. ROMS was run with and without meltwater to test the sensitivity of phytoplankton photosynthetic rates to the meltwater input. With meltwater, the pycnocline was shallower during late summer and early fall and thus light limitation on photosynthesis was reduced. Averaged over all years, added meltwater had the potential to increase gross primary production by 3-12% in the summer (July-August), and 13-60% in the fall (September-October). This meltwater effect was amplified when light was more limiting, and thus was greatest in the fall, under cloudier conditions, with higher self-shading, and with more light-sensitive phytoplankton groups. As the GrIS melt is projected to increase, late summer primary production in this region has the potential to increase as well, which could constitute an important biosphere response to high-latitude climate change.

Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from G.O. SARS in the Barents Sea, North Greenland Sea and others from 2007-02-12 to 2007-10-28 (NCEI Accession 0157392)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157392 includes Surface underway, chemical, meteorological and physical data collected from G.O. SARS in the Barents Sea, North Greenland Sea, North...

Arctic Ocean UNCLOS Article 76 Work for Greenland Starts on Land

Science.gov (United States)

Dahl-Jensen, T.; Marcussen, C.; Jackson, R.; Voss, P.

2005-12-01

One of the most lonely and desolate stretches of coastline on the planet has become the target for UNCLOS article 76 related research. The Danish Continental Shelf Project has launched a work program to investigate the possibilities for Greenland to claim an area outside the 200 nm limit in the Arctic Ocean. The role of the Lomonosov Ridge as a Natural Prolongation of Greenland/Canada is an important issue, and in order to better evaluate the connection between Greenland and the Lomonosov Ridge the nature of not only the ridge but also of Northern Greenland is the target of deep crustal investigations. The North Greenland Fold belt covers the ice-free part of North Greenland and continues west in the Canadian Arctic. The foldbelt was formed during the Ellesmerian orogeny, where sediments from the Franklinian Basin where compressed and deformed. The deep structure of basin and its subsequent closure are broadly unknown. Three broad band earthquake seismological stations where installed in North Greenland to supplement the existing stations at Alert (Canada) and Station Nord to the east, and the first data was available summer 2005. Crustal thickness data from these first results are presented. Plans for the spring 2006 consist of wide-angle acquisition on the sea ice from the Greenland-Canadian mainland out onto the Lomonosov Ridge, a joint Danish - Canadian project with a 400 km long profile over difficult ice conditions, 18 tons of explosives, three helicopters, a Twin Otter and about 30 participants.

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HAKON MOSBY in the North Atlantic Ocean, North Greenland Sea and Norwegian Sea from 2001-05-27 to 2001-06-19 (NODC Accession 0113754)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113754 includes chemical, discrete sample, physical and profile data collected from HAKON MOSBY in the North Atlantic Ocean, North Greenland Sea and...

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the G.O. SARS in the North Atlantic Ocean, North Greenland Sea and Norwegian Sea from 2003-09-22 to 2003-10-13 (NODC Accession 0113752)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113752 includes chemical, discrete sample, physical and profile data collected from G.O. SARS in the North Atlantic Ocean, North Greenland Sea and...

Design and results of the ice sheet model initialisation experiments initMIP-Greenland: an ISMIP6 intercomparison

Science.gov (United States)

Goelzer, Heiko; Nowicki, Sophie; Edwards, Tamsin; Beckley, Matthew; Abe-Ouchi, Ayako; Aschwanden, Andy; Calov, Reinhard; Gagliardini, Olivier; Gillet-Chaulet, Fabien; Golledge, Nicholas R.; Gregory, Jonathan; Greve, Ralf; Humbert, Angelika; Huybrechts, Philippe; Kennedy, Joseph H.; Larour, Eric; Lipscomb, William H.; Le clec'h, Sébastien; Lee, Victoria; Morlighem, Mathieu; Pattyn, Frank; Payne, Antony J.; Rodehacke, Christian; Rückamp, Martin; Saito, Fuyuki; Schlegel, Nicole; Seroussi, Helene; Shepherd, Andrew; Sun, Sainan; van de Wal, Roderik; Ziemen, Florian A.

2018-04-01

Earlier large-scale Greenland ice sheet sea-level projections (e.g. those run during the ice2sea and SeaRISE initiatives) have shown that ice sheet initial conditions have a large effect on the projections and give rise to important uncertainties. The goal of this initMIP-Greenland intercomparison exercise is to compare, evaluate, and improve the initialisation techniques used in the ice sheet modelling community and to estimate the associated uncertainties in modelled mass changes. initMIP-Greenland is the first in a series of ice sheet model intercomparison activities within ISMIP6 (the Ice Sheet Model Intercomparison Project for CMIP6), which is the primary activity within the Coupled Model Intercomparison Project Phase 6 (CMIP6) focusing on the ice sheets. Two experiments for the large-scale Greenland ice sheet have been designed to allow intercomparison between participating models of (1) the initial present-day state of the ice sheet and (2) the response in two idealised forward experiments. The forward experiments serve to evaluate the initialisation in terms of model drift (forward run without additional forcing) and in response to a large perturbation (prescribed surface mass balance anomaly); they should not be interpreted as sea-level projections. We present and discuss results that highlight the diversity of data sets, boundary conditions, and initialisation techniques used in the community to generate initial states of the Greenland ice sheet. We find good agreement across the ensemble for the dynamic response to surface mass balance changes in areas where the simulated ice sheets overlap but differences arising from the initial size of the ice sheet. The model drift in the control experiment is reduced for models that participated in earlier intercomparison exercises.

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from KNORR in the North Atlantic Ocean, North Greenland Sea and others from 1972-07-18 to 1973-04-01 (NCEI Accession 0143398)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0143398 includes discrete sample and profile data collected from KNORR in the North Atlantic Ocean, North Greenland Sea, Norwegian Sea, South Atlantic...

Mountain building and the initiation of the Greenland Ice Sheet

DEFF Research Database (Denmark)

Solgaard, Anne Munck; Bonow, Johan; Langen, Peter Lang

2013-01-01

The effects of a new hypothesis about mountain building in Greenland on ice sheet initiation are investigated using an ice sheet model in combination with a climate model. According to this hypothesis, low-relief landscapes near sea level characterised Greenland in Miocene times until two phases...... superimposed by cold and warm excursions. The modelling results show that no ice initiates in the case of the low-lying and almost flat topography prior to the uplifts. However, the results demonstrate a significant ice sheet growth in response to the orographically induced increase in precipitation....... Under conditions that are colder than the present, the ice can overcome the Föhn effect, flow into the interior and form a coherent ice sheet. The results thus indicate that the Greenland Ice Sheet of today is a relict formed under colder conditions. The modelling results are consistent...

Influence of Late Paleozoic Gondwana glaciations on the depositional evolution of the northern Pangean shelf, North Greenland, Svalbard and the Barents Sea

DEFF Research Database (Denmark)

Stemmerik, Lars

2008-01-01

Outcrop and subsurface data from the central northern margin of the Pangean shelf in North Greenland, Svalbard, and the Norwegian Barents Sea record the depositional response of a Northern Hemisphere subtropical shelf to Late Carboniferous-Early Permian (Bashkirian-Sakmarian) Gondwana glaciations....... The dominant motif is that of meters to tens of meters of exposure-capped cycles of carbonates, mixed carbonates, and siliciclastics and, in older stratigraphic levels, siliciclastics and gypsum. Halitegypsum-carbonate cycles developed in deeper, isolated basins. Individual cycles of carbonate and mixed...

The role of jet and film drops in controlling the mixing state of submicron sea spray aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiaofei; Deane, Grant B.; Moore, Kathryn A.; Ryder, Olivia S.; Stokes, M. Dale; Beall, Charlotte M.; Collins, Douglas B.; Santander, Mitchell V.; Burrows, Susannah M.; Sultana, Camille M.; Prather, Kimberly A.

2017-06-19

Covering 71% of the Earth’s surface, oceans represent a significant global source of atmospheric aerosols. The size and composition of sea spray aerosols (SSA) affect their ability to serve as cloud seeds and thus understanding the factors controlling their composition is critical to predicting their impact on clouds and climate. SSA particles have been shown to be an external mixture of particles with different compositions. Film and jet drop production mechanisms ultimately determine the individual particle compositions which are comprised of an array of salt/organic mixtures ranging from pure sea salt to nearly pure organic particles. It is often assumed that the majority of submicron SSA are formed by film drops produced from bursting hydrophobic organic-rich bubble film caps at the sea surface, and in contrast, jet drops are postulated to produce larger supermicron particles from underlying seawater comprised largely of salts and water soluble organic species. However, here we show that jet drops produced by bursting sub-100 m bubbles account for up to 40 % of all submicron particles. They have distinct chemical compositions, organic volume fractions and ice nucleating activities from submicron film drops. Thus a substantial fraction of submicron particles will not necessarily be controlled by the composition of the sea surface microlayer as has been assumed in many studies. This finding has significant ramifications for the size-resolved mixing states of SSA particles which must be taken into consideration when accessing SSA impacts on clouds.

Greenland from Archaean to Quaternary, Descriptive text to the 1995 Geological Map of Greenland 1:2 500 000, 2nd edition

Directory of Open Access Journals (Sweden)

Kalsbeek, Feiko

2009-11-01

opening of the North Atlantic Ocean in the late Paleocene. Sea-floor spreading was accompanied by extrusion of Palaeogene (early Tertiary plateau basalts in both central West and central–southern East Greenland. During the Quaternary Greenland was almost completely covered by ice, and the present day Inland Ice is a relic from the Pleistocene ice ages. Vast amounts of glacially eroded detritus were deposited on the continental shelves around Greenland. Mineral exploitation in Greenland has so far encompassed cryolite, lead-zinc, gold, olivine and coal. Current prospecting activities in Greenland are concentrated on gold, base metals, platinum group elements, molybdenum, iron ore, diamonds and lead-zinc. Hydrocarbon potential is confined to the major Phanerozoic sedimentary basins, notably the large basins offshore North-East and West Greenland. While reserves of oil or gas have yet to be found, geophysical data com bined with discoveries of oil seeps onshore have revealed a considerable potential for offshore oil and gas.

Volcanic influence on centennial to millennial Holocene Greenland temperature change.

Science.gov (United States)

Kobashi, Takuro; Menviel, Laurie; Jeltsch-Thömmes, Aurich; Vinther, Bo M; Box, Jason E; Muscheler, Raimund; Nakaegawa, Toshiyuki; Pfister, Patrik L; Döring, Michael; Leuenberger, Markus; Wanner, Heinz; Ohmura, Atsumu

2017-05-03

Solar variability has been hypothesized to be a major driver of North Atlantic millennial-scale climate variations through the Holocene along with orbitally induced insolation change. However, another important climate driver, volcanic forcing has generally been underestimated prior to the past 2,500 years partly owing to the lack of proper proxy temperature records. Here, we reconstruct seasonally unbiased and physically constrained Greenland Summit temperatures over the Holocene using argon and nitrogen isotopes within trapped air in a Greenland ice core (GISP2). We show that a series of volcanic eruptions through the Holocene played an important role in driving centennial to millennial-scale temperature changes in Greenland. The reconstructed Greenland temperature exhibits significant millennial correlations with K + and Na + ions in the GISP2 ice core (proxies for atmospheric circulation patterns), and δ 18 O of Oman and Chinese Dongge cave stalagmites (proxies for monsoon activity), indicating that the reconstructed temperature contains hemispheric signals. Climate model simulations forced with the volcanic forcing further suggest that a series of large volcanic eruptions induced hemispheric-wide centennial to millennial-scale variability through ocean/sea-ice feedbacks. Therefore, we conclude that volcanic activity played a critical role in driving centennial to millennial-scale Holocene temperature variability in Greenland and likely beyond.

A multi-archive coherent chronology: from Greenland to the Mediterranean sea

Science.gov (United States)

Bazin, Lucie; Landais, Amaelle; Lemieux-Dudon, Bénédicte; Siani, Giuseppe; Michel, Elisabeth; Combourieu-Nebout, Nathalie; Blamart, Dominique; Genty, Dominique

2015-04-01

Understanding the climate mechanisms requires a precise knowledge of the sequence of events during major climate changes. In order to provide precise relationships between changes in orbital and/or greenhouse gases concentration forcing, sea level changes and high vs low latitudes temperatures, a common chronological framework for different paleoclimatic archives is required. Coherent chronologies for ice cores have been recently produced using a bayesian dating tool, DATICE (Lemieux-Dudon et al., 2010, Bazin et al., 2013, Veres et al., 2013). Such tool has been recently developed to include marine cores and speleothems in addition to ice cores. This new development should enable one to test the coherency of different chronologies using absolute and stratigraphic links as well as to provide relationship between climatic changes recorded in different archives. We present here a first application of multi-archive coherent dating including paleoclimatic archives from (1) Greenland (NGRIP ice core), (2) Mediterranean sea (marine core MD90-917, 41° N17° E, 1010 m) and (3) speleothems from the South of France and North Tunisia (Chauvet, Villars and La Mine speleothems, Genty et al., 2006). Thanks to the good absolute chronological constraints from annual layer counting in NGRIP, 14C and tephra layers in MD90-917 and U-Th dating in speleothems, we can provide a precise chronological framework for the last 50 ka (ie. thousand years before present). Then, we present different tests on how to combine the records from the different archives and give the most plausible scenario for the sequence of events at different latitudes over the last deglaciation. Bazin, L., Landais, A. ; Lemieu¬-Dudon, B. ; Kele, H. T. M. ; Veres, D. ; Parrenin, F. ; Martinerie, P. ; Ritz, C. ; Capron, E. ; Lipenkov, V. ; Loutre, M.-F. ; Raynaud, D. ; Vinther, B. ; Svensson, A. ; Rasmussen, S. ; Severi, M. ; Blunier, T. ; Leuenberger, M. ; Fischer, H. ; Masson-¬-Delmotte, V. ; Chappellaz, J

How effective is albedo modification (solar radiation management geoengineering) in preventing sea-level rise from the Greenland Ice Sheet?

International Nuclear Information System (INIS)

Applegate, Patrick J; Keller, Klaus

2015-01-01

Albedo modification (AM) is sometimes characterized as a potential means of avoiding climate threshold responses, including large-scale ice sheet mass loss. Previous work has investigated the effects of AM on total sea-level rise over the present century, as well as AM’s ability to reduce long-term (≫10 3 yr) contributions to sea-level rise from the Greenland Ice Sheet (GIS). These studies have broken new ground, but neglect important feedbacks in the GIS system, or are silent on AM’s effectiveness over the short time scales that may be most relevant for decision-making (<10 3 yr). Here, we assess AM’s ability to reduce GIS sea-level contributions over decades to centuries, using a simplified ice sheet model. We drive this model using a business-as-usual base temperature forcing scenario, as well as scenarios that reflect AM-induced temperature stabilization or temperature drawdown. Our model results suggest that (i) AM produces substantial near-term reductions in the rate of GIS-driven sea-level rise. However, (ii) sea-level rise contributions from the GIS continue after AM begins. These continued sea level rise contributions persist for decades to centuries after temperature stabilization and temperature drawdown begin, unless AM begins in the next few decades. Moreover, (iii) any regrowth of the GIS is delayed by decades or centuries after temperature drawdown begins, and is slow compared to pre-AM rates of mass loss. Combined with recent work that suggests AM would not prevent mass loss from the West Antarctic Ice Sheet, our results provide a nuanced picture of AM’s possible effects on future sea-level rise. (letter)

An Intensive Observation of Calving at Helheim Glacier, East Greenland

Science.gov (United States)

Holland, David M.; Voytenko, Denis; Christianson, Knut; Dixon, Timothy H.; Mei, M. Jeffrey; Parizek, Byron R.; Vankova, Irena; Walker, Ryan T.; Walter, Jacob I.; Nicholls, Keith;

Arctic Ocean outflow and glacier-ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

DEFF Research Database (Denmark)

Dmitrenko, Igor A.; Kirillov, Sergey A.; Rudels, Bert

2017-01-01

The first-ever conductivity-temperature-depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April-May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014-2015 drift. The CTD profiles are used to reveal...... the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has...... interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater...

Envisioning Greenland

DEFF Research Database (Denmark)

Ren, Carina Bregnholm

2012-01-01

Currently, the traditional ‘cool’ representation of Greenland as a frozen landscape devoid of people and human structures is being challenged by an emerging vision of Greenland as ‘hot’. This article presents and describes these two versions of Greenland, showing how demarcations of what is ‘nature...

Improved estimates of global sea level change from Ice Sheets, glaciers and land water storage using GRACE

Science.gov (United States)

Velicogna, I.; Hsu, C. W.; Ciraci, E.; Sutterley, T. C.

2015-12-01

We use observations of time variable gravity from GRACE to estimate mass changes for the Antarctic and Greenland Ice Sheets, the Glaciers and Ice Caps (GIC) and land water storage for the time period 2002-2015 and evaluate their total contribution to sea level. We calculate regional sea level changes from these present day mass fluxes using an improved scaling factor for the GRACE data that accounts for the spatial and temporal variability of the observed signal. We calculate a separate scaling factor for the annual and the long-term components of the GRACE signal. To estimate the contribution of the GIC, we use a least square mascon approach and we re-analyze recent inventories to optimize the distribution of mascons and recover the GRACE signal more accurately. We find that overall, Greenland controls 43% of the global trend in eustatic sea level rise, 16% for Antarctica and 29% for the GIC. The contribution from the GIC is dominated by the mass loss of the Canadian Arctic Archipelago, followed by Alaska, Patagonia and the High Mountains of Asia. We report a marked increase in mass loss for the Canadian Arctic Archipelago. In Greenland, following the 2012 high summer melt, years 2013 and 2014 have slowed down the increase in mass loss, but our results will be updated with summer 2015 observations at the meeting. In Antarctica, the mass loss is still on the rise with increased contributions from the Amundsen Sea sector and surprisingly from the Wilkes Land sector of East Antarctica, including Victoria Land. Conversely, the Queen Maud Land sector experienced a large snowfall in 2009-2013 and has now resumed to a zero mass gain since 2013. We compare sea level changes from these GRACE derived mass fluxes after including the atmospheric and ocean loading signal with sea level change from satellite radar altimetry (AVISO) corrected for steric signal of the ocean using Argo measurements and find an excellent agreement in amplitude, phase and trend in these estimates

North America-Greenland-Eurasian relative motions: implications for circum-arctic tectonic reconstructions

Energy Technology Data Exchange (ETDEWEB)

Rowley, D.B.; Lottes, A.L.; Ziegler, A.M.

1985-02-01

The Mesozoic-Cenozoic tectonic evolution of the Circum-Arctic region is based on constraints imposed by (1) relative motion histories of the three major plates (North America, Greenland, and Eurasia) and a number of smaller pieces, and (2) distribution and age of sutures, accretionary prisms, volcanic arcs, fold-thrust belts, stretched continental crust, strike-slip faults, and ocean floor. The authors conclude that: (1) North America and Eurasia remained relatively fixed to each other until the latest Cretaceous-Paleocene opening of the Labrador Sea-Baffin Bay and Greenland-Norwegian and Eurasian basins (earlier convergence between North America and Eurasia in the Bering Sea region shown on many reconstructions are artifacts of incorrect plate reconstructions); (2) the North Slope-Seward-Chukotka block has constituted an isthmus connection between North America and northeast Asia since at least the middle Paleozoic and did not rotate away from the Canadian Arctic; (3) the Canada basin opened behind a clockwise-rotating Alpha Cordillera-Mendeleyev ridge arc during the Early to middle Cretaceous and consumed older, Paleozoic(.) Makarov basin ocean floor (the Chukchi cap is a detached continental fragment derived from the Beaufort Sea; the North Slope Arctic margin is a left-lateral transform fault associated with the opening of the Canada basin); and (4) the Nares Strait fault has a net relative displacement of approximately 25 km, but actual motion between Greenland and northern Ellesmere was about 250 km of strongly transpressive motion that resulted in the Eurekan and Svalbardian orogenies.

Regional seesaw between the North Atlantic and Nordic Seas during the last glacial abrupt climate events

Directory of Open Access Journals (Sweden)

M. Wary

2017-06-01

Full Text Available Dansgaard–Oeschger oscillations constitute one of the most enigmatic features of the last glacial cycle. Their cold atmospheric phases have been commonly associated with cold sea-surface temperatures and expansion of sea ice in the North Atlantic and adjacent seas. Here, based on dinocyst analyses from the 48–30 ka interval of four sediment cores from the northern Northeast Atlantic and southern Norwegian Sea, we provide direct and quantitative evidence of a regional paradoxical seesaw pattern: cold Greenland and North Atlantic phases coincide with warmer sea-surface conditions and shorter seasonal sea-ice cover durations in the Norwegian Sea as compared to warm phases. Combined with additional palaeorecords and multi-model hosing simulations, our results suggest that during cold Greenland phases, reduced Atlantic meridional overturning circulation and cold North Atlantic sea-surface conditions were accompanied by the subsurface propagation of warm Atlantic waters that re-emerged in the Nordic Seas and provided moisture towards Greenland summit.

West Greenlandic Eskimo

DEFF Research Database (Denmark)

Trondhjem, Naja Blytmann; Fortescue, Michael David

West Greenlandic Eskimo. The current situation of the West Greenlandic language as principal means of communication among the majority Greenlandic population will be presented with special emphasis on the northwest hunting district of Upernavik, where traditional marine mammal hunting is still...... the principal economic activity. Research projects and language initiatives currently in progress within Greenland will be touched upon, as will the possibilities of communication with North American Inuit. West Greenlandic is unique among the native languages of the North American Arctic and Sub...

A Synthesis of the Basal Thermal State of the Greenland Ice Sheet

Science.gov (United States)

Macgregor, J. A.; Fahnestock, M. A.; Catania, G. A.; Aschwanden, A.; Clow, G. D.; Colgan, W. T.; Gogineni, S. P.; Morlighem, M.; Nowicki, S. M. J.; Paden, J. D.;

Effects of Cross-axis Wind Jet Events on the Northern Red Sea Circulation

Science.gov (United States)

Menezes, V. V.; Bower, A. S.; Farrar, J. T.

2016-12-01

Despite its small size, the Red Sea has a complex circulation. There are boundary currents in both sides of the basin, a meridional overturning circulation, water mass formation in the northern part and an intense eddy activity. This complex pattern is driven by strong air-sea interactions. The Red Sea has one of the largest evaporation rates of the global oceans (2m/yr), an intricate and seasonally varying wind pattern. The winds blowing over the Northern Rea Sea (NRS, north of 20N) are predominantly southeastward along the main axis all year round; in the southern, they reverse seasonally due to the monsoonal regime. Although the winds are mostly along-axis in the NRS, several works have shown that sometimes during the boreal winter, the winds blow in a cross-axis direction. The westward winds from Saudi Arabia bring relatively cold dry air and dust from the desert, enhancing heat loss and evaporation off the Red Sea. These wind-jet events may contribute to increased eddy activity and are a trigger for water mass formation. Despite that, our knowledge about the cross-axis winds and their effect on NRS circulation is still incipient. In the present work we analyze 10-years of Quikscat scatterometer winds and altimetric sea surface height anomalies, together with 2-yrs of mooring data, to characterize the westward wind jet events and their impacts on the circulation. We show that the cross-axis winds are, indeed, an important component of the wind regime, explaining 11% of wind variability of the NRS (well-described by a 2nd EOF mode). The westward events occur predominantly in the winter, preferentially in January (about 15 events in 10-years) and have a mean duration of 4-5 days, with a maximum of 12 days (north of 22N). There are around 6 events per year, but in 2002-2003 and 2007-2008, twice more events were detected. The westward wind events are found to strongly modify the wind stress curl, causing a distinct positive/negative curl pattern along the main axis

Adjustment to reality - Social response to climate changes in Greenland

DEFF Research Database (Denmark)

Rasmussen, Rasmus Ole

2007-01-01

Greenland has experienced three major socio-economic shifts during the 19th and 20th century, all of them induced by the interactions between the natural system of climate change, and the socio-economic and sociotechnical system of resource exploitation The first was the shift from a sea mammal b...

Strategic environmental impact assessment of hydrocarbon activities in the Disko West area[Greenland

Energy Technology Data Exchange (ETDEWEB)

Mosbech, A; Boertmann, D; Jespersen, Martin

2007-05-15

This publication is a strategic environmental impact assessment of activities related to exploration, development and exploitation of hydrocarbons in the sea of West Greenland between 67 deg. and 71 deg. N (= the Disko West Area). (au)

What can we learn from the self-attraction and loading fingerprints about pre-GRACE mass-loss acceleration from Greenland and Antarctica?

Science.gov (United States)

Davis, J. L.; Vinogradova, N. T.

2017-12-01

Tide-gauge records from the North Atlantic reveal significant acceleration in sea level starting in the late 20th century. We have analyzed the tide-gauge data using a model in which the accelerations are assumed to be zero prior to 1990. The estimated accelerations range from -1 to +3 m cy-2 and exhibit a systematic spatial variability. Davis and Vinogradova [2017] demonstrated that to model this variability in sea-level acceleration requires contributions from several distinct physical processes: accelerated mass loss from the Greenland and Antarctic Ice Sheets and acceleration associated with ocean circulation and heat uptake. Atmospheric pressure also contributes to the observed changes in sea level, at a much smaller amplitude. Because we are focusing on sea-level accelerations (i.e., sea-level rate changes), the contribution from Glacial Isostatic Adjustment (GIA) is negligible. Modeling of observed sea-level acceleration is achieved using external constraints for the important physical processes. Using GRACE results, we can calculate the sea-level "fingerprints" for Greenland and Antarctica associated with mass loading and gravitational perturbations. For the North Atlantic, Greenland induces a significant spatial variation in sea-level change—dominated by the solid-Earth response to the mass loss—whereas Antarctica contributes a spatially constant acceleration. The observations prefer a scaling of the solid-Earth/gravitational response, and we present the implications of this result for ice-mass changes prior to the onset of GRACE observations (2002-3).

Arctic Ocean outflow and glacier-ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

Science.gov (United States)

Dmitrenko, Igor A.; Kirillov, Sergey A.; Rudels, Bert; Babb, David G.; Toudal Pedersen, Leif; Rysgaard, Søren; Kristoffersen, Yngve; Barber, David G.

2017-12-01

The first-ever conductivity-temperature-depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April-May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014-2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature-salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean-glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

A multisensor approach to sea ice classification for the validation of DMSP-SSM/I passive microwave derived sea ice products

Science.gov (United States)

Steffen, K.; Schweiger, A. J.

1990-01-01

The validation of sea ice products derived from the Special Sensor Microwave Imager (SSM/I) on board a DMSP platform is examined using data from the Landsat MSS and NOAA-AVHRR sensors. Image processing techniques for retrieving ice concentrations from each type of imagery are developed and results are intercompared to determine the ice parameter retrieval accuracy of the SSM/I NASA-Team algorithm. For case studies in the Beaufort Sea and East Greenland Sea, average retrieval errors of the SSM/I algorithm are between 1.7 percent for spring conditions and 4.3 percent during freeze up in comparison with Landsat derived ice concentrations. For a case study in the East Greenland Sea, SSM/I derived ice concentration in comparison with AVHRR imagery display a mean error of 9.6 percent.

Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Atlantic Ocean, North Greenland Sea and Norwegian Sea from 1992-07-12 to 1992-07-28 (NODC Accession 0113558)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113558 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Atlantic Ocean, North Greenland Sea and...

Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Atlantic Ocean, North Greenland Sea and Norwegian Sea from 1994-07-23 to 1994-08-16 (NODC Accession 0113560)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113560 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Atlantic Ocean, North Greenland Sea and...

On the Origin of Multidecadal to Centennial Greenland Temperature Anomalies Over the Past 800 yr

Science.gov (United States)

Kobashi, T.; Shindell, D. T.; Kodera, K.; Box, J. E.; Nakaegawa, T.; Kawamura, K.

2013-01-01

The surface temperature of the Greenland ice sheet is among the most important climate variables for assessing how climate change may impact human societies due to its association with sea level rise. However, the causes of multidecadal-to-centennial temperature changes in Greenland temperatures are not well understood, largely owing to short observational records. To examine these, we calculated the Greenland temperature anomalies (GTA[G-NH]) over the past 800 yr by subtracting the standardized northern hemispheric (NH) temperature from the standardized Greenland temperature. This decomposes the Greenland temperature variation into background climate (NH); polar amplification; and regional variability (GTA[G-NH]). The central Greenland polar amplification factor as expressed by the variance ratio Greenland/NH is 2.6 over the past 161 yr, and 3.3-4.2 over the past 800 yr. The GTA[G-NH] explains 31-35%of the variation of Greenland temperature in the multidecadal-to-centennial time scale over the past 800 yr. We found that the GTA[G-NH] has been influenced by solar-induced changes in atmospheric circulation patterns such as those produced by the North Atlantic Oscillation/Arctic Oscillation (NAO/AO). Climate modeling and proxy temperature records indicate that the anomaly is also likely linked to solar-paced changes in the Atlantic meridional overturning circulation (AMOC) and associated changes in northward oceanic heat transport.

On the origin of multidecadal to centennial Greenland temperature anomalies over the past 800 yr

Directory of Open Access Journals (Sweden)

T. Kobashi

2013-03-01

Full Text Available The surface temperature of the Greenland ice sheet is among the most important climate variables for assessing how climate change may impact human societies due to its association with sea level rise. However, the causes of multidecadal-to-centennial temperature changes in Greenland temperatures are not well understood, largely owing to short observational records. To examine these, we calculated the Greenland temperature anomalies (GTA[G-NH] over the past 800 yr by subtracting the standardized northern hemispheric (NH temperature from the standardized Greenland temperature. This decomposes the Greenland temperature variation into background climate (NH; polar amplification; and regional variability (GTA[G-NH]. The central Greenland polar amplification factor as expressed by the variance ratio Greenland/NH is 2.6 over the past 161 yr, and 3.3–4.2 over the past 800 yr. The GTA[G-NH] explains 31–35% of the variation of Greenland temperature in the multidecadal-to-centennial time scale over the past 800 yr. We found that the GTA[G-NH] has been influenced by solar-induced changes in atmospheric circulation patterns such as those produced by the North Atlantic Oscillation/Arctic Oscillation (NAO/AO. Climate modeling and proxy temperature records indicate that the anomaly is also likely linked to solar-paced changes in the Atlantic meridional overturning circulation (AMOC and associated changes in northward oceanic heat transport.

Greenland

DEFF Research Database (Denmark)

Gad, Ulrik Pram

2014-01-01

in 1979 and made the 1985 withdrawal possible. On 25 November 2008, a majority of the people of Greenland voted in favour of enhanced home rule – ‘self-government’ – still within formal Danish sovereignty. Denmark and Greenland alike are preparing for a future envisioned as involving climate change...

Towards an assessment of the balance state of the Greenland Ice Sheet

Energy Technology Data Exchange (ETDEWEB)

Boeggild, C.E.; Mayer, C.; Podlech, S.; Taurisano, A.; Nielsen, S.

2004-07-01

The climate of Europe is strongly influenced by heat transport by ocean currents flowing from equatorial regions towards the Arctic. During recent years, research has been increasingly focused on factors affecting this circulation, e.g. the freshwater budget of the Arctic that is influenced by glacial melt water from north and East Greenland outlet glaciers. Furthermore, the climate is affected by snow cover, which, apart from its contribution to the freshwater budget, provides feedback effects in that it reflects most of the solar radiation. Apart from Arctic sea-ice cover, the Greenland Ice Sheet is the largest permanent ice- and snow-covered area in the northern hemisphere, with an area of 1.67 x 10{sup 6} km{sup 2} and by far the largest storage of ice with a volume of 2.93 x 10{sup 6} km{sup 3}. Most of the mass loss from the Greenland Ice Sheet occurs in the marginal region of the ice sheet, which is also the area where the largest changes in albedo occur. The Geological Survey of Denmark and Greenland (GEUS) has for many years carried out research along the Greenland Ice Sheet margin to monitor changes of mass balance and melt conditions. (BA)

The peopling of Greenland

DEFF Research Database (Denmark)

Pereira, Vania; Tomas Mas, Carmen; Sanchez, Juan J

2015-01-01

The peopling of Greenland has a complex history shaped by population migrations, isolation and genetic drift. The Greenlanders present a genetic heritage with components of European and Inuit groups; previous studies using uniparentally inherited markers in Greenlanders have reported evidence...... of a sex-biased, admixed genetic background. This work further explores the genetics of the Greenlanders by analysing autosomal and X-chromosomal data to obtain deeper insights into the factors that shaped the genetic diversity in Greenlanders. Fourteen Greenlandic subsamples from multiple geographical...... settlements were compared to assess the level of genetic substructure in the Greenlandic population. The results showed low levels of genetic diversity in all sets of the genetic markers studied, together with an increased number of X-chromosomal loci in linkage disequilibrium in relation to the Danish...

The Quaternary geology of the Narssaq area, South Greenland

DEFF Research Database (Denmark)

Funder, Svend Visby

1979-01-01

The topography and glacial striations in th~ Narssaq area indicate that the ice age glacial regime in this part of Greenland was characterized by ice movement constrained by the local topography, and a shallow depth of the ice cover. Erratics observed 1200 m above sea level provide a minimum esti...... in the ice sheet. The low altitudes of the marine limits (47-60 m above sea level) also may be interpreted to reflect shallow ice thicknesses, while the few available dates for the timing of the isostatic upheaval, indicate that the Narssaq area was free of ice c. 11 000 years ago....

A Meteorological Experiment in the Melting Zone of the Greenland Ice Sheet

NARCIS (Netherlands)

Oerlemans, J.; Vugts, H.F.

1993-01-01

Preliminary results are described from a glaciometeorological experiment carried out in the margin (melting zone) of the Greenland ice sheet in the summers of 1990 and 1991. This work was initiated within the framework of a Dutch research program on land ice and sea level change. Seven

A 10,000-year record of Arctic Ocean sea-ice variability—view from the beach

DEFF Research Database (Denmark)

Funder, Svend Visby; Goosse, Hugues; Jepsen, Hans Festersen

2011-01-01

We present a sea-ice record from northern Greenland covering the past 10,000 years. Multiyear sea ice reached a minimum between ~8500 and 6000 years ago, when the limit of year-round sea ice at the coast of Greenland was located ~1000 kilometers to the north of its present position. The subsequen...... of uniformity in past sea-ice changes, which is probably related to large-scale atmospheric anomalies such as the Arctic Oscillation, is not well reproduced in models. This needs to be further explored, as it is likely to have an impact on predictions of future sea-ice distribution...

Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the ARANDA in the North Atlantic Ocean and North Greenland Sea from 1997-08-05 to 1997-09-25 (NODC Accession 0115602)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115602 includes chemical, discrete sample, physical and profile data collected from ARANDA in the North Atlantic Ocean and North Greenland Sea from...

Arctic Ocean outflow and glacier–ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland

Directory of Open Access Journals (Sweden)

I. A. Dmitrenko

2017-12-01

Full Text Available The first-ever conductivity–temperature–depth (CTD observations on the Wandel Sea shelf in northeastern Greenland were collected in April–May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014–2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature–salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean–glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

BedMachine v3: Complete Bed Topography and Ocean Bathymetry Mapping of Greenland From Multibeam Echo Sounding Combined With Mass Conservation

DEFF Research Database (Denmark)

Morlighem, M.; Williams, C. N.; Rignot, E.

2017-01-01

Greenland's bed topography is a primary control on ice flow, grounding line migration, calving dynamics, and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic water (AW) that rapidly melts and undercuts Greenland's marine‐terminating glaciers. Here we...... present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness data through a mass conservation approach. A new 150 m horizontal resolution bed topography/bathymetric map of Greenland is constructed with seamless transitions at the ice/ocean interface......, yielding major improvements over previous data sets, particularly in the marine‐terminating sectors of northwest and southeast Greenland. Our map reveals that the total sea level potential of the Greenland ice sheet is 7.42 ± 0.05 m, which is 7 cm greater than previous estimates. Furthermore, it explains...

New interpretations based on seismic and modelled well data and their implications for the tectonic evolution of the west Greenland continental margin

DEFF Research Database (Denmark)

Mcgregor, E.D.; Nielsen, S.B.; Stephenson, R.A.

Davis Strait is situated between Baffin Island and Greenland and forms part of a sedimentary basin system, linking Labrador Sea and Baffin Bay, developed during Cretaceous and Palaeocene rifting that culminated in a brief period of sea-floor spreading in the late Palaeocene and Eocene. Seismic...... reflection profiles and exploration wells along the Greenland margin of Davis Strait have been analysed in order to elucidate uplift events affecting sedimentary basin development during the Cenozoic with a focus on postulated Neogene (tectonic) uplift affecting the west Greenland continental margin...... tectonic event. An interpretation in which the inferred onshore cooling is related to erosion of pre-existing topography is more consistent with our new results from the offshore region. These results will have important implications for other continental margins developed throughout the Atlantic...

TopoGreenland: Lithospheric structure and topography in Central-Eastern Greenland

Science.gov (United States)

Thybo, H.; Shulgin, A.; Kraft, H. A.; Vinnik, L. P.

2017-12-01

We present models of the seismic structure of the crust and upper mantle in the interior of Greenland based on new seismological data from the TopoGreenland experiment. Until this experiment, all seismic data in Greenland was acquired close to the coast, where the crustal structure is affected by oceanic break-up. The TopoGreenland data acquisition programme in central-eastern Greenland included the first controlled source seismic experiment in interior Greenland and deployment of 24 broadband (BB) onshore stations for 3 years, partly on the ice cap. The 320 km long seismic refraction/wide-angle reflection profile was acquired on the ice cap by a team of six people during two-months in summer of 2011. We present a 2D velocity model of the crust based on tomographic inversion and forward ray tracing modelling of the controlled source data. It shows a decrease of crustal thickness from 47 km below the centre of Greenland in the western to 40 km in its eastern part of the profile. High lower crustal velocities (Vp 6.8 - 7.3 km/s) below central Greenland may result from past collision tectonics or be related to the passage of the Iceland mantle plume. Crustal receiver functions in the surrounding area demonstrate constant structure along the coast and pronounced, relatively sharp variation in crustal thickness around the mountains at the edge of the ice cap. Surprisingly the thickest crust is observed below the lowest topography under the ice cap, whereas the crust is thin below the high mountains at its edge, and thins further below elevated topography out to the coast. Receiver Function interpretation of the mantle and transition zone structure shows a complicated mosaic variation that cannot be correlated to the variation in topography. The origin of the pronounced mountain ranges around the North Atlantic Ocean with average elevation above 1500 m and peak elevations of more than 3.5 km near Scoresby Sund in Eastern Greenland, is unknown. Our new results demonstrate

White Sea's Severe Winter Hydrological Hazard and Its Effect On Decrease of Population of Greenland Seals (1998/99 Winter Ecological Catastrophe)

Science.gov (United States)

Melentyev, Konstantin V.; Chernook, Vladimir I.

Types of hydrological hazards are various but its agencies are especially diversified . At this study hazard effects will be assessed for White Sea population of Greenland seals - a representatives of high level of marine fodder chains and the prime part of the Arctic nature. Number of population and type of their migration are strongly depended from different meteorological and hydrological parameters and processes, climate change and anthropogenical press, including pollution and fur-seal fishery, create additional problems. Especially hard situation happens now with the ice- associated sea mammals (p olar bear, seal, walrus, etc.). Mass destruction of seals in the White Sea (ecological catastrophe) which happens periodically is close connected with different kind of meteorological and hydrological hazard. Greenland seals selected these water areas for whelping where a rookeries are organized on pack ice. But severe winter conditions (long-run severe frosts and NE winds) can modify ice regime of the White Sea which lead to effect "blocking" of pack ice (and whelping rookeries) inside the "Basin". These features stimulated strong reduction number ofseals (especially pups). Marine biology use modelling of the system "sea mammal-media", study "behavior factors" and mammals biodiversity at the different natural conditions. But the main critical goal is the development of special observational network for the White Sea and contiguous regions. A contemporary technologies assume integration of remote sensing and in situ hydro-chemical measurements. Airborne IR and visible observation of the marginal Arctic seas became now an indispensable part of marine ecological investigations. Application of satellite data for monitoring of sea mammals has been attractive also but practical use is restrained by its small spatial resolution, daytime illumination and cloud influence in the Arctic. Launching ERS synthetic aperture radar (SAR) in 1991, which provides global all- weather

Post-colonial identity in Greenland?

DEFF Research Database (Denmark)

Gad, Ulrik Pram

2009-01-01

could be furthered by bringing politics back in. Based on a discourse analysis of the Greenlandic debate on language, this paper makes three claims: First, the identity projects promoted in Greenland are based on an essentialist conception of identity. Secondly, Greenlandic identity discourse combines......In the gradual unravelling of Greenland’s colonial relationship to Denmark, an essentialist conceptualization of Greenlandic identity has played a significant role. However, both our scholarly understanding of post-colonial Greenlandic identity and the process towards independence for Greenland...... elements of traditional Inuit culture and elements of colonial modernity. Thirdly, monolingual Greenlanders are those with the most to gain from abandoning the dichotomy of essentialist identities. Strategically, the paper suggests a post-post-colonial Greenlandic identity as a means of avoiding...

The peripheral olfactory organ in the Greenland shark Somniosus microcephalus (Bloch and Schneider, 1801

Directory of Open Access Journals (Sweden)

Laura Ghigliotti

2015-11-01

Full Text Available The Greenland shark Somniosus microcephalus (Bloch and Schneider, 1801 is the largest predatory fish in Arctic waters. The socio-economic significance of Greenland shark is demonstrated by its impact on the fishing cultures in Greenland, Scandinavia and Iceland for centuries. The fundamental biology and ecological role of Greenland shark, on the other hand, is virtually unknown. Although knowledge of its life history is limited, increasing evidence indicates that the Greenland shark may undertake long-distance migrations and perform vertical movements from the surface to the deep sea. It is an omnivorous species feeding on carrion and a wide variety of pelagic and bottom-dwelling organisms ranging from invertebrates to mammals, and including active species such as fishes and seals. Accordingly, Greenland shark should be recognized as a top predator, with a strong potential to influence the trophic dynamics of the Arctic marine ecosystem. The sensory biology of Greenland shark is scarcely studied, and considering the importance of olfaction in chemoreception, feeding and other behavioral traits, we examined the architecture of the peripheral olfactory organ where olfactory cues are received from the environment – the olfactory rosette. The structural organization of the olfactory rosette, in terms of histological features of the sensory epithelium, number of primary lamellae and total sensory surface area, provides a first proxy of the olfactory capability of Greenland shark. Based on own results and published studies, the overall morphology of the olfactory rosette is viewed in context of the functional and trophic ecology among other elasmobranch species.

An approach to estimate the freshwater contribution from glacial melt and precipitation in East Greenland shelf waters using colored dissolved organic matter (CDOM)

DEFF Research Database (Denmark)

Stedmon, Colin; Granskog, Mats A.; Dodd, Paul A.

2015-01-01

Changes in the supply and storage of freshwater in the Arctic Ocean and its subsequent export to the North Atlantic can potentially influence ocean circulation and climate. In order to understand how the Arctic freshwater budget is changing and the potential impacts, it is important to develop......, and precipitation) and sea ice melt. We develop this approach further and investigate the use of an additional tracer, colored dissolved organic matter (CDOM), which is largely specific to freshwater originating from Arctic rivers. A robust relationship between the freshwater contribution from meteoric water...... processes (riverine input and sea ice formation), while previously, these waters where thought to be derived from open sea processes (cooling and sea ice formation) in the northern Barents and Kara Seas. In Greenlandic coastal waters the meteoric water contribution is influenced by Greenland ice sheet...

Lithostratigraphy of the Cretaceous–Paleocene Nuussuaq Group, Nuussuaq Basin, West Greenland

Directory of Open Access Journals (Sweden)

Dam, Gregers

2009-12-01

Full Text Available The Nuussuaq Basin is the only exposed Cretaceous–Paleocene sedimentary basin in West Greenland and is one of a complex of linked rift basins stretching from the Labrador Sea to northern Baffin Bay. These basins developed along West Greenland as a result of the opening of the Labrador Sea in Late Mesozoic to Early Cenozoic times. The Nuussuaq Basin is exposed in West Greenland between 69°N and 72°N on Disko, Nuussuaq, Upernivik Ø, Qeqertarsuaq, Itsaku and Svartenhuk Halvø and has also been recorded in a number of shallow and deep wells in the region. The sediments are assigned to the more than 6 km thick Nuussuaq Group (new which underlies the Palaeogene plateau basalts of the West Greenland Basalt Group. The sediment thickness is best estimated from seismic data; in the western part of the area, seismic and magnetic data suggest that the succession is at least 6 km and possibly as much as 10 km thick. The exposed Albian–Paleocene part of the succession testifies to two main episodes of regional rifting and basin development: an EarlyCretaceous and a Late Cretaceous – Early Paleocene episode prior to the start of sea-floor spreading in mid-Paleocene time. This exposed section includes fan delta, fluviodeltaic, shelfal and deepmarine deposits. The Nuussuaq Group is divided into ten formations, most of which have previously been only briefly described, with the exception of their macrofossil content. In ascending stratigraphic order, the formations are: the Kome Formation, the Slibestensfjeldet Formation (new, the Upernivik Næs Formation, the Atane Formation (including four new members – the Skansen, Ravn Kløft, Kingittoq and Qilakitsoq Members – and one new bed, the Itivnera Bed, the Itilli Formation (new, including four new members: the Anariartorfik, Umiivik, Kussinerujuk and Aaffarsuaq Members, the Kangilia Formation (including the revised Annertuneq Conglomerate Member andthe new Oyster–Ammonite Conglomerate Bed, the

The fate of the Greenland Ice Sheet in a geoengineered, high CO2 world

International Nuclear Information System (INIS)

Irvine, Peter J; Lunt, Daniel J; Stone, Emma J; Ridgwell, Andy

2009-01-01

Solar radiation management (SRM) geoengineering has been proposed as one means of helping avoid the occurrence of dangerous climate change and undesirable state transitions ('tipping points') in the Earth system. The irreversible melting of the Greenland Ice Sheet is a case in point-a state transition that could occur as a result of CO 2 -driven elevated global temperatures, and one leading to potentially catastrophic sea-level rise. SRM schemes such as the creation of a 'sunshade' or injection of sulfate aerosols into the stratosphere could reduce incoming solar radiation, and in theory balance, in a global mean, the greenhouse warming resulting from elevated concentrations of CO 2 in the atmosphere. Previous work has highlighted that a geoengineered world would have: warming towards the poles, cooling in the tropics, and a reduction in the global hydrological cycle, which may have important implications for the Greenland Ice Sheet. Using a fully coupled global climate model in conjunction with an ice sheet model, we assess the consequences for the mass balance of the Greenland Ice Sheet of the reorganization of climate patterns by the combination of high CO 2 and geoengineering. We find that Greenland surface temperature and precipitation anomalies, compared to the pre-industrial situation, decrease almost linearly with increasing levels of SRM geoengineering, but that these combine to create a highly non-linear response of the ice sheet. The substantial melting of the Greenland Ice Sheet predicted for four times pre-industrial CO 2 levels is prevented in our model with only a partial application of SRM, and hence without having to fully restore the global average temperature back to pre-industrial levels. This suggests that the degree of SRM geoengineering required to mitigate the worst impacts of greenhouse warming, such as sea-level rise, need not be as extensive as generally assumed.

Dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the POLARSTERN in the Arctic Ocean and North Greenland Sea from 1987-07-04 to 1987-09-02 (NODC Accession 0113916)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113916 includes chemical, discrete sample, physical and profile data collected from POLARSTERN in the Arctic Ocean and North Greenland Sea from...

Airborne Lidar and Radar Measurments In and Around Greenland CryoVEx 2006

DEFF Research Database (Denmark)

Stenseng, Lars; Hvidegaard, Sine Munk; Skourup, Henriette

Air Greenland. The main purpose was to collect coincident ASIRAS and laser data at validation sites placed on land ice and sea ice in the Arctic area and offer logistic support to ground teams. The data collected will be important for the understanding of CryoSat-2 radar signals. A number...

Greenland ice sheet surface mass balance: evaluating simulations and making projections with regional climate models

Directory of Open Access Journals (Sweden)

J. G. L. Rae

2012-11-01

Full Text Available Four high-resolution regional climate models (RCMs have been set up for the area of Greenland, with the aim of providing future projections of Greenland ice sheet surface mass balance (SMB, and its contribution to sea level rise, with greater accuracy than is possible from coarser-resolution general circulation models (GCMs. This is the first time an intercomparison has been carried out of RCM results for Greenland climate and SMB. Output from RCM simulations for the recent past with the four RCMs is evaluated against available observations. The evaluation highlights the importance of using a detailed snow physics scheme, especially regarding the representations of albedo and meltwater refreezing. Simulations with three of the RCMs for the 21st century using SRES scenario A1B from two GCMs produce trends of between −5.5 and −1.1 Gt yr⁻² in SMB (equivalent to +0.015 and +0.003 mm sea level equivalent yr⁻², with trends of smaller magnitude for scenario E1, in which emissions are mitigated. Results from one of the RCMs whose present-day simulation is most realistic indicate that an annual mean near-surface air temperature increase over Greenland of ~ 2°C would be required for the mass loss to increase such that it exceeds accumulation, thereby causing the SMB to become negative, which has been suggested as a threshold beyond which the ice sheet would eventually be eliminated.

Angalasut, an education and outreach project to create a bridge between scientists, local population in Greenland and the general public

Science.gov (United States)

Bourgain, Pascaline

2015-04-01

Bridging Science and Society has now become a necessity for scientists to develop new partnerships with local communities and to raise the public interest for scientific activities. The French-Greenlandic educational project called "Angalasut" reflects this desire to create a bridge between science, local people and the general public. This program was set up on the 2012-2013 school year, as part of an international scientific program dedicated to study the interactions between the ocean and glaciers on the western coast of Greenland, in the Uummannaq fjord. Greenlandic and French school children were involved in educational activities, in classrooms and out on the field, associated with the scientific observations conducted in Greenland (glacier flow, ocean chemical composition and circulation, instrumentation...). In Greenland, the children had the opportunity to come on board the scientific sailing boat, and in France, several meetings were organized between the children and the scientists of the expedition. In the small village of Ikerasak, the children interviewed Elders about sea ice evolution in the area. These activities, coupled to the organization of public conferences and to the creation of a trilingual website of the project (French, Greenlandic, English) aimed at explaining why scientists come to study Greenland environment. This was the opportunity for scientists to discuss with villagers who could testify on their changing environment over the past decades. A first step toward a future collaboration between scientists and villagers that would deserve further development... The project Angalasut was also the opportunity for Greenlandic and French school children to exchange about their culture and their environment through Skype communications, the exchange of mails (drawings, shells...), the creation of a society game about European fauna and flora... A meeting in France between the two groups of children is considered, possibly in summer 2015

Satellite altimetry in sea ice regions - detecting open water for estimating sea surface heights

Science.gov (United States)

Müller, Felix L.; Dettmering, Denise; Bosch, Wolfgang

2017-04-01

The Greenland Sea and the Farm Strait are transporting sea ice from the central Arctic ocean southwards. They are covered by a dynamic changing sea ice layer with significant influences on the Earth climate system. Between the sea ice there exist various sized open water areas known as leads, straight lined open water areas, and polynyas exhibiting a circular shape. Identifying these leads by satellite altimetry enables the extraction of sea surface height information. Analyzing the radar echoes, also called waveforms, provides information on the surface backscatter characteristics. For example waveforms reflected by calm water have a very narrow and single-peaked shape. Waveforms reflected by sea ice show more variability due to diffuse scattering. Here we analyze altimeter waveforms from different conventional pulse-limited satellite altimeters to separate open water and sea ice waveforms. An unsupervised classification approach employing partitional clustering algorithms such as K-medoids and memory-based classification methods such as K-nearest neighbor is used. The classification is based on six parameters derived from the waveform's shape, for example the maximum power or the peak's width. The open-water detection is quantitatively compared to SAR images processed while accounting for sea ice motion. The classification results are used to derive information about the temporal evolution of sea ice extent and sea surface heights. They allow to provide evidence on climate change relevant influences as for example Arctic sea level rise due to enhanced melting rates of Greenland's glaciers and an increasing fresh water influx into the Arctic ocean. Additionally, the sea ice cover extent analyzed over a long-time period provides an important indicator for a globally changing climate system.

Annual Greenland Accumulation Rates (2009-2012) from Airborne Snow Radar

Science.gov (United States)

Koenig, Lora S.; Ivanoff, Alvaro; Alexander, Patrick M.; MacGregor, Joseph A.; Fettweis, Xavier; Panzer, Ben; Paden, John D.; Forster, Richard R.; Das, Indrani; McConnell, Joseph R.;

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HAKON MOSBY in the North Greenland Sea from 1996-11-21 to 1996-11-30 (NODC Accession 0113544)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113544 includes chemical, discrete sample, physical and profile data collected from HAKON MOSBY in the North Greenland Sea from 1996-11-21 to...

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HAKON MOSBY in the North Greenland Sea from 1994-02-03 to 1994-02-23 (NODC Accession 0117371)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0117371 includes chemical, discrete sample, physical and profile data collected from HAKON MOSBY in the North Greenland Sea from 1994-02-03 to...

Investigating Margin and Grounding Line Dynamics with a Coupled Ice and Sea Level Model

Science.gov (United States)

Kuchar, J.; Milne, G. A.

2017-12-01

We present results from the coupling of an adaptive mesh glaciological model (BISICLES) with a model of glacial isostatic adjustment and sea level. We apply this coupled model to study the deglaciation of the Greenland Ice Sheet (GrIS) from the last glacial maximum. The proximity of the GrIS to the much larger Laurentide results in an east-west gradient in sea level rates across Greenland during the deglaciation. We investigate the impacts of this sea level gradient on ice and grounding line dynamics at the margins, as well as the influence of both local and non-local ice on sea level and ice dynamics.

Greenland and Natural Resources

DEFF Research Database (Denmark)

Lyck, Lise

Greenland policy can delay and maybe change the future of the forecasted development of the use of natural resources. This book is relevant for anyone interested in Greenland in general and the development of Greenland both politically and economically and in relation natural resources....

On the Application of Science Systems Engineering and Uncertainty Quantification for Ice Sheet Science and Sea Level Projections

Science.gov (United States)

Schlegel, Nicole-Jeanne; Boening, Carmen; Larour, Eric; Limonadi, Daniel; Schodlok, Michael; Seroussi, Helene; Watkins, Michael

2017-04-01

Research and development activities at the Jet Propulsion Laboratory (JPL) currently support the creation of a framework to formally evaluate the observational needs within earth system science. One of the pilot projects of this effort aims to quantify uncertainties in global mean sea level rise projections, due to contributions from the continental ice sheets. Here, we take advantage of established uncertainty quantification tools embedded within the JPL-University of California at Irvine Ice Sheet System Model (ISSM). We conduct sensitivity and Monte-Carlo style sampling experiments on forward simulations of the Greenland and Antarctic ice sheets. By varying internal parameters and boundary conditions of the system over both extreme and credible worst-case ranges, we assess the impact of the different parameter ranges on century-scale sea level rise projections. The results inform efforts to a) isolate the processes and inputs that are most responsible for determining ice sheet contribution to sea level; b) redefine uncertainty brackets for century-scale projections; and c) provide a prioritized list of measurements, along with quantitative information on spatial and temporal resolution, required for reducing uncertainty in future sea level rise projections. Results indicate that ice sheet mass loss is dependent on the spatial resolution of key boundary conditions - such as bedrock topography and melt rates at the ice-ocean interface. This work is performed at and supported by the California Institute of Technology's Jet Propulsion Laboratory. Supercomputing time is also supported through a contract with the National Aeronautics and Space Administration's Cryosphere program.

Modelling the short-term response of the Greenland ice-sheet to global warming

NARCIS (Netherlands)

Wal, R.S.W. van de; Oerlemans, J.

1997-01-01

A two-dimensional vertically integrated ice flow model has been developed to test the importance of various processes and concepts used for the prediction of the contribution of the Greenland ice-sheet to sea-level rise over the next 350 y (short-term response). The mass balance is modelled by the

Solitary Waves of Ice Loss Detected in Greenland Crustal Motion

Science.gov (United States)

Adhikari, S.; Ivins, E. R.; Larour, E. Y.

2017-12-01

The annual cycle and secular trend of Greenland mass loading are well recorded in measurements of solid Earth deformation. While bedrock vertical displacements are in phase with loading as inferred from space observations, horizontal motions have received almost no attention. The horizontal bedrock displacements can potentially track the spatiotemporal detail of mass changes with great fidelity. Our analysis of Greenland crustal motion data reveals that a significant excitation of horizontal amplitudes occurs during the intense Greenland melting. A suite of space geodetic observations and climate reanalysis data cannot explain these large horizontal displacements. We discover that solitary seasonal waves of substantial mass transport traveled through Rink Glacier in 2010 and 2012. We deduce that intense summer melting enhanced either basal lubrication or shear softening, or both, causing the glacier to thin dynamically. The newly routed upstream sublglacial water was likely to be both retarded and inefficient, thus providing a causal mechanism for the prolonged ice transport to continue well into the winter months. As the climate continues to produce increasingly warmer spring and summer, amplified seasonal waves of mass transport may become ever more present in years of future observations. Increased frequency of amplified seasonal mass transport may ultimately strengthen the Greenland's dynamic ice mass loss, a component of the balance that will have important ramifications for sea level rise. This animation shows a solitary wave passing through Rink Glacier, Greenland, in 2012, recorded by the motion of a GPS station (circle with arrow). Darker blue colors within the flow indicate mass loss, red colors show mass gain. The star marks the center of the wave. Credit: NASA/JPL-Caltech

Telemedicine in Greenland: Citizens' Perspectives.

Science.gov (United States)

Nielsen, Lasse O; Krebs, Hans J; Albert, Nancy M; Anderson, Nick; Catz, Sheryl; Hale, Timothy M; Hansen, John; Hounsgaard, Lise; Kim, Tae Youn; Lindeman, David; Spindler, Helle; Marcin, James P; Nesbitt, Thomas; Young, Heather M; Dinesen, Birthe

2017-05-01

Telemedicine may have the possibility to provide better access to healthcare delivery for the citizens. Telemedicine in arctic remote areas must be tailored according to the needs of the local population. Therefore, we need more knowledge about their needs and their view of telemedicine. The aim of this study has been to explore how citizens living in the Greenlandic settlements experience the possibilities and challenges of telemedicine when receiving healthcare delivery in everyday life. Case study design was chosen as the overall research design. Qualitative interviews (n = 14) were performed and participant observations (n = 80 h) carried out in the local healthcare center in the settlements and towns. A logbook was kept and updated each day during the field research in Greenland. Observations were made of activities in the settlements. Data collected on citizens' views about the possibilities of using telemedicine in Greenland revealed the following findings: Greenlandic citizens are positive toward telemedicine, and telemedicine can help facilitate improved access to healthcare for residents in these Greenlandic settlements. Regarding challenges in using telemedicine in Greenland, the geographical and cultural context hinders accessibility to the Greenlandic healthcare system, and telemedicine equipment is not sufficiently mobile. Greenlandic citizens are positive toward telemedicine and regard telemedicine as a facilitator for improved access for healthcare in the Greenlandic settlements. We have identified challenges, such as geographical and cultural context, that hinder accessibility to the Greenlandic healthcare system.

Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from unknown platforms in the North Greenland Sea from 2014-03-17 to 2014-03-19 (NCEI Accession 0160541)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0160541 includes chemical, discrete sample, physical and profile data collected from unknown platforms in the North Greenland Sea from 2014-03-17 to...

Stationary spiraling eddies in presence of polar amplification of global warming as a governing factor of ecology of Greenland seals White Sea population: results of verification study

Science.gov (United States)

Melentyev, K.; Chernook, V.; Melentyev, V.

2003-04-01

Ice-associated forms of marine mammals are representatives of a high level of fodder chains in the ocean and taxation of population number for different group, as assessment of ecology and animal welfare are the important tasks for marine biology, ecology, fishery and other application uses. Many problems create a global warming and antropogenical impact on marine and coastal ecosystem. In order to investigate ice covered Arctic Ocean and charting the number of seals were performed annual inspections onboard research aircraft PINRO "Arktika". Multi-spectral airborne and satellite observations were fulfilled regularly from Barents and White Sea to the Bering and Okhotsk Sea (1996-2002). A contemporary status of different group of sea mammals was evaluated, where number of adults and pups were checked separately. In situ observations were provided with using helicopter and icebreaker for gathering a water samples and ice cores (with following biochemical and toxicological analysis). A prevailing part of life cycle of Greenland seals (harp seal) is strongly depended from winter hydrology (water masses, stable currents, meandering fronts, stationary eddies) and closely connected with type of ice (pack, fast ice) and other parameters of ice (age, origin, salinity, ice edge.). First-year ice floes which has a specific properties and distinctive features are used by harp seals for pupping, lactation, molting, pairing and resting. Ringed seals, inversely, use for corresponding purposes only fast-ice. Different aspects of ecology, and migration features of harp seals were analyzed in frame of verification study. It was revealed a scale of influence of winter severity and wind regime, but stationary eddies in the White Sea is most effective governing factor (novelty). Following relationship " eddies - ecology of Greenland seal White Sea population " will be discussed: A) regularities of eddies formation and their spatial arrangement, temporal (seasonal and annual

Telemedicine in Greenland

DEFF Research Database (Denmark)

Nielsen, Lasse Overballe; Krebs, Hans Jørgen; Albert, Nancy M.

2017-01-01

BACKGROUND: Telemedicine may have the possibility to provide better access to healthcare delivery for the citizens. Telemedicine in arctic remote areas must be tailored according to the needs of the local population. Therefore, we need more knowledge about their needs and their view of telemedicine......: Data collected on citizens' views about the possibilities of using telemedicine in Greenland revealed the following findings: Greenlandic citizens are positive toward telemedicine, and telemedicine can help facilitate improved access to healthcare for residents in these Greenlandic settlements...

The value of Inuit participation when conserving the common eider duck in Arctic Canada and Greenland

DEFF Research Database (Denmark)

Gilchrist, Grant; Merkel, Flemming Ravn; Sonne, Christian

, Denmark, and northerners. This presentation will review the meaningful involvement and direct participation of Inuit during many aspects of historical and ongoing eider duck conservation efforts. These include studies that examined the sustainability of harvest, the establishment of new harvest......The northern common eider duck nests in the eastern Canadian Arctic and west Greenland, and migrates to winter in Atlantic Canada and southwest Greenland. The eider is harvested for its meat, feather down and eggs and its ongoing conservation is the shared responsibility of Canada, Greenland...... regulations, long term monitoring of breeding colonies in remote coastal locations, reporting on emerging disease epidemics, and ongoing field studies which examine the impacts of polar bear predation under changing sea ice conditions. This presentation will review how working relationships were established...

Brief communication: Getting Greenland's glaciers right - a new data set of all official Greenlandic glacier names

Science.gov (United States)

Bjørk, A. A.; Kruse, L. M.; Michaelsen, P. B.

2015-12-01

Place names in Greenland can be difficult to get right, as they are a mix of Greenlandic, Danish, and other foreign languages. In addition, orthographies have changed over time. With this new data set, we give the researcher working with Greenlandic glaciers the proper tool to find the correct name for glaciers and ice caps in Greenland and to locate glaciers described in the historic literature with the old Greenlandic orthography. The data set contains information on the names of 733 glaciers, 285 originating from the Greenland Ice Sheet (GrIS) and 448 from local glaciers and ice caps (LGICs).

110 years of local glacier and ice cap changes in Central- and North East Greenland

Science.gov (United States)

Bjork, A. A.; Aagaard, S.; Kjaer, K. H.; Khan, S. A.; Box, J.

2014-12-01

The local glaciers and ice caps of Greenland are becoming more apparent players in global sea-level rise, and their contribution to future changes is significant. Very little information on their historical fluctuations exists as much of the focus has been on the Greenland Ice Sheet. Now, we can for the first time present historic data that spans 110 years for more than 200 of the local glaciers and ice caps covering this large and important region of the Arctic. The central- and north eastern part of Greenland is of particular interest as these areas are predicted to exhibit a more active behavior with higher mass loss in the future - simultaneously with an increase in precipitation. Our results show that the glaciers and ice caps in the region are responding very rapidly to changes in temperature and precipitation. The present retreat is the fastest observed within the last eight decades, only surpassed by the rapid post LIA retreat. The 1930s was the golden era for scientific exploration in Central- and North East Greenland as several large expeditions visited the area and photographed from land, sea and air. We use historic recordings from Danish and Norwegian aerial missions and terrestrial recordings from the renowned American Explorer Louise Boyd. These unique pictures from the early 1930s form the backbone of the study and are supplemented the more recent aerial photographs the 1940s and onwards and satellite imagery from the mid-1960s and up until present. From high resolution aerial photographs we are able to map the maximum extent of the glaciers during the LIA (Little Ice Age), from which retreat in this area is estimated to commence in 1900. Using a new SMB (Surface Mass Balance) model and its components covering the entire observational period along with high resolution DEMs and historic sea-ice records we are now able to extract valuable information on the past and present triggers of glacial change.

Evolution of a Greenland Ice sheet Including Shelves and Regional Sea Level Variations

Science.gov (United States)

Bradley, Sarah; Reerink, Thomas; van de Wal, Roderik S. W.; Helsen, Michiel; Goelzer, Heiko

2016-04-01

Observational evidence, including offshore moraines and marine sediment cores infer that at the Last Glacial maximum (LGM) the Greenland ice sheet (GIS) grounded out across the Davis Strait into Baffin Bay, with fast flowing ice streams extending out to the continental shelf break along the NW margin. These observations lead to a number of questions as to weather the GIS and Laurentide ice sheet (LIS) coalesced during glacial maximums, and if so, did a significant ice shelf develop across Baffin Bay and how would such a configuration impact on the relative contribution of these ice sheets to eustatic sea level (ESL). Most previous paleo ice sheet modelling simulations of the GIS recreated an ice sheet that either did not extend out onto the continental shelf or utilised a simplified marine ice parameterisation to recreate an extended GIS, and therefore did not fully include ice shelf dynamics. In this study we simulate the evolution of the GIS from 220 kyr BP to present day using IMAU-ice; a 3D thermodynamical ice sheet model which fully accounts for grounded and floating ice, calculates grounding line migration and ice shelf dynamics. As there are few observational estimates of the long-term (yrs) sub marine basal melting rates (mbm) for the GIS, we developed a mbm parameterization within IMAU-ice controlled primarily by changes in paleo water depth. We also investigate the influence of the LIS on the GIS evolution by including relative sea level forcing's derived from a Glacial Isostatic Adjustment model. We will present results of how changes in the mbm directly impacts on the ice sheet dynamics, timing and spatial extent of the GIS at the glacial maximums, but also on the rate of retreat and spatial extent at the Last interglacial (LIG) minimum. Results indicate that with the inclusion of ice shelf dynamics, a larger GIS is generated which is grounded out into Davis strait, up to a water depth of -750 m, but significantly reduces the GIS contribution to Last

Understanding Greenland ice sheet hydrology using an integrated multi-scale approach

International Nuclear Information System (INIS)

Rennermalm, A K; Moustafa, S E; Mioduszewski, J; Robinson, D A; Chu, V W; Smith, L C; Forster, R R; Hagedorn, B; Harper, J T; Mote, T L; Shuman, C A; Tedesco, M

2013-01-01

Improved understanding of Greenland ice sheet hydrology is critically important for assessing its impact on current and future ice sheet dynamics and global sea level rise. This has motivated the collection and integration of in situ observations, model development, and remote sensing efforts to quantify meltwater production, as well as its phase changes, transport, and export. Particularly urgent is a better understanding of albedo feedbacks leading to enhanced surface melt, potential positive feedbacks between ice sheet hydrology and dynamics, and meltwater retention in firn. These processes are not isolated, but must be understood as part of a continuum of processes within an integrated system. This letter describes a systems approach to the study of Greenland ice sheet hydrology, emphasizing component interconnections and feedbacks, and highlighting research and observational needs. (letter)

Past sea-level data from Lakse Bugt, Disko Island, West Greenland from ground-penetrating radar data

Science.gov (United States)

Souza, Priscila E.; Nielsen, Lars; Kroon, Aart; Clemmensen, Lars B.

2016-04-01

Beach-ridge deposits have been used as sea-level indicators in numerous studies from temperate coastal regions. However, their present surface morphology in artic regions may not accurately correspond to past sea-level, because subsequent surface erosion, solifluction processes and/or later sediment deposition may have altered the surface significantly. The internal structure of these beach ridges, however, is often well-preserved and thus constitutes an important key to reconstruction of past sea levels as seen elsewhere. In the present study, high-resolution reflection GPR data and high-precision topographic data were collected at Lakse Bugt (Disko Island, West Greenland) using a shielded 250 MHz antennae system and a RTK-Trimble R8 DGPS, respectively. Three transects were collected across a sequence of fossil, raised beach ridge deposits, and two transects were obtained across modern beach deposits at the shoreline of the mesotidal regime. Along all radar profiles we observed downlap reflection points, which we interpret to represent the boundary between sediments deposited on the beachface and sediments deposited in the upper shoreface regime. Both the upper shoreface and the beachface deposits exhibit reflection patterns dipping in the seaward direction. The beachface deposits show the strongest dip. At or just below the downlap points strong diffractions are often observed indicating the presence of a layer containing stones. These stones are large enough to generate significant signal scattering. At the present day beach a sharp transition defined by the presence of large stones is observed near the low tide water level: cobbles characterize the seaside, while the land side is characterized by sand and gravel. Therefore, it seems reasonable to conclude that downlap points observed in the GPR data serve as indicators of past low-tide levels (at the time of deposition). The downlap points show a consistent offset with respect to present surface topography

The response of the southern Greenland ice sheet to the Holocene thermal maximum

DEFF Research Database (Denmark)

Larsen, Nicolaj Krog; Kjaer, Kurt H.; Lecavalier, Benoit

2015-01-01

contribution of 0.16 m sea-level equivalent from the entire Greenland ice sheet, with a centennial ice loss rate of as much as 100 Gt/yr for several millennia during the Holocene thermal maximum. Our results provide an estimate of the long-term rates of volume loss that can be expected in the future...

SEA effectiveness and power in decision-making

DEFF Research Database (Denmark)

Hansen, Anne Merrild

environmental considerations into strategic decision-making processes. Greenland is presently facing the potential of rapid and significant industrial development. The development can cause unforeseen induced environmental and societal effects. Therefore important strategic decisions are to be made......Strategic Environmental Assessment is a tool developed with the aim of endorsing protection of the environment and promoting sustainable development. Strategic Environmental Assessment is contributing to environmental protection and sustainable development by providing an arena to incorporate...... in this regard. Based on the challenges for Greenland, this thesis investigates the effectiveness of a Strategic Environmental Assessment carried out for a potential aluminium production in Greenland. The thesis uses theories of effectiveness and power to answer the research question: How does SEA become...

Inter-Relationship Between Subtropical Pacific Sea Surface Temperature, Arctic Sea Ice Concentration, and the North Atlantic Oscillation in Recent Summers and Winters

Science.gov (United States)

Lim, Young-Kwon; Cullather, Richard I.; Nowicki, Sophie M.; Kim, Kyu-Myong

2017-01-01

The inter-relationship between subtropical western-central Pacific sea surface temperatures (STWCPSST), sea ice concentration in the Beaufort Sea (SICBS), and the North Atlantic Oscillation (NAO) are investigated for the last 37 summers and winters (1980-2016). Lag-correlation of the STWCPSST×(-1) in spring with the NAO phase and SICBS in summer increases over the last two decades, reaching r = 0.4-0.5 with significance at 5 percent, while winter has strong correlations in approximately 1985-2005. Observational analysis and the atmospheric general circulation model experiments both suggest that STWCPSST warming acts to increase the Arctic geopotential height and temperature in the following season. This atmospheric response extends to Greenland, providing favorable conditions for developing the negative phase of the NAO. SIC and surface albedo tend to decrease over the Beaufort Sea in summer, linked to the positive surface net shortwave flux. Energy balance considering radiative and turbulent fluxes reveal that available energy that can heat surface is larger over the Arctic and Greenland and smaller over the south of Greenland, in response to the STWCPSST warming in spring. XXXX Arctic & Atlantic: Positive upper-level height/T anomaly over the Arctic and Greenland, and a negative anomaly over the central-eastern Atlantic, resembling the (-) phase of the NAO. Pacific: The negative height/T anomaly over the mid-latitudes, along with the positive anomaly over the STWCP, where 1degC warming above climatology is prescribed. Discussion: It is likely that the Arctic gets warm and the NAO is in the negative phase in response to the STWCP warming. But, there are other factors (e.g., internal variability) that contribute to determination of the NAO phase: not always the negative phase of the NAO in the event of STWCP warming (e.g.: recent winters and near neutral NAO in 2017 summer).

PREVALENCE OF ANTIBODIES AGAINST TOXOPLASMA GONDII IN POLAR BEARS (URSUS MARITIMUS) FROM SVALBARD AND EAST GREENLAND

Science.gov (United States)

Serum samples from 419 polar bears (Ursus maritimus) from Svalbard and the Barents Sea (collected 1990 - 2000) and 108 polar bears from East Greenland (collected 1999 - 2004) were assayed for antibodies against Toxoplasma gondii using the modified agglutination test (MAT). Antibody prevalences were ...

Multibeam Mapping of Remote Fjords in Southeast-Greenland

Science.gov (United States)

Weinrebe, W.; Kjaer, K. H.; Kjeldsen, K. K.; Bjork, A. A.

2015-12-01

The fjords of Southeast-Greenland are among the most remote areas of the Northern Hemisphere. Access to this area is hampered by a broad belt of sea ice floating along the East-Greenland coast from North to South. Consequently, the majority of those fjords have never been surveyed in detail until now. During an expedition by the Center of GeoGenetics of the University of Copenhagen in summer of 2014 we were able to map the Skjoldungen Fjord system with multibeam bathymetry. The topsail schooner ACTIV, built 1951 as a cargo ship to supply remote settlements in Greenland was chosen for the expedition. Though a vintage vessel, the ACTIV was well suited to cross the belt of sea ice and to cruise the ice covered fjords. A portable ELAC-Seabeam 1050 multibeam system was temporarily installed on the vessel. The two transducer of the system were mounted at the lower end of a 6 m long pole attached outboard at port side to the hull of the vessel. Though the installation was quite demanding without any winches or cranes, the construction was sufficiently stable and easy to manage throughout the entire cruise. Nearly the entire fjord system, leaving only a small gap of 5 km at the innermost part and small stripes close to the shorelines could be surveyed during the cruise. For the first time, a comprehensive map of Skjoldungen Fjord is now available. The map displays water depths from close to zero up to 800 m, the deepest part along a stretch of about 10 km in the Southwest. The bathymetry of the northern fjord is remarkably different from the southern fjord: the southern fjord features an outer deep part showing water depths between 500 m and 800 m and a shallow inner part with depths less than 300 m and a prominent sill in between. The northern fjord shows a more gradual increase of water depths from 200 m in the inner part to 600 m at the entrance.

MIS 5e relative sea-level changes in the Mediterranean Sea: Contribution of isostatic disequilibrium

Science.gov (United States)

Stocchi, Paolo; Vacchi, Matteo; Lorscheid, Thomas; de Boer, Bas; Simms, Alexander R.; van de Wal, Roderik S. W.; Vermeersen, Bert L. A.; Pappalardo, Marta; Rovere, Alessio

2018-04-01

Sea-level indicators dated to the Last Interglacial, or Marine Isotope Stage (MIS) 5e, have a twofold value. First, they can be used to constrain the melting of Greenland and Antarctic Ice Sheets in response to global warming scenarios. Second, they can be used to calculate the vertical crustal rates at active margins. For both applications, the contribution of glacio- and hydro-isostatic adjustment (GIA) to vertical displacement of sea-level indicators must be calculated. In this paper, we re-assess MIS 5e sea-level indicators at 11 Mediterranean sites that have been generally considered tectonically stable or affected by mild tectonics. These are found within a range of elevations of 2-10 m above modern mean sea level. Four sites are characterized by two separate sea-level stands, which suggest a two-step sea-level highstand during MIS 5e. Comparing field data with numerical modeling we show that (i) GIA is an important contributor to the spatial and temporal variability of the sea-level highstand during MIS 5e, (ii) the isostatic imbalance from the melting of the MIS 6 ice sheet can produce a >2.0 m sea-level highstand, and (iii) a two-step melting phase for the Greenland and Antarctic Ice Sheets reduces the differences between observations and predictions. Our results show that assumptions of tectonic stability on the basis of the MIS 5e records carry intrinsically large uncertainties, stemming either from uncertainties in field data and GIA models. The latter are propagated to either Holocene or Pleistocene sea-level reconstructions if tectonic rates are considered linear through time.

The Greenland Ice Sheet at the peak of warming during the previous Interglacial

Directory of Open Access Journals (Sweden)

O. O. Rybak

2014-01-01

Full Text Available The Last Interglacial (LIG or the Eemian between ca. 130 and 115 kyr BP is probably the best analogue for future climate warming for which increasingly better proxy data are becoming available. The volume of the Greenland Ice Sheet (GrIS during this period is of particular interest to better assess how much and how fast sea-level can rise in a future Earth undergoing gradual climatic warming. Sea-level during the LIG is inferred to have been up to 9 meter higher than today, but contribution of the GrIS into this rise remains unclear. Various ice-sheet modeling studies have come up with a very broad range of the LIG volume loss by the GrIS to between 60 cm and 6 m of equivalent sea-level rise. This wide range is explained by the sensitivity of GrIS models to the imposed climatic conditions and to poor knowledge of the LIG climate itself in terms of the magnitude and precise timing of the maximum warming, as well as in terms of spatial and annual patterns. To partially circumvent these uncertainties we made use of the newest temperature record over the Central Greenland reconstructed from the isotopic composition of the recently obtained NEEM ice core containing undisturbed LIG segment to build the climatic forcing of the model. The NEEM record unequivocally indicates times of the start and of the end of the LIG warming in Greenland as well as the duration of the warmest time period within the Eemian. Using a three-dimensional thermomechanical ice-sheet model, we produced an ensemble of possible LIG configurations by varying only four key parameters for temperature, precipitation rate, surface melting magnitude and melting pattern within realistic bounds. The outcome of a series of the numerical experiments is a variety of glaciologically consistent GrIS geometries corresponding to a wide range of possible «climates». To constrain the ensemble of GrIS geometries, we used data inferred from 5 Greenland ice cores such as the presence or absence of

Arctic tides from GPS on sea ice

OpenAIRE

Kildegaard Rose, Stine; Skourup, Henriette; Forsberg, René

2012-01-01

The presence of sea-ice in the Arctic Ocean plays a significant role in the Arctic climate. Sea ice dampens the ocean tide amplitude with the result that global tidal models which use only astronomical data perform less accurately in the polar regions. This study presents a kinematic processing of Global Positioning System (GPS) buoys placed on sea-ice at five different sites north of Greenland for the study of sea level height and tidal analysis to improve tidal models in the Central Arctic....

Short-term impacts of enhanced Greenland freshwater fluxes in an eddy-permitting ocean model

Directory of Open Access Journals (Sweden)

R. Marsh

2010-07-01

Full Text Available In a sensitivity experiment, an eddy-permitting ocean general circulation model is forced with realistic freshwater fluxes from the Greenland Ice Sheet, averaged for the period 1991–2000. The fluxes are obtained with a mass balance model for the ice sheet, forced with the ERA-40 reanalysis dataset. The freshwater flux is distributed around Greenland as an additional term in prescribed runoff, representing seasonal melting of the ice sheet and a fixed year-round iceberg calving flux, for 8.5 model years. By adding Greenland freshwater fluxes with realistic geographical distribution and seasonality, the experiment is designed to investigate the oceanic response to a sudden and spatially/temporally uniform amplification of ice sheet melting and discharge, rather than localized or gradual changes in freshwater flux. The impacts on regional hydrography and circulation are investigated by comparing the sensitivity experiment to a control experiment, without additional fluxes. By the end of the sensitivity experiment, the majority of additional fresh water has accumulated in Baffin Bay, and only a small fraction has reached the interior of the Labrador Sea, where winter mixed layer depth is sensitive to small changes in salinity. As a consequence, the impact on large-scale circulation is very slight. An indirect impact of strong freshening off the west coast of Greenland is a small anti-cyclonic component to the circulation around Greenland, which opposes the wind-driven cyclonic circulation and reduces net southward flow through the Canadian Archipelago by ~10%. Implications for the post-2000 acceleration of Greenland mass loss are discussed.

Improved regional sea-level estimates from Ice Sheets, Glaciers and land water storage using GRACE time series and other data

Science.gov (United States)

He, Z.; Velicogna, I.; Hsu, C. W.; Rignot, E. J.; Mouginot, J.; Scheuchl, B.; Fettweis, X.; van den Broeke, M. R.

2017-12-01

Changes in ice sheets, glaciers and ice caps (GIC) and land water mass cause regional sea level variations that differ significantly from a uniform re-distribution of mass over the ocean, with a decrease in sea level compared to the global mean sea level contribution (GMSL) near the sources of mass added to the ocean and an increase up to 30% larger than the GMSL in the far field. The corresponding sea level fingerprints (SLF) are difficult to separate from ocean dynamics on short time and spatial scales but as ice melt continues, the SLF signal will become increasingly dominant in the pattern of regional sea level rise. It has been anticipated that it will be another few decades before the land ice SLF could be identified in the pattern of regional sea level rise. Here, we combine 40 years of observations of ice sheet mass balance for Antarctica (1975-present) and Greenland (1978-present), along with surface mass balance reconstructions of glacier and ice caps mass balance (GIC) from 1970s to present to determine the contribution to the SLF from melting land ice (MAR and RACMO). We compare the results with observations from GRACE for the time period 2002 to present for evaluation of our approach. Land hydrology is constrained by GRACE data for the period 2002-present and by the GLDAS-NOAH land hydrology model for the longer time period. Over the long time period, we find that the contribution from land ice dominates. We quantify the contribution to the total SLF from Greenland and Antarctica in various parts of the world over the past 40 years. More important, we compare the cumulative signal from SLF with tide gauge records around the world, corrected for earth dynamics, to determine whether the land ice SLF can be detected in that record. Early results will be reported at the meeting. This work was performed at UC Irvine and at Caltech's Jet Propulsion Laboratory under a contract with NASA's Cryospheric Science Program.

Impact of Seawater Nonlinearities on Nordic Seas Circulation

Science.gov (United States)

Helber, R. W.; Wallcraft, A. J.; Shriver, J. F.

2017-12-01

The Nordic Seas (Greenland, Iceland, and Norwegian Seas) form an ocean basin important for Arctic-mid-latitude climate linkages. Cold fresh water from the Arctic Ocean and warm salty water from the North Atlantic Ocean meet in the Nordic Seas, where a delicate balance between temperature and salinity variability results in deep water formation. Seawater non-linearities are stronger at low temperatures and salinities making high-latitude oceans highly subject to thermbaricity and cabbeling. This presentation highlights and quantifies the impact of seawater non-linearities on the Nordic Seas circulation. We use two layered ocean circulation models, the Hybrid Coordinate Ocean Model (HYOCM) and the Modular Ocean Model version 6 (MOM6), that enable accurate representation of processes along and across density or neutral density surfaces. Different equations-of-state and vertical coordinates are evaluated to clarify the impact of seawater non-linearities. Present Navy systems, however, do not capture some features in the Nrodic Seas vertical structure. For example, observations from the Greenland Sea reveal a subsurface temperature maximum that deepens from approximately 1500 m during 1998 to 1800 m during 2005. We demonstrate that in terms of density, salinity is the largest source of error in Nordic Seas Navy forecasts, regional scale models can represent mesoscale features driven by thermobaricity, vertical coordinates are a critical issue in Nordic Sea circulation modeling.

The Background Level of the Summer Tropospheric Aerosol over Greenland and the North Atlantic Ocean

DEFF Research Database (Denmark)

Flyger, H.; Hansen, K. A.; Megaw, W.J.

1973-01-01

An experiment to measure the concentration and size of Aitken nuclei, the concentration of cloud nuclei active at a supersaturation of 1%, the concentration of freezing nuclei activated at -20C, and the chemical nature of the tropospheric aerosol over Greenland and the seas surrounding it is desc...

Characterization of icebergs and floating sea ice in the Yung Sund fjord in Greenland from satellite radar and optical images.

Science.gov (United States)

Guillaso, Stephane; Gay, Michel; Gervaise, Cedric

2017-04-01

At the Zackenberg site, sea ice starts to move between June and September resulting in icebergs flowing freely on the sea. Splitting into smaller parts, they reduce in size. Icebergs represent a risk for maritime transport and needs to be studied. In order to determine iceberg density per surface unit, size distribution, and movement of icebergs, we need to observe, detect, range and track them. The use of SAR images is particularly well adapted in regions where cloud cover is very present. We focused our study on the Yung Sund fjord in Greenland, where lots of icebergs and sea ice are generated during the summer. In the beginning of July, sea ice breaks up first, followed by icebergs created by the different glaciers based in the ocean. During our investigation, we noticed that the iceberg and sea ice were drifting very fast and thus, we needed to adapt our methodology. To achieve our goal, we collected all remote sensing data available in the region, principally Sentinel 1/2 and LandSAT 8 during one ice free season (from July 1st 2016 to September 30th, 2016). We developed an original approach in order to detect, characterize and track icebergs and sea ice independently from data. The iceberg detection was made using a watershed technique. The advantage of this technique is that it can be applied to both optical and radar images. For the latter, calibrated intensity is transformed into an image using a scaling function, in order to make ice brighter. Land data is masked using a topographic map. When data is segmented, a statistical test derived from the CFAR approach is performed to isolate an iceberg and floating sea ice from the ocean. Finally, a method, such SIFT or BRISK is used to identify and track the different segmented object. These approaches give a representation of the object and make the tracking easier and independent of the scale and rotation, which can occur because icebergs are dependent on ocean currents and wind. Finally, to fill in the gap

Walrus Movements in Smith Sound: A Canada - Greenland Shared Stock

DEFF Research Database (Denmark)

Heide-Jorgensen, Mads Peter; Flora, Janne; Andersen, Astrid O.

2017-01-01

Fifty of 58 walruses (Odobenus rosmarus rosmarus) instrumented with satellite-linked transmitters in four areas in eastern Smith Sound, Northwest Greenland, during May and June of 2010 – 13 and 2015 provided data for this study. These animals departed from the feeding banks along the Greenland...... coast in June – July (average 14th June), simultaneously with the disappearance of sea ice from these areas. Most of them moved to Canadian waters in western Smith Sound. The most frequently used summering grounds were along the coasts of Ellesmere Island: on the eastern coast, the area around Alexandra...... of Jones Sound and Lancaster Sound for short periods during the summer, though this cannot be confirmed with certainty. The return migration from western Smith Sound to the wintering area in eastern Smith Sound takes place in October. The tracked walrus showed high affinity to coastal areas, while walruses...

Effect of specific pathways to 1.5°C global warming on the contribution of Greenland to sea level rise

Science.gov (United States)

Humbert, A.; Rückamp, M.; Falk, U.; Frieler, K.

2017-12-01

Sea level rise associated with changing climate is expected to pose a major challenge for societies. Here, we estimate the future contribution of the Greenland ice sheet (GrIS) to sea level change in terms of different emission scenarios. We investigate the effect of different pathways of global warming on the dynamics and mass balance of the GrIS with a focus on scenarios in line with limiting global warming to 2.0° or even 1.5° by the end of 2100 (Paris Agreement). We particularly address the issue of peak and decline scenarios temporarily exceeding a given temperature limit. This kind of overshooting might have strong effects on the evolution of the GrIS. Furthermore, we investigate the long-term effects of different levels of climate change to estimate the threshold for stabilizing the GrIS. For modeling the flow dynamics and future evolution of the GrIS, we apply the thermo-mechanical coupled Ice Sheet System Model (ISSM). The model is forced with anomalies for temperature and surface mass balance derived from different GCM data from the CMIP5 RCP2.6 scenario provided from the ISIMIP2b project. In order to obtain these anomalies from the GCM data, a surface energy balance model is applied.

Oceans Melting Greenland: Early Results from NASA's Ocean-Ice Mission in Greenland

DEFF Research Database (Denmark)

Fenty, Ian; Willis, Josh K.; Khazendar, Ala

2016-01-01

the continental shelf, and about the extent to which the ocean interacts with glaciers. Early results from NASA's five-year Oceans Melting Greenland (OMG) mission, based on extensive hydrographic and bathymetric surveys, suggest that many glaciers terminate in deep water and are hence vulnerable to increased...... melting due to ocean-ice interaction. OMG will track ocean conditions and ice loss at glaciers around Greenland through the year 2020, providing critical information about ocean-driven Greenland ice mass loss in a warming climate....

Mapping Greenland's Firn Aquifer using L-band Microwave Radiometry

Science.gov (United States)

Miller, J.; Bringer, A.; Jezek, K. C.; Johnson, J. T.; Scambos, T. A.; Long, D. G.

2016-12-01

Greenland's recently discovered firn aquifer is one of the most interesting, yet still mysterious, components of the ice sheet system. Many open questions remain regarding timescales of refreezing and/or englacial drainage of liquid meltwater, and the connections of firn aquifers to the subglacial hydrological system. If liquid meltwater production at the surface of the Greenland ice sheet continues to increase, subsequent increases in the volume of mobile liquid meltwater retained within Greenland's firn aquifer may increase the possibility of crevasse-deepening via hydrofracture. Hydrofracture is an important component of supraglacial lake drainage leading to at least temporary accelerated flow velocities and ice sheet mass balance changes. Firn aquifers may also support hydrofracture-induced drainage and thus are potentially capable of significantly influencing ice sheet mass balance and sea level rise. Spaceborne L-band microwave radiometers provide an innovative tool for ice-sheet wide mapping of the spatiotemporal variability of Greenland's firn aquifer. Both refreezing and englacial drainage may be observable given the sensitivity of the microwave response to the upper surface of liquid meltwater retained within snow and firn pore space as well as the ability of L band instruments to probe the ice sheet from the surface to the firn-ice transition at pore close-off depth. Here we combine L-band (1.4 GHz) brightness temperature observations from multiple sources to demonstrate the potential of mapping firn aquifers on ice sheets using L-band microwave radiometry. Data sources include the interferometric MIRAS instrument aboard ESA's Soil Moisture and Ocean Salinity (SMOS) satellite mission and the radiometer aboard NASA's Soil Moisture Active Passive (SMAP) satellite mission. We will also present mulit-frequency L-band brightness temperature data (0.5-2 GHz) that will be collected over several firn aquifer areas on the Greenland ice sheet by the Ohio State

Storm-induced water dynamics and thermohaline structure at the tidewater Flade Isblink Glacier outlet to theWandel Sea (NE Greenland)

DEFF Research Database (Denmark)

Kirillov, Sergei; Dmitrenko, Igor; Rysgaard, Soren

2017-01-01

In April 2015, an ice-tethered conductivity-temperature-depth (CTD) profiler and a down-looking acoustic Doppler current profiler (ADCP) were deployed from the landfast ice near the tidewater glacier terminus of the Flade Isblink Glacier in the Wandel Sea, NE Greenland. The 3-week time series...... are likely attributable to subglacial water from the Flade Isblink Ice Cap. It was also found that the semidiurnal periodicities in the temperature and salinity time series were associated with the lunar semidiurnal tidal flow. The vertical structure of tidal currents corresponded to the first baroclinic...... mode of the internal tide with a velocity minimum at similar to 40 m. The tidal ellipses rotate in opposite directions above and below this depth and cause a divergence of tidal flow, which was observed to induce semidiurnal internal waves of about 3 m height at the front of the glacier terminus...

Enhanced melting of the Greenland ice sheet and its impact on the Subpolar North Atlantic and AMOC

NARCIS (Netherlands)

Bamber, J.L.; Behrens, E.; Boening, C.; van den Broeke, M.; Lenaerts, J.; Ettema, J.; Rignot, E.

2012-01-01

Freshwater (FW) fluxes from river runoff and precipitation minus evaporation for the pan Arctic seas are relatively well documented and prescribed in ocean GCMs. Fluxes from Greenland on the other hand are generally ignored altogether, despite their potential impacts on ocean circulation and marine

Spatial and temporal melt variability at Helheim Glacier, East Greenland, and its effect on ice dynamics

DEFF Research Database (Denmark)

Andersen, M. L.; Larsen, T. B.; Nettles, M.

2010-01-01

Understanding the behavior of large outlet glaciers draining the Greenland Ice Sheet is critical for assessing the impact of climate change on sea level rise. The flow of marine-terminating outlet glaciers is partly governed by calving-related processes taking place at the terminus but is also in...

Changing surface-atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland

NARCIS (Netherlands)

Charalampidis, C.; van As, D.; Box, J. E.; van den Broeke, M. R.; Colgan, W. T.; Doyle, S. H.; Hubbard, A. L.; MacFerrin, M.; Machguth, H.; Smeets, C. J. P. P.

2015-01-01

We present 5 years (2009–2013) of automatic weather station measurements from the lower accumulation area (1840 m a.s.l. – above sea level) of the Greenland ice sheet in the Kangerlussuaq region. Here, the summers of 2010 and 2012 were both exceptionally warm, but only 2012 resulted in a strongly

Comparison of modelled runoff with observed proglacial discharge across the western margin of the Greenland ice sheet

Science.gov (United States)

Moustafa, S.; Rennermalm, A.; van As, D.; Overeem, I.; Tedesco, M.; Mote, T. L.; Koenig, L.; Smith, L. C.; Hagedorn, B.; Sletten, R. S.; Mikkelsen, A. B.; Hasholt, B.; Hall, D. K.; Fettweis, X.; Pitcher, L. H.; Hubbard, A.

2017-12-01

Greenland ice sheet surface ablation now dominates its total mass loss contributions to sea-level rise. Despite the increasing importance of Greenland's sea-level contribution, a quantitative inter-comparison between modeled and measured melt, runoff and discharge across multiple drainage basins is conspicuously lacking. Here we investigate the accuracy of model discharge estimates from the Modèle Atmosphérique Régionale (MAR v3.5.2) regional climate model by comparison with in situ proglacial river discharge measurements at three West Greenland drainage basins - North River (Thule), Watson River (Kangerlussuaq), and Naujat Kuat River (Nuuk). At each target catchment, we: 1) determine optimal drainage basin delineations; 2) assess primary drivers of melt; 3) evaluate MAR at daily, 5-, 10- and 20-day time scales; and 4) identify potential sources for model-observation discrepancies. Our results reveal that MAR resolves daily discharge variability poorly in the Nuuk and Thule basins (r2 = 0.4-0.5), but does capture variability over 5-, 10-, and 20-day means (r2 > 0.7). Model agreement with river flow data, though, is reduced during periods of peak discharge, particularly for the exceptional melt and discharge events of July 2012. Daily discharge is best captured by MAR across the Watson River basin, whilst there is lower correspondence between modeled and observed discharge at the Thule and Naujat Kuat River basins. We link the main source of model error to an underestimation of cloud cover, overestimation of surface albedo, and apparent warm bias in near-surface air temperatures. For future inter-comparison, we recommend using observations from catchments that have a self-contained and well-defined drainage area and an accurate discharge record over variable years coincident with a reliable automatic weather station record. Our study highlights the importance of improving MAR modeled surface albedo, cloud cover representation, and delay functions to reduce model

High serum coenzyme Q10, positively correlated with age, selenium and cholesterol in Inuit of Greenland

DEFF Research Database (Denmark)

Pedersen, Henning Sloth; Mortensen, S.A.; Rhode, M.

1999-01-01

impact. From a health survey we chose the subpopulation from the most remote area, where the traditional Greenlandic diet with high intake of sea mammals and fish predominates. The mean (SD) of S-CoQ10 in males was 1.495 (0.529) nmol/ml and 1.421 (0.629) nmol/ml in females, significantly higher (p ....001) compared to a Danish population. In a linear multiple regression model the S-CoQ10 level is significantly positively associated with age and S-selenium in males, and S-total cholesterol in females. The high level of CoQ10 in Greenlanders probably reflects diet, since no bioaccumulation takes place...

APO observations in Southern Greenland: evaluation of modelled air-sea O2 and CO2 fluxes

Science.gov (United States)

Bonne, Jean-Louis; Bopp, Laurent; Delmotte, Marc; Cadule, Patricia; Resplandy, Laure; Nevison, Cynthia; Manizza, Manfredi; Valentin Lavric, Jost; Manning, Andrew C.; Masson-Delmotte, Valérie

2014-05-01

Since September 2007, the atmospheric CO2 mole fraction and O2/N2 ratio (a proxy for O2 concentration) have been monitored continuously at the coastal site of Ivittuut, southern Greenland (61.21° N, 48.17° W). From 2007 to 2013, our measurements show multi-annual trends of +2.0 ppm/year and -20 per meg/year respectively for CO2 and O2/N2, with annual average peak-to-peak seasonal amplitudes of 14+/-1 ppm and 130+/-15 per meg. We investigate the implications of our data set in terms of APO (Atmospheric Potential Oxygen). This tracer, obtained by a linear combination of CO2 and O2/N2 data, is invariant to CO2 and O2 exchanges in the land biota, but sensitive to the oceanic component of the O2 cycle. It is used as a bridge to evaluate air-sea CO2 and O2 fluxes from atmospheric variations of CO2 and O2/N2. Global ocean biogeochemical models produce estimates of CO2 and O2 air-sea fluxes. Atmospheric APO variations can be simulated through transportation of these fluxes in the atmosphere by Eulerian transport models. Thus, model values of atmospheric APO can be extracted at the station location. This study is based on air-sea flux outputs from CMIP5 simulations. After atmospheric transportation, they give access to atmospheric APO climatologies which can be compared, in terms of seasonal cycles and inter-annual variability, to the in situ observations. A preliminary study is based on the CCSM ocean model air-sea fluxes transported in the atmosphere with the MATCH transport model, over the period 1979-2004. The amplitude of the APO seasonal cycle is correctly captured, but year to year variations on this seasonal cycle appears to be underestimated compared to observations. The LMDZ atmospheric transport model is also used to transport the ocean fluxes from five CMIP5 models, over the period 1979-2005, showing different amplitudes and timings of APO seasonal cycles. This methodology is a first step to evaluate the origin of observed APO variations at our site and then

Experience with cochlear implants in Greenlanders with profound hearing loss living in Greenland

Directory of Open Access Journals (Sweden)

Preben Homøe

2013-08-01

Full Text Available Objective. Cochlear implant (CI treatment was introduced to the world in the 1980s and has become a routine treatment for congenital or acquired severe-to-profound hearing loss. CI treatment requires access to a highly skilled team of ear, nose and throat specialists, audiologists and speech-language pathologists for evaluation, surgery and rehabilitation. In particular, children treated with CI are in need of long-term post-operative auditory training and other follow-up support. Design. The study is retrospective with updated information on present performance. Results. Since 2001, a total of 11 Greenlandic patients living in Greenland have been treated with CI, 7 children and 4 adults. Of these children, 4 use oral communication only and are full-time CI-users, 2 with full-time use of CI are still in progress with use of oral communication, and 1 has not acquired oral language yet, but has started auditory and speech training. Six children attend mainstream public school while one child is in kindergarten. Of the adults, only 1 has achieved good speech perception with full-time use of CI while 3 do not use the CI. Discussion. From an epidemiological point of view, approximately 1–3 children below 6 years are in need of a CI every second year in Greenland often due to sequelae from meningitis, which may cause postinfectious deafness. Screening of new-borns for hearing has been started in Greenland establishing the basis for early diagnosis of congenital hearing impairment and subsequent intervention. The logistics and lack of availability of speech therapists in Greenland hampers possibilities for optimal language and speech therapy of CI patients in Greenland. This study aims at describing the results of CI treatment in Greenlanders and the outcome of the CI operations along with the auditory and speech/language outcomes. Finally, we present a suggestion for the future CI treatment and recommendations for an increased effort in the

TopoGreenland: crustal structure in central-eastern Greenland along a new refraction profile

Science.gov (United States)

Shulgin, Alexey; Thybo, Hans; Field Team TopoGreenland

2013-04-01

We present the seismic structure in the interior of Greenland based on the first measurements by the seismic refraction/wide angle reflection method. Previous seismic surveys have only been carried out offshore and near the coast of Greenland, where the crustal structure is affected by oceanic break-up and may not be representative of the interior of the island. Acquisition of geophysical data in onshore Greenland is logistically complicated by the presence of an up to 3.4 km thick ice sheet, permanently covering most of the land mass. The seismic data was acquired by a team of six people during a two-month long experiment in summer of 2011 on the ice cap in the interior of central-eastern Greenland. The EW-trending profile extends 310 km inland from the approximate edge of the stable ice cap near Scoresby Sund across the center of the ice cap. The planned extension of the profile by use of OBSs and air gun shooting in Scoresbysund Fjord to the east coast of Greenland was unfortunately canceled, because navigation was prevented by ice drift. 350 Reftek Texan receivers recorded high-quality seismic data from 8 equidistant shots along the profile. Explosive charge sizes were 1 ton at the ends and ca. 500 kg along the profile, loaded with about 125 kg at 35-85 m depth in individual boreholes. Two-dimensional velocity model based on tomographic inversion and forward ray tracing modeling shows a decrease of crustal thickness from 47 km below the center of Greenland in the western part to 40 km in the eastern part of the profile. Earlier studies show that crustal thickness further decreases eastward to ca. 30 km below the fjord system, but details of the changes are unknown. Relatively high lower crustal velocities (Vp 6.8 - 7.3) in the western part of the TopoGreenland profile may indicate past collision tectonics or may be related or to the passage of the Iceland mantle plume. The origin of the pronounced circum-Atlantic mountain ranges in Norway and eastern Greenland

Modulation of frontogenetic plankton production along a meandering jet by zonal wind forcing: An application to the Alboran Sea

Science.gov (United States)

Oguz, Temel; Mourre, Baptiste; Tintoré, Joaquin

2017-08-01

We present a coupled physical-biological modeling study to elucidate the changes in ageostrophic frontal dynamics and the frontogenetic plankton production characteristics of a meandering jet under the impacts of successive westerly/easterly wind events combined with seasonal variations in the upstream transport and buoyancy flux characteristics of the jet, using a case study for the Alboran Sea (Western Mediterranean). Their nonlinear coupling is shown to result in different forms of physical and biological characteristics of the background jet structure that follows a meandering path around two anticyclonic gyres in the western and eastern basins and a cyclonic eddy in between. The westerly, downfront wind events broaden the jet, and result in stronger cross-frontal density contrast and intensify ageostrophic cross-frontal secondary circulation. Thus, they improve the frontogenetic plankton production with respect to the no-wind case. They also support higher production along the northern coast in response to wind-induced coastal upwelling and spreading of resulting nutrient-rich, productive water by mesoscale stirring. These features weaken gradually as the jet transport reduces. In contrast, stronger and longer-lasting easterlies during the reduced jet transport phase weaken the currents and frontal density structure, change the circular Western Alboran Gyre to an elongated form, and shift the main axis of the jet towards the southern basin. Then, frontogenesis fails to contribute to phytoplankton production that becomes limited to the eddy pumping within cyclones. Apart from the frontogenetic production, eddy pumping, mesoscale stirring, and diapycnal mixing of nutrients support intermittent and localized phytoplankton patches over the basin.

Greenland Fracture Zone-East Greenland Ridge(s) revisited: Indications of a C22-change in plate motion?

DEFF Research Database (Denmark)

Døssing, Arne; Funck, T.

2012-01-01

a reinterpretation of the Greenland Fracture Zone -East Greenland Ridge based on new and existing geophysical data. Evidence is shown for two overstepping ridge segments (Segments A and B) of which Segment A corresponds to the already known East Greenland Ridge while Segment B was not detected previously......Changes in the lithospheric stress field, causing axial rift migration and reorientation of the transform, are generally proposed as an explanation for anomalously old crust and/or major aseismic valleys in oceanic ridge-transform-ridge settings. Similarly, transform migration of the Greenland...... Fracture Zone and separation of the 200-km-long, fracture-zone-parallel continental East Greenland Ridge from the Eurasia plate is thought to be related to a major change in relative plate motions between Greenland and Eurasia during the earliest Oligocene (Chron 13 time). This study presents...

Sustainable Mobile Tourist Hut for Greenland

DEFF Research Database (Denmark)

Qu, Jing; Villumsen, O.; Villumsen, Arne

Greenland is experiencing growing tourism in recent years, which increases demand for tourists’ accommodation. Small huts are a traditional way for overnight stays in Greenland due to scattered population and lack of infrastructure. However, the existing huts in Greenland cannot provide satisfact...

Inuit dietary patterns in modern Greenland

DEFF Research Database (Denmark)

Bjerregaard, Peter; Jeppesen, Charlotte

2010-01-01

The purpose of the study was to apply two different approaches of dietary pattern definition to data from Greenland and to analyse the contemporary dietary patterns of the Inuit in Greenland in relation to urbanization and socio-economic positions.......The purpose of the study was to apply two different approaches of dietary pattern definition to data from Greenland and to analyse the contemporary dietary patterns of the Inuit in Greenland in relation to urbanization and socio-economic positions....

Inuit health in Greenland

DEFF Research Database (Denmark)

Bjerregaard, P; Curtis, T; Borch-Johnsen, K

2003-01-01

During 1997-2001 a population survey was carried out amongst Greenland Inuit living in Denmark and West Greenland (Nuuk, Sisimiut, Qasigiannguit and four villages in Uummannaq municipality). Data collection comprised an interview, a questionnaire, clinical examinations and sampling of biological ...

Hydrographic variability in the Irminger Sea

NARCIS (Netherlands)

de Jong, M.F.

2010-01-01

This thesis deals with the hydrography of the northwestern North Atlantic Ocean, particularly the Irminger Sea. The data sets used for this study include historical observations (since 1950), near-annual observations (since 1990) of the AR7E section from Greenland to Ireland and daily observations

Vegetation phenology gradients along the west and east coasts of Greenland from 2001 to 2015

DEFF Research Database (Denmark)

Karami, Mojtaba; Hansen, Birger Ulf; Westergaard-Nielsen, Andreas

2017-01-01

, as well as the climatic response. The date of the start of season (SOS) was significantly earlier (24 days), length of season longer (25 days), and time-integrated NDVI higher in West Greenland. The sea ice concentration during May was found to have a significant effect on the date of the SOS only in West...

The effect of sea-ice loss on beluga whales (Delphinapterus leucas) in West Greenland

DEFF Research Database (Denmark)

Heide-Jørgensen, M.P.; Laidre, K.L.; Simon, Malene Juul

2009-01-01

An aerial survey was conducted to estimate the abundance of belugas (Delphinapterus leucas) on their wintering ground in West Greenland in March-April 2006 and 2008. The survey was conducted as a double platform aerial line transect survey, and sampled approximately 17% of the total survey area o...

Cryostratigraphy, sedimentology, and the late Quaternary evolution of the Zackenberg River delta, northeast Greenland

DEFF Research Database (Denmark)

Gilbert, Graham L.; Cable, Stefanie; Thiel, Christine

2017-01-01

The Zackenberg River delta is located in northeast Greenland (74 degrees 30' N, 20 degrees 30' E) at the outlet of the Zackenberg fjord valley. The fjord-valley fill consists of a series of terraced deltaic deposits (ca. 2 km2) formed during relative sea-level (RSL) fall. We investigated the depo......The Zackenberg River delta is located in northeast Greenland (74 degrees 30' N, 20 degrees 30' E) at the outlet of the Zackenberg fjord valley. The fjord-valley fill consists of a series of terraced deltaic deposits (ca. 2 km2) formed during relative sea-level (RSL) fall. We investigated...... the deposits using sedimentological and cryostratigraphic techniques together with optically stimulated luminescence (OSL) dating. We identify four facies associations in sections (4 to 22 m in height) exposed along the modern Zackenberg River and coast. Facies associations relate to (I) overriding glaciers......, (II) retreating glaciers and quiescent glaciomarine conditions, (III) delta progradation in a fjord valley, and (IV) fluvial activity and niveo-aeolian processes. Pore, layered, and suspended cryofacies are identified in two 20 m deep ice-bonded sediment cores. The cryofacies distribution, together...

Oxygen isotope ratios in the shell of Mytilus edulis: archives of glacier meltwater in Greenland?

DEFF Research Database (Denmark)

Versteegh, E. A. A.; Blicher, Martin E.; Mortensen, J.

2012-01-01

Melting of the Greenland Ice Sheet (GrIS) is accelerating and will contribute significantly to global sea level rise during the 21st century. Instrumental data on GrIS melting only cover the last few decades, and proxy data extending our knowledge into the past are vital for validating models pre...

Atlantic water variability on the SE Greenland continental shelf and its relationship to SST

Science.gov (United States)

Sutherland, D. A.; Straneo, F.; Rosing-Asvid, A.; Stenson, G.; Davidson, F. J.; Hammill, M.

2012-12-01

Interaction of warm, Atlantic-origin water (AW) and colder, polar origin water (PW) advecting southward in the East Greenland Current (EGC) influences the heat content of water entering Greenland's outlet glacial fjords. Here we use depth and temperature data derived from deep-diving seals to map out water mass variability across the continental shelf and to augment existing bathymetric products. We find two dominant modes in the vertical temperature structure: a cold mode, with the typical AW/PW layering observed in the EGC, and a warm mode, where AW is present throughout the water column. The prevalence of these modes varies seasonally and spatially across the continental shelf, implying distinct AW pathways. In addition, we find that satellite sea surface temperatures (SST) correlate significantly with temperatures in the upper 50 m (R=0.54), but this correlation decreases with depth (R=0.22 at 200 m), and becomes insignificant below 250 m. Thus, care must be taken in using SST as a proxy for heat content, as AW mainly resides in these deeper layers. Regional map showing the location of all seal tracks originating from Canada and Greenland (stars). Tracks passing inside (red) or outside (blue) the SE Greenland region (black) were subdivided into continental shelf regions (green boxes) near Sermilik Fjord (SF), Cape Farewell (CF) and Kangerdlugssuaq Fjord (KG). GEBCO bathymetry is contoured at 200, 1000, 2000, and 3000 m.

Geodetic measurements reveal similarities between post–Last Glacial Maximum and present-day mass loss from the Greenland ice sheet

DEFF Research Database (Denmark)

Khan, Shfaqat Abbas; Sasgen, Ingo; Bevis, Michael

2016-01-01

and ocean load changes occurring since the Last Glacial Maximum (LGM; ~21 thousand years ago) and may be used to constrain the GrIS deglaciation history. We use data from the Greenland Global Positioning System network to directly measure GIA and estimate basinwide mass changes since the LGM. Unpredicted......Accurate quantification of the millennial-scale mass balance of the Greenland ice sheet (GrIS) and its contribution to global sea-level rise remain challenging because of sparse in situ observations in key regions. Glacial isostatic adjustment (GIA) is the ongoing response of the solid Earth to ice...

Popular music from Greenland

DEFF Research Database (Denmark)

Otte, Andreas Roed

a sense of place in popular music. The second probes different strategies for co-branding popular music and Greenland. The third is concerned with music consumption patterns among Greenlandic youth. And the fourth article engages with an alternative form of nationalism found within the Nuuk underground...

Simple models for the simulation of submarine melt for a Greenland glacial system model

Science.gov (United States)

Beckmann, Johanna; Perrette, Mahé; Ganopolski, Andrey

2018-01-01

Two hundred marine-terminating Greenland outlet glaciers deliver more than half of the annually accumulated ice into the ocean and have played an important role in the Greenland ice sheet mass loss observed since the mid-1990s. Submarine melt may play a crucial role in the mass balance and position of the grounding line of these outlet glaciers. As the ocean warms, it is expected that submarine melt will increase, potentially driving outlet glaciers retreat and contributing to sea level rise. Projections of the future contribution of outlet glaciers to sea level rise are hampered by the necessity to use models with extremely high resolution of the order of a few hundred meters. That requirement in not only demanded when modeling outlet glaciers as a stand alone model but also when coupling them with high-resolution 3-D ocean models. In addition, fjord bathymetry data are mostly missing or inaccurate (errors of several hundreds of meters), which questions the benefit of using computationally expensive 3-D models for future predictions. Here we propose an alternative approach built on the use of a computationally efficient simple model of submarine melt based on turbulent plume theory. We show that such a simple model is in reasonable agreement with several available modeling studies. We performed a suite of experiments to analyze sensitivity of these simple models to model parameters and climate characteristics. We found that the computationally cheap plume model demonstrates qualitatively similar behavior as 3-D general circulation models. To match results of the 3-D models in a quantitative manner, a scaling factor of the order of 1 is needed for the plume models. We applied this approach to model submarine melt for six representative Greenland glaciers and found that the application of a line plume can produce submarine melt compatible with observational data. Our results show that the line plume model is more appropriate than the cone plume model for simulating

The HIV epidemic in Greenland - a slow spreading infection among adult heterosexual Greenlanders

DEFF Research Database (Denmark)

Bjørn-Mortensen, Karen; Ladefoged, Karin; Obel, Niels

2013-01-01

We aimed to characterise the HIV epidemic in Greenland and to determine incidence, prevalence, mortality rates (MR) and specific causes of deaths.......We aimed to characterise the HIV epidemic in Greenland and to determine incidence, prevalence, mortality rates (MR) and specific causes of deaths....

The multimillennial sea-level commitment of global warming.

Science.gov (United States)

Levermann, Anders; Clark, Peter U; Marzeion, Ben; Milne, Glenn A; Pollard, David; Radic, Valentina; Robinson, Alexander

2013-08-20

Global mean sea level has been steadily rising over the last century, is projected to increase by the end of this century, and will continue to rise beyond the year 2100 unless the current global mean temperature trend is reversed. Inertia in the climate and global carbon system, however, causes the global mean temperature to decline slowly even after greenhouse gas emissions have ceased, raising the question of how much sea-level commitment is expected for different levels of global mean temperature increase above preindustrial levels. Although sea-level rise over the last century has been dominated by ocean warming and loss of glaciers, the sensitivity suggested from records of past sea levels indicates important contributions should also be expected from the Greenland and Antarctic Ice Sheets. Uncertainties in the paleo-reconstructions, however, necessitate additional strategies to better constrain the sea-level commitment. Here we combine paleo-evidence with simulations from physical models to estimate the future sea-level commitment on a multimillennial time scale and compute associated regional sea-level patterns. Oceanic thermal expansion and the Antarctic Ice Sheet contribute quasi-linearly, with 0.4 m °C(-1) and 1.2 m °C(-1) of warming, respectively. The saturation of the contribution from glaciers is overcompensated by the nonlinear response of the Greenland Ice Sheet. As a consequence we are committed to a sea-level rise of approximately 2.3 m °C(-1) within the next 2,000 y. Considering the lifetime of anthropogenic greenhouse gases, this imposes the need for fundamental adaptation strategies on multicentennial time scales.

Avoidable deaths in Greenland 1968-1985

DEFF Research Database (Denmark)

Bjerregaard, Peter; Juel, K

1990-01-01

and several showed an increasing time trend. The regional patterns were particularly clear for infectious diseases and accidents, which showed low mortality rates in the capital and other towns and high mortality rates in settlements and in the remote East Greenland, while mortality rates from suicides...... and political will of the society. A list of avoidable deaths is proposed for Greenland which includes, inter alia, meningitis, lung cancer, acute respiratory infections, suicides, boat accidents and alcohol related diseases and accidents. All were considerably more common in Greenland than in Denmark...... and alcohol related diseases were high in the capital and East Greenland and low in West Greenlandic settlements. It is concluded that further studies on preventable diseases and causes of death, in particular certain infectious diseases, accidents and suicides, are needed....

Algae Drive Enhanced Darkening of Bare Ice on the Greenland Ice Sheet

Science.gov (United States)

Stibal, Marek; Box, Jason E.; Cameron, Karen A.; Langen, Peter L.; Yallop, Marian L.; Mottram, Ruth H.; Khan, Alia L.; Molotch, Noah P.; Chrismas, Nathan A. M.; Calı Quaglia, Filippo; Remias, Daniel; Smeets, C. J. P. Paul; van den Broeke, Michiel R.; Ryan, Jonathan C.; Hubbard, Alun; Tranter, Martyn; van As, Dirk; Ahlstrøm, Andreas P.

2017-11-01

Surface ablation of the Greenland ice sheet is amplified by surface darkening caused by light-absorbing impurities such as mineral dust, black carbon, and pigmented microbial cells. We present the first quantitative assessment of the microbial contribution to the ice sheet surface darkening, based on field measurements of surface reflectance and concentrations of light-absorbing impurities, including pigmented algae, during the 2014 melt season in the southwestern part of the ice sheet. The impact of algae on bare ice darkening in the study area was greater than that of nonalgal impurities and yielded a net albedo reduction of 0.038 ± 0.0035 for each algal population doubling. We argue that algal growth is a crucial control of bare ice darkening, and incorporating the algal darkening effect will improve mass balance and sea level projections of the Greenland ice sheet and ice masses elsewhere.

Environmental and social benefits of improved handling and disposal of black wastewater in Greenland

DEFF Research Database (Denmark)

Gunnarsdottir, Ragnhildur; Jenssen, Petter Deinboll; Nyborg, Ingrid L.P.

2010-01-01

Wastewater collection and treatment is difficult in arctic climate due to, i.e. permafrost and cold climate. Currently all toilet wastewater (blackwater) in Greenland is discharged untreated, mainly to the sea. Water from bathing, washing and kitchen (greywater) is usually not collected...... flush toilets with collection at the household level and improved greywater treatment. This will improve the indoor and outdoor hygiene and thus status for the families. The blackwater can be sanitized and converted to small volumes of soil amendment and fertilizer and used in e.g. greenhouses...... in Greenland causes visual contamination of the coast near many towns and settlements. Furthermore the nutrients in the wastewater may cause local eutrophication where the water exchange is poor. Another and maybe more serious consequence of discharging untreated wastewater into the arctic waters are organic...

A synthesis of the basal thermal state of the Greenland Ice Sheet

Science.gov (United States)

MacGregor, Joseph A; Fahnestock, Mark A; Catania, Ginny A; Aschwanden, Andy; Clow, Gary D.; Colgan, William T.; Gogineni, Prasad S.; Morlighem, Mathieu; Nowicki, Sophie M .J.; Paden, John D; Price, Stephen F.; Seroussi, Helene

2016-01-01

The basal thermal state of an ice sheet (frozen or thawed) is an important control upon its evolution, dynamics and response to external forcings. However, this state can only be observed directly within sparse boreholes or inferred conclusively from the presence of subglacial lakes. Here we synthesize spatially extensive inferences of the basal thermal state of the Greenland Ice Sheet to better constrain this state. Existing inferences include outputs from the eight thermomechanical ice-flow models included in the SeaRISE effort. New remote-sensing inferences of the basal thermal state are derived from Holocene radiostratigraphy, modern surface velocity and MODIS imagery. Both thermomechanical modeling and remote inferences generally agree that the Northeast Greenland Ice Stream and large portions of the southwestern ice-drainage systems are thawed at the bed, whereas the bed beneath the central ice divides, particularly their west-facing slopes, is frozen. Elsewhere, there is poor agreement regarding the basal thermal state. Both models and remote inferences rarely represent the borehole-observed basal thermal state accurately near NorthGRIP and DYE-3. This synthesis identifies a large portion of the Greenland Ice Sheet (about one third by area) where additional observations would most improve knowledge of its overall basal thermal state.

A synthesis of the basal thermal state of the Greenland Ice Sheet.

Science.gov (United States)

MacGregor, Joseph A; Fahnestock, Mark A; Catania, Ginny A; Aschwanden, Andy; Clow, Gary D; Colgan, William T; Gogineni, S Prasad; Morlighem, Mathieu; Nowicki, Sophie M J; Paden, John D; Price, Stephen F; Seroussi, Hélène

2016-08-10

The basal thermal state of an ice sheet (frozen or thawed) is an important control upon its evolution, dynamics and response to external forcings. However, this state can only be observed directly within sparse boreholes or inferred conclusively from the presence of subglacial lakes. Here we synthesize spatially extensive inferences of the basal thermal state of the Greenland Ice Sheet to better constrain this state. Existing inferences include outputs from the eight thermomechanical ice-flow models included in the SeaRISE effort. New remote-sensing inferences of the basal thermal state are derived from Holocene radiostratigraphy, modern surface velocity and MODIS imagery. Both thermomechanical modeling and remote inferences generally agree that the Northeast Greenland Ice Stream and large portions of the southwestern ice-drainage systems are thawed at the bed, whereas the bed beneath the central ice divides, particularly their west-facing slopes, is frozen. Elsewhere, there is poor agreement regarding the basal thermal state. Both models and remote inferences rarely represent the borehole-observed basal thermal state accurately near NorthGRIP and DYE-3. This synthesis identifies a large portion of the Greenland Ice Sheet (about one third by area) where additional observations would most improve knowledge of its overall basal thermal state.

Significant Impact of Glacial Meltwater on the Pelagic Carbon Cycle in a High Arctic Greenland Fjord

DEFF Research Database (Denmark)

Dalsgaard, Tage; Bruhn, Annette; Sejr, Mikael Kristian

2014-01-01

a concentrations, mainly concentrated in a pronounced deep chlorophyll maximum (DCM), reflected the overlap between the nitracline and the photic zone, with 5-10 fold higher values in the outer part of the fjord and in the Greenland Sea, as compared to the inner fjord. The depth of the DCM increased from 5–40 m...

Estimating the Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR

Directory of Open Access Journals (Sweden)

X. Fettweis

2013-03-01

Full Text Available To estimate the sea level rise (SLR originating from changes in surface mass balance (SMB of the Greenland ice sheet (GrIS, we present 21st century climate projections obtained with the regional climate model MAR (Modèle Atmosphérique Régional, forced by output of three CMIP5 (Coupled Model Intercomparison Project Phase 5 general circulation models (GCMs. Our results indicate that in a warmer climate, mass gain from increased winter snowfall over the GrIS does not compensate mass loss through increased meltwater run-off in summer. Despite the large spread in the projected near-surface warming, all the MAR projections show similar non-linear increase of GrIS surface melt volume because no change is projected in the general atmospheric circulation over Greenland. By coarsely estimating the GrIS SMB changes from GCM output, we show that the uncertainty from the GCM-based forcing represents about half of the projected SMB changes. In 2100, the CMIP5 ensemble mean projects a GrIS SMB decrease equivalent to a mean SLR of +4 ± 2 cm and +9 ± 4 cm for the RCP (Representative Concentration Pathways 4.5 and RCP 8.5 scenarios respectively. These estimates do not consider the positive melt–elevation feedback, although sensitivity experiments using perturbed ice sheet topographies consistent with the projected SMB changes demonstrate that this is a significant feedback, and highlight the importance of coupling regional climate models to an ice sheet model. Such a coupling will allow the assessment of future response of both surface processes and ice-dynamic changes to rising temperatures, as well as their mutual feedbacks.

When Does the Warmest Water Reach Greenland?

Science.gov (United States)

Grist, J. P.; Josey, S. A.; Boehme, L.; Meredith, M. P.; Laidre, K. L.; Heide-Jørgensen, M. P.; Kovacs, K. M.; Lydersen, C.; Davidson, F. J. M.; Stenson, G. B.; Hammill, M. O.; Marsh, R.; Coward, A.

2016-02-01

The warmest water reaching the east and west coast of Greenland is found between 200 and 600 m, in the warm Atlantic Water Layer (WL). Temperature changes within the WL have been highlighted as a possible cause of accelerated melting of tidewater glaciers and therefore are an important consideration for understanding global sea level rise. However, a limited number of winter observations of the WL have prohibited determining its seasonal variability. To address this, temperature data from Argo profiling floats, a range of sources within the World Ocean Database, and unprecedented coverage from marine-mammal borne sensors have been analyzed for the period 2002-2011. A significant seasonal range in temperature ( 1-2°C) is found in the warm layer, in contrast to most of the surrounding ocean. The magnitude of the seasonal cycle is thus comparable with the 1990s warming that was associated with an increased melt rate in a marine terminating glacier of West Greenland. The phase of the seasonal cycle exhibits considerable spatial variability; with high-resolution ocean model trajectory analysis suggesting it is determined by the time taken for waters to be advected from the subduction site in the Irminger Basin. For western Greenland, the annual temperature maximum occurs near or after the turn of the calendar year. This is significant because a recent study suggested that it is in the non-summer months when fjord-shelf exchanges allow the WL to most strongly influence glacier melt rate. However this is also the time of the year when the WL is least well observed. It is therefore clear that year-round subsurface temperature measurements are still required for a complete description of the WL seasonality, and in particular to ensure that the ice-melting potential of the WL is not underestimated.

Clouds enhance Greenland ice sheet mass loss

Science.gov (United States)

Van Tricht, Kristof; Gorodetskaya, Irina V.; L'Ecuyer, Tristan; Lenaerts, Jan T. M.; Lhermitte, Stef; Noel, Brice; Turner, David D.; van den Broeke, Michiel R.; van Lipzig, Nicole P. M.

2015-04-01

Clouds have a profound influence on both the Arctic and global climate, while they still represent one of the key uncertainties in climate models, limiting the fidelity of future climate projections. The potentially important role of thin liquid-containing clouds over Greenland in enhancing ice sheet melt has recently gained interest, yet current research is spatially and temporally limited, focusing on particular events, and their large scale impact on the surface mass balance remains unknown. We used a combination of satellite remote sensing (CloudSat - CALIPSO), ground-based observations and climate model (RACMO) data to show that liquid-containing clouds warm the Greenland ice sheet 94% of the time. High surface reflectivity (albedo) for shortwave radiation reduces the cloud shortwave cooling effect on the absorbed fluxes, while not influencing the absorption of longwave radiation. Cloud warming over the ice sheet therefore dominates year-round. Only when albedo values drop below ~0.6 in the coastal areas during summer, the cooling effect starts to overcome the warming effect. The year-round excess of energy due to the presence of liquid-containing clouds has an extensive influence on the mass balance of the ice sheet. Simulations using the SNOWPACK snow model showed not only a strong influence of these liquid-containing clouds on melt increase, but also on the increased sublimation mass loss. Simulations with the Community Earth System Climate Model for the end of the 21st century (2080-2099) show that Greenland clouds contain more liquid water path and less ice water path. This implies that cloud radiative forcing will be further enhanced in the future. Our results therefore urge the need for improving cloud microphysics in climate models, to improve future projections of ice sheet mass balance and global sea level rise.

Spontaneous abrupt climate change due to an atmospheric blocking-sea-ice-ocean feedback in an unforced climate model simulation.

Science.gov (United States)

Drijfhout, Sybren; Gleeson, Emily; Dijkstra, Henk A; Livina, Valerie

2013-12-03

Abrupt climate change is abundant in geological records, but climate models rarely have been able to simulate such events in response to realistic forcing. Here we report on a spontaneous abrupt cooling event, lasting for more than a century, with a temperature anomaly similar to that of the Little Ice Age. The event was simulated in the preindustrial control run of a high-resolution climate model, without imposing external perturbations. Initial cooling started with a period of enhanced atmospheric blocking over the eastern subpolar gyre. In response, a southward progression of the sea-ice margin occurred, and the sea-level pressure anomaly was locked to the sea-ice margin through thermal forcing. The cold-core high steered more cold air to the area, reinforcing the sea-ice concentration anomaly east of Greenland. The sea-ice surplus was carried southward by ocean currents around the tip of Greenland. South of 70 °N, sea ice already started melting and the associated freshwater anomaly was carried to the Labrador Sea, shutting off deep convection. There, surface waters were exposed longer to atmospheric cooling and sea surface temperature dropped, causing an even larger thermally forced high above the Labrador Sea. In consequence, east of Greenland, anomalous winds changed from north to south, terminating the event with similar abruptness to its onset. Our results imply that only climate models that possess sufficient resolution to correctly represent atmospheric blocking, in combination with a sensitive sea-ice model, are able to simulate this kind of abrupt climate change.

Greenland Ice Sheet Mass Balance

Science.gov (United States)

Reeh, N.

1984-01-01

Mass balance equation for glaciers; areal distribution and ice volumes; estimates of actual mass balance; loss by calving of icebergs; hydrological budget for Greenland; and temporal variations of Greenland mass balance are examined.

Early to middle Holocene valley glaciations on northernmost Greenland

DEFF Research Database (Denmark)

Möller, Per; Larsen, Nicolaj K.; Kjær, Kurt H.

2010-01-01

This paper presents the glacial stratigraphy and palaeoenvironmental evolution around Constable Bugt, Johannes V. Jensen Land, located on the north coast of Greenland. This is a land of extreme climate: polar desert conditions and a coast bound by a permanent sea ice cover. Our data covers....... This observation can be explained by the altitudinal and temporal distribution of beach-ridge complexes that must have formed by wave action and thus requiring at least partial open-water conditions. With a moisture source at hand, we propose that this lead to enhanced precipitation in the near-coastal areas which...

The Nordic Seas carbon budget: Sources, sinks, and uncertainties

OpenAIRE

Jeansson, Emil; Olsen, Are; Eldevik, Tor; Skjelvan, Ingunn; Omar, Abdirahman M.; Lauvset, Siv K.; Nilsen, Jan Even Ø.; Bellerby, Richard G. J; Johannessen, Truls; Falck, Eva

2011-01-01

A carbon budget for the Nordic Seas is derived by combining recent inorganic carbon data from the CARINA database with relevant volume transports. Values of organic carbon in the Nordic Seas' water masses, the amount of carbon input from river runoff, and the removal through sediment burial are taken from the literature. The largest source of carbon to the Nordic Seas is the Atlantic Water that enters the area across the Greenland-Scotland Ridge; this is in particular true for the anthropogen...

Permafrost degradation in West Greenland

DEFF Research Database (Denmark)

Foged, Niels Nielsen; Ingeman-Nielsen, Thomas

2012-01-01

Important aspects of civil engineering in West Greenland relate to the presence of permafrost and mapping of the annual and future changes in the active layer due to the ongoing climatically changes in the Arctic. The Arctic Technology Centre (ARTEK) has worked more than 10 years on this topic...... and the first author has been involved since 1970 in engineering geology, geotechnical engineering and permafrost related studies for foundation construction and infrastructures in towns and communities mainly in West Greenland. We have since 2006 together with the Danish Meteorological Institute, Greenland...... Survey (ASIAQ) and the University of Alaska Fairbanks carried out the US NSF funded project ARC-0612533: Recent and future permafrost variability, retreat and degradation in Greenland and Alaska: An integrated approach. This contribution will present data and observations from the towns Ilulissat...

The Jurassic of Denmark and Greenland: The Jurassic of East Greenland: a sedimentary record of thermal subsidence, onset and culmination of rifting

Directory of Open Access Journals (Sweden)

Surlyk, Finn

2003-10-01

Full Text Available The Late Palaeozoic – Mesozoic extensional basin complex of East Greenland contains a record of deposition during a period of Rhaetian – Early Bajocian thermal subsidence, the onset of riftingin the Late Bajocian, its growth during the Bathonian–Kimmeridgian, culmination of rifting in the Volgian – Early Ryazanian, and waning in the Late Ryazanian – Hauterivian. The area was centred over a palaeolatitude of about 45°N in the Rhaetian and drifted northwards to about 50°N in the Hauterivian. A major climate change from arid to humid subtropical conditions took place at the Norian–Rhaetian transition. Deposition was in addition governed by a long-term sea-level rise with highstands in the Toarcian–Aalenian, latest Callovian and Kimmeridgian, and lowstands in the latest Bajocian – earliest Bathonian, Middle Oxfordian and Volgian.The Rhaetian – Lower Bajocian succession is considered the upper part of a megasequence, termed J1, with its base in the upper Lower Triassic, whereas the Upper Bajocian – Hauterivian succession forms a complete, syn-rift megasequence, termed J2. The southern part of the basin complex in Jameson Land contains a relatively complete Rhaetian–Ryazanian succession and underwent only minor tilting during Middle Jurassic – earliest Cretaceous rifting. Rhaetian – Lower Jurassic deposits are absent north of Jameson Land and this region was fragmented into strongly tilted fault blocks during the protracted rift event. The syn-rift successions of the two areas accordingly show different long-term trends in sedimentary facies. In the southern area, the J2 syn-rift megasequence forms a symmetrical regressive–transgressive–regressive cycle, whereas the J2 megasequence in the northern area shows an asymmetrical, stepwise deepening trend.A total of eight tectonostratigraphic sequences are recognised in the Rhaetian–Hauterivian interval. They reflect major changes in basin configuration, drainage systems

Greenland's 20th Century retreat illuminated - great spatial variability with strong connections to subglacial topography and fjord bathymetry

Science.gov (United States)

Bjork, A. A.; Kjeldsen, K. K.; Boeckel, M. V.; Korsgaard, N. J.; Fenty, I. G.; Khan, S. A.; Mouginot, J.; Morlighem, M.; Rignot, E. J.; Dowdeswell, J. A.; Kjaer, K. H.

2017-12-01

Mass loss acceleration from the Greenland Ice Sheet is a dominant contributor in recent global sea-level rise, and has been for several decades. While ice sheet wide mass loss has recently been documented from the end of the Little Ice Age (c. 1900 CE) to the 1980s, the detailed changes during this period remain poorly known. In this study, we map glacier margins of Greenland's 310 largest outlet glaciers in order to get the full picture of the 20th Century mass loss. We take advantage of the rich history of aerial photography over Greenland and combine photos from archives in Denmark, Norway, United Kingdom, and United States. We supplement the historical aerial photographs with declassified US spy satellite imagery and recent satellite imagery to document glacial retreat and advance on a decadal scale. With recent advances in bathymetry mapping and subglacial topography mapping, we are able to show that spatial differences in retreat throughout the last 100 years are largely controlled by the underlying topography. Our study further highlights hotspots of past rapid mass loss in Greenland, and discusses implications for periods of regional stability and advance.

Population Structure of West Greenland Narwhals

DEFF Research Database (Denmark)

Riget, F.; Dietz, R.; Møller, P.

The hypothesis that different populations of narwhals in the West Greenland area exist has been tested by different biomarkers (metal and organochlorine concentrations, stable isotopes and DNA). Samples of muscle, liver, kidney, blubber and skin tissues of narwhals from West Greenland have been...... isotopes could not support the population structure with two West Greenland populations suggested by the genetic study....

Mountain glaciers vs Ice sheet in Greenland - learning from a new monitoring site in West Greenland

Science.gov (United States)

Abermann, Jakob; van As, Dirk; Wacker, Stefan; Langley, Kirsty

2017-04-01

Only 5 out of the 20.000 peripheral glaciers and ice caps surrounding Greenland are currently monitored due to logistical challenges and despite their significance for sea level rise. Large spatial coast-to-icesheet mass and energy balance gradients limit simple upscaling methods from ice-sheet observations, which builds the motivation for this study. We present results from a new mass and energy balance time series at Qasigiannguit glacier (64°09'N; 51°21'W) in Southwest Greenland. Inter-annual variability is discussed and the surface energy balance over two summers is quantified and a ranking of the main drivers performed. We find that short-wave net radiation is by far the most dominant energy source during summer, followed by similar amounts of net longwave radiation and sensible heat, respectively. We then relate these observations to synchronous measurements at similar latitude on an outlet glacier of the ice sheet a mere 100 km away. We find very pronounced horizontal surface mass balance gradients, with generally more positive values closer to the coast. We conclude that despite minor differences of atmospheric parameters (i.e. humidity, radiation, and temperature) the main reason for the strongly different signal is a pronounced winter precipitation gradient that translates in a different duration of ice exposure and through that an albedo gradient. Modelled energy balance gradients converted into mass changes show good agreement to measured surface mass balance gradients and we explore a latitudinal signal of these findings.

Seasonal variability of the circulation system in a West Greenland tidewater outlet glacier fjord, Godthåbsfjord (64°N)

DEFF Research Database (Denmark)

Mortensen, John; Bendtsen, Jørgen; Lennert, Kunuk

2014-01-01

Many tidewater outlet glacier fjords surround the coast of Greenland, and their dynamics and circulation are of great importance for understanding the heat transport toward glaciers from the ice sheet. Thus, fjord circulation is a critical aspect for assessing the threat of global sea level rise...... due to melting of the ice sheet. However, very few observational studies describe the seasonal dynamics of fjord circulation. Here we present the first continuous current measurements (April–November) from a deep mooring deployed in a west Greenland tidewater outlet glacier fjord. Four distinct...... circulation phases are identified during the period, and they are related to exchange processes with coastal waters, tidal mixing, and melt processes on the Greenland Ice Sheet. During early summer, warm intermediate water is transported toward the glacier at an average velocity of about 7 cm s−1. In late...

The Jurassic of Denmark and Greenland: The Middle Jurassic of western and northern Europe: its subdivisions, geochronology and correlations

Directory of Open Access Journals (Sweden)

Callomon, John H.

2003-10-01

Full Text Available The palaeogeographic settings of Denmark and East Greenland during the Middle Jurassic are outlined. They lay in the widespread epicontinental seas that covered much of Europe in the post-Triassic transgression. It was a period of continuing eustatic sea-level rise, with only distant connections to world oceans: to the Pacific, via the narrow Viking Straits between Greenland and Norway and hence the arctic Boreal Sea to the north; and to the subtropical Tethys, via some 1200 km of shelf-seas to the south. The sedimentary history of the region was strongly influenced by two factors: tectonism and climate. Two modes of tectonic movement governed basinal evolution: crustal extension leading to subsidence through rifting, such as in the Viking and Central Grabens of the North Sea; and subcrustal thermal upwelling, leading to domal uplift and the partition of marine basins through emergent physical barriers, as exemplified by the Central North Sea Dome with its associated volcanics. The climatic gradient across the 30º of temperate latitude spanned by the European seas governed biotic diversity and biogeography, finding expression in rock-forming biogenic carbonates that dominate sediments in the south and give way to largely siliciclastic sediments in the north. Geochronology of unrivalled finesse is provided by standard chronostratigraphy based on the biostratigraphy of ammonites. The Middle Jurassic saw the onset of considerable bioprovincial endemisms in these guide-fossils, making it necessary to construct parallel standard zonations for Boreal, Subboreal or NW European and Submediterranean Provinces, of which the NW European zonation provides the primary international standard. The current versions of these zonations are presented and reviewed.

Geodetic measurements reveal similarities between post–Last Glacial Maximum and present-day mass loss from the Greenland ice sheet

DEFF Research Database (Denmark)

Khan, Shfaqat A.; Sasgen, Ingo; Bevis, Michael

2016-01-01

Accurate quantification of the millennial-scale mass balance of the Greenland ice sheet (GrIS) and its contribution to global sea-level rise remain challenging because of sparse in situ observations in key regions. Glacial isostatic adjustment (GIA) is the ongoing response of the solid Earth to ice...

Alcohol in Greenland 1951-2010

DEFF Research Database (Denmark)

Aage, Hans

2012-01-01

Background. Fluctuations in alcohol consumption in Greenland have been extreme since alcohol became available to the Greenland Inuit in the 1950s, increasing from low levels in the 1950s to very high levels in the 1980s about twice as high as alcohol consumption in Denmark. Since then, consumption...... has declined, and current consumption is slightly below alcohol consumption in Denmark, while alcohol prices are far above Danish prices. Objective. Description of historical trends and possible causal connections of alcohol prices, alcohol consumption and alcohol-related mortality in Greenland 1951......-2010 as a background for the evaluation of the impact of various types of policy. Design. Time series for Greenland 1951-2010 for alcohol prices, consumption and mortality are compiled, and variation and correlations are discussed in relation to various policies aimed at limiting alcohol consumption. Corresponding...

Extreme temperature events on Greenland in observations and the MAR regional climate model

Science.gov (United States)

Leeson, Amber A.; Eastoe, Emma; Fettweis, Xavier

2018-03-01

Meltwater from the Greenland Ice Sheet contributed 1.7-6.12 mm to global sea level between 1993 and 2010 and is expected to contribute 20-110 mm to future sea level rise by 2100. These estimates were produced by regional climate models (RCMs) which are known to be robust at the ice sheet scale but occasionally miss regional- and local-scale climate variability (e.g. Leeson et al., 2017; Medley et al., 2013). To date, the fidelity of these models in the context of short-period variability in time (i.e. intra-seasonal) has not been fully assessed, for example their ability to simulate extreme temperature events. We use an event identification algorithm commonly used in extreme value analysis, together with observations from the Greenland Climate Network (GC-Net), to assess the ability of the MAR (Modèle Atmosphérique Régional) RCM to reproduce observed extreme positive-temperature events at 14 sites around Greenland. We find that MAR is able to accurately simulate the frequency and duration of these events but underestimates their magnitude by more than half a degree Celsius/kelvin, although this bias is much smaller than that exhibited by coarse-scale Era-Interim reanalysis data. As a result, melt energy in MAR output is underestimated by between 16 and 41 % depending on global forcing applied. Further work is needed to precisely determine the drivers of extreme temperature events, and why the model underperforms in this area, but our findings suggest that biases are passed into MAR from boundary forcing data. This is important because these forcings are common between RCMs and their range of predictions of past and future ice sheet melting. We propose that examining extreme events should become a routine part of global and regional climate model evaluation and that addressing shortcomings in this area should be a priority for model development.

Elements and inorganic ions as source tracers in recent Greenland snow

Science.gov (United States)

Lai, Alexandra M.; Shafer, Martin M.; Dibb, Jack E.; Polashenski, Chris M.; Schauer, James J.

2017-09-01

Atmospheric transport of aerosols leads to deposition of impurities in snow, even in areas of the Arctic as remote as Greenland. Major ions (e.g. Na+, Ca2+, NH4+, K+, SO42-) are frequently used as tracers for common aerosol sources (e.g. sea spray, dust, biomass burning, anthropogenic emissions). Trace element data can supplement tracer ion data by providing additional information about sources. Although many studies have considered either trace elements or major ions, few have reported both. This study determined total and water-soluble concentrations of 31 elements (Al, As, Ca, Cd, Ce, Co, Cr, Dy, Eu, Fe, Gd, K, La, Mg, Mn, Na, Nb, Nd, Pb, Pr, S, Sb, Si, Sm, Sn, Sr, Ti, V, U, Y, Zn) in shallow snow pits at 22 sampling sites in Greenland, along a transect from Summit Station to sites in the northwest. Black carbon (BC) and inorganic ions were measured in colocated samples. Sodium, which is typically used as a tracer of sea spray, did not appear to have any non-marine sources. The rare earth elements, alkaline earth elements (Mg, Ca, Sr), and other crustal elements (Fe, Si, Ti, V) were not enriched above crustal abundances relative to Al, indicating that these elements are primarily dust sourced. Calculated ratios of non-sea salt Ca (nssCa) to estimated dust mass affirm the use of nssCa as a dust tracer, but suggest up to 50% uncertainty in that estimate in the absence of other crustal element data. Crustal enrichment factors indicated that As, Cd, Pb, non-sea-salt S, Sb, Sn, and Zn were enriched in these samples, likely by anthropogenic sources. Principal component analysis indicated more than one crustal factor, and a variety of factors related to anthropogenically enriched elements. Analysis of trace elements alongside major tracer ions does not change interpretation of ion-based source attribution for sources that are well-characterized by ions, but is valuable for assessing uncertainty in source attribution and identifying sources not represented by major ions.

Uranium geology and prospecting in Greenland

International Nuclear Information System (INIS)

Steenfelt, A.; Neilson, B.L.; Secher, K.

1977-01-01

The Geological Survey of Greenland is responsible for most of the uranium and thorium prospecting activity in Greenland, which involves airborne gamma spectrometry and scintillometry, geochemical sampling, geological investigations and ground scintillometry. Since 1971 large areas of east and west Greenland have been investigated by aerial surveys, geochemical sampling and most of the detailed scintillometric work having been restricted to small areas in east Greenland. Anomalous radioactivity in west Greenland is recorded from carbonatite intrusions, and from units in Proterozoic and Archaean gneisses. No mineralization has been found to date. In south Greenland investigations have been centred on the uranium and thorium deposit at Kvanefjeld, which is situated in a corner of the Ilimaussaq alkaline intrusion. The coincidence of favourable conditions during the differentiation and crystallization of the magma led to an extreme enrichment of uranium and thorium in the rocks that were last formed - the lujavrites. The deposit comprises parts of the lujavrites and a secondary enrichment zone in the contact between lujavrite and basaltic cover rocks. Reasonably assured reserves are 5800 t U with a grade of 310 ppm U. In the Caledonides of east Greenland some gneisses in basement cores, a dark siltstone in late Precambrian sediments and the Devonian acid magmatic rocks are characterized by a higher radiation level. A number of small mineral occurrences have been found, the majority of which are associated with the Devonian acid magmatic rocks. (author)

Seasonal changes in Fe along a glaciated Greenlandic fjord.

Directory of Open Access Journals (Sweden)

Mark James Hopwood

2016-03-01

Full Text Available Greenland’s ice sheet is the second largest on Earth, and is under threat from a warming Arctic climate. An increase in freshwater discharge from Greenland has the potential to strongly influence the composition of adjacent water masses with the largest impact on marine ecosystems likely to be found within the glaciated fjords. Here we demonstrate that physical and chemical estuarine processes within a large Greenlandic fjord are critical factors in determining the fate of meltwater derived nutrients and particles, especially for non-conservative elements such as Fe. Concentrations of Fe and macronutrients in surface waters along Godthåbsfjord, a southwest Greenlandic fjord with freshwater input from 6 glaciers, changed markedly between the onset and peak of the meltwater season due to the development of a thin (<10 m, outflowing, low-salinity surface layer. Dissolved (<0.2 µm Fe concentrations in meltwater entering Godthåbsfjord (200 nM, in freshly melted glacial ice (mean 38 nM and in surface waters close to a land terminating glacial system (80 nM all indicated high Fe inputs into the fjord in summer. Total dissolvable (unfiltered at pH <2.0 Fe was similarly high with concentrations always in excess of 100 nM throughout the fjord and reaching up to 5.0 µM close to glacial outflows in summer. Yet, despite the large seasonal freshwater influx into the fjord, Fe concentrations near the fjord mouth in the out-flowing surface layer were similar in summer to those measured before the meltwater season. Furthermore, turbidity profiles indicated that sub-glacial particulate Fe inputs may not actually mix into the outflowing surface layer of this fjord. Emphasis has previously been placed on the possibility of increased Fe export from Greenland as meltwater fluxes increase. Here we suggest that in-fjord processes may be effective at removing Fe from surface waters before it can be exported to coastal seas.

Knowledge-based sea ice classification by polarimetric SAR

DEFF Research Database (Denmark)

Skriver, Henning; Dierking, Wolfgang

2004-01-01

Polarimetric SAR images acquired at C- and L-band over sea ice in the Greenland Sea, Baltic Sea, and Beaufort Sea have been analysed with respect to their potential for ice type classification. The polarimetric data were gathered by the Danish EMISAR and the US AIRSAR which both are airborne...... systems. A hierarchical classification scheme was chosen for sea ice because our knowledge about magnitudes, variations, and dependences of sea ice signatures can be directly considered. The optimal sequence of classification rules and the rules themselves depend on the ice conditions/regimes. The use...... of the polarimetric phase information improves the classification only in the case of thin ice types but is not necessary for thicker ice (above about 30 cm thickness)...

The Greenland shark

DEFF Research Database (Denmark)

Costantini, David; Smith, Shona; Killen, Shaun S.

2017-01-01

the oxidative status of the Greenland shark (Somniosus microcephalus), which has recently been found as the longest living vertebrate animal known to science with a lifespan of at least 272years. As compared to other species, the Greenland shark had body mass-corrected values of muscle glutathione peroxidase...... that the values of metrics of oxidative status we measured might be linked to ecological features (e.g., adaptation to cold waters and deep dives) of this shark species rather to its lifespan....

Last Interglacial climate and sea-level evolution from a coupled ice sheet-climate model

Science.gov (United States)

Goelzer, Heiko; Huybrechts, Philippe; Loutre, Marie-France; Fichefet, Thierry

2016-12-01

As the most recent warm period in Earth's history with a sea-level stand higher than present, the Last Interglacial (LIG, ˜ 130 to 115 kyr BP) is often considered a prime example to study the impact of a warmer climate on the two polar ice sheets remaining today. Here we simulate the Last Interglacial climate, ice sheet, and sea-level evolution with the Earth system model of intermediate complexity LOVECLIM v.1.3, which includes dynamic and fully coupled components representing the atmosphere, the ocean and sea ice, the terrestrial biosphere, and the Greenland and Antarctic ice sheets. In this setup, sea-level evolution and climate-ice sheet interactions are modelled in a consistent framework.Surface mass balance change governed by changes in surface meltwater runoff is the dominant forcing for the Greenland ice sheet, which shows a peak sea-level contribution of 1.4 m at 123 kyr BP in the reference experiment. Our results indicate that ice sheet-climate feedbacks play an important role to amplify climate and sea-level changes in the Northern Hemisphere. The sensitivity of the Greenland ice sheet to surface temperature changes considerably increases when interactive albedo changes are considered. Southern Hemisphere polar and sub-polar ocean warming is limited throughout the Last Interglacial, and surface and sub-shelf melting exerts only a minor control on the Antarctic sea-level contribution with a peak of 4.4 m at 125 kyr BP. Retreat of the Antarctic ice sheet at the onset of the LIG is mainly forced by rising sea level and to a lesser extent by reduced ice shelf viscosity as the surface temperature increases. Global sea level shows a peak of 5.3 m at 124.5 kyr BP, which includes a minor contribution of 0.35 m from oceanic thermal expansion. Neither the individual contributions nor the total modelled sea-level stand show fast multi-millennial timescale variations as indicated by some reconstructions.

Impacts of food web structure and feeding behavior on mercury exposure in Greenland Sharks (Somniosus microcephalus).

Science.gov (United States)

McMeans, Bailey C; Arts, Michael T; Fisk, Aaron T

2015-03-15

Benthic and pelagic food web components in Cumberland Sound, Canada were explored as sources of total mercury (THg) to Greenland Sharks (Somniosus microcephalus) via both bottom-up food web transfer and top-down shark feeding behavior. Log10THg increased significantly with δ(15)N and trophic position from invertebrates (0.01 ± 0.01 μg · g(-1) [113 ± 1 ng · g(-1)] dw in copepods) to Greenland Sharks (3.54 ± 1.02 μg · g(-1)). The slope of the log10THg vs. δ(15)N linear regression was higher for pelagic compared to benthic food web components (excluding Greenland Sharks, which could not be assigned to either food web), which resulted from THg concentrations being higher at the base of the benthic food web (i.e., in benthic than pelagic primary consumers). However, feeding habitat is unlikely to consistently influence shark THg exposure in Cumberland Sound because THg concentrations did not consistently differ between benthic and pelagic shark prey. Further, size, gender and feeding behavior (inferred from stable isotopes and fatty acids) were unable to significantly explain THg variability among individual Greenland Sharks. Possible reasons for this result include: 1) individual sharks feeding as generalists, 2) high overlap in THg among shark prey, and 3) differences in turnover time between ecological tracers and THg. This first assessment of Greenland Shark THg within an Arctic food web revealed high concentrations consistent with biomagnification, but low ability to explain intra-specific THg variability. Our findings of high THg levels and consumption of multiple prey types, however, suggest that Greenland Sharks acquire THg through a variety of trophic pathways and are a significant contributor to the total biotic THg pool in northern seas. Copyright © 2014 Elsevier B.V. All rights reserved.

Carbon cycling in a high-arctic marine ecosystem - Young Sound, NE Greenland

Science.gov (United States)

Rysgaard, Søren; Nielsen, Torkel Gissel

2006-10-01

Young Sound is a deep-sill fjord in NE Greenland (74°N). Sea ice usually begins to form in late September and gains a thickness of ∼1.5 m topped with 0-40 cm of snow before breaking up in mid-July the following year. Primary production starts in spring when sea ice algae begin to flourish at the ice-water interface. Most biomass accumulation occurs in the lower parts of the sea ice, but sea ice algae are observed throughout the sea ice matrix. However, sea ice algal primary production in the fjord is low and often contributes only a few percent of the annual phytoplankton production. Following the break-up of ice, the immediate increase in light penetration to the water column causes a steep increase in pelagic primary production. Usually, the bloom lasts until August-September when nutrients begin to limit production in surface waters and sea ice starts to form. The grazer community, dominated by copepods, soon takes advantage of the increased phytoplankton production, and on an annual basis their carbon demand (7-11 g C m -2) is similar to phytoplankton production (6-10 g C m -2). Furthermore, the carbon demand of pelagic bacteria amounts to 7-12 g C m -2 yr -1. Thus, the carbon demand of the heterotrophic plankton is approximately twice the estimated pelagic primary production, illustrating the importance of advected carbon from the Greenland Sea and from land in fuelling the ecosystem. In the shallow parts of the fjord (dominate primary production. As a minimum estimate, a total of 41 g C m -2 yr -1 is fixed by primary production, of which phytoplankton contributes 15%, sea ice algae dominated by polychaetes and bivalves exists in these shallow-water sediments (accounts for 17%. In deeper waters benthic mineralization is 40% lower than in shallow waters and megafauna, primarily brittle stars, accounts for 27% of the benthic mineralization. The carbon that escapes degradation is permanently accumulated in the sediment, and for the locality investigated a rate

How Greenland melts

Directory of Open Access Journals (Sweden)

van den Broeke M.R.

2010-12-01

Full Text Available Satellite altimetry and gravimetry show that the Greenland ice sheet has been losing volume and mass since the beginning of this century. However, from these short time series of direct measurements we cannot infer what the causes of the mass loss are, i.e. ice dynamics or surface processes, or that maybe the ice sheet returns to normal after a period of volume increase and mass gain. By modelling and observing the individual components of the ice sheet mass balance, i.e. snowfall, meltwater runoff and iceberg production, we are able to identify the processes that led to the recent mass loss. We conclude that the Greenland ice sheet is significantly out of balance. Acceleration of outlet glaciers and increased runoff have contributed equally to recent Greenland mass loss. The potential for mass loss by surface processes, however, was three times greater than actually observed, due to refreezing and enhanced snowfall.

Robots could assist scientists working in Greenland

Science.gov (United States)

Showstack, Randy

2011-07-01

GREENLAND—Tom Lane and Suk Joon Lee, recent graduates of Dartmouth University's Thayer School of Engineering, in Hanover, N. H., are standing outside in the frigid cold testing an autonomous robot that could help with scientific research and logistics in harsh polar environments. This summer, Lane, Lee, and others are at Summit Station, a U.S. National Science Foundation (NSF)-sponsored scientific research station in Greenland, fine-tuning a battery-powered Yeti robot as part of a team working on the NSF-funded Cool Robot project. The station, also known as Summit Camp, is located on the highest point of the Greenland Ice Sheet (72°N, 38°W, 3200 meters above sea level) near the middle of the island. It is a proving ground this season for putting the approximately 68-kilogram, 1-cubic-meter robot through its paces, including improving Yeti's mobility capabilities and field-testing the robot. (See the electronic supplement to this Eos issue for a video of Yeti in action (http://www.agu.org/eos_elec/).) During field-testing, plans call for the robot to collect data on elevation and snow surface characteristics, including accumulation. In addition, the robot will collect black carbon and elemental carbon particulate matter air samples around Summit Camp's power generator to help study carbon dispersion over snow.

Seabird Colonies in Western Greenland

DEFF Research Database (Denmark)

Boertmann, D.; Mosbech, A.; Falk, K.

About 1 million seabirds (indvs) breed in 1032 colonies distributed along the coasts of western Greenland (Fig. 1). However, this figure does not include the little auk colonies in Avanersuaq. These colonies are roughly estimated to hold about 20 mill. pairs. All the basic information on seabird...... colonies in Greenland is compiled in a database maintained by NERI-AE. This report presents data on distribution, population numbers and population trends of 19 species of breeding colonial seabirds in western Greenland. Distributions are depicted on maps in Fig. 18-39. It is apparent that the major...... colonies are found in the northern part of the region, viz. Upernavik and Avanersuaq. The numbers of birds recorded in the database for each species are presented in Tab. 4, and on the basis of these figures estimates of the populations in western Greenland are given (Tab. 5). The most numerous species...

Vitamins and minerals in the traditional Greenland diet

DEFF Research Database (Denmark)

Andersen, S. M.

The relative importance of traditional Greenlandic food items has diminished during the last decades. Today these account for 25% of the Greenland diet with a dominance of fish, seabirds, and marine mammals. This report synthesises the available information on concentrations of vitamins and miner......The relative importance of traditional Greenlandic food items has diminished during the last decades. Today these account for 25% of the Greenland diet with a dominance of fish, seabirds, and marine mammals. This report synthesises the available information on concentrations of vitamins...... and minerals in the various food items that form the traditional Greenlandic diet. However, through this diet people in Greenland are also exposed to a high intake of heavy metals and organochlorines, due to a contamination of many of these food items. In combination with information on the concentration...... of contaminants, the information about vitamins and minerals will potentially make it possible to adjust the diet in Greenland, taking both nutrients and contaminants into account...

Glacier dynamics over the last quarter of a century at Helheim, Kangerdlugssuaq and 14 other major Greenland outlet glaciers

Directory of Open Access Journals (Sweden)

S. L. Bevan

2012-09-01

Full Text Available The Greenland ice sheet is experiencing increasing rates of mass loss, the majority of which results from changes in discharge from tidewater glaciers. Both atmospheric and ocean drivers have been implicated in these dynamic changes, but understanding the nature of the response has been hampered by the lack of measurements of glacier flow rates predating the recent period of warming. Here, using Landsat-5 data from 1985 onwards, we extend back in time the record of surface velocities and ice-front position for 16 of Greenland's fastest-flowing tidewater glaciers, and compare these to more recent data from Landsat-7 and satellite-borne synthetic-aperture radar. Climate re-analysis data and sea surface temperatures from 1982 show that since 1995 most of Greenland and its surrounding oceans have experienced significant overall warming, and a switch to a warming trend. During the period from 1985 to 1995 when Greenland and the surrounding oceans were not warming, major tidewater outlet glaciers around Greenland, including Kangerdlugssuaq and Helheim, were dynamically stable. Since the mid-1990s, glacier discharge has consistently been both greater and more variable. Together, these observations support the hypothesis that recent dynamic change is a rapid response to climate forcing. Both air and ocean temperatures in this region are predicted to continue to warm, and will therefore likely drive further change in outlet glacier discharge.

Seasonal migration, vertical activity and winter temperature experience of Greenland halibut Reinhardtius hippoglossoides (Walbaum) in West Greenland waters

DEFF Research Database (Denmark)

Boje, Jesper; Neuenfeldt, Stefan; Sparrevohn, Claus Reedtz

2014-01-01

resident in Disko Bay (mean range 2.6°C) than when resident in the ice fjord (mean range 1.4°C). Using the tagged halibut as a 'live tool,' we show that parts of the ice fjord are hundreds of meters deeper than previously thought. We also document the first seawater temperature measurements made beneath......The deep-water flatfish Greenland halibut Reinhardtius hippoglossoides (Walbaum) is common along the West Greenland coast. In the northwestern fjords, Greenland halibut is an important socio-economic resource for the Greenland community, but due to the deep and partly ice-covered environment, very...

Exploration history and place names of northern East Greenland: Colophon, abstract, introduction, official place names in Greenland

Directory of Open Access Journals (Sweden)

Higgins, Anthony K.

2010-12-01

Full Text Available The first recorded landing by Europeans on the coast of northern East Greenland (north of 69°N was that of William Scoresby Jr., a British whaler, in 1822. This volume includes a chronological summary of the pioneer 19th century exploration voyages made by British, Danish, Norwegian, Swedish, French and German expeditions – all of whom reported that the region had previously been occupied by the Inuit or Eskimo; also included are brief outlines of the increasing number of government and privately sponsored expeditions throughout the 20th century, whose objectives included cartography, geology, zoology, botany, trapping and the ascent of the highest mountain summits. In 1934 the Place Name Committee for Greenland was established, the tasks of which included a review of all place names hitherto recorded on published maps of Greenland, their formal adoption in danicised form, and the approval or rejection of new name proposals. In northern East Greenland, by far the largest numbers of new place names were those proposed by scientists associated with Lauge Koch’s geological expeditions that lasted from 1926 until 1958. This volume records the location and origin of more than 3000 officially approved place names as well as about 2650 unapproved names.The author’s interest in the exploration history and place names of northern East Greenland started in 1968, when the Geological Survey of Greenland initiated a major five-year geological mapping programme in the Scoresby Sund region. Systematic compilation of names began about 1970, initially with the names given by William Scoresby Jr., and subsequently broadened in scope to include the names proposed by all expeditions to northern East Greenland. The author has participated in 16 summer mapping expeditions with the Survey to northern East Greenland. Publication of this volume represents the culmination of a lifetime working in the Arctic.

Arctic Intermediate Water in the Nordic Seas, 1991-2009

Science.gov (United States)

Jeansson, Emil; Olsen, Are; Jutterström, Sara

2017-10-01

The evolution of the different types of Arctic Intermediate Water (AIW) in the Nordic Seas is evaluated and compared utilising hydro-chemical data from 1991 to 2009. It has been suggested that these waters are important components of the Norwegian Sea Arctic Intermediate Water (NSAIW), and of the dense overflows to the North Atlantic. Thus, it is important to understand how their properties and distribution vary with time. The AIWs from the Greenland and Iceland Seas, show different degrees of variability during the studied period; however, only the Greenland Sea Arctic Intermediate Water (GSAIW) shows an increasing temperature and salinity throughout the 2000s, which considerably changed the properties of this water mass. Optimum multiparameter (OMP) analysis was conducted to assess the sources of the NSAIW. The analysis shows that the Iceland Sea Arctic Intermediate Water (ISAIW) and the GSAIW both contribute to NSAIW, at different densities corresponding to their respective density range. This illustrates that they flow largely isopycnally from their source regions to the Norwegian Sea. The main source of the NSAIW, however, is the upper Polar Deep Water, which explains the lower concentrations of oxygen and chlorofluorocarbons, and higher salinity and nutrient concentrations of the NSAIW layer compared with the ISAIW and GSAIW. This shows how vital it is to include chemical tracers in any water mass analysis to correctly assess the sources of the water mass being studied.

Causes of Greenland temperature variability over the past 4000 yr: implications for northern hemispheric temperature changes

Directory of Open Access Journals (Sweden)

T. Kobashi

2013-10-01

Full Text Available Precise understanding of Greenland temperature variability is important in two ways. First, Greenland ice sheet melting associated with rising temperature is a major global sea level forcing, potentially affecting large populations in coming centuries. Second, Greenland temperatures are highly affected by North Atlantic Oscillation/Arctic Oscillation (NAO/AO and Atlantic multidecadal oscillation (AMO. In our earlier study, we found that Greenland temperature deviated negatively (positively from northern hemispheric (NH temperature trend during stronger (weaker solar activity owing to changes in atmospheric/oceanic changes (e.g. NAO/AO over the past 800 yr (Kobashi et al., 2013. Therefore, a precise Greenland temperature record can provide important constraints on the past atmospheric/oceanic circulation in the region and beyond. Here, we investigated Greenland temperature variability over the past 4000 yr reconstructed from argon and nitrogen isotopes from trapped air in a GISP2 ice core, using a one-dimensional energy balance model with orbital, solar, volcanic, greenhouse gas, and aerosol forcings. The modelled northern Northern Hemisphere (NH temperature exhibits a cooling trend over the past 4000 yr as observed for the reconstructed Greenland temperature through decreasing annual average insolation. With consideration of the negative influence of solar variability, the modelled and observed Greenland temperatures agree with correlation coefficients of r = 0.34–0.36 (p = 0.1–0.04 in 21 yr running means (RMs and r = 0.38–0.45 (p = 0.1–0.05 on a centennial timescale (101 yr RMs. Thus, the model can explain 14 to 20% of variance of the observed Greenland temperature in multidecadal to centennial timescales with a 90–96% confidence interval, suggesting that a weak but persistent negative solar influence on Greenland temperature continued over the past 4000 yr. Then, we estimated the distribution of multidecadal NH and northern high

Towards Introducing a Geocoding Information System for Greenland

Science.gov (United States)

Siksnans, J.; Pirupshvarre, Hans R.; Lind, M.; Mioc, D.; Anton, F.

2011-08-01

Currently, addressing practices in Greenland do not support geocoding. Addressing points on a map by geographic coordinates is vital for emergency services such as police and ambulance for avoiding ambiguities in finding incident locations (Government of Greenland, 2010) Therefore, it is necessary to investigate the current addressing practices in Greenland. Asiaq (Asiaq, 2011) is a public enterprise of the Government of Greenland which holds three separate databases regards addressing and place references: - list of locality names (towns, villages, farms), - technical base maps (including road center lines not connected with names, and buildings), - the NIN registry (The Land Use Register of Greenland - holds information on the land allotments and buildings in Greenland). The main problem is that these data sets are not interconnected, thus making it impossible to address a point in a map with geographic coordinates in a standardized way. The possible solutions suffer from the fact that Greenland has a scattered habitation pattern and the generalization of the address assignment schema is a difficult task. A schema would be developed according to the characteristics of the settlement pattern, e.g. cities, remote locations and place names. The aim is to propose an ontology for a common postal address system for Greenland. The main part of the research is dedicated to the current system and user requirement engineering. This allowed us to design a conceptual database model which corresponds to the user requirements, and implement a small scale prototype. Furthermore, our research includes resemblance findings in Danish and Greenland's addressing practices, data dictionary for establishing Greenland addressing system's logical model and enhanced entity relationship diagram. This initial prototype of the Greenland addressing system could be used to evaluate and build the full architecture of the addressing information system for Greenland. Using software engineering

Impacts of food web structure and feeding behavior on mercury exposure in Greenland Sharks (Somniosus microcephalus)

Energy Technology Data Exchange (ETDEWEB)

McMeans, Bailey C., E-mail: bcmcmeans@gmail.com [Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Arts, Michael T. [Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4 (Canada); National Water Research Institute, Environment Canada, 867 Lakeshore Road, PO Box 5050, Burlington, Ontario L7R 4A6 (Canada); Fisk, Aaron T. [Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

2015-03-15

Benthic and pelagic food web components in Cumberland Sound, Canada were explored as sources of total mercury (THg) to Greenland Sharks (Somniosus microcephalus) via both bottom-up food web transfer and top-down shark feeding behavior. Log{sub 10}THg increased significantly with δ{sup 15}N and trophic position from invertebrates (0.01 ± 0.01 μg·g{sup −1} [113 ± 1 ng·g{sup −1}] dw in copepods) to Greenland Sharks (3.54 ± 1.02 μg·g{sup −1}). The slope of the log{sub 10}THg vs. δ{sup 15}N linear regression was higher for pelagic compared to benthic food web components (excluding Greenland Sharks, which could not be assigned to either food web), which resulted from THg concentrations being higher at the base of the benthic food web (i.e., in benthic than pelagic primary consumers). However, feeding habitat is unlikely to consistently influence shark THg exposure in Cumberland Sound because THg concentrations did not consistently differ between benthic and pelagic shark prey. Further, size, gender and feeding behavior (inferred from stable isotopes and fatty acids) were unable to significantly explain THg variability among individual Greenland Sharks. Possible reasons for this result include: 1) individual sharks feeding as generalists, 2) high overlap in THg among shark prey, and 3) differences in turnover time between ecological tracers and THg. This first assessment of Greenland Shark THg within an Arctic food web revealed high concentrations consistent with biomagnification, but low ability to explain intra-specific THg variability. Our findings of high THg levels and consumption of multiple prey types, however, suggest that Greenland Sharks acquire THg through a variety of trophic pathways and are a significant contributor to the total biotic THg pool in northern seas. - Highlights: • THg significantly increased with δ{sup 15}N from invertebrates to Greenland Sharks. • THg increased with δ{sup 15}N at a faster rate through the pelagic than

Impacts of food web structure and feeding behavior on mercury exposure in Greenland Sharks (Somniosus microcephalus)

International Nuclear Information System (INIS)

McMeans, Bailey C.; Arts, Michael T.; Fisk, Aaron T.

2015-01-01

Benthic and pelagic food web components in Cumberland Sound, Canada were explored as sources of total mercury (THg) to Greenland Sharks (Somniosus microcephalus) via both bottom-up food web transfer and top-down shark feeding behavior. Log 10 THg increased significantly with δ 15 N and trophic position from invertebrates (0.01 ± 0.01 μg·g −1 [113 ± 1 ng·g −1 ] dw in copepods) to Greenland Sharks (3.54 ± 1.02 μg·g −1 ). The slope of the log 10 THg vs. δ 15 N linear regression was higher for pelagic compared to benthic food web components (excluding Greenland Sharks, which could not be assigned to either food web), which resulted from THg concentrations being higher at the base of the benthic food web (i.e., in benthic than pelagic primary consumers). However, feeding habitat is unlikely to consistently influence shark THg exposure in Cumberland Sound because THg concentrations did not consistently differ between benthic and pelagic shark prey. Further, size, gender and feeding behavior (inferred from stable isotopes and fatty acids) were unable to significantly explain THg variability among individual Greenland Sharks. Possible reasons for this result include: 1) individual sharks feeding as generalists, 2) high overlap in THg among shark prey, and 3) differences in turnover time between ecological tracers and THg. This first assessment of Greenland Shark THg within an Arctic food web revealed high concentrations consistent with biomagnification, but low ability to explain intra-specific THg variability. Our findings of high THg levels and consumption of multiple prey types, however, suggest that Greenland Sharks acquire THg through a variety of trophic pathways and are a significant contributor to the total biotic THg pool in northern seas. - Highlights: • THg significantly increased with δ 15 N from invertebrates to Greenland Sharks. • THg increased with δ 15 N at a faster rate through the pelagic than benthic food web. • Benthic primary

Building sustained partnerships in Greenland through shared science

Science.gov (United States)

Culler, L. E.; Albert, M. R.; Ayres, M. P.; Grenoble, L. A.; Virginia, R. A.

2013-12-01

Greenland is a hotspot for polar environmental change research due to rapidly changing physical and ecological conditions. Hundreds of international scientists visit the island each year to carry out research on diverse topics ranging from atmospheric chemistry to ice sheet dynamics to Arctic ecology. Despite the strong links between scientific, social, and political issues of rapid environmental change in Greenland, communication with residents of Greenland is often neglected by researchers. Reasons include language barriers, difficulties identifying pathways for communication, balancing research and outreach with limited resources, and limited social and cultural knowledge about Greenland by scientists. Dartmouth College has a legacy of work in the Polar Regions. In recent years, a National Science Foundation (NSF) Integrative Graduate Education and Research Traineeship (IGERT) in Polar Environmental Change funded training for 25 Ph.D. students in the Ecology, Earth Science, and Engineering graduate programs at Dartmouth. An overarching goal of this program is science communication between these disciplines and to diverse audiences, including communicating about rapid environmental change with students, residents, and the government of Greenland. Students and faculty in IGERT have been involved in the process of engaging with and sustaining partnerships in Greenland that support shared cultural and educational experiences. We have done this in three ways. First, a key component of our program has been hosting students from Ilisimatusarfik (the University of Greenland). Since 2009, five Greenlandic students have come to Dartmouth and formed personal connections with Dartmouth students while introducing their Greenlandic culture and language (Kalaallisut). Second, we have used our resources to extend our visits to Greenland, which has allowed time to engage with the community in several ways, including sharing our science via oral and poster presentations at Katuaq

Understanding Recent Mass Balance Changes of the Greenland Ice Sheet

Science.gov (United States)

vanderVeen, Cornelius

2003-01-01

The ultimate goal of this project is to better understand the current transfer of mass between the Greenland Ice Sheet, the world's oceans and the atmosphere, and to identify processes controlling the rate of this transfer, to be able to predict with greater confidence future contributions to global sea level rise. During the first year of this project, we focused on establishing longer-term records of change of selected outlet glaciers, reevaluation of mass input to the ice sheet and analysis of climate records derived from ice cores, and modeling meltwater production and runoff from the margins of the ice sheet.

Spatiotemporal dynamics of the Atlantic salmon (Salmo salar) Greenland fishery inferred from mixed-stock analysis

Science.gov (United States)

Gauthier-Ouellet, M.; Dionne, M.; Caron, F.; King, T.L.; Bernatchez, L.

2009-01-01

Mixed-stock fisheries refer to the exploitation of admixed fish stocks coming from different origins. We identified the North American origin of 2835 Atlantic salmon (Salmo salar) in the Greenland mixed-stock fishery during 11 years (1995-2006) at three localities using 13 microsatellites. The study included 52 baseline populations representing nine genetically distinct regional groups. The contribution of each group ranged from increasing contribution for Labrador (+14.9%) was observed during the time course of the study. The estimated regional contribution to the Greenland fishery was significantly correlated to the number of multi-sea-winter salmon regionally produced in 2002 (r = 0.79) and 2004 (r = 0.92). No difference in contribution was found between the three Greenland sampling localities. Ungava and Southern Qu??bec regions showed the highest mortality estimates caused by the fishery, ranging from 12.10% to 18.08%, for both years tested. No regional group was overrepresented in landings compared with their respective productivity. Yet, management precautions should still be taken as the fishery strongly selects large females, which could have evolutionary impacts on populations over the long term.

Application of GRACE to the Evaluation of an Ice Flow Model of the Greenland Ice Sheet

Science.gov (United States)

Schlegel, N.; Wiese, D. N.; Watkins, M. M.; Larour, E. Y.; Box, J. E.; Fettweis, X.; van den Broeke, M. R.; Morlighem, M.; Boening, C.; Seroussi, H. L.

2014-12-01

Quantifying Greenland's future contribution to sea level rise is a challenging task and requires accurate estimates of ice flow sensitivity to climate change. Transient ice flow models are promising tools for estimating future ice sheet behavior. However, confidence in these types of future projections is low, especially because evaluation of model historical runs is so challenging due to the scarcity of continental-wide data for validation. For more than a decade, NASA's GRACE has continuously acquired time-variable measurements of the Earth's gravity field and has provided unprecedented surveillance of mass balance of the ice sheets, offering an opportunity for ice sheet model evaluation. Here, we take advantage of a new high-resolution (~300 km) monthly mascon solution for the purpose of mass balance comparison with an independent, historical ice flow model simulation using the Ice Sheet System Model (ISSM). The comparison highlights which regions of the ice sheet differ most from GRACE. Investigation of regional differences in trends and seasonal amplitudes between simulations forced with three different Regional Climate Model (RCM)-based estimates of surface mass balance (SMB) allows us to make conclusions about the relative contributions of various error sources in the model hindcast. This study constitutes the first regional comparison of GRACE data and an ice sheet model. Conclusions will aid in the improvement of RCM SMB estimates as well as ice sheet simulation estimates of present and future rates of sea level rise. This work was performed at the California Institute of Technology's Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration's Cryosphere Program and President's and Director's Fund Program.

Sexual and reproductive health in Greenland: evaluation of implementing sexual peer-to-peer education in Greenland (the SexInuk project).

Science.gov (United States)

Homøe, Anne-Sophie; Knudsen, Ane-Kersti Skaarup; Nielsen, Sigrid Brisson; Grynnerup, Anna Garcia-Alix

2015-01-01

For decades, the rates of sexually transmitted infections (STIs), such as gonorrhoea, chlamydia and syphilis, have increased in Greenland, especially within the young age groups (15-29 years). From 2006 to 2013, the number of abortions has been consistent with approximately 800-900 abortions per year in Greenland, which is nearly as high as the total number of births during the same period. Previous studies in Greenland have reported that knowledge about sexual health is important, both as prevention and as facilitator to stop the increasing rates of STIs. A peer-to-peer education programme about sexual health requires adaption to cultural values and acceptance among the population and government in order to be sustainable. Formative evaluation of a voluntary project (SexInuk), in relation to peer-to-peer education with focus on sexual health. Two workshops were conducted in Nuuk, Greenland, to recruit Greenlandic students. Qualitative design with focus group interviews (FGIs) to collect qualitative feedback on feasibility and implementation of the project. Supplemented with a brief questionnaire regarding personal information (gender, age, education) and questions about the educational elements in the SexInuk project. Eight Greenlandic students, who had completed one or two workshops, were enrolled. The FGIs showed an overall consensus regarding the need for improving sexual health education in Greenland. The participants requested more voluntary educators, to secure sustainability. The articulation of taboo topics in the Greenlandic society appeared very important. The participants suggested more awareness by promoting the project. Cultural values and language directions were important elements in the FGIs. To our knowledge, voluntary work regarding peer-to-peer education and sexual health has not been structurally evaluated in Greenland before. To achieve sustainability, the project needs educators and financial support. Further research is needed to investigate

The Northeast Greenland Shelf - Evidence of the existence of a pronounced salt-province

Science.gov (United States)

Schmitz, T.; Jokat, W.

2003-04-01

The Northeast Greenland shelf (NEGS) is the part of the continental margin of east Greenland located between the Jan Mayen Fracture Zone at about 72°N in the south and the Spitzbergen Fracture Zone at 81°N in the north. The eastern boundary, at the shelf edge, is the approximate position of the boundary between continental and oceanic crust and the western boundary is the coastline of Greenland. The shelf has a N-S orientation, is about 1000 km long, and between 125 km (southern part) and 380 km (at 78°N) wide. Based on present data the NEGS can be subdivided into a southern part influenced by Tertiary tectonism and volcanism (approx. 72°N to 75°N) and a northern, nonvolcanic, part (approx. 75°N to 81°N). Today the sedimentary history, stratigraphy, structure and origin of the basement below the sedimentary shelf south of 74°N are reasonable known, but only sparse information exists about the northern part of the shelf. Until 1990 there weren't any seismic lines north of 74°N, and all interpretations of stratigraphy and basin structures of the northern part of the NEGS were based on aeromagnetic data. During the last decade, the first seismic lines were shot over the northern part of the shelf to give more detailed information about sediment thickness, stratigraphy, and the structure of the sedimentary shelf. The area under investigation lies on the nonvolcanic northern part of the shelf between 78°30'N and 81°N. The sea floor topography indicates some submarine banks with water depth as shallow as 30 m, which are separated by valleys up to 500 m deep. These valleys were formed through erosion processes caused by cyclic movements of big grounded glacier tongues during the last ice-ages with a maximum expansion during the Wisconsin-Weichselian glaciation. During two scientific expeditions with the German research icebreaker Polarstern in 1997 and 1999, more than 1100 km of multichannel seismic data were collected. The cruise tracks during seismic

Chemostratigraphy of Late Cretaceous deltaic and marine sedimentary rocks from high northern palaeolatitudes in the Nuussuaq Basin, West Greenland

DEFF Research Database (Denmark)

Lenniger, Marc; Pedersen, Gunver Krarup; Bjerrum, Christian J.

The Nuussuaq Basin in the Baffin Bay area in West Greenland formed as a result of the opening of the Labrador Sea in Late Mesozoic to Early Cenozoic times. The first rifting and the development of the Nuussuaq Basin took place during the Early Cretaceous and was followed by a second rifting phase...

Temperature, salinity, oxygen and nutrients bottle and CTD data collected in the northern North Atlantic, Nordic and Arctic Seas from 1901 to 2011 (NODC Accession 0105532)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Historical temperature, salinity, oxygen and nutrients bottle and CTD data collected in the Arctic Ocean, Barents Sea, Greenland Sea, Kara Sea, North Atlantic Ocean,...

Estimates of reproductive potential of Greenland halibut (Reinhardtius hippoglossoides) in East Greenland based on an update of maturity status

DEFF Research Database (Denmark)

Kennedy, James; Hedeholm, Rasmus B.; Gundersen, Agnes C.

2014-01-01

When estimating reproductive potential (RP), correct interpretation of the maturity status is essential. It has now become apparent the presence of vitellogenic oocytes within the ovary of Greenland halibut (Reinhardtius hippoglossoides) does not necessarily indicate they will spawn within the next...... twelve months. This has led to a revision of the interpretation of the maturity scale where fish which contain only a developing cohort (DC) of oocytes are considered immature. Comparisons were made of estimates of L50 of female Greenland halibut in East Greenland using the previous interpretation......), respectively. Combining the maturity data with abundance data of Greenland halibut in East Greenland, spawning stock biomass (SSB) and total egg production (TEP) was estimated in four quadrants between 1998 and 2012 using both the previous and current interpretation of the maturity scale. Using the new...

Success and failure of reindeer herding in Greenland

Directory of Open Access Journals (Sweden)

Christine Cuyler

1999-04-01

Full Text Available Animal husbandry is a recent innovation in Greenland, specifically reindeer husbandry is less than 50 years old. Reindeer husbandry was first established in mid-west Greenland and later in southern Greenland. The Greenland hunter tradition and culture is, however, still dominant in many communities. During the 1980s and 1990s, the incompatibility of these two traditions resulted in the failure of reindeer husbandry in mid-west Greenland. There were neither herding nor seasonal herd movements. Animals remained year round on the winter range, which was destroyed as lichens were trampled every summer. Without seasonal herd movements both sustainable range use and control of the herd were lost. Today, there are just two semi-domestic reindeer herds left, and both are in southern Greenland. One herd is commercially successful, and the other is under development. In mid-west Greenland, semi-domestic reindeer husbandry officially ended in 1998, and a hunt was initiated to remove the remaining population. Possibly, by the year 2000 any animals left in this region will be considered wild caribou.

Markers of futurity and aspect in West Greenlandic

DEFF Research Database (Denmark)

Trondhjem, Naja Blytmann

2014-01-01

if necessary. The Alaskan Iñupiaq has an opposition between past, present and future. In Inuktitut and West Greenlandic tense is marked by optional derivational affixes. In Inuktitut the tense affixes have developed a complicated remoteness system (future and past) (Swift, 2004). In West Greenlandic the future...... is unmarked and past time reference can be marked if necessary. The Alaskan Iñupiaq has an opposition between past, present and future. In Inuktitut and West Greenlandic tense is marked by optional derivational affixes. In Inuktitut the tense affixes have developed a complicated remoteness system (future......Markers of futurity and aspect in West Greenlandic Unlike European languages tense in the West Greenlandic (WG) language is not marked in the inflection, but it is marked by derivational affixes (henceforth affixes). The West Greenlandic language belongs to Inuit-languages, (Iñupiaq (Alaska...

Sea ice and millennial-scale climate variability in the Nordic seas 90 kyr ago to present.

Science.gov (United States)

Hoff, Ulrike; Rasmussen, Tine L; Stein, Ruediger; Ezat, Mohamed M; Fahl, Kirsten

2016-07-26

In the light of rapidly diminishing sea ice cover in the Arctic during the present atmospheric warming, it is imperative to study the distribution of sea ice in the past in relation to rapid climate change. Here we focus on glacial millennial-scale climatic events (Dansgaard/Oeschger events) using the sea ice proxy IP25 in combination with phytoplankton proxy data and quantification of diatom species in a record from the southeast Norwegian Sea. We demonstrate that expansion and retreat of sea ice varies consistently in pace with the rapid climate changes 90 kyr ago to present. Sea ice retreats abruptly at the start of warm interstadials, but spreads rapidly during cooling phases of the interstadials and becomes near perennial and perennial during cold stadials and Heinrich events, respectively. Low-salinity surface water and the sea ice edge spreads to the Greenland-Scotland Ridge, and during the largest Heinrich events, probably far into the Atlantic Ocean.

East Greenland Caledonides: stratigraphy, structure and geochronology: Lower Palaeozoic stratigraphy of the East Greenland Caledonides

Directory of Open Access Journals (Sweden)

Smith, M. Paul

2004-12-01

Full Text Available The Lower Palaeozoic stratigraphy of the East Greenland Caledonides, from the fjord region of North-East Greenland northwards to Kronprins Christian Land, is reviewed and a number of new lithostratigraphical units are proposed. The Slottet Formation (new is a Lower Cambrian quartzite unit, containing Skolithos burrows, that is present in the Målebjerg and Eleonore Sø tectonic windows, in the nunatak region of North-East Greenland. The unit is the source of common and often-reported glacial erratic boulders containing Skolithos that are distributed throughout the fjord region. The Målebjerg Formation (new overlies the Slottet Formation in the tectonic windows, and comprises limestones and dolostones of assumed Cambrian–Ordovician age. The Lower Palaeozoic succession of the fjord region of East Greenland (dominantly limestones and dolostones is formally placed in the Kong Oscar Fjord Group (new. Amendments are proposed for several existing units in the Kronprins Christian Land and Lambert Land areas, where they occur in autochthonous, parautochthonous and allochthonous settings.

Occurrence of anisakid nematodes in Atlantic cod (Gadus morhua) and Greenland cod (Gadus ogac), West Greenland

DEFF Research Database (Denmark)

Mouritsen, Kim N.; Hedeholm, Rasmus; Schack, Henriette B.

2010-01-01

Anisakid nematodes commonly infect gadids, and are of economic and aesthetic importance to the commercial fishing industry in Greenland as some species are pathogenic to humans. However, very little is known about the occurrence of these parasites and their impact on the hosts in Greenland waters....... During a survey in 2005, stomach sample of 227 Atlantic cod (Gadus morhua) and 64 Greenland cod (Gadus ogac) was collected in Godthaab and Sisimiut fiord systems in West Greenland waters. All cod were dissected for stomach contents and anisakid nematodes were removed from the visceral cavity. Third stage...... nematode species regarding prevalence of infection and mean infection intensity was evident, and there was no relationship between fish condition and the intensity of nematode infections. Standardised for size, capelin-eating cod were in better condition and more heavily infected than fish subsisting...

Modelling the surface mass balance of the Greenland ice sheet and neighbouring ice caps : A dynamical and statistical downscaling approach

NARCIS (Netherlands)

Noël, B.P.Y.

2018-01-01

The Greenland ice sheet (GrIS) is the world’s second largest ice mass, storing about one tenth of the Earth’s freshwater. If totally melted, global sea level would rise by 7.4 m, affecting low-lying regions worldwide. Since the mid-1990s, increased atmospheric and oceanic temperatures have

Developing renewable energy in discontiguous Greenland

DEFF Research Database (Denmark)

Carruth, Susan

2016-01-01

Infrastructural Urbanism’s advocacy of creating synergies between technological, economical, and ecological processes holds great potential for guiding domestic energy planning in a transforming Greenland. However, the movement has largely been conceived in the context of regional paradigms very...... different from Greenland, and has yet to fully engage with the sociocultural dimensions of infrastructures. This article proposes that for Infrastructural Urbanism to offer real potential in Greenland it must engage with micro-scale, everyday material practices, thereby thickening the scale and the scope...

Traditional Knowledge About Polar Bears (Ursus maritimus in East Greenland: Changes in the Catch and Climate Over Two Decades

Directory of Open Access Journals (Sweden)

Kristin L. Laidre

2018-05-01

Full Text Available In Greenland, polar bears (Ursus maritimus are nutritional, economic, and cultural subsistence resources for Inuit. Traditional Ecological Knowledge (TEK collected from subsistence hunters can provide important insights and improve management decisions when collected systematically. We report on the results of a TEK survey of subsistence polar bear hunters living in the areas around Tasiilaq and Ittoqqortoormiit, East Greenland. Twenty-five full-time polar bear hunters were interviewed between December 2014 and March 2015 in a conversation-style interview, where a local interviewer fluent in the East Greenlandic dialect asked a series of 55 predetermined questions. The primary goals were to (1 gather Inuit perspectives on polar bear subsistence quotas and hunting strategies, (2 understand how climate change is affecting the polar bear subsistence hunt, and (3 document observed changes in polar bear distribution, abundance, and biology. Approximately 40% of the Tasiilaq respondents had caught between 10 and 19 polar bears in their lifetime, while 67% of Ittoqqortoormiit respondents reported lifetime catches of ≥20 bears. In both areas, polar bears were most commonly hunted between February and April. Hunters noted large changes to the climate in the areas where they hunt polar bears. Most hunters reported loss of sea ice, receding glaciers, unstable weather, and warmer temperatures. In Tasiilaq 73% of the hunters said climate changes had affected the polar bear hunt and in Ittoqqortoormiit about 88% of respondents reported the same. Hunters indicated that sea ice loss has created more areas of open water so dog sledges have become unsafe for hunting transportation compared to 10–15 years ago (reported by 100% of hunters in Tasiilaq and 80% in Ittoqqortoormiit. In Ittoqqortoormiit, the distance traveled during polar bear hunting trips has decreased dramatically. In both areas hunters noted that more polar bears are coming into their

Homicide in Greenland 1985-2010

DEFF Research Database (Denmark)

Christensen, Martin R; Thomsen, Asser H; Høyer, Christian B

2016-01-01

PURPOSE: Homicide in Greenland has not often been investigated. The latest published study documented a dramatic rise in the homicide rate from around 1/100,000 inhabitants to more than 23/100,000 inhabitants from 1946 to 1984. The aim of our study was to characterize homicides in Greenland from ...

New marine geophysical and sediment record of the Northeast Greenland Ice Stream.

Science.gov (United States)

Callard, L.; Roberts, D. H.; O'Cofaigh, C.; Lloyd, J. M.; Smith, J. A.; Dorschel, B.

2017-12-01

The NE Greenland Ice Stream (NEGIS) drains 16% of the Greenland Ice Sheet (GrIS) and has a sea-level equivalent of 1.1-1.4 m. Stabilised by two floating ice shelves, 79N and Zachariae Isstrom, until recently it has shown little response to increased atmospheric and oceanic warming. However, since 2010 it has experienced an accelerated rate of grounding line retreat ( 4 km) and significant ice shelf loss that indicates that this sector of the GrIS is now responding to current oceanic and/or climatic change and has the potential to be a major contributor to future global sea-level rise. The project `NEGIS', a collaboration between Durham University and AWI, aims to reconstruct the history of the NE Greenland Ice Stream from the Last Glacial Maximum (LGM) to present using both onshore and offshore geological archives to better understand past ice stream response to a warming climate. This contribution presents results and interpretations from an offshore dataset collected on the RV Polarstern, cruises PS100 and PS109 in 2016 and 2017. Gravity and box cores, supplemented by swath bathymetric and sub-bottom profiler data, were acquired and initial core analysis including x-radiographs and MSCL data logging has been performed. Data collection focused principally in the Norske Trough and the area directly in front of the 79N ice shelf, a sub-ice shelf environment as recently as two years ago. On the outer shelf streamlined subglacial bedforms, grounding-zone wedges and moraines as well as overconsolidated subglacial tills, record an extensive ice sheet advance to the shelf edge. On the inner shelf and in front of the 79N ice shelf, deep, glacially-eroded bedrock basins are infilled with stratified sediment. The stratified muds represent deglacial and Holocene glacimarine sedimentation, and capture the recent transition from sub-ice shelf to shelf free conditions. Multiproxy palaeoenvironmental reconstructions, including foraminifera and diatom analysis, and radiocarbon

The Northeast Greenland Shelf as a Potential Habitat for the Northeast Arctic Cod

Directory of Open Access Journals (Sweden)

Kjersti O. Strand

2017-09-01

Full Text Available Observations (1978–1991 of distributions of pelagic juvenile Northeast Arctic cod (Gadus morhua L. show that up to 1/3 of the year class are dispersed off the continental shelf and into the deep Norwegian Sea while on the way from the spring-spawning areas along the Norwegian coast to the autumn-settlement areas in the Barents Sea. The fate of this variable fraction of pelagic juveniles off-shelf has been an open question ever since Johan Hjort's (1914 seminal work. We have examined both the mechanisms causing offspring off-shelf transport, and their subsequent destiny using an individual-based biophysical model applied to quantify growth and dispersal. Our results show, consistently with the observations, that total off-shelf transport is highly variable between years and may be up to 27.4%. Offspring from spawning grounds around Lofoten have a higher chance of being displaced off the shelf. The off-shelf transport is dominated by episodic events where frequencies and dates vary between years. Northeasterly wind conditions over a 3–7-day period prior to the off-shelf events are a good proxy for dispersal of offspring off the shelf. Offspring transported into the open ocean are on average carried along three following routes: back onto the adjacent eastern shelves and into the Barents Sea (36.9%, recirculating within the Lofoten Basin (60.7%, or drifting northwest to the northeast Greenland shelf (2.4%. For the latter fraction the transport may exceed 12% depending on year. Recent investigations have discovered distributions of young cod on the northeast Greenland shelf indicating that conditions may support survival for Northeast Arctic cod offspring.

Bottom fish assemblages at the shelf and continental slope off East Greenland

DEFF Research Database (Denmark)

Jørgensen, Ole A; Hvingel, Carsten; Møller, P.R.

2015-01-01

During 2006 and 2008 two bottom trawl surveys were conducted at East Greenland to 72°N covering depths down to 1500 m. In the 149 trawl hauls in total 113 fish species were recorded of which 37 were considered pelagic and excluded from the analyses. As a first step the abundance data for the 76...... benthic species were used for analyses of the fish fauna diversity and fish assemblages. Nine assemblages were found by a standard type of cluster analysis. A Bayesian multinomial logit model was then applied to calculate vectors of probabilities defining the likelihood of each haul belonging to each...... distribution, species composition, temperature and depth. Three of the assemblages were located in the cold Iceland Sea while six were found in the somewhat warmer Irminger Sea...

Plutonium and americium in arctic waters, the North Sea and Scottish and Irish coastal zones

DEFF Research Database (Denmark)

Hallstadius, L.; Aarkrog, Asker; Dahlgaard, Henning

1986-01-01

Plutonium and americium have been measured in surface waters of the Greenland and Barents Seas and in the northern North Sea from 1980 through 1984. Measurements in water and biota, Fucus, Mytilus and Patella, were carried out in North-English and Scottish waters in 1982 and Fucus samples were co...

MASS BALANCE CHANGES AND ICE DYNAMICS OF GREENLAND AND ANTARCTIC ICE SHEETS FROM LASER ALTIMETRY

Directory of Open Access Journals (Sweden)

G. S. Babonis

2016-06-01

Full Text Available During the past few decades the Greenland and Antarctic ice sheets have lost ice at accelerating rates, caused by increasing surface temperature. The melting of the two big ice sheets has a big impact on global sea level rise. If the ice sheets would melt down entirely, the sea level would rise more than 60 m. Even a much smaller rise would cause dramatic damage along coastal regions. In this paper we report about a major upgrade of surface elevation changes derived from laser altimetry data, acquired by NASA’s Ice, Cloud and land Elevation Satellite mission (ICESat and airborne laser campaigns, such as Airborne Topographic Mapper (ATM and Land, Vegetation and Ice Sensor (LVIS. For detecting changes in ice sheet elevations we have developed the Surface Elevation Reconstruction And Change detection (SERAC method. It computes elevation changes of small surface patches by keeping the surface shape constant and considering the absolute values as surface elevations. We report about important upgrades of earlier results, for example the inclusion of local ice caps and the temporal extension from 1993 to 2014 for the Greenland Ice Sheet and for a comprehensive reconstruction of ice thickness and mass changes for the Antarctic Ice Sheets.

Spatial gradients of temperature, accumulation and δ18O-ice in Greenland over a series of Dansgaard–Oeschger events

Directory of Open Access Journals (Sweden)

M. Guillevic

2013-05-01

Full Text Available Air and water stable isotope measurements from four Greenland deep ice cores (GRIP, GISP2, NGRIP and NEEM are investigated over a series of Dansgaard–Oeschger events (DO 8, 9 and 10, which are representative of glacial millennial scale variability. Combined with firn modeling, air isotope data allow us to quantify abrupt temperature increases for each drill site (1σ = 0.6 °C for NEEM, GRIP and GISP2, 1.5 °C for NGRIP. Our data show that the magnitude of stadial–interstadial temperature increase is up to 2 °C larger in central and North Greenland than in northwest Greenland: i.e., for DO 8, a magnitude of +8.8 °C is inferred, which is significantly smaller than the +11.1 °C inferred at GISP2. The same spatial pattern is seen for accumulation increases. This pattern is coherent with climate simulations in response to reduced sea-ice extent in the Nordic seas. The temporal water isotope (δ18O–temperature relationship varies between 0.3 and 0.6 (±0.08 ‰ °C−1 and is systematically larger at NEEM, possibly due to limited changes in precipitation seasonality compared to GISP2, GRIP or NGRIP. The gas age−ice age difference of warming events represented in water and air isotopes can only be modeled when assuming a 26% (NGRIP to 40% (GRIP lower accumulation than that derived from a Dansgaard–Johnsen ice flow model.

Partial pressure (or fugacity) of carbon dioxide, pH, salinity and other variables collected from time series observations using Bubble type equilibrator for autonomous carbon dioxide (CO2) measurement, Carbon dioxide (CO2) gas analyzer and other instruments from MOORING_ICELAND_12W_68N in the North Greenland Sea from 2013-08-16 to 2014-08-21 (NCEI Accession 0157396)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157396 includes chemical, meteorological, physical and time series data collected from MOORING_ICELAND_12W_68N in the North Greenland Sea from...

Greenland ice sheet mass balance: a review.

Science.gov (United States)

Khan, Shfaqat A; Aschwanden, Andy; Bjørk, Anders A; Wahr, John; Kjeldsen, Kristian K; Kjær, Kurt H

2015-04-01

Over the past quarter of a century the Arctic has warmed more than any other region on Earth, causing a profound impact on the Greenland ice sheet (GrIS) and its contribution to the rise in global sea level. The loss of ice can be partitioned into processes related to surface mass balance and to ice discharge, which are forced by internal or external (atmospheric/oceanic/basal) fluctuations. Regardless of the measurement method, observations over the last two decades show an increase in ice loss rate, associated with speeding up of glaciers and enhanced melting. However, both ice discharge and melt-induced mass losses exhibit rapid short-term fluctuations that, when extrapolated into the future, could yield erroneous long-term trends. In this paper we review the GrIS mass loss over more than a century by combining satellite altimetry, airborne altimetry, interferometry, aerial photographs and gravimetry data sets together with modelling studies. We revisit the mass loss of different sectors and show that they manifest quite different sensitivities to atmospheric and oceanic forcing. In addition, we discuss recent progress in constructing coupled ice-ocean-atmosphere models required to project realistic future sea-level changes.

Recent Changes in Arctic Sea Ice Melt Onset, Freeze-Up, and Melt Season Length

Science.gov (United States)

Markus, Thorsten; Stroeve, Julienne C.; Miller, Jeffrey

2010-01-01

In order to explore changes and trends in the timing of Arctic sea ice melt onset and freeze-up and therefore melt season length, we developed a method that obtains this information directly from satellite passive microwave data, creating a consistent data set from 1979 through present. We furthermore distinguish between early melt (the first day of the year when melt is detected) and the first day of continuous melt. A similar distinction is made for the freeze-up. Using this method we analyze trends in melt onset and freeze-up for 10 different Arctic regions. In all regions except for the Sea of Okhotsk, which shows a very slight and statistically insignificant positive trend (O.4 days/decade), trends in melt onset are negative, i.e. towards earlier melt. The trends range from -1.0day/decade for the Bering Sea to -7.3 days/decade for the East Greenland Sea. Except for the Sea of Okhotsk all areas also show a trend towards later autumn freeze onset. The Chukchi/Beaufort Seas and Laptev/East Siberian Seas observe the strongest trends with 7 days/decade. For the entire Arctic, the melt season length has increased by about 20 days over the last 30 years. Largest trends of over 1O days/decade are seen for Hudson Bay, the East Greenland Sea the Laptev/East Siberian Seas, and the Chukchi/Beaufort Seas. Those trends are statistically significant a1 the 99% level.

Bourdieu in Greenland

DEFF Research Database (Denmark)

Hussain, Naimah

2017-01-01

. There is almost no previous research on Greenlandic media in general and journalism practice in particular. Mapping this small but contested field allows us to highlight some of the key analytical strengths of Bourdieu’s field theory and its ability to capture the dynamic actor relationships in such a complex......, structured space. At the same time, however, the “post-colonial” realities of Greenlandic journalism can help us to pose some questions about the limits – or the need for further development – of Bourdieu’s initial sketch about the journalistic field. This chapter tests the analytical concepts of capital...

Weather Test Reference Year of Greenland

DEFF Research Database (Denmark)

Kragh, Jesper; Pedersen, Frank; Svendsen, Svend

2005-01-01

the construction of two test reference years of Greenland used in the work of establishing new energy frame for the coming building code of Greenland. The first test reference year is constructed using measurements of climatic parameters from the town Nuuk located in the southwestern part of Greenland. The second...... test reference year is constructed using measurements from the town Uummannaq located in the north part of Greenland on the west coast. The construction of the test reference years fulfills the procedures described in the standard EN ISO 15927-4 using the following main weather parameters: Dry bulb...... temperature, global radiation, relative humidity and mean wind speed. To construct the test reference years a program called REFYEAR was developed in MatLab. REFYEAR automatically constructs the test reference year using an input file containing the climatic measurements. The two constructed test reference...

Future markers of the West Greenlandic

DEFF Research Database (Denmark)

Trondhjem, Naja Blytmann

2010-01-01

Abstract West Greenlandic, a polysynthetic language, belongs to Inuit languages. In Inuktitut (Canada) and West Greenlandic (Inuit languages) tense is marked by optional tense suffixes and in both languages the temporal systems are based on a future/ non-future opposition. In Inuktitut the tense...... suffixes have developed a complicated remoteness system. In West Greenlandic the future tense suffixes have a distinction between vague and inevitable future, and the past time suffixes have developed different perfect meanings. In Iñupiaq (Alaska), the temporal system is based on an opposition between...... past, present and future, where tense is marked in the flectional morpheme, but only in the indicative mood. There are only a few tense suffixes. The meanings of these tense suffixes are the same as those of the West Greenlandic tense suffixes. My current work is a typological investigation about...

A combined DNA-microsatellite and isozyme analysis of the population structure of the harbour porpoise in Danish waters and west Greenland

DEFF Research Database (Denmark)

Andersen, L W; Holm, L E; Siegismund, Hans Redlef

1997-01-01

deviations from the expected Hardy-Weinberg distribution were only observed in the total sample and at a single locus in the North Sea-summer sample and at two loci in the West Greenland sample. Whenever this occurred a surplus of homozygotes was observed, suggesting a Wahlund effect, a null allele...

Holocene climate and fjord glaciations in Northeast Greenland: implications for IRD deposition in the North Atlantic

DEFF Research Database (Denmark)

Reeh, Niels

2004-01-01

been released by intensive sub-glacial melting during the long stay of the ice-islands in coastal waters. The Holocene glacial geological record from Northeast Greenland is compared to the record of ice rafted debris (IRD) from North Atlantic deep-sea sediment cores. The comparison shows that transport...... by icebergs in the form of basal debris is unlikely to be the dominant transport mechanism of IRD to deposition sites in the North Atlantic during the Holocene. The ice rafted debris is more likely to be carried at the surface of sea- (or glacier) ice. This supports the result of previous studies by other...... workers that changes of atmospheric and ocean-surface circulation and temperature are the likely causes of Holocene cycles in IRD concentration in North Atlantic deep-sea sediments....

A reconciled estimate of glacier contributions to sea level rise: 2003 to 2009.

Science.gov (United States)

Gardner, Alex S; Moholdt, Geir; Cogley, J Graham; Wouters, Bert; Arendt, Anthony A; Wahr, John; Berthier, Etienne; Hock, Regine; Pfeffer, W Tad; Kaser, Georg; Ligtenberg, Stefan R M; Bolch, Tobias; Sharp, Martin J; Hagen, Jon Ove; van den Broeke, Michiel R; Paul, Frank

2013-05-17

Glaciers distinct from the Greenland and Antarctic Ice Sheets are losing large amounts of water to the world's oceans. However, estimates of their contribution to sea level rise disagree. We provide a consensus estimate by standardizing existing, and creating new, mass-budget estimates from satellite gravimetry and altimetry and from local glaciological records. In many regions, local measurements are more negative than satellite-based estimates. All regions lost mass during 2003-2009, with the largest losses from Arctic Canada, Alaska, coastal Greenland, the southern Andes, and high-mountain Asia, but there was little loss from glaciers in Antarctica. Over this period, the global mass budget was -259 ± 28 gigatons per year, equivalent to the combined loss from both ice sheets and accounting for 29 ± 13% of the observed sea level rise.

Seismic stratigraphic architecture of the Disko Bay trough-mouth fan system, West Greenland

Science.gov (United States)

Hofmann, Julia C.; Knutz, Paul C.

2015-04-01

Spatial and temporal changes of the Greenland Ice Sheet on the continental shelf bordering Baffin Bay remain poorly constrained. Then as now, fast-flowing ice streams and outlet glaciers have played a key role for the mass balance and stability of polar ice sheets. Despite their significance for Greenland Ice Sheet dynamics and evolution, our understanding of their long-term behaviour is limited. The central West Greenland margin is characterized by a broad continental shelf where a series of troughs extend from fjords to the shelf margin, acting as focal points for trough-mouth fan (TMF) accummulations. The sea-ward bulging morphology and abrupt shelf-break of these major depositional systems is generated by prograding depocentres that formed during glacial maxima when ice streams reached the shelf edge, delivering large amounts of subglacial sediment onto the continental slope (Ó Cofaigh et al., 2013). The aim of this study is to unravel the seismic stratigraphic architecture and depositional processes of the Disko Bay TMF, aerially the largest single sedimentary system in West Greenland, using 2D and 3D seismic reflection data, seabed bathymetry and stratigraphic information from exploration well Hellefisk-1. The south-west Disko Bay is intersected by a deep, narrow trough, Egedesminde Dyb, which extends towards the southwest and links to the shallower and broader cross-shelf Disko Trough (maximum water depths of > 1000 m and a trough length of c. 370 km). Another trough-like depression (trough length of c. 120 km) in the northern part of the TMF, indicating a previous position of the ice stream, can be distinguished on the seabed topographic map and the seismic images. The Disko Bay TMF itself extends from the shelf edge down to the abyssal plain (abyssal floor depths of 2000 m) of the southern Baffin Bay. Based on seismic stratigraphic configurations relating to reflection terminations, erosive patterns and seismic facies (Mitchum et al., 1977), the TMF

Storm-induced water dynamics and thermohaline structure at the tidewater Flade Isblink Glacier outlet to the Wandel Sea (NE Greenland)

Science.gov (United States)

Kirillov, Sergei; Dmitrenko, Igor; Rysgaard, Søren; Babb, David; Toudal Pedersen, Leif; Ehn, Jens; Bendtsen, Jørgen; Barber, David

2017-11-01

In April 2015, an ice-tethered conductivity-temperature-depth (CTD) profiler and a down-looking acoustic Doppler current profiler (ADCP) were deployed from the landfast ice near the tidewater glacier terminus of the Flade Isblink Glacier in the Wandel Sea, NE Greenland. The 3-week time series showed that water dynamics and the thermohaline structure were modified considerably during a storm event on 22-24 April, when northerly winds exceeded 15 m s-1. The storm initiated downwelling-like water dynamics characterized by on-shore water transport in the surface (0-40 m) layer and compensating offshore flow at intermediate depths. After the storm, currents reversed in both layers, and the relaxation phase of downwelling lasted ˜ 4 days. Although current velocities did not exceed 5 cm s-1, the enhanced circulation during the storm caused cold turbid intrusions at 75-95 m depth, which are likely attributable to subglacial water from the Flade Isblink Ice Cap. It was also found that the semidiurnal periodicities in the temperature and salinity time series were associated with the lunar semidiurnal tidal flow. The vertical structure of tidal currents corresponded to the first baroclinic mode of the internal tide with a velocity minimum at ˜ 40 m. The tidal ellipses rotate in opposite directions above and below this depth and cause a divergence of tidal flow, which was observed to induce semidiurnal internal waves of about 3 m height at the front of the glacier terminus. Our findings provide evidence that shelf-basin interaction and tidal forcing can potentially modify coastal Wandel Sea waters even though they are isolated from the atmosphere by landfast sea ice almost year-round. The northerly storms over the continental slope cause an enhanced circulation facilitating a release of cold and turbid subglacial water to the shelf. The tidal flow may contribute to the removal of such water from the glacial terminus.

Storm-induced water dynamics and thermohaline structure at the tidewater Flade Isblink Glacier outlet to the Wandel Sea (NE Greenland

Directory of Open Access Journals (Sweden)

S. Kirillov

2017-11-01

Full Text Available In April 2015, an ice-tethered conductivity–temperature–depth (CTD profiler and a down-looking acoustic Doppler current profiler (ADCP were deployed from the landfast ice near the tidewater glacier terminus of the Flade Isblink Glacier in the Wandel Sea, NE Greenland. The 3-week time series showed that water dynamics and the thermohaline structure were modified considerably during a storm event on 22–24 April, when northerly winds exceeded 15 m s−1. The storm initiated downwelling-like water dynamics characterized by on-shore water transport in the surface (0–40 m layer and compensating offshore flow at intermediate depths. After the storm, currents reversed in both layers, and the relaxation phase of downwelling lasted ∼ 4 days. Although current velocities did not exceed 5 cm s−1, the enhanced circulation during the storm caused cold turbid intrusions at 75–95 m depth, which are likely attributable to subglacial water from the Flade Isblink Ice Cap. It was also found that the semidiurnal periodicities in the temperature and salinity time series were associated with the lunar semidiurnal tidal flow. The vertical structure of tidal currents corresponded to the first baroclinic mode of the internal tide with a velocity minimum at ∼ 40 m. The tidal ellipses rotate in opposite directions above and below this depth and cause a divergence of tidal flow, which was observed to induce semidiurnal internal waves of about 3 m height at the front of the glacier terminus. Our findings provide evidence that shelf–basin interaction and tidal forcing can potentially modify coastal Wandel Sea waters even though they are isolated from the atmosphere by landfast sea ice almost year-round. The northerly storms over the continental slope cause an enhanced circulation facilitating a release of cold and turbid subglacial water to the shelf. The tidal flow may contribute to the removal of such water from the glacial terminus.

East Greenland Ridge in the North Atlantic Ocean

DEFF Research Database (Denmark)

Andreasen, Arne Døssing; Dahl-Jensen, T.; Thybo, Hans

2008-01-01

The combined Greenland-Senja Fracture Zones (GSFZ) represent a first-order plate tectonic feature in the North Atlantic Ocean. The GSFZ defines an abrupt change in the character of magnetic anomalies with well-defined seafloor spreading anomalies in the Greenland and Norwegian basins to the south...... but ambiguous and weak magnetic anomalies in the Boreas Basin to the north. Substantial uncertainty exists concerning the plate tectonic evolution of the latter area, including the role of the East Greenland Ridge, which is situated along the Greenland Fracture Zone. In 2002, a combined ocean-bottom seismometer...

Crustal structure of the Central-Eastern Greenland: results from the TopoGreenland refraction profile

Science.gov (United States)

Shulgin, Alexey; Thybo, Hans

2014-05-01

Until present, seismic surveys have only been carried out offshore and near the coasts of Greenland, where the crustal structure is affected by oceanic break-up. We present the deep seismic structure of the crust of the interior of Greenland, based on the new and the only existing so far seismic refraction/wide-angle reflection profile. The seismic data was acquired by a team of six people during a two-month long experiment in summer of 2011 on the ice cap in the interior of central-eastern Greenland. The presence of an up to 3.4 km thick ice sheet, permanently covering most of the land mass, made acquisition of geophysical data logistically complicated. The profile extends 310 km inland in E-W direction from the approximate edge of the stable ice cap near the Scoresby Sund across the center of the ice cap. 350 Reftek Texan receivers recorded high-quality seismic data from 8 equidistant shots along the profile. Explosive charge sizes were 1 ton at the ends and ca. 500 kg along the profile, loaded with about 125 kg at 35-85 m depth in individual boreholes. Given that the data acquisition was affected by the thick ice sheet, we questioned the quality of seismic records in such experiment setup. We have developed an automatic routine to check the amplitudes and spectra of the selected seismic phases and to check the differences/challenges in making seismic experiments on ice and the effects of ice on data interpretation. Using tomographic inversion and forward ray tracing modelling we have obtained the two-dimensional velocity model down to a 50 km depth. The model shows a decrease of crustal thickness from 47 km below the centre of Greenland in the western part of the profile to 40 km in its eastern part. Relatively high lower crustal velocities (Vp 6.8 - 7.3 km/s) in the western part of the TopoGreenland profile may result from past collision tectonics or, alternatively, may be related to the speculated passage of the Iceland mantle plume. Comparison of our results

The East Greenland rifted volcanic margin

Directory of Open Access Journals (Sweden)

C. Kent Brooks

2011-12-01

the emplacement of small volumes of basalts of the Vindtoppen Formation to the south of Scoresby Sund.Although the basalts were extruded close to sea level, this part of East Greenland is a plateau raised to c. 2 km, but the timing of uplift is controversial. Superimposed on the plateau is a major dome at Kangerlussuaq.East Greenland presents a rich interplay between magmatic and tectonic events reflecting the birth of the North Atlantic Ocean. It was active over a much longer period (36 Ma than other parts of the province (5 Ma in the Hebrides, Northern Ireland and the Faroe Islands and contains a wider range of products, including carbonatites, and felsic rocks tend to be granitic rather than syenitic. As expected, there are many similarities with Iceland, the present-day expression of activity in the province. Differences are readily explained by higher production rates and the thicker lithospheric lid during the early stages of development in East Greenland. The igneous and related activity clearly results from plate-tectonic factors, but the relationship is not understood in detail. In particular, the nature of the underlying mantle processes, primarily the presence or absence of a plume, is still not resolved.

The rise of sea level. To understand and to anticipate

International Nuclear Information System (INIS)

2013-03-01

By proposing and briefly commenting graphs and drawings, this publication propose brief presentations of the main issues related to sea level rise: global warming and climate disturbance, description of the phenomenon of sea level rise (difference between sea ice and ground ice, melting of glaciers), increase of sea level rise during the twentieth century, territories at risk (examples of Greenland, Tuvalu, Shanghai), acceleration of ice melting during the twenty first century with many coastal areas at risk, already noticed and possible future impacts in France (glaciers runoff, threatened coasts, example of the Xynthia tempest), how to be united and to anticipate (a threat for millions of people, adaptation to sea level rise, limitation of global warming to limit sea level rise)

Trends of cervical cancer in Greenland

DEFF Research Database (Denmark)

Sander, Bente B; Rebolj, Matejka; Lynge, Elsebeth

2014-01-01

BACKGROUND: Due to its extraordinarily fast economic and social transition, virtually closed borders before 1940 and, moreover, that 85% of the population has the distinctive genetics of the Inuit, Greenland is a very interesting country to study cervical cancer from a historical perspective....... Nevertheless, little has been reported about long-term cancer trends in Greenland. Our aim was to describe and interpret the incidence of cervical cancer from 1950 to 2009. MATERIAL AND METHODS: We systematically searched PubMed for articles reporting the incidence of cervical cancer in Greenland. We...... supplemented this with data for 1980-2009 obtained from the Chief Medical Officer of Greenland. RESULTS: Incidence of cervical cancer was around 10 per 100 000 women (age-standardised, world population, ASW) in the 1950s, 30 per 100 000 in the 1960s, and in the 1980s around 60 per 100 000. From 1985 onwards...

Physical activity patterns in Greenland: A country in transition

DEFF Research Database (Denmark)

Dahl-Petersen, Inger; Jørgensen, Marit E; Bjerregaard, Peter

2011-01-01

To examine differences in physical activity patterns among Inuit in Greenland in relation to social transition. The Inuit in Greenland are an indigenous population in the circumpolar north who are experiencing rapid social transition.......To examine differences in physical activity patterns among Inuit in Greenland in relation to social transition. The Inuit in Greenland are an indigenous population in the circumpolar north who are experiencing rapid social transition....

Q fever in Greenland

DEFF Research Database (Denmark)

Koch, Anders; Svendsen, Claus Bo; Christensen, Jens Jorgen

2010-01-01

We report a patient with Q fever endocarditis in a settlement in eastern Greenland (Isortoq, Ammassalik area). Likely animal sources include sled dogs and seals. Q fever may be underdiagnosed in Arctic areas but may also represent an emerging infection.......We report a patient with Q fever endocarditis in a settlement in eastern Greenland (Isortoq, Ammassalik area). Likely animal sources include sled dogs and seals. Q fever may be underdiagnosed in Arctic areas but may also represent an emerging infection....

Palaeoecology of Holocene peat deposits from Nordvestø, north-west Greenland

DEFF Research Database (Denmark)

Bennike, Ole; Goodsite, Michael Evan; Heinemeier, Jan

2008-01-01

Two extensive peat deposits on Nordvestø, between Greenland and Canada, were examined for macroscopic remains of plants and animals. One of the peat deposits accumulated during the period from c. 7,100 to 5,100 cal. years BP. This peat is guanogenic and completely dominated by the coprophilous...... bryophyte Aplodon wormskioldii, and also contains frequent remains of feathers. The peat formed close to a large former sea bird colony, probably a puffin (Fratercula arctica) colony. Puffins are now rare in the region, but the population may have been larger during the mid Holocene, when the sea was ice......-free for a longer period than at present. The other peat deposit is dated to c. 9,300-7,400 cal. years BP, it is minerogenic and the macrofossils reflect deposition in a shallow, richly vegetated pond. This peat formed during warmer summers than at present....

Potential for bias in 21st century semiempirical sea level projections

DEFF Research Database (Denmark)

Jevrejeva, S.; Moore, J. C.; Grinsted, A.

2012-01-01

by satellite altimetry. Nonradiative forcing contributors, such as long-term adjustment of Greenland and Antarctica ice sheets since Last Glacial Maximum, abyssal ocean warming, and terrestrial water storage, may bias model calibration which, if corrected for, tend to reduce median sea level projections...

Hydrologic Outlets of the Greenland Ice Sheet

Data.gov (United States)

National Aeronautics and Space Administration — The Hydrologic Outlets of the Greenland Ice Sheet data set contains GIS point shapefiles that include 891 observed and potential hydrologic outlets of the Greenland...

Improving the Greenlandic Greenhouse Gas Inventory

DEFF Research Database (Denmark)

Nielsen, Ole-Kenneth; Baunbæk, Lene; Gyldenkærne, Steen

The project to improve the Greenlandic greenhouse gas (GHG) inventory was undertaken due to the recommendations made by the UNFCCC review team in connection with the 2008 and 2009 submissions by the Kingdom of Denmark. The improvements made to the Greenlandic GHG emission inventory were substantial...

Reuse of harbour sediments in the Greenlandic construction industry

DEFF Research Database (Denmark)

Belmonte, Louise Josefine; Kirkelund, Gunvor Marie; Ottosen, Lisbeth M.

2010-01-01

The purpose of this study is to investigate possibilities of using harbour sediments from the Greenlandic harbours as substitutes in the Greenlandic construction industry, mainly for concrete production and road construction. Materials for use in the Greenlandic construction industry are shipped...

Present conditions in Greenland and the Kangerlussuaq area

International Nuclear Information System (INIS)

Nielsen, A. B.

2010-01-01

Greenland is the world's largest island, with an area of 2.2 million square kilometres, 80 % of which is covered by the ice sheet. The climate is Arctic, but as Greenland stretches 2600 km from north to south, there is a huge variability in climate, with temperature decreasing from south to north. Due to the influence of oceanic currents, the west coast is slightly warmer than the east coast. Precipitation also decreases strongly from the south to the north, and also with distance from the coast. Kangerlussuaq is located in the dry, continental area of central west Greenland. The bedrock of Greenland is dominated by Precambrian gneisses, with sedimentary rocks occurring in some areas of East and North Greenland, and smaller areas of basalts. All of Greenland has been glaciated several times and has thus been eroded and shaped by the ice, as it still is at the ice margin. Soils are generally thin, and especially in the gneiss regions rather poor in plant nutrients. Permafrost occurs throughout the ice free areas of Greenland. It is continuous in the north, discontinuous along parts of the central east and west coast and occurs as isolated patches in the south. Kangerlussuaq is in the southernmost part of the continuous permafrost zone. The spatial variability in climate is also reflected in the vegetation zones, which range from Arctic dessert in the far north, through dwarf shrub zones with increasing plant height and density towards the south, to the arctic shrub zone in the continental parts of West Greenland and subarctic Birch forest in South Greenland. The terrestrial food chains in Greenland are generally short and with few species. Cyclic variation in population sizes has been observed in some mammal species, including lemming and caribou. Many species of mammals and birds are associated with the coastal environment, which is therefore also and important resource area for the human population. Fishery is the most economically important industry in Greenland

Resources of Greenland and the possibilities of a joint Danish/Greenland exploitation of specially the energy resources in a period of economic crisis

International Nuclear Information System (INIS)

Taagholt, J.

1983-01-01

As Greenland is very dependent on imported articles and fuels, mainly petroleum, economic crisis or just an energy crisis will affect Greenland very much. To evaluate Greenlands situation in a crisis an account is given of the climatic conditions, of the present economic situation, and of planned development projects, The Greenland Area has Denmarks largest potential energy reserves of known coal deposits, of partially surveyed uranium deposits, of partially surveyed potential hydroelectric power reserves, and of petroleum and natural gas deposits not yet pointed out. An analysis is made of the utilization of the Greenland energy resources today, and the plans of future extended utilization. (LN)

A System of Oceanic Reanalysis (SOR) fot the Nordic Seas

Science.gov (United States)

Pnyushkov, A.

2009-04-01

A system of oceanic reanalysis of the Nordic seas (Norwegian, Greenland and Barents seas) directed to the investigations of long period changes in the oceanic climate of the Arctic sub-polar seas was developed. The system of oceanic reanalysys (SOR) includes hybrid coordinate 22-th level ocean model HYCOM [Bleck,2002] and modern oceanographic data assimilation technique based on spectral nudging method. A series of test experiments was carried out and optimal parameters for assimilation routine were choused. These parameters take into account the accuracy of spatial restoring by means objective analysis procedure and phase distortion in modeling fields during monotonous assimilation of monthly distributions. On the basis of modeling results a set of monthly mean hydrological distributions of thermohaline parameters was created for the Nordic seas that was used for climatic field compilations on the standard levels for period 1957-1990. The data of reanalysis system projections allow us to restore the information about structure and dynamic of oceanographic fields for the periods and areas with a small number of direct measurements, for example East-Greenland currents area, north and north-east parts of the Barents sea. A series of additional experiments with SOR were performed directed to the simple assimilation of sea ice concentration data. A significant improvement of the system of objectively analyzed field preparation was done during 2008 including additional validation procedure of gridded arrays with using the direct data of oceanographic stations. This work was supported by Russian Foundation for Basic Research (grant 07-05-00393).

Oxygen isotope ratios in the shell of Mytilus edulis: archives of glacier meltwater in Greenland?

DEFF Research Database (Denmark)

Versteegh, E. A. A.; Blicher, Martin E.; Mortensen, J.

2012-01-01

Melting of the Greenland Ice Sheet (GrIS) is accelerating and will contribute significantly to global sea level rise during the 21st century. Instrumental data on GrIS melting only cover the last few decades, and proxy data extending our knowledge into the past are vital for validating models...... predicting the influence of ongoing climate change. We investigated a potential meltwater proxy in Godthåbsfjord (West Greenland), where glacier meltwater causes seasonal excursions with lower oxygen isotope water (δ18Ow) values and salinity. The blue mussel (Mytilus edulis) potentially records...... its potential as a palaeo-meltwater proxy. First, we confirmed that M. edulis shell calcite oxygen isotope (δ18Oc) values are in equilibrium with ambient water and generally reflect meltwater conditions. Subsequently we investigated if this species recorded the full range of δ18Ow values occurring...

Norse Greenland

DEFF Research Database (Denmark)

Arneborg, Jette

2015-01-01

human agency, landscape changes, climate changes, resilience, sustainability and adaptation are key words and research has moved from local to more global perspectives. New results from research projects in recent years have diversified the discussion claiming that the Norse Greenlanders created...

Application of GRACE to the assessment of model-based estimates of monthly Greenland Ice Sheet mass balance (2003-2012)

Science.gov (United States)

Schlegel, Nicole-Jeanne; Wiese, David N.; Larour, Eric Y.; Watkins, Michael M.; Box, Jason E.; Fettweis, Xavier; van den Broeke, Michiel R.

2016-09-01

Quantifying the Greenland Ice Sheet's future contribution to sea level rise is a challenging task that requires accurate estimates of ice sheet sensitivity to climate change. Forward ice sheet models are promising tools for estimating future ice sheet behavior, yet confidence is low because evaluation of historical simulations is challenging due to the scarcity of continental-wide data for model evaluation. Recent advancements in processing of Gravity Recovery and Climate Experiment (GRACE) data using Bayesian-constrained mass concentration ("mascon") functions have led to improvements in spatial resolution and noise reduction of monthly global gravity fields. Specifically, the Jet Propulsion Laboratory's JPL RL05M GRACE mascon solution (GRACE_JPL) offers an opportunity for the assessment of model-based estimates of ice sheet mass balance (MB) at ˜ 300 km spatial scales. Here, we quantify the differences between Greenland monthly observed MB (GRACE_JPL) and that estimated by state-of-the-art, high-resolution models, with respect to GRACE_JPL and model uncertainties. To simulate the years 2003-2012, we force the Ice Sheet System Model (ISSM) with anomalies from three different surface mass balance (SMB) products derived from regional climate models. Resulting MB is compared against GRACE_JPL within individual mascons. Overall, we find agreement in the northeast and southwest where MB is assumed to be primarily controlled by SMB. In the interior, we find a discrepancy in trend, which we presume to be related to millennial-scale dynamic thickening not considered by our model. In the northwest, seasonal amplitudes agree, but modeled mass trends are muted relative to GRACE_JPL. Here, discrepancies are likely controlled by temporal variability in ice discharge and other related processes not represented by our model simulations, i.e., hydrological processes and ice-ocean interaction. In the southeast, GRACE_JPL exhibits larger seasonal amplitude than predicted by the

The future sea-level rise contribution of Greenland’s glaciers and ice caps

DEFF Research Database (Denmark)

Machguth, H.; Rastner, P.; Bolch, T.

2013-01-01

We calculate the future sea-level rise contribution from the surface mass balance of all of Greenland's glaciers and ice caps (GICs, ~90 000 km2) using a simplified energy balance model which is driven by three future climate scenarios from the regional climate models HIRHAM5, RACMO2 and MAR...... experiments suggest that mass loss could be higher by 20–30% if a strong lowering of the surface albedo were to take place in the future. It is shown that the sea-level rise contribution from the north-easterly regions of Greenland is reduced by increasing precipitation while mass loss in the southern half...... feedback mechanisms are considered. The mass loss of all GICs by 2098 is calculated to be 2016 ± 129 Gt (HIRHAM5 forcing), 2584 ± 109 Gt (RACMO2) and 3907 ± 108 Gt (MAR). This corresponds to a total contribution to sea-level rise of 5.8 ± 0.4, 7.4 ± 0.3 and 11.2 ± 0.3 mm, respectively. Sensitivity...

Experience with cochlear implants in Greenlanders with profound hearing loss living in Greenland

DEFF Research Database (Denmark)

Homøe, Preben; Andersen, Ture; Grøntved, Aksel

2013-01-01

OBJECTIVE: Cochlear implant (CI) treatment was introduced to the world in the 1980s and has become a routine treatment for congenital or acquired severe-to-profound hearing loss. CI treatment requires access to a highly skilled team of ear, nose and throat specialists, audiologists and speech...... years are in need of a CI every second year in Greenland often due to sequelae from meningitis, which may cause postinfectious deafness. Screening of new-borns for hearing has been started in Greenland establishing the basis for early diagnosis of congenital hearing impairment and subsequent...

Cervical cancer screening in Greenland, 1997-2011

DEFF Research Database (Denmark)

Holst, Signe; Wohlfahrt, Jan; Kjær, Susanne Krüger

2016-01-01

of the screening program and to examine possible changes in cervical intraepithelial neoplasia (CIN3) incidence in Greenland during 1997-2011 according to calendar period and age. METHODS: Using nationwide registries, we calculated age-standardized incidence rates for all women born and living in Greenland......OBJECTIVE: In spite of the high incidence of cervical cancer in Greenland, no assessment has been made of the impact of organized cervical screening, introduced in 1998, in relation to occurrence of high-grade cervical lesions. The objectives of the present study were to estimate coverage...

Impact of public health research in Greenland

DEFF Research Database (Denmark)

Bjerregaard, Peter; Curtis, Tine

2004-01-01

research. Two health surveys have been carried out in Greenland by the National Institute of Public Health, and a follow-up is being planned together with the Directorate of Health. The results have been widely used by politicians, administrators, and health care professionals.......In 1992, the Greenland Home Rule Government took over the responsibility for health care. There has since been a growing cooperation between the Directorate of Health and researchers in Denmark and Greenland, for instance by the Directorate supporting workshops and funding a chair in health...

Hepatitis B prevalence and incidence in Greenland

DEFF Research Database (Denmark)

Børresen, Malene Landbo; Andersson, Mikael; Wohlfahrt, Jan

2015-01-01

Greenland remains a highly endemic area for hepatitis B virus (HBV) infection. This is in sharp contrast to other modern societies, such as Denmark. To address this discrepancy, we investigated the natural history of HBV infection in Greenland by estimating the age-specific incidence of HBV...... from all available HBV registries in Greenland to determine changes in HBV status over time. Incidence rates of HBV infection and hepatitis B surface antigen seroclearance were estimated after taking into account interval censoring. The incidence of HBV infection in 5-14-year-old subjects was less than...

A Case of Greenlandic Fisheries Co-Politics

DEFF Research Database (Denmark)

Jacobsen, Rikke Becker; Raakjær, Jesper

2012-01-01

Greenlandic governance institutions have been criticised for their colonial heritage of centralisation and lack of democratic participation. In the same manner, Greenlandic fisheries management is notorious in the academic literature for its centralised and locally illegitimate character. While r...

Holocene sea level, a semi-empirical contemplation

Science.gov (United States)

Bittermann, K.; Kemp, A.; Vermeer, M.; Rahmstorf, S.

2017-12-01

Holocene eustatic sea level from approximately -10,000-1800 CE was characterized by an increase of about 60m, with the rate progressively slowing down until sea level almost stabilizes between 500-1800 CE. Global and northern-hemisphere temperatures rose from the last glacial termination until the `Holocene Optimum'. From ­­there, up to the start of the recent anthropogenic rise, they almost steadily decline. How are the sea-level and temperature evolutions linked? We investigate this with semi-empirical sea-level models. We found that, due to the nature of Milankovitch forcing, northern-hemisphere temperature (we used the Greenland temperature by Vinther et al., 2009) is a better model driver than global mean temperature because the evolving mass of northern-hemisphere land ice was the dominant cause of Holocene global sea-level trends. The adjustment timescale for this contribution is 1200 years (900-1500 years; 90% confidence interval). To fit the observed sea-level history, the model requires a small additional constant rate (Bittermann 2016). This rate turns out to be of the same order of magnitude as reconstructions of Antarctic sea-level contributions (Briggs et al. 2014, Golledge et al. 2014). In reality this contribution is unlikely to be constant but rather has a dominant timescale that is large compared to the time considered. We thus propose that Holocene sea level can be described by a linear combination of a temperature driven rate, which becomes negative in the late Holocene (as Northern Hemisphere ice masses are diminished), and a positive, approximately constant term (possibly from Antarctica), which starts to dominate from the middle of the Holocene until the start of industrialization. Bibliography: Bittermann, K. 2016. Semi-empirical sea-level modelling. PhD Thesis University of Potsdam. Briggs, R.D., et al. 2014. A data-constrained large ensemble analysis of Antarctic evolution since the Eemian. Quaternary science reviews, 103, 91

Seasonal variation in the input of atmospheric selenium to northwestern Greenland snow

Energy Technology Data Exchange (ETDEWEB)

Lee, Khanghyun; Hong, Sang-Bum [Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 406–840 (Korea, Republic of); Lee, Jeonghoon [Department of Science Education, Ewha womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750 (Korea, Republic of); Chung, Jiwoong; Hur, Soon-Do [Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 406–840 (Korea, Republic of); Hong, Sungmin, E-mail: smhong@inha.ac.kr [Department of Ocean Sciences, Inha University, 100 Inharo, Nam-gu, Incheon 402-751 (Korea, Republic of)

2015-09-01

Oxygen isotope ratio (δ{sup 18}O) and concentrations of Al, Na{sup +}, methanesulfonic acid (MSA), SO{sub 4}{sup 2−}, and selenium (Se) in a continuous series of 70 snow samples from a 3.2-m snow pit at a site in northwestern Greenland were determined using ultraclean procedures. Well-defined depth profiles of δ{sup 18}O, Al, and sea-salt-Na{sup +} allowed the determination of chronology of the snow pit that spanned approximately 6 years from spring 2003 to summer 2009. Se concentrations were at a low pg/g level, ranging from 7.2 to 45 pg/g, and exhibited high variability with generally higher values during winter and spring and lower values during summer and fall. Very high crustal enrichment factors (EF{sub c}) of Se averaging approximately 26,600 for the entire time period indicate a small contribution from crust dust. High Se/MSA ratios are generally observed in the winter and spring snow layers, in which the Se concentrations were relatively high (> 20 pg/g). This suggests that a significant component of the Se present in the snow layers is of anthropogenic origin. During the summer season, however, high EF{sub c} values are accompanied with low Se/MSA, indicating an increased contribution of marine biogenic sources. Significant correlations between Se, Al, and non-sea-salt SO{sub 4}{sup 2−} highlight that significant inputs of Se to the snow are likely controlled by the seasonality in the transport efficiency of anthropogenic Se from the source regions to the site. Based on the seasonal changes in Se concentrations, Se/MSA, and Se/S ratios observed in the samples, the input of anthropogenic Se to the site appears to be governed by the long-range transportation of Se emitted from coal combustion in East Asian countries, especially in China. - Highlights: • The first comprehensive seasonal variation of Se in Greenland snow is presented. • Data exhibit pronounced seasonality in the fallout of Se to Greenland. • High Se/MSA ratios indicate a

Seasonal variation in the input of atmospheric selenium to northwestern Greenland snow

International Nuclear Information System (INIS)

Lee, Khanghyun; Hong, Sang-Bum; Lee, Jeonghoon; Chung, Jiwoong; Hur, Soon-Do; Hong, Sungmin

2015-01-01

Oxygen isotope ratio (δ 18 O) and concentrations of Al, Na + , methanesulfonic acid (MSA), SO 4 2− , and selenium (Se) in a continuous series of 70 snow samples from a 3.2-m snow pit at a site in northwestern Greenland were determined using ultraclean procedures. Well-defined depth profiles of δ 18 O, Al, and sea-salt-Na + allowed the determination of chronology of the snow pit that spanned approximately 6 years from spring 2003 to summer 2009. Se concentrations were at a low pg/g level, ranging from 7.2 to 45 pg/g, and exhibited high variability with generally higher values during winter and spring and lower values during summer and fall. Very high crustal enrichment factors (EF c ) of Se averaging approximately 26,600 for the entire time period indicate a small contribution from crust dust. High Se/MSA ratios are generally observed in the winter and spring snow layers, in which the Se concentrations were relatively high (> 20 pg/g). This suggests that a significant component of the Se present in the snow layers is of anthropogenic origin. During the summer season, however, high EF c values are accompanied with low Se/MSA, indicating an increased contribution of marine biogenic sources. Significant correlations between Se, Al, and non-sea-salt SO 4 2− highlight that significant inputs of Se to the snow are likely controlled by the seasonality in the transport efficiency of anthropogenic Se from the source regions to the site. Based on the seasonal changes in Se concentrations, Se/MSA, and Se/S ratios observed in the samples, the input of anthropogenic Se to the site appears to be governed by the long-range transportation of Se emitted from coal combustion in East Asian countries, especially in China. - Highlights: • The first comprehensive seasonal variation of Se in Greenland snow is presented. • Data exhibit pronounced seasonality in the fallout of Se to Greenland. • High Se/MSA ratios indicate a significant contribution from anthropogenic sources. �

Sea-ice induced growth decline in Arctic shrubs.

Science.gov (United States)

Forchhammer, Mads

2017-08-01

Measures of increased tundra plant productivity have been associated with the accelerating retreat of the Arctic sea-ice. Emerging studies document opposite effects, advocating for a more complex relationship between the shrinking sea-ice and terrestrial plant productivity. I introduce an autoregressive plant growth model integrating effects of biological and climatic conditions for analysing individual ring-width growth time series. Using 128 specimens of Salix arctica , S. glauca and Betula nana sampled across Greenland to Svalbard, an overall negative effect of the retreating June sea-ice extent was found on the annual growth. The negative effect of the retreating June sea-ice was observed for younger individuals with large annual growth allocations and with little or no trade-off between previous and current year's growth. © 2017 The Author(s).

Crustal structure of the Central-Eastern Greenland: results from the Topo Greenland refraction profile

DEFF Research Database (Denmark)

Shulgin, Alexey; Thybo, Hans

2014-01-01

Until present, seismic surveys have only been carried out offshore and near the coasts of Greenland, where the crustal structure is affected by oceanic break-up. We present the deep seismic structure of the crust of the interior of Greenland, based on the new and the only existing so far seismic...... refraction/wide-angle reflection profile. The seismic data was acquired by a team of six people during a two-month long experiment in summer of 2011 on the ice cap in the interior of central-eastern Greenland. The presence of an up to 3.4 km thick ice sheet, permanently covering most of the land mass, made...... acquisition of geophysical data logistically complicated. The profile extends 310 km inland in E-W direction from the approximate edge of the stable ice cap near the Scoresby Sund across the center of the ice cap. 350 Reftek Texan receivers recorded high-quality seismic data from 8 equidistant shots along...

Identity and acculturation: The case of food consumption by Greenlanders in Denmark

DEFF Research Database (Denmark)

Askegaard, Søren; Kjeldgaard, Dannie; Arnould, Eric J.

relations are structured around the acquisition, consumption and disposal of food. 4. Food consumption in Greenlandic food culture was organised around experience of scarcity - scarcity of the provisions of the Greenlandic natural environment as well as the provisions available in the retail environment....... The experience of Danish food culture was dominated by a discourse of abundance - although the informants experienced scarcity of Greenlandic food products when in Denmark. 5. The symbolic values of Greenlandic food were tied to authenticity, and consumption of Greenlandic food was often associated...... with a more or less dual cultural background (due to the strong Danish cultural influence in Greenland). This duality of cultural identity means that Greenlandic immigrants' consumption reflects a well-known negotiation of Danish and Greenlandic consumer cultures under new conditions, rather than a classic...

High Arctic Holocene temperature record from the Agassiz ice cap and Greenland ice sheet evolution.

Science.gov (United States)

Lecavalier, Benoit S; Fisher, David A; Milne, Glenn A; Vinther, Bo M; Tarasov, Lev; Huybrechts, Philippe; Lacelle, Denis; Main, Brittany; Zheng, James; Bourgeois, Jocelyne; Dyke, Arthur S

2017-06-06

We present a revised and extended high Arctic air temperature reconstruction from a single proxy that spans the past ∼12,000 y (up to 2009 CE). Our reconstruction from the Agassiz ice cap (Ellesmere Island, Canada) indicates an earlier and warmer Holocene thermal maximum with early Holocene temperatures that are 4-5 °C warmer compared with a previous reconstruction, and regularly exceed contemporary values for a period of ∼3,000 y. Our results show that air temperatures in this region are now at their warmest in the past 6,800-7,800 y, and that the recent rate of temperature change is unprecedented over the entire Holocene. The warmer early Holocene inferred from the Agassiz ice core leads to an estimated ∼1 km of ice thinning in northwest Greenland during the early Holocene using the Camp Century ice core. Ice modeling results show that this large thinning is consistent with our air temperature reconstruction. The modeling results also demonstrate the broader significance of the enhanced warming, with a retreat of the northern ice margin behind its present position in the mid Holocene and a ∼25% increase in total Greenland ice sheet mass loss (∼1.4 m sea-level equivalent) during the last deglaciation, both of which have implications for interpreting geodetic measurements of land uplift and gravity changes in northern Greenland.

Millennial oscillations in greenland dust and Eurasian Aeolian records - a paleosol-loess perspective (Hans Oeschger Medal Lecture)

Science.gov (United States)

Rousseau, Denis-Didier

2017-04-01

Greenland ice cores, and a critical study of their source variations, reconciles these records with those observed on the Eurasian continent. This allows demonstrating the link between European and Chinese loess sequences, dust records in Greenland, and variations of the North Atlantic sea ice extent. The sources of the emitted and transported dust material are variable and relate to different environments corresponding to present desert areas in Asia, but also hidden regions related to lower sea level stands, dry rivers, or zones close to the frontal moraines of the main Northern Hemisphere ice sheets in Europe. As a conclusion of this presentation, I address the short term past climatic changes as preserved in the continental eolian records, in line with the Hans Oeschger medal description. Furthermore one can anticipate such study to be at the origin of more sophisticated and elaborated investigations of millennial and sub-millennial continental climate variability on the Northern Hemisphere. The overview presented during this presentation would not have been possible without the help and close collaboration of many colleagues among whom are Niklas BOERS, Adriana SIMA, Anders SVENSSON, Matthias BIGLER, France LAGROIX, Samuel TAYLOR, Pierre ANTOINE, Christine HATTE, Michael GHIL, George KUKLA, Sigfus JOHNSEN, Markus FUCHS, Andreas LANG, Gilles BERGAMETTI, Beatrice MARTICORENA and Ludwig ZOELLER.

Greenland unveils terms for offshore licenses

International Nuclear Information System (INIS)

Anon.

1992-01-01

This paper reports that Greenland has spelled out terms for its first round of offshore licensing. The action off western Greenland could lead to the first oil and gas exploration there since an unsuccessful campaign in the 1970s. The Mineral Resources Administration (MRA) for Greenland pegged exploration license terms on 133 blocks, all south of the 66th parallel, at 10 years with options for 2 year extensions to a maximum of 6 more years. The license can cover as many as six blocks. In the first 3 year period companies will have only a seismic obligation of 1,588 km per six blocks. For the second 3 year period there will be a one well obligation and one well in each subsequent 2 year periods

Pathways of warm water to the Northeast Greenland outlet glaciers

Science.gov (United States)

Schaffer, Janin; Timmermann, Ralph; Kanzow, Torsten; Arndt, Jan Erik; Mayer, Christoph; Schauer, Ursula

2015-04-01

The ocean plays an important role in modulating the mass balance of the Greenland Ice Sheet by delivering heat to the marine-terminating outlet glaciers surrounding the Greenland coast. The warming and accumulation of Atlantic Water in the subpolar North Atlantic has been suggested to be a potential driver of the glaciers' retreat over the last decades. The shelf regions thus play a critical role for the transport of Atlantic Water towards the glaciers, but also for the transfer of freshwater towards the deep ocean. A key region for the mass balance of the Greenland Ice Sheet is the Northeast Greenland Ice Stream. This large ice stream drains the second-largest basin of the Greenland Ice Sheet and feeds three outlet glaciers. The largest one is Nioghalvfjerdsfjorden (79°N-Glacier) featuring an 80 km long floating ice tongue. Both the ocean circulation on the continental shelf off Northeast Greenland and the circulation in the cavity below the ice tongue are weakly constrained so far. In order to study the relevant processes of glacier-ocean interaction we combine observations and model work. Here we focus on historic and recent hydrographic observations and on the complex bathymetry in the Northeast Greenland shelf region, which is thought to steer the flux of warm Atlantic water onto the continental shelf and into the sub-ice cavity beneath the 79°N-Glacier. We present a new global topography data set, RTopo-2, which includes the most recent surveys on the Northeast Greenland continental shelf and provides a detailed bathymetry for all around Greenland. In addition, RTopo-2 contains ice and bedrock surface topographies for Greenland and Antarctica. Based on the updated ocean bathymetry and a variety of hydrographic observations we show the water mass distribution on the continental shelf off Northeast Greenland. These maps enable us to discuss possible supply pathways of warm modified Atlantic waters on the continental shelf and thus potential ways of heat

Public Consultation Processes in Greenland Regarding the Mining Industry

Directory of Open Access Journals (Sweden)

Maria Ackrén

2016-05-01

Full Text Available Since the Greenland Self-Government Act came into force in 2009, economic development and the right to utilize natural resources in Greenland lies in the hands of the Self-Government. Earlier efforts to establish this authority were made back in the 1970s, when discussions on Home Rule were first on the agenda. Mining industries are not a new activity in Greenland. During the Second World War, Greenlandic cryolite was used to produce aluminum for the North American aircraft industry. Other essential natural resources, such as gold and gemstones, have also received international interest over the years. Greenland's new development aim is to build up a large-scale mining industry. This article elucidates the form of public consultation processes followed in Greenland in connection with two large-scale mining projects and the different views various actors have regarding these events. How did the deliberative democratic process unfold in Greenland regarding these projects? Was the process followed an effective way to manage these kinds of projects? The article shows that two projects that received a lot of media attention: the 2005 iron ore mine project in Isukasia, and the 2001 TANBREEZ-project to extract rare earth elements, used highly different approaches when it comes to deliberative democracy. In the former case, a limited degree of deliberative democracy was used, while in the latter case, the opposite applies.

Circulation and fjord-shelf exchange during the ice-covered period in Young Sound-Tyrolerfjord, Northeast Greenland (74°N)

Science.gov (United States)

Boone, W.; Rysgaard, S.; Kirillov, S.; Dmitrenko, I.; Bendtsen, J.; Mortensen, J.; Meire, L.; Petrusevich, V.; Barber, D. G.

2017-07-01

Fjords around Greenland connect the Greenland Ice Sheet to the ocean and their hydrography and circulation are determined by the interplay between atmospheric forcing, runoff, topography, fjord-shelf exchange, tides, waves, and seasonal growth and melt of sea ice. Limited knowledge exists on circulation in high-Arctic fjords, particularly those not impacted by tidewater glaciers, and especially during winter, when they are covered with sea-ice and freshwater input is low. Here, we present and analyze seasonal observations of circulation, hydrography and cross-sill exchange of the Young Sound-Tyrolerfjord system (74°N) in Northeast Greenland. Distinct seasonal circulation phases are identified and related to polynya activity, meltwater and inflow of coastal water masses. Renewal of basin water in the fjord is a relatively slow process that modifies the fjord water masses on a seasonal timescale. By the end of winter, there is two-layer circulation, with outflow in the upper 45 m and inflow extending down to approximately 150 m. Tidal analysis showed that tidal currents above the sill were almost barotropic and dominated by the M2 tidal constituent (0.26 m s-1), and that residual currents (∼0.02 m s-1) were relatively small during the ice-covered period. Tidal pumping, a tidally driven fjord-shelf exchange mechanism, drives a salt flux that is estimated to range between 145 kg s-1 and 603 kg s-1. Extrapolation of these values over the ice-covered period indicates that tidal pumping is likely a major source of dense water and driver of fjord circulation during the ice-covered period.

Recent increases in Arctic freshwater flux affects Labrador Sea convection and Atlantic overturning circulation

NARCIS (Netherlands)

Yang, Qian; Dixon, Timothy H.; Myers, Paul G.; Bonin, Jennifer; Chambers, Don; Van Den Broeke, M. R.|info:eu-repo/dai/nl/073765643

2016-01-01

The Atlantic Meridional Overturning Circulation (AMOC) is an important component of ocean thermohaline circulation. Melting of Greenland's ice sheet is freshening the North Atlantic; however, whether the augmented freshwater flux is disrupting the AMOC is unclear. Dense Labrador Sea Water (LSW),

Impact of public health research in Greenland

DEFF Research Database (Denmark)

Bjerregaard, Peter; Curtis, Tine

2004-01-01

In 1992, the Greenland Home Rule Government took over the responsibility for health care. There has since been a growing cooperation between the Directorate of Health and researchers in Denmark and Greenland, for instance by the Directorate supporting workshops and funding a chair in health resea...

The future sea-level rise contribution of Greenland’s glaciers and ice caps

International Nuclear Information System (INIS)

Machguth, H; Rastner, P; Bolch, T; Mölg, N; Sørensen, L Sandberg; Aðalgeirsdottir, G; Van Angelen, J H; Van den Broeke, M R; Fettweis, X

2013-01-01

We calculate the future sea-level rise contribution from the surface mass balance of all of Greenland’s glaciers and ice caps (GICs, ∼90 000 km 2 ) using a simplified energy balance model which is driven by three future climate scenarios from the regional climate models HIRHAM5, RACMO2 and MAR. Glacier extent and surface elevation are modified during the mass balance model runs according to a glacier retreat parameterization. Mass balance and glacier surface change are both calculated on a 250 m resolution digital elevation model yielding a high level of detail and ensuring that important feedback mechanisms are considered. The mass loss of all GICs by 2098 is calculated to be 2016 ± 129 Gt (HIRHAM5 forcing), 2584 ± 109 Gt (RACMO2) and 3907 ± 108 Gt (MAR). This corresponds to a total contribution to sea-level rise of 5.8 ± 0.4, 7.4 ± 0.3 and 11.2 ± 0.3 mm, respectively. Sensitivity experiments suggest that mass loss could be higher by 20–30% if a strong lowering of the surface albedo were to take place in the future. It is shown that the sea-level rise contribution from the north-easterly regions of Greenland is reduced by increasing precipitation while mass loss in the southern half of Greenland is dominated by steadily decreasing summer mass balances. In addition we observe glaciers in the north-eastern part of Greenland changing their characteristics towards greater activity and mass turnover. (letter)

The Greenland shark (Somniosus microcephalus)

DEFF Research Database (Denmark)

Nielsen, Julius

radiocarbon dating and a Bayesian calibration model to estimate longevity of the Greenland shark. The analyzed tissue stems from the eye lens nucleus – unique material which presumably reflects age 0 of the shark, as it has not undergone metabolic changes during the animal’s life. By studying 28 Greenland...... shark females between 81 cm and 502 cm, I estimate the oldest shark to be between 272 years and 512 years. With an estimated lifespan of at least 272 years, the Greenland shark is the longest living vertebrate animal in the world. In order to produce these age estimates, it has been necessary to study...... continental shelf waters in southern Greenland at depths between 200 and 550 m and fed primarily on cod, redfish and seals. From previous investigations of predatory sharks and whales in the north Atlantic, bomb radiocarbon has been widely applied, and I argue that a similar calibration approach is valid...

Sea level changes from monthly solutions of ice sheet mass balance

DEFF Research Database (Denmark)

Barletta, Valentina Roberta; Sørensen, Louise Sandberg; Forsberg, René

We present mass change time series at basin scale for both Greenland and Antarctica, de-rived from GRACE data, and use these data to find the associated global sea level changes. We use two independent methods for GRACE ice mass loss estimation, including use of different GIA models and estimatio...

Spatial and temporal trends of selected trace elements in liver tissue from polar bears (Ursus maritimus) from Alaska, Canada and Greenland.

Science.gov (United States)

Routti, Heli; Letcher, Robert J; Born, Erik W; Branigan, Marsha; Dietz, Rune; Evans, Thomas J; Fisk, Aaron T; Peacock, Elizabeth; Sonne, Christian

2011-08-01

Spatial trends and comparative changes in time of selected trace elements were studied in liver tissue from polar bears from ten different subpopulation locations in Alaska, Canadian Arctic and East Greenland. For nine of the trace elements (As, Cd, Cu, Hg, Mn, Pb, Rb, Se and Zn) spatial trends were investigated in 136 specimens sampled during 2005-2008 from bears from these ten subpopulations. Concentrations of Hg, Se and As were highest in the (northern and southern) Beaufort Sea area and lowest in (western and southern) Hudson Bay area and Chukchi/Bering Sea. In contrast, concentrations of Cd showed an increasing trend from east to west. Minor or no spatial trends were observed for Cu, Mn, Rb and Zn. Spatial trends were in agreement with previous studies, possibly explained by natural phenomena. To assess temporal changes of Cd, Hg, Se and Zn concentrations during the last decades, we compared our results to previously published data. These time comparisons suggested recent Hg increase in East Greenland polar bears. This may be related to Hg emissions and/or climate-induced changes in Hg cycles or changes in the polar bear food web related to global warming. Also, Hg:Se molar ratio has increased in East Greenland polar bears, which suggests there may be an increased risk for Hg(2+)-mediated toxicity. Since the underlying reasons for spatial trends or changes in time of trace elements in the Arctic are still largely unknown, future studies should focus on the role of changing climate and trace metal emissions on geographical and temporal trends of trace elements.

Experimental Studies for the characterization of the mixing processes in negative buoyant jets

Directory of Open Access Journals (Sweden)

Querzoli G.

2013-04-01

Full Text Available A negatively buoyant jet (NBJ corresponds to the physical phenomenon that develops when a fluid is discharged upwards into a lighter environment or downwards into a heavier receptor fluid. In a NBJ the flow is initially driven mostly by the momentum, so it basically behaves as a simple jet released withthe same angle, while far from the outlet the buoyancy prevails, bending the jet axis down and making it similar to a plume. The coexistence in the same phenomenon of both the characteristics of simple jets and plumes makes the NBJs a phenomenon still not entirely explained but, considering also the numerous practical applications, very interesting to study. Here some of the experimental results are presented. The laboratory experiment were obtained on a model simulating a typical sea discharge of brine from desalination plants: a pipe laid down on the sea bottom, with orifices on its lateral wall, releasing brine (heavier than the sea water with a certain angle to the horizontal, in order to increase the jet path before sinking to the seafloor. A non-intrusive image analysis technique, namely Feature Tracking Velocimetry, is applied to measure velocity fields, with the aim at understanding the influence of some non-dimensional parameters driving the phenomenon (e.g. Reynolds number, release angle on the structure of the NBJ and of the turbulence.

The link between eddy-driven jet variability and weather regimes in the North Atlantic-European sector

Science.gov (United States)

Madonna, E.; Li, C.; Grams, C. M.; Woollings, T.

2017-12-01

Understanding the variability of the North Atlantic eddy-driven jet is key to unravelling the dynamics, predictability and climate change response of extratropical weather in the region. This study aims to 1) reconcile two perspectives on wintertime variability in the North Atlantic-European sector and 2) clarify their link to atmospheric blocking. Two common views of wintertime variability in the North Atlantic are the zonal-mean framework comprising three preferred locations of the eddy-driven jet (southern, central, northern), and the weather regime framework comprising four classical North Atlantic-European regimes (Atlantic ridge AR, zonal ZO, European/Scandinavian blocking BL, Greenland anticyclone GA). We use a k-means clustering algorithm to characterize the two-dimensional variability of the eddy-driven jet stream, defined by the lower tropospheric zonal wind in the ERA-Interim reanalysis. The first three clusters capture the central jet and northern jet, along with a new mixed jet configuration; a fourth cluster is needed to recover the southern jet. The mixed cluster represents a split or strongly tilted jet, neither of which is well described in the zonal-mean framework, and has a persistence of about one week, similar to the other clusters. Connections between the preferred jet locations and weather regimes are corroborated - southern to GA, central to ZO, and northern to AR. In addition, the new mixed cluster is found to be linked to European/Scandinavian blocking, whose relation to the eddy-driven jet was previously unclear. The results highlight the necessity of bridging from weather to climate scales for a deeper understanding of atmospheric circulation variability.

Direct measurements of meltwater runoff on the Greenland ice sheet surface.

Science.gov (United States)

Smith, Laurence C; Yang, Kang; Pitcher, Lincoln H; Overstreet, Brandon T; Chu, Vena W; Rennermalm, Åsa K; Ryan, Jonathan C; Cooper, Matthew G; Gleason, Colin J; Tedesco, Marco; Jeyaratnam, Jeyavinoth; van As, Dirk; van den Broeke, Michiel R; van de Berg, Willem Jan; Noël, Brice; Langen, Peter L; Cullather, Richard I; Zhao, Bin; Willis, Michael J; Hubbard, Alun; Box, Jason E; Jenner, Brittany A; Behar, Alberto E

2017-12-12

Meltwater runoff from the Greenland ice sheet surface influences surface mass balance (SMB), ice dynamics, and global sea level rise, but is estimated with climate models and thus difficult to validate. We present a way to measure ice surface runoff directly, from hourly in situ supraglacial river discharge measurements and simultaneous high-resolution satellite/drone remote sensing of upstream fluvial catchment area. A first 72-h trial for a 63.1-km 2 moulin-terminating internally drained catchment (IDC) on Greenland's midelevation (1,207-1,381 m above sea level) ablation zone is compared with melt and runoff simulations from HIRHAM5, MAR3.6, RACMO2.3, MERRA-2, and SEB climate/SMB models. Current models cannot reproduce peak discharges or timing of runoff entering moulins but are improved using synthetic unit hydrograph (SUH) theory. Retroactive SUH applications to two older field studies reproduce their findings, signifying that remotely sensed IDC area, shape, and supraglacial river length are useful for predicting delays in peak runoff delivery to moulins. Applying SUH to HIRHAM5, MAR3.6, and RACMO2.3 gridded melt products for 799 surrounding IDCs suggests their terminal moulins receive lower peak discharges, less diurnal variability, and asynchronous runoff timing relative to climate/SMB model output alone. Conversely, large IDCs produce high moulin discharges, even at high elevations where melt rates are low. During this particular field experiment, models overestimated runoff by +21 to +58%, linked to overestimated surface ablation and possible meltwater retention in bare, porous, low-density ice. Direct measurements of ice surface runoff will improve climate/SMB models, and incorporating remotely sensed IDCs will aid coupling of SMB with ice dynamics and subglacial systems. Copyright © 2017 the Author(s). Published by PNAS.

Direct measurements of meltwater runoff on the Greenland ice sheet surface

Science.gov (United States)

Smith, Laurence C.; Yang, Kang; Pitcher, Lincoln H.; Overstreet, Brandon T.; Chu, Vena W.; Rennermalm, Åsa K.; Ryan, Jonathan C.; Cooper, Matthew G.; Gleason, Colin J.; Tedesco, Marco; Jeyaratnam, Jeyavinoth; van As, Dirk; van den Broeke, Michiel R.; van de Berg, Willem Jan; Noël, Brice; Langen, Peter L.; Cullather, Richard I.; Zhao, Bin; Willis, Michael J.; Hubbard, Alun; Box, Jason E.; Jenner, Brittany A.; Behar, Alberto E.

2017-12-01

Meltwater runoff from the Greenland ice sheet surface influences surface mass balance (SMB), ice dynamics, and global sea level rise, but is estimated with climate models and thus difficult to validate. We present a way to measure ice surface runoff directly, from hourly in situ supraglacial river discharge measurements and simultaneous high-resolution satellite/drone remote sensing of upstream fluvial catchment area. A first 72-h trial for a 63.1-km2 moulin-terminating internally drained catchment (IDC) on Greenland's midelevation (1,207–1,381 m above sea level) ablation zone is compared with melt and runoff simulations from HIRHAM5, MAR3.6, RACMO2.3, MERRA-2, and SEB climate/SMB models. Current models cannot reproduce peak discharges or timing of runoff entering moulins but are improved using synthetic unit hydrograph (SUH) theory. Retroactive SUH applications to two older field studies reproduce their findings, signifying that remotely sensed IDC area, shape, and supraglacial river length are useful for predicting delays in peak runoff delivery to moulins. Applying SUH to HIRHAM5, MAR3.6, and RACMO2.3 gridded melt products for 799 surrounding IDCs suggests their terminal moulins receive lower peak discharges, less diurnal variability, and asynchronous runoff timing relative to climate/SMB model output alone. Conversely, large IDCs produce high moulin discharges, even at high elevations where melt rates are low. During this particular field experiment, models overestimated runoff by +21 to +58%, linked to overestimated surface ablation and possible meltwater retention in bare, porous, low-density ice. Direct measurements of ice surface runoff will improve climate/SMB models, and incorporating remotely sensed IDCs will aid coupling of SMB with ice dynamics and subglacial systems.

Spirometry in Greenland

DEFF Research Database (Denmark)

Nielsen, Lasse Overballe; Olsen, Sequssuna; Jarbøl, D. E.

2016-01-01

be common. International guidelines recommend the usage of spirometry as a golden standard for diagnosing COPD. The current number of spirometries performed among patients treated with medication targeting obstructive pulmonary disease in Greenland remains unexplored. Objective. To estimate the prevalence...... of patients aged 50 years or above treated with medication targeting obstructive pulmonary disease and the extent to which spirometry was performed among them within 2 years. Design. An observational, cross-sectional study based on the review of data obtained from electronic medical records in Greenland...... of the identified users of medication targeting obstructive pulmonary disease. Information on age, gender, town and spirometry was registered for each patient within the period from October 2013 to October 2015. Results. The prevalence of patients treated with medication targeting obstructive pulmonary disease aged...

Scientific activities in and about Greenland

DEFF Research Database (Denmark)

Graversen, Ebbe Krogh; Pedersen, Asger Dalsgaard

2018-01-01

This report presents the results of an investigation and analysis of opportunities, strengths and challenges of scientific activities involving Greenland as a research area or research object relative to other Arctic areas.......This report presents the results of an investigation and analysis of opportunities, strengths and challenges of scientific activities involving Greenland as a research area or research object relative to other Arctic areas....

Possible Greenland

DEFF Research Database (Denmark)

2012-01-01

at Greenland's structure, and ask some threshold questions. Which aspects of society are rooted in our human hardware? And, if we had the rare opportunity to build a new nation, what would we choose for ourselves? We hope this will inspire an open, imaginative and thoroughly human discussion about how...

Life on thin ice: Insights from Uummannaq, Greenland for connecting climate science with Arctic communities

Science.gov (United States)

Baztan, Juan; Cordier, Mateo; Huctin, Jean-Michel; Zhu, Zhiwei; Vanderlinden, Jean-Paul

2017-09-01

What are the links between mainstream climate science and local community knowledge? This study takes the example of Greenland, considered one of the regions most impacted by climate change, and Inuit people, characterized as being highly adaptive to environmental change, to explore this question. The study is based on 10 years of anthropological participatory research in Uummannaq, Northwest Greenland, along with two fieldwork periods in October 2014 and April 2015, and a quantitative bibliometric analysis of the international literature on sea ice - a central subject of concern identified by Uummannaq community members during the fieldwork periods. Community members' perceptions of currently available scientific climate knowledge were also collected during the fieldwork. This was done to determine if community members consider available scientific knowledge salient and if it covers issues they consider relevant. The bibliometric analysis of the sea ice literature provided additional insight into the degree to which scientific knowledge about climate change provides information relevant for the community. Our results contribute to the ongoing debate on the missing connections between community worldviews, cultural values, livelihood needs, interests and climate science. Our results show that more scientific research efforts should consider local-level needs in order to produce local-scale knowledge that is more salient, credible and legitimate for communities experiencing climate change. In Uummannaq, as in many Inuit communities with similar conditions, more research should be done on sea ice thickness in winter and in areas through which local populations travel. This paper supports the growing evidence that whenever possible, climate change research should focus on environmental features that matter to communities, at temporal and spatial scales relevant to them, in order to foster community adaptations to change. We recommend such research be connected to and

Pneumatization and otitis media in Greenlandic Inuit before European colonization

DEFF Research Database (Denmark)

Homøe, P; Lynnerup, N; Skovgaard, L T

1995-01-01

A total of 127 Greenlandic Inuit crania from before the European colonization of Greenland and deriving from the West (W), Southeast (SE), and Northeast (NE) coast of Greenland were examined for sequelae of infectious middle ear disease (IMED) and for a relationship between the size of the pneuma...

Laboratory experiments on the interaction between inclined negatively buoyant jets and regular waves

Directory of Open Access Journals (Sweden)

Ferrari Simone

2015-01-01

Full Text Available In this paper we present the results from a series of laboratory experiments on inclined negatively buoyant jets released in a receiving environment with waves. This simulates the case, typical of many practical applications, of the sea discharge of fluids denser than the receiving environment, as in the case of the brine from a desalination plant. The experiments were performed employing a Light Induced Fluorescence (LIF technique, in order to measure the concentration fields. Both the jet and the wave motion features were varied, in order to simulate a typical discharge into the Mediterranean Sea. Reference discharges in a stagnant environment were performed as well. The jet behaviour was analyzed from a statistical point of view, both considering the global phenomenon and its single phases. The influence of the wave motion on the inclined negatively buoyant jet geometry and dilution turns out to be a combined action of a split into two branches of the jet and a rotation. Their combined action decreases the jet maximum height and the impact distance, and is the main cause for the higher dilution reached in a wavy environment.

Balance Velocities of the Greenland Ice Sheet

Science.gov (United States)

Joughin, Ian; Fahnestock, Mark; Ekholm, Simon; Kwok, Ron

1997-01-01

We present a map of balance velocities for the Greenland ice sheet. The resolution of the underlying DEM, which was derived primarily from radar altimetry data, yields far greater detail than earlier balance velocity estimates for Greenland. The velocity contours reveal in striking detail the location of an ice stream in northeastern Greenland, which was only recently discovered using satellite imagery. Enhanced flow associated with all of the major outlets is clearly visible, although small errors in the source data result in less accurate estimates of the absolute flow speeds. Nevertheless, the balance map is useful for ice-sheet modelling, mass balance studies, and field planning.

Carbon isotope variations in the upper Carboniferous - Permian Mallemuk Mountain Group, eastern North Greenland

International Nuclear Information System (INIS)

Stemmerik, L.; Magaritz, M.

1989-01-01

Isotope data from Late Palaeozoic limestones of the Wandel Sea Basin in eastern North Greenland show a variation of δ 13 C from 0.0 0/00 to 5.7 0/00 vs PDB. Carbonates depleted in 13 C occur in the basal part of lower Moscovian, upper Moscovian and middle Gzhelian transgressive sequences. 13 C enriched limestones occur later in the cycles. The most 13 C enriched limestones occur in the youngest (late Early Permian-early Late Permian) part of the sequence in Amdrup Land. The isotopic data is believed to represent changes in the global carbon cycle. Thus 13 C enriched carbonates correlate to periods of burial of organic carbon mostly as coal, while 13 C depleted carbonates formed as the result of erosion and oxidation of organic carbon during sea-level low stands. (author)

Ice sheet-ocean interactions and sea level change

Science.gov (United States)

Heimbach, Patrick

2014-03-01

Mass loss from the Greenland and Antarctic ice sheets has increased rapidly since the mid-1990s. Their combined loss now accounts for about one-third of global sea level rise. In Greenland, a growing body of evidence points to the marine margins of these glaciers as the region from which this dynamic response originated. Similarly, ice streams in West Antarctica that feed vast floating ice shelves have exhibited large decadal changes. We review observational evidence and present physical mechanisms that might explain the observed changes, in particular in the context of ice sheet-ocean interactions. Processes involve cover 7 orders of magnitudes of scales, ranging from mm boundary-layer processes to basin-scale coupled atmosphere-ocean variability. We discuss observational needs to fill the gap in our mechanistic understanding.

Accumulation of cadmium in livers and kidneys in Greenlanders

International Nuclear Information System (INIS)

Johansen, Poul; Mulvad, Gert; Pedersen, Henning Sloth; Hansen, Jens C.; Riget, Frank

2006-01-01

In the Arctic, the traditional diet exposes its people to a very high intake of cadmium because it is highly concentrated in the liver and kidneys of commonly eaten marine mammals. In one study in Greenland, the cadmium intake was estimated to 182 μg/day/person in the fall and 346 in the spring. To determine whether the cadmium is accumulated in humans, we analyzed autopsy samples of liver and kidneys from 95 ethnic Greenlanders (aged 19-89) who died from a wide range of causes. The cadmium concentration in liver (overall mean 1.97 μg/g wet wt) appeared to be unrelated to any particular age group, whereas the concentrations in the kidneys peaked in Greenlanders between 40 and 50 years of age (peak concentration 22.3 μg/g wet wt). Despite the high cadmium levels in the typical Greenlander diet, we found that the cadmium concentrations in livers and kidneys were comparable to those reported from Denmark, Sweden, Australia and Great Britain. Furthermore, even though the mean cadmium intake from the diet was estimated to be 13-25 times higher in Greenlanders than in Danes, we found similar cadmium levels in the kidneys of both. Seal livers and kidneys are the main source of cadmium in the diet of Greenlanders, but these tissues are not eaten in Denmark. Thus, our results suggest that the accumulation of cadmium from Greenlander's marine diet is very low

Accumulation of cadmium in livers and kidneys in Greenlanders

Energy Technology Data Exchange (ETDEWEB)

Johansen, Poul [National Environmental Research Institute, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)]. E-mail: poj@dmu.dk; Mulvad, Gert [Primary Health Care Center, DK-3900 Nuuk, Greenland (Denmark); Centre for Arctic Environmental Medicine, University of Aarhus, Universitetsparken, DK-8000 Aarhus C (Denmark); Pedersen, Henning Sloth [Primary Health Care Center, DK-3900 Nuuk, Greenland (Denmark); Centre for Arctic Environmental Medicine, University of Aarhus, Universitetsparken, DK-8000 Aarhus C (Denmark); Hansen, Jens C. [Centre for Arctic Environmental Medicine, University of Aarhus, Universitetsparken, DK-8000 Aarhus C (Denmark); Riget, Frank [National Environmental Research Institute, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)

2006-12-15

In the Arctic, the traditional diet exposes its people to a very high intake of cadmium because it is highly concentrated in the liver and kidneys of commonly eaten marine mammals. In one study in Greenland, the cadmium intake was estimated to 182 {mu}g/day/person in the fall and 346 in the spring. To determine whether the cadmium is accumulated in humans, we analyzed autopsy samples of liver and kidneys from 95 ethnic Greenlanders (aged 19-89) who died from a wide range of causes. The cadmium concentration in liver (overall mean 1.97 {mu}g/g wet wt) appeared to be unrelated to any particular age group, whereas the concentrations in the kidneys peaked in Greenlanders between 40 and 50 years of age (peak concentration 22.3 {mu}g/g wet wt). Despite the high cadmium levels in the typical Greenlander diet, we found that the cadmium concentrations in livers and kidneys were comparable to those reported from Denmark, Sweden, Australia and Great Britain. Furthermore, even though the mean cadmium intake from the diet was estimated to be 13-25 times higher in Greenlanders than in Danes, we found similar cadmium levels in the kidneys of both. Seal livers and kidneys are the main source of cadmium in the diet of Greenlanders, but these tissues are not eaten in Denmark. Thus, our results suggest that the accumulation of cadmium from Greenlander's marine diet is very low.

Modelling snow accumulation on Greenland in Eemian, glacial inception, and modern climates in a GCM

Directory of Open Access Journals (Sweden)

H. J. Punge

2012-11-01

Full Text Available Changing climate conditions on Greenland influence the snow accumulation rate and surface mass balance (SMB on the ice sheet and, ultimately, its shape. This can in turn affect local climate via orography and albedo variations and, potentially, remote areas via changes in ocean circulation triggered by melt water or calving from the ice sheet. Examining these interactions in the IPSL global model requires improving the representation of snow at the ice sheet surface. In this paper, we present a new snow scheme implemented in LMDZ, the atmospheric component of the IPSL coupled model. We analyse surface climate and SMB on the Greenland ice sheet under insolation and oceanic boundary conditions for modern, but also for two different past climates, the last glacial inception (115 kyr BP and the Eemian (126 kyr BP. While being limited by the low resolution of the general circulation model (GCM, present-day SMB is on the same order of magnitude as recent regional model findings. It is affected by a moist bias of the GCM in Western Greenland and a dry bias in the north-east. Under Eemian conditions, the SMB decreases largely, and melting affects areas in which the ice sheet surface is today at high altitude, including recent ice core drilling sites as NEEM. In contrast, glacial inception conditions lead to a higher mass balance overall due to the reduced melting in the colder summer climate. Compared to the widely applied positive degree-day (PDD parameterization of SMB, our direct modelling results suggest a weaker sensitivity of SMB to changing climatic forcing. For the Eemian climate, our model simulations using interannually varying monthly mean forcings for the ocean surface temperature and sea ice cover lead to significantly higher SMB in southern Greenland compared to simulations forced with climatological monthly means.

Uncovering the genetic history of the present-day greenlandic population

DEFF Research Database (Denmark)

Moltke, Ida; Fumagalli, Matteo; Korneliussen, Thorfinn Sand

2015-01-01

Because of past limitations in samples and genotyping technologies, important questions about the history of the present-day Greenlandic population remain unanswered. In an effort to answer these questions and in general investigate the genetic history of the Greenlandic population, we analyzed...... between the Norse Vikings who lived in Greenland for a limited period ∼600-1,000 years ago and the Inuit, we found no evidence supporting this hypothesis. Similarly, we found no evidence supporting a previously hypothesized admixture event between the Inuit in East Greenland and the Dorset people, who...

Contaminants in the Greenland terrestrial and freshwater environment. National assessment

International Nuclear Information System (INIS)

Riget, F.; Aastrup, P.; Dietz, R.

1997-01-01

The present report reviews the available information on heavy metals, persistent organic pollutants and radioactivity in the Greenland freshwater and terrestrial environments. Levels in lake sediments, soil, humus and organisms are presented, spatial and temporal trends are discussed and where possible also biological effects. Many of the contaminants that occur in the Greenland environment originate from distant sources outside of the region, and are transported to the Arctic via three major pathways - atmospheric, terrestrial/freshwater and marine. The main sources of pollution in Greenland is considered to be the industrialization of Eurasia. Pollutants are mainly. The organochlorine levels in Greenland char are typically in the low range compared to values reported from Canada. The Greenland sediment samples showed all organochlorine values below the detection limits of 0.1 μg/kg dry weight, thus being among the lowest contaminated sediments within the Arctic. The total content of PAH in the Greenland sediment samples ranged between 78-635 μ3 g/kg dry wight, with a geometric mean of 178 μg/kg, comparable to or lower than reported values from other arctic countries. The lowest concentrations of anthropogenic radionuclides in the Greenland terrestrial and freshwater environment are found in the northern parts of Greenland and the highest in the south western parts. The main source of anthropogenic radioactivity is nuclear weapons testing in the atmosphere and the fallout from this activity is closely related to the amounts of precipitation. The predominant foodchain in the Arctic with regard to transport of radiocaesium to man is: Lichen-reindeer-man. Although the doses from the terrestrial foodchain are 20 times higher than those received from the marine foodchain, they are not considered to be of any relevance for the human health in Greenland. 4 appendices contain experimental results. (EG)

The Jurassic of North-East Greenland: Jurassic dinoflagellate cysts from Hochstetter Forland, North-East Greenland

Directory of Open Access Journals (Sweden)

Piasecki, Stefan

2004-11-01

Full Text Available Three sections in Hochstetter Forland, North-East Greenland, referred to the Jurassic Payer Dal and Bernbjerg Formations, have been analysed for dinoflagellate cysts. The dinoflagellate cysts,new finds of ammonites and previously recorded marine faunas form the basis for improved dating of the succession. The basal strata of the Payer Dal Formation at Kulhus is here dated as Late Callovian, Peltoceras athleta Chronozone, based on the presence of relatively abundant Limbicysta bjaerkei, Mendicodinium groenlandicum, Rhychoniopsis cladophora and Tubotuberella dangeardii in an otherwise poor Upper Callovian dinoflagellate assemblage. Ammoniteshave not been recorded from these strata. The upper Payer Dal Formation at Agnetesøelven is dated as Late Oxfordian, Amoeboceras glosense – Amoeboceras serratum Chronozones, based onthe presence of Sciniodinium crystallinum, together with Cribroperidinium granuligera and Stephanelytron sp. The age is in accordance with ammonites present in the uppermost part ofthe formation at Søndre Muslingebjerg. New ammonites in the Bernbjerg Formation at Agnetesøelven together with dinoflagellate cysts indicate an earliest Kimmeridgian age, Raseniacymodoce and Aulacostephanoides mutabilis Chronozones.The Upper Callovian dinoflagellate cysts from Hochstetter Forland belong to a local brackish to marginal marine assemblage, which only allows a fairly broad correlation to coeval assemblagesin central East Greenland. In contrast, the Oxfordian and Kimmeridgian assemblages are fully marine and can be correlated from Milne Land in central East Greenland via Hochstetter Forland to Peary Land in eastern North Greenland.

Physical and chemical oceanographic profile data, and meteorological data collected in the Atlantic and Arctic Oceans, and adjoining seas by multiple platforms from 14 August 1951 to 27 October 1994 (NODC Accession 0073741)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, oxygen, silicate, phosphate, nitrite, nitrate, alkalinity, and pH data collected in Arctic Ocean, Barents Sea, East Siberian Sea, Greenland...

A Stabilizing Feedback Between Cloud Radiative Effects and Greenland Surface Melt: Verification From Multi-year Automatic Weather Station Measurements

Science.gov (United States)

Zender, C. S.; Wang, W.; van As, D.

2017-12-01

Clouds have strong impacts on Greenland's surface melt through the interaction with the dry atmosphere and reflective surfaces. However, their effects are uncertain due to the lack of in situ observations. To better quantify cloud radiative effects (CRE) in Greenland, we analyze and interpret multi-year radiation measurements from 30 automatic weather stations encompassing a broad range of climatological and topographical conditions. During melt season, clouds warm surface over most of Greenland, meaning the longwave greenhouse effect outweighs the shortwave shading effect; on the other hand, the spatial variability of net (longwave and shortwave) CRE is dominated by shortwave CRE and in turn by surface albedo, which controls the potential absorption of solar radiation when clouds are absent. The net warming effect decreases with shortwave CRE from high to low altitudes and from north to south (Fig. 1). The spatial correlation between albedo and net CRE is strong (r=0.93, palbedo determines the net CRE seasonal trend, which decreases from May to July and increases afterwards. On an hourly timescale, we find two distinct radiative states in Greenland (Fig. 2). The clear state is characterized by clear-sky conditions or thin clouds, when albedo and solar zenith angle (SZA) weakly correlates with CRE. The cloudy state is characterized by opaque clouds, when the combination of albedo and SZA strongly correlates with CRE (r=0.85, palbedo and solar zenith angle, explains the majority of the CRE variation in spatial distribution, seasonal trend in the ablation zone, and in hourly variability in the cloudy radiative state. Clouds warm the brighter and colder surfaces of Greenland, enhance snow melt, and tend to lower the albedo. Clouds cool the darker and warmer surfaces, inhibiting snow melt, which increases albedo, and thus stabilizes surface melt. This stabilizing mechanism may also occur over sea ice, helping to forestall surface melt as the Arctic becomes dimmer.

Nivation forms and processes in unconsolidated sediments, NE Greenland

DEFF Research Database (Denmark)

Christiansen, Hanne Hvidtfeldt

1998-01-01

Nivation, Nivation Hollow, Nival Backwall Faliure, Active layer Interflow, Pronival alluvial fans, NE Greenland......Nivation, Nivation Hollow, Nival Backwall Faliure, Active layer Interflow, Pronival alluvial fans, NE Greenland...

Cultural change and mental health in Greenland

DEFF Research Database (Denmark)

Bjerregaard, Peter; Curtis, Tine; Greenland, Population Study

2002-01-01

In Greenland, the rapid sociocultural change of the last 50 years has been paralleled by an epidemiological transition characterized by a reduction in infectious diseases, an increase in cancer and cardiovascular diseases, and an increased prevalence of mental health problems. During 1993......-94 and 1997-98, two health interview surveys were conducted among Inuit in Greenland and Inuit migrants in Denmark. The response rates were 71 and 55%. Information on mental health was obtained from 1388 and 1769 adults. As indicators of mental health, the prevalence of potential psychiatric cases according...... of poor mental health: as a result of successful integration into the modern Greenlandic society, some population groups have better mental health compared to other groups....

Iron status markers in 224 indigenous Greenlanders

DEFF Research Database (Denmark)

Milman, N; Byg, K E; Mulvad, G

2001-01-01

OBJECTIVE: To evaluate iron status in indigenous Greenlanders and its relationship to gender, age and intake of traditional Greenlandic foods. Methods: Serum ferritin, serum transferrin saturation and haemoglobin were evaluated in a population survey in 1993-1994 comprising 224 Greenlandic...... of living. Consumption of traditional foods was assessed by questionnaire. RESULTS: Intake of traditional foods was more prevalent among elderly than among young individuals and more frequent in Uummannaq than in Ilulissat and Nuuk. Ferritin levels were higher in men than in women (p....06; women, r(s)=0.73, ptraditional foods was correlated with ferritin in men (r(s)=0.29, p=0.01) and women (r(s)=0.40, p

Gestational diabetes mellitus in Greenland: a national study of prevalence and testing efficacy

Directory of Open Access Journals (Sweden)

Michael Lynge Pedersen

2016-08-01

Full Text Available Background: Within the last 20 years, the prevalence of gestational diabetes mellitus (GDM has been reported to be increasing worldwide in correlation with ethnic and geographic variations. The actual prevalence of GDM throughout all of Greenland remains unknown. Objective: The aim of this study was to estimate the prevalence of GDM among Greenlanders and non-Greenlanders living in Greenland and to estimate the efficacy of testing for GDM. Design: This study was performed as an observational, cross-sectional study including all women with permanent address in Greenland who had given birth to a singleton during 2014. The prevalence of GDM was calculated as the proportion of all pregnant women tested with a 75-g 2-h glucose tolerance test who had a 2-h capillary whole-blood glucose value of 8.5 mmol/l or above. Testing efficacy was calculated as the proportion of women who fulfilled the testing criteria who were actually tested in Greenland in 2014. Results: A total of 794 women (727 Greenlanders and 67 non-Greenlanders were included in the study. The prevalence of GDM among tested women was 3.3% (confidence interval, CI: 0.9–5.6 among Greenlanders and 12.5% (CI: 0–25.7 among non-Greenlanders, corresponding, respectively, to 1.0% (CI: 0.3–1.3 and 4.5% (CI: 0–9.4 of all singleton pregnancies in Greenland in 2014. The overall testing efficacy was 69.0% among all eligible residents of Greenland and 85.1% among eligible residents in the capital city, Nuuk. Conclusion: In conclusion, the prevalence of GDM seems quite low in Greenland. Although diagnostic testing activity has improved within the last 6 years, still around one-third of all pregnant women in all Greenland fulfilling the testing criteria were not tested. Universal testing for GDM may be needed to improve testing of GDM in Greenland.

Balance velocities of the Greenland ice sheet

DEFF Research Database (Denmark)

Joughin, I.; Fahnestock, M.; Ekholm, Simon

1997-01-01

We present a map of balance velocities for the Greenland ice sheet. The resolution of the underlying DEM, which was derived primarily from radar altimetery data, yields far greater detail than earlier balance velocity estimates for Greenland. The velocity contours reveal in striking detail......, the balance map is useful for ice-sheet modelling, mass balance studies, and field planning....

A 500 kyr record of global sea-level oscillations in the Gulf of Lion, Mediterranean Sea: new insights into MIS 3 sea-level variability

Directory of Open Access Journals (Sweden)

J. Frigola

2012-06-01

Full Text Available Borehole PRGL1-4 drilled in the upper slope of the Gulf of Lion provides an exceptional record to investigate the impact of late Pleistocene orbitally-driven glacio-eustatic sea-level oscillations on the sedimentary outbuilding of a river fed continental margin. High-resolution grain-size and geochemical records supported by oxygen isotope chronostratigraphy allow reinterpreting the last 500 ka upper slope seismostratigraphy of the Gulf of Lion. Five main sequences, stacked during the sea-level lowering phases of the last five glacial-interglacial 100-kyr cycles, form the upper stratigraphic outbuilding of the continental margin. The high sensitivity of the grain-size record down the borehole to sea-level oscillations can be explained by the great width of the Gulf of Lion continental shelf. Sea level driven changes in accommodation space over the shelf cyclically modified the depositional mode of the entire margin. PRGL1-4 data also illustrate the imprint of sea-level oscillations at millennial time-scale, as shown for Marine Isotopic Stage 3, and provide unambiguous evidence of relative high sea-levels at the onset of each Dansgaard-Oeschger Greenland warm interstadial. The PRGL1-4 grain-size record represents the first evidence for a one-to-one coupling of millennial time-scale sea-level oscillations associated with each Dansgaard-Oeschger cycle.

Evidence for link between modelled trends in Antarctic sea ice and underestimated westerly wind changes.

Science.gov (United States)

Purich, Ariaan; Cai, Wenju; England, Matthew H; Cowan, Tim

2016-02-04

Despite global warming, total Antarctic sea ice coverage increased over 1979-2013. However, the majority of Coupled Model Intercomparison Project phase 5 models simulate a decline. Mechanisms causing this discrepancy have so far remained elusive. Here we show that weaker trends in the intensification of the Southern Hemisphere westerly wind jet simulated by the models may contribute to this disparity. During austral summer, a strengthened jet leads to increased upwelling of cooler subsurface water and strengthened equatorward transport, conducive to increased sea ice. As the majority of models underestimate summer jet trends, this cooling process is underestimated compared with observations and is insufficient to offset warming in the models. Through the sea ice-albedo feedback, models produce a high-latitude surface ocean warming and sea ice decline, contrasting the observed net cooling and sea ice increase. A realistic simulation of observed wind changes may be crucial for reproducing the recent observed sea ice increase.

Toxaphene in the aquatic environment of Greenland

International Nuclear Information System (INIS)

Vorkamp, Katrin; Rigét, Frank F.; Dietz, Rune

2015-01-01

The octa- and nonachlorinated bornanes (toxaphene) CHBs 26, 40, 41, 44, 50 and 62 were analysed in Arctic char (Salvelinus alpinus), shorthorn sculpin (Myoxocephalus scorpius), ringed seal (Pusa hispida) and black guillemot eggs (Cepphus grylle) from Greenland. Despite their high trophic level, ringed seals had the lowest concentrations of these species, with a Σ 6 Toxaphene median concentration of 13–20 ng/g lipid weight (lw), suggesting metabolisation. The congener composition also suggests transformation of nona- to octachlorinated congeners. Black guillemot eggs had the highest concentrations (Σ 6 Toxaphene median concentration of 971 ng/g lw). Although concentrations were higher in East than in West Greenland differences were smaller than for other persistent organic pollutants. In a circumpolar context, toxaphene had the highest concentrations in the Canadian Arctic. Time trend analyses showed significant decreases for black guillemot eggs and juvenile ringed seals, with annual rates of −5 to −7% for Σ 6 Toxaphene. The decreases were generally steepest for CHBs 40, 41 and 44. - Highlights: • Toxaphene was detected in freshwater and marine species of Greenland. • Relatively low concentrations in ringed seal suggest metabolisation. • The concentrations in Greenland appear lower than those in the Canadian Arctic. • Significant decreases were found in juvenile ringed seals and black guillemot eggs. - The banned insecticide toxaphene is widely present in the aquatic environment of Greenland, but concentrations are decreasing

The smallest jet drops produced by bursting bubbles

Science.gov (United States)

Brasz, Frederik; Bartlett, Casey; Walls, Peter; Flynn, Elena; Bird, James

2017-11-01

Aerosol droplets are produced from the breakup of jets formed when small air bubbles burst at an air-liquid interface. These jet drops transfer sea salt and organic matter from the oceans to the atmosphere, where they act as cloud condensation nuclei and can spread pathogens. The smallest aerosols persist the longest in the air and advect the furthest from their source, but because they are too small to be observed directly, little is known about what size ocean bubbles create them or how their formation depends on seawater properties. We show, both experimentally and numerically, that the minimum size of primary jet drops is set by the interplay between viscous and inertial-capillary forces and is significantly smaller than previous estimates. We find that viscous stresses modify both the shape of the collapsing bubble and the breakup of the resulting jet, leading to a non-monotonic size relationship between the bubble and primary jet drop. Supported by the National Science Foundation under Grant No. 1351466.

Hydrologic Outlets of the Greenland Ice Sheet, Version 1

Data.gov (United States)

National Aeronautics and Space Administration — The Hydrologic Outlets of the Greenland Ice Sheet data set contains GIS point shapefiles that include 891 observed and potential hydrologic outlets of the Greenland...

The Impact of Atmospheric Modeling Errors on GRACE Estimates of Mass Loss in Greenland and Antarctica

Science.gov (United States)

Hardy, Ryan A.; Nerem, R. Steven; Wiese, David N.

2017-12-01

Systematic errors in Gravity Recovery and Climate Experiment (GRACE) monthly mass estimates over the Greenland and Antarctic ice sheets can originate from low-frequency biases in the European Centre for Medium-Range Weather Forecasts (ECMWF) Operational Analysis model, the atmospheric component of the Atmospheric and Ocean Dealising Level-1B (AOD1B) product used to forward model atmospheric and ocean gravity signals in GRACE processing. These biases are revealed in differences in surface pressure between the ECMWF Operational Analysis model, state-of-the-art reanalyses, and in situ surface pressure measurements. While some of these errors are attributable to well-understood discrete model changes and have published corrections, we examine errors these corrections do not address. We compare multiple models and in situ data in Antarctica and Greenland to determine which models have the most skill relative to monthly averages of the dealiasing model. We also evaluate linear combinations of these models and synthetic pressure fields generated from direct interpolation of pressure observations. These models consistently reveal drifts in the dealiasing model that cause the acceleration of Antarctica's mass loss between April 2002 and August 2016 to be underestimated by approximately 4 Gt yr-2. We find similar results after attempting to solve the inverse problem, recovering pressure biases directly from the GRACE Jet Propulsion Laboratory RL05.1 M mascon solutions. Over Greenland, we find a 2 Gt yr-1 bias in mass trend. While our analysis focuses on errors in Release 05 of AOD1B, we also evaluate the new AOD1B RL06 product. We find that this new product mitigates some of the aforementioned biases.

Seasonal variations in active microwave signatures of sea ice in the Greenland Sea during 1992 and 1993

DEFF Research Database (Denmark)

Thomsen, Bjørn Bavnehøj; Skriver, Henning; Pedersen, Leif Toudal

1995-01-01

into the research of other statistical features of the sea ice than the mean value and also their seasonal variations. This paper investigates the backscatter coefficient and texture of different sea ice types and water by using calibrated precision images (PRI) acquired by the synthetic aperture radar (SAR...

The sensitivity of the Greenland Ice Sheet to glacial-interglacial oceanic forcing

Science.gov (United States)

Tabone, Ilaria; Blasco, Javier; Robinson, Alexander; Alvarez-Solas, Jorge; Montoya, Marisa

2018-04-01

Observations suggest that during the last decades the Greenland Ice Sheet (GrIS) has experienced a gradually accelerating mass loss, in part due to the observed speed-up of several of Greenland's marine-terminating glaciers. Recent studies directly attribute this to warming North Atlantic temperatures, which have triggered melting of the outlet glaciers of the GrIS, grounding-line retreat and enhanced ice discharge into the ocean, contributing to an acceleration of sea-level rise. Reconstructions suggest that the influence of the ocean has been of primary importance in the past as well. This was the case not only in interglacial periods, when warmer climates led to a rapid retreat of the GrIS to land above sea level, but also in glacial periods, when the GrIS expanded as far as the continental shelf break and was thus more directly exposed to oceanic changes. However, the GrIS response to palaeo-oceanic variations has yet to be investigated in detail from a mechanistic modelling perspective. In this work, the evolution of the GrIS over the past two glacial cycles is studied using a three-dimensional hybrid ice-sheet-shelf model. We assess the effect of the variation of oceanic temperatures on the GrIS evolution on glacial-interglacial timescales through changes in submarine melting. The results show a very high sensitivity of the GrIS to changing oceanic conditions. Oceanic forcing is found to be a primary driver of GrIS expansion in glacial times and of retreat in interglacial periods. If switched off, palaeo-atmospheric variations alone are not able to yield a reliable glacial configuration of the GrIS. This work therefore suggests that considering the ocean as an active forcing should become standard practice in palaeo-ice-sheet modelling.

Upper Limit for Regional Sea Level Projections

Science.gov (United States)

Jevrejeva, Svetlana; Jackson, Luke; Riva, Riccardo; Grinsted, Aslak; Moore, John

2016-04-01

With more than 150 million people living within 1 m of high tide future sea level rise is one of the most damaging aspects of warming climate. The latest Intergovernmental Panel on Climate Change report (AR5 IPCC) noted that a 0.5 m rise in mean sea level will result in a dramatic increase the frequency of high water extremes - by an order of magnitude, or more in some regions. Thus the flood threat to the rapidly growing urban populations and associated infrastructure in coastal areas are major concerns for society. Hence, impact assessment, risk management, adaptation strategy and long-term decision making in coastal areas depend on projections of mean sea level and crucially its low probability, high impact, upper range. With probabilistic approach we produce regional sea level projections taking into account large uncertainties associated with Greenland and Antarctica ice sheets contribution. We calculate the upper limit (as 95%) for regional sea level projections by 2100 with RCP8.5 scenario, suggesting that for the most coastlines upper limit will exceed the global upper limit of 1.8 m.

Spatial and temporal trends of selected trace elements in liver tissue from polar bears (Ursus maritimus) from Alaska, Canada and Greenland

Science.gov (United States)

Routti, H.; Letcher, R.J.; Born, E.W.; Branigan, M.; Dietz, R.; Evans, T.J.; Fisk, A.T.; Peacock, E.; Sonne, C.

2011-01-01

Spatial trends and comparative changes in time of selected trace elements were studied in liver tissue from polar bears from ten different subpopulation locations in Alaska, Canadian Arctic and East Greenland. For nine of the trace elements (As, Cd, Cu, Hg, Mn, Pb, Rb, Se and Zn) spatial trends were investigated in 136 specimens sampled during 2005-2008 from bears from these ten subpopulations. Concentrations of Hg, Se and As were highest in the (northern and southern) Beaufort Sea area and lowest in (western and southern) Hudson Bay area and Chukchi/Bering Sea. In contrast, concentrations of Cd showed an increasing trend from east to west. Minor or no spatial trends were observed for Cu, Mn, Rb and Zn. Spatial trends were in agreement with previous studies, possibly explained by natural phenomena. To assess temporal changes of Cd, Hg, Se and Zn concentrations during the last decades, we compared our results to previously published data. These time comparisons suggested recent Hg increase in East Greenland polar bears. This may be related to Hg emissions and/or climate-induced changes in Hg cycles or changes in the polar bear food web related to global warming. Also, Hg:Se molar ratio has increased in East Greenland polar bears, which suggests there may be an increased risk for Hg 2+-mediated toxicity. Since the underlying reasons for spatial trends or changes in time of trace elements in the Arctic are still largely unknown, future studies should focus on the role of changing climate and trace metal emissions on geographical and temporal trends of trace elements. ?? 2011 The Royal Society of Chemistry.

The Jurassic of Denmark and Greenland: key elements in the reconstruction of the North Atlantic Jurassic rift system

Directory of Open Access Journals (Sweden)

Surlyk, Finn

2003-10-01

Full Text Available The Jurassic succession of Denmark is largely confined to the subsurface with the exception of exposures on the island of Bornholm in the Baltic Sea. In East Greenland, in contrast, the Jurassic is extensively exposed. Comparison of basin evolution in the two regions, which now occur on two separate plates, thus relies on highly different datasets. It is possible nevertheless to construct an integrated picture allowing testing of hypotheses concerning basin evolution, regional uplift, onset and climax of rifting, relative versus eustatic sea-level changes and sequence stratigraphic subdivision and correlation. On a smaller scale, it is possible to compare the signatures of sequence stratigraphic surfaces as seen on well logs, in cores and at outcrop and of sequences recognised and defined on the basis of very different data types. Breakdown of the successions into tectonostratigraphic megasequences highlights the high degree of similarity in overall basin evolution and tectonic style. An important difference, however, lies in the timing. Major events such as late Early - Middle Jurassic uplift, followed by onset of rifting, basin reorganisation and rift climax were delayed in East Greenland relative to the Danish region. This has important implications both for regional reconstructions of the rift system and for the understanding and testing of classical sequence stratigraphic concepts involving eustatic versus tectonic controls of basin evolution and stratigraphy.

Land motion due to 20th century mass balance of the Greenland Ice Sheet

Science.gov (United States)

Kjeldsen, K. K.; Khan, S. A.

2017-12-01

Quantifying the contribution from ice sheets and glaciers to past sea level change is of great value for understanding sea level projections into the 21st century. However, quantifying and understanding past changes are equally important, in particular understanding the impact in the near-field where the signal is highest. We assess the impact of 20th century mass balance of the Greenland Ice Sheet on land motion using results from Kjeldsen et al, 2015. These results suggest that the ice sheet on average lost a minimum of 75 Gt/yr, but also show that the mass balance was highly spatial- and temporal variable, and moreover that on a centennial time scale changes were driven by a decreasing surface mass balance. Based on preliminary results we discuss land motion during the 20th century due to mass balance changes and the driving components surface mass balance and ice dynamics.

Children in Greenland

DEFF Research Database (Denmark)

Kløvgaard, Marius; Nielsen, Nina Odgaard; Sørensen, Thomas Lund

2016-01-01

in Nuuk or Ilulissat (n=332). Data on diseases and health care system contacts were extracted. Diagnoses were validated retrospectively. Primary health care contacts were reviewed for a random sample of 1:6. RESULTS: In 311 children with valid social security number, the total number of health care system......, 39.5 versus 34.6 during the study period, p=0.02. The highest annual contact rates for diseases were: hospitalisations/acute respiratory diseases 13.9:1,000; outpatient contacts/otitis media 5.1:1,000; primary care/conjunctivitis or nasopharyngitis 410:1,000 children. Outpatient screening......BACKGROUND: Previous studies of Greenlandic children's disease pattern and contacts to the health care system are sparse and have focused on the primary health care sector. OBJECTIVE: We aimed to identify the disease pattern and use of health care facilities of children aged 0-10 in two Greenlandic...

Predicting the Geothermal Heat Flux in Greenland: A Machine Learning Approach

Science.gov (United States)

Rezvanbehbahani, Soroush; Stearns, Leigh A.; Kadivar, Amir; Walker, J. Doug; van der Veen, C. J.

2017-12-01

Geothermal heat flux (GHF) is a crucial boundary condition for making accurate predictions of ice sheet mass loss, yet it is poorly known in Greenland due to inaccessibility of the bedrock. Here we use a machine learning algorithm on a large collection of relevant geologic features and global GHF measurements and produce a GHF map of Greenland that we argue is within ˜15% accuracy. The main features of our predicted GHF map include a large region with high GHF in central-north Greenland surrounding the NorthGRIP ice core site, and hot spots in the Jakobshavn Isbræ catchment, upstream of Petermann Gletscher, and near the terminus of Nioghalvfjerdsfjorden glacier. Our model also captures the trajectory of Greenland movement over the Icelandic plume by predicting a stripe of elevated GHF in central-east Greenland. Finally, we show that our model can produce substantially more accurate predictions if additional measurements of GHF in Greenland are provided.

Recent increases in Arctic freshwater flux affects Labrador Sea convection and Atlantic overturning circulation

Science.gov (United States)

Yang, Qian; Dixon, Timothy H.; Myers, Paul G.; Bonin, Jennifer; Chambers, Don; van den Broeke, M. R.

2016-01-01

The Atlantic Meridional Overturning Circulation (AMOC) is an important component of ocean thermohaline circulation. Melting of Greenland's ice sheet is freshening the North Atlantic; however, whether the augmented freshwater flux is disrupting the AMOC is unclear. Dense Labrador Sea Water (LSW), formed by winter cooling of saline North Atlantic water and subsequent convection, is a key component of the deep southward return flow of the AMOC. Although LSW formation recently decreased, it also reached historically high values in the mid-1990s, making the connection to the freshwater flux unclear. Here we derive a new estimate of the recent freshwater flux from Greenland using updated GRACE satellite data, present new flux estimates for heat and salt from the North Atlantic into the Labrador Sea and explain recent variations in LSW formation. We suggest that changes in LSW can be directly linked to recent freshening, and suggest a possible link to AMOC weakening.

Measured and modelled absolute gravity changes in Greenland

DEFF Research Database (Denmark)

Nielsen, Jens Emil; Forsberg, René; Strykowski, Gabriel

2014-01-01

in Greenland. Theresult is compared with the initial measurements of absolute gravity (AG) change at selected GreenlandNetwork (GNET) sites.We find that observations are highly influenced by the direct attraction from the ice and ocean. Thisis especially evident in the measurements conducted at the GNET...

Conceptualizing and contextualizing food insecurity among Greenlandic children

DEFF Research Database (Denmark)

Niclasen, B.; Molcho, M.; Arnfjord, S.

2013-01-01

OBJECTIVE: To review the context of food insecurity in Greenlandic children, to review and compare the outcomes related to food insecurity in Greenlandic children, in other Arctic child populations and in other western societies, and to explore the measure used by the Health Behaviour in School-a...

Victimisation and PTSD in a Greenlandic youth sample

Directory of Open Access Journals (Sweden)

Sidsel H. Karsberg

2012-08-01

Full Text Available Background. Despite a growing number of studies and reports indicating a very high and increasing prevalence of trauma exposure in Greenlandic adolescents, the knowledge on this subject is still very limited. The purpose of the present study was twofold: To estimate the lifetime prevalence of potentially traumatic events (PTEs and post-traumatic stress disorder (PTSD and to examine the relationship between PTEs, estimated PTSD, and sociodemographic variables. Methods. In a Greenlandic sample from 4 different schools in 2 different minor towns in Northern Greenland, 269 students, aged 12–18 (M=15.4; SD=1.84 were assessed for their level of exposure to 20 PTEs along with the psychological impact of these events. Results. Of the Greenlandic students, 86% had been directly exposed to at least 1 PTE and 74.3% had been indirectly exposed to at least 1 PTE. The mean number of directly experienced PTEs was 2.8 and the mean number of indirectly experienced PTEs was 3.9. The most frequent direct events recorded were death of someone close, near drowning, threat of assault/beating, humiliation or persecution by others and attempted suicide. The estimated lifetime prevalence of PTSD was 17.1%, whereas another 14.2% reached a subclinical level of PTSD (missing the full diagnosis by 1 symptom. Education level of the father, and being exposed to multiple direct and indirect PTEs were significantly associated with an increase in PTSD symptoms. Conclusion. The findings indicate substantial mental health problems in Greenlandic adolescents and that these are associated with various types of PTEs. Furthermore, the findings indicate that Greenlandic adolescents are more exposed to certain specific PTEs than adolescents in similar studies from other nations. The present study revealed that Greenlandic girls are particularly vulnerable towards experiencing PTEs. Indeed, in general, girls reported more experiences of direct and indirect PTEs. Furthermore, girls

Summer distribution and ecological role of seabirds and marine mammals in the Norwegian and Greenland seas (June 1988)

Science.gov (United States)

Joiris, Claude R.

1992-03-01

During the ARK V /2 expedition of RV Polarstern in the Norwegian and Greenland seas in June 1988, 380 half hour counts for marine vertebrates (seabirds, pinnipeds and cetaceans) were carried out. Results are presented as total numbers encountered and then converted into density and food intake. Mean food intake was 2.2 kg fresh weight per km 2 per day for seabirds, with a higher value in Atlantic water (2.5) lower values in polar water and the pack ice (1.7 and 1.9), and an intermediate value at the ice edge. The main species were the alcids (1.5, primarily Little Auk, Alle alle and Brünnich's Guillemot, Urea Iomvia) ,the Fulmar, Fulmarus glacialis (0.5), and the Kittiwake, Rissa tridactyla (0.2). The ecological role of cetaceans was clearly lower, with a mean value of 0.2 and a maximum of 0.7 in Atlantic water (rough evaluation, due to the low number of contacts). The food intake by pinnipeds was 0.55 kg/km 2 day at the ice edge and 0.4 in the pack ice; they were mainly harp, Phoca groenlandica and hooded seals, Cystophora cristata, in one main concentration each and ringed seals, Phoca hispida, scattered on the pack. Data for July 1988 show a great similarity with these results, except for a lower density of alcids, which probably reflects that Little Auk, Brünnich's Guillemot and Common Guillemot, Uria aalge already had started to leave the region.

Holocene environmental changes and climate development in Greenland

International Nuclear Information System (INIS)

Engels, Stefan; Helmens, Karin

2010-12-01

The primary aim of this report is to give an overview of the Holocene environmental and climatic changes in Greenland and to describe the development of the periglacial environment during the Holocene. Special emphasis is given to the influence of the ice sheet on its surroundings, both in terms of time (with respect to the response of the biosphere to deglaciation or ice sheet proximity) and in space (through the influence of the ice sheet on the regional climate, more specifically on temperature and aridity). Published records are reviewed, and regional trends are summarized. A range of different natural archives is available for such studies, including ice-core data, marine records, and continental sources of information, including peat profiles and lacustrine records. Because of the high number of lakes in all ice-free areas of Greenland, the lacustrine records offer the opportunity to get a spatial overview of past changes in environment and climate as well. This report focuses on (palaeo-) ecological studies, as it is intended to assemble basic information for future studies on adaptation of the biosphere to changes in climate. There is a bias towards pollen- and macro-remain-based reconstructions of past changes, as these dominate performed palaeoecological studies in Greenland; unfortunately, only a limited number of studies exist that include more modern proxies such as diatoms or chironomids (climate-indicators), but where available in the literature, these have been included. The report starts with an introduction where the current climatic and biological zonation of Greenland is discussed together with an overview of the geology of Greenland (on the full geological timescale) in order to put the following sections in perspective. Chapter 2 discusses the ice sheet history of Greenland from the Last Glacial Maximum (LGM) onward where special emphasis is given to the spatial variability of deglaciation at the onset of the Holocene. To enhance the

Holocene environmental changes and climate development in Greenland

Energy Technology Data Exchange (ETDEWEB)

Engels, Stefan; Helmens, Karin (Dept. of Physical Geography and Quaternary Geology, Stockholm Univ., Stockholm (Sweden))

2010-12-15

The primary aim of this report is to give an overview of the Holocene environmental and climatic changes in Greenland and to describe the development of the periglacial environment during the Holocene. Special emphasis is given to the influence of the ice sheet on its surroundings, both in terms of time (with respect to the response of the biosphere to deglaciation or ice sheet proximity) and in space (through the influence of the ice sheet on the regional climate, more specifically on temperature and aridity). Published records are reviewed, and regional trends are summarized. A range of different natural archives is available for such studies, including ice-core data, marine records, and continental sources of information, including peat profiles and lacustrine records. Because of the high number of lakes in all ice-free areas of Greenland, the lacustrine records offer the opportunity to get a spatial overview of past changes in environment and climate as well. This report focuses on (palaeo-) ecological studies, as it is intended to assemble basic information for future studies on adaptation of the biosphere to changes in climate. There is a bias towards pollen- and macro-remain-based reconstructions of past changes, as these dominate performed palaeoecological studies in Greenland; unfortunately, only a limited number of studies exist that include more modern proxies such as diatoms or chironomids (climate-indicators), but where available in the literature, these have been included. The report starts with an introduction where the current climatic and biological zonation of Greenland is discussed together with an overview of the geology of Greenland (on the full geological timescale) in order to put the following sections in perspective. Chapter 2 discusses the ice sheet history of Greenland from the Last Glacial Maximum (LGM) onward where special emphasis is given to the spatial variability of deglaciation at the onset of the Holocene. To enhance the

Imaging the Iceland Hotspot Track Beneath Greenland with Seismic Noise Correlations

Science.gov (United States)

Mordret, A.

2017-12-01

During the past 65 million years, the Greenland craton drifted over the Iceland hotspot; however, uncertainties in geodynamic modeling and a lack of geophysical evidence prevent an accurate reconstruction of the hotspot track. I image the Greenland lithosphere down to 300 km depth with seismic noise tomography. The hotspot track is observed as a linear high-velocity anomaly in the middle crust associated with magmatic intrusions. In the upper mantle, the remnant thermal signature of the hotspot manifests as low velocity and low viscosity bodies. This new detailed picture of the Greenland lithosphere will drive more accurate geodynamic reconstructions of tectonic plate motions and prediction of Greenland heat flow, which in turn will enable more precise estimations of the Greenland ice-sheet mass balance.

Studying health in Greenland

DEFF Research Database (Denmark)

Bjerregaard, Peter; Mulvad, Gert; Olsen, Jørn

2003-01-01

Health research in Greenland has contributed with several findings of interest for the global scientific community and has documented health problems and risk factors of importance for planning the local health care system. The study of how health develops in small, scattered communities during...... rapid epidemiological transition carries prospects of global significance. The Inuit are a genetically distinct people living under extreme physical conditions. Their traditional living conditions and diet are currently undergoing a transformation, which may approach their disease pattern...... to that of the industrialized world, while still including local outbreaks of tuberculosis. Health research in Greenland is logistically difficult and costly, but offers opportunities not found elsewhere in the world. A long tradition of registration enhances the possibilities for research. A number of research institutions...

Greenland and the international politics of a changing arctic

DEFF Research Database (Denmark)

Greenland and the International Politics of a Changing Arctic examines the international politics of semi-independent Greenland in a changing and increasingly globalised Arctic. Without sovereign statehood, but with increased geopolitical importance, independent foreign policy ambitions......, and a solidified self-image as a trailblazer for Arctic indigenous peoples’ rights, Greenland is making its mark on the Arctic and is in turn affected – and empowered – by Arctic developments. The chapters in this collection analyse how a distinct Greenlandic foreign policy identity shapes political ends and means...... for regional change in the Arctic. This is the first comprehensive and interdisciplinary examination of Greenland’s international relations and how they are connected to wider Arctic politics. It will be essential reading for students and scholars interested in Arctic governance and security, international...

China and Greenland

DEFF Research Database (Denmark)

Jakobsen, Uffe

2014-01-01

More thorough analysis and outreach on facts about Chinese activities in the Arctic are highly needed, not least in view of the almost alarmist response in Danish political debate to the prospects of growing Chinese interest in the Arctic in general and especially in Greenland...

Cloud amount/frequency, TRANSMISSIVITY and other data from NOAA Ship MILLER FREEMAN in the Bering Sea, NW Pacific and other waters from 1992-04-04 to 1992-09-25 (NODC Accession 9300022)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD) and other data were collected in NW Pacific (limit-180), NE Pacific (limit-180), Greenland Sea and Bering Sea as part...

Coupled Long-Term Evolution of Climate and the Greenland Ice Sheet During the Last Interglacial and Implications for the Future

Science.gov (United States)

Otto-Bliesner, B. L.; Lofverstrom, M.; Lipscomb, W.; Fyke, J. G.; Marshall, S.; Sacks, B.

2017-12-01

The Greenland Ice Sheet (GrIS) is expected to contribute increasingly to global sea level rise by the end of this century, and potentially several meters in this millennium, but still with considerable uncertainty. The rate of Greenland melt will impact on regional sea levels. The Last Interglacial (LIG, 129 ka to 116 ka) is recognized as an important period for testing our knowledge of climate-ice sheet interactions in warm climate states. Although the LIG was discussed in the First Assessment Report of the IPCC, it gained more prominence in the IPCC Fourth and Fifth Assessment (AR4 and AR5) with reconstructions highlighting that global mean sea level was at least 5 m higher (but probably no more than 10 m higher) than present for several thousand years during the LIG. Model results assessed for the AR5 suggest a sea level contribution of 1.4 to 4.3 m from the GrIS. These model simulations, though, did not include all the feedbacks of the climate system and the GrIS. Here, we examine the response of the Arctic climate system and the GrIS in simulations with the Community Earth System Model (CESM) fully coupled to the Community Ice Sheet Model (CISM), using a surface energy balance scheme and without bias corrections. The analysis focuses on how the GrIS responds to the imposed high boreal summer insolation of the LIG and in addition, to the long-term feedbacks of high-latitude vegetation changes. Results will highlight the evolution of the ice sheet and the surface mass balance (patterns of ablation and accumulation) as compared to data-based reconstructions for the LIG. We conclude with a discussion on how the LIG may be informative as a potential process analogue for the GrIS response for future centuries to come.

Radiation Climatology of the Greenland Ice Sheet Derived from Greenland Climate Network Data

Science.gov (United States)

Steffen, Konrad; Box, Jason

2003-01-01

The magnitude of shortwave and longwave dative fluxes are critical to surface energy balance variations over the Greenland ice sheet, affecting many aspects of its climate, including melt rates, the nature of low-level temperature inversions, the katabatic wind regime and buoyant stability of the atmosphere. Nevertheless, reliable measurements of the radiative fluxes over the ice sheet are few in number, and have been of limited duration and areal distribution (e.g. Ambach, 1960; 1963, Konzelmann et al., 1994, Harding et al., 1995, Van den Broeke, 1996). Hourly GC-Net radiation flux measurements spanning 1995-2001 period have been used to produce a monthly dataset of surface radiation balance components. The measurements are distributed widely across Greenland and incorporate multiple sensors

Ice-sheet model sensitivities to environmental forcing and their use in projecting future sea level (the SeaRISE project)

OpenAIRE

Bindschadler, Robert A.; Nowicki, Sophie; Abe-Ouchi, Ayako; Aschwanden, Andy; Choi, Hyeungu; Fastook, Jim; Granzow, Glen; Greve, Ralf; Gutowski, Gail; Herzfeld, Ute; Jackson, Charles; Johnson, Jesse; Khroulev, Constantine; Levermann, Anders; Lipscomb, William H.

2013-01-01

Ten ice-sheet models are used to study sensitivity of the Greenland and Antarctic ice sheets to prescribed changes of surface mass balance, sub-ice-shelf melting and basal sliding. Results exhibit a large range in projected contributions to sea-level change. In most cases, the ice volume above flotation lost is linearly dependent on the strength of the forcing. Combinations of forcings can be closely approximated by linearly summing the contributions from single forcing experiments, suggestin...

Episodes of subsidence and uplift of the conjugate margins of Greenland and Norway after opening of the NE Atlantic

Science.gov (United States)

Japsen, Peter; Green, Paul F.; Bonow, Johan M.; Chalmers, James A.

2015-04-01

We have undertaken a regional study of the thermo-­tectonic development of East Greenland (68-75°N) and of southern Norway (58-64°N). We take advantage of the general observation that that the effects of uplift often are reflected more clearly onshore than offshore, and of the specific condition that the mountains of southern East Greenland expose thick basalts that were extruded onto a largely horizontal lava plain near sea level during breakup of the NE Atlantic at the Paleocene-Eocene transition. It is thus clear that the present-­day elevation of these basalts up to 3.7 km a.s.l. were reached after breakup. Our results based on apatite fission-­track analysis (AFTA) data from East Greenland reveal a long history of post-­Palaeozoic burial and exhumation across the region and show that the terrains of Palaeozoic and older rocks were buried below a 2-3 km­-thick cover prior to a series of Mesozoic events of uplift and exhumation. The AFTA results from southern Norway reveal events of Mesozoic uplift and exhumation that are broadly simultaneous with those in Greenland. Volcanic and sedimentary rocks accumulated on the subsiding, East Greenland margin during and following breakup and then began to be exhumed during late Eocene uplift that preceded a major, early Oligocene plate reorganization in the NE Atlantic. The Norwegian margin also experienced Eocene subsidence and burial. Our AFTA data from southern Norway show evidence of an event of mid­Cenozoic uplift and exhumation that overlap with the early Oligocene onset of progradation of clastic wedges towards the south and with the formation of a major, late Eocene unconformity along the NW European margin. The uplift event at the Eocene-Oligocene transition that affected wide areas in the NE Atlantic domain was followed by two regional events of uplift and incision of the East Greenland margin in the late Miocene and Pliocene whereas the Neogene uplift of southern Norway began in the early Miocene and was

Sea level change: lessons from the geologic record

Science.gov (United States)

,

1995-01-01

Rising sea level is potentially one of the most serious impacts of climatic change. Even a small sea level rise would have serious economic consequences because it would cause extensive damage to the world's coastal regions. Sea level can rise in the future because the ocean surface can expand due to warming and because polar ice sheets and mountain glaciers can melt, increasing the ocean's volume of water. Today, ice caps on Antarctica and Greenland contain 91 and 8 percent of the world's ice, respectively. The world's mountain glaciers together contain only about 1 percent. Melting all this ice would raise sea level about 80 meters. Although this extreme scenario is not expected, geologists know that sea level can rise and fall rapidly due to changing volume of ice on continents. For example, during the last ice age, about 18,000 years ago, continental ice sheets contained more than double the modem volume of ice. As ice sheets melted, sea level rose 2 to 3 meters per century, and possibly faster during certain times. During periods in which global climate was very warm, polar ice was reduced and sea level was higher than today.

Oxygen isotope ratios in the shell of Mytilus edulis: Archives of glacier meltwater in Greenland?

DEFF Research Database (Denmark)

Versteegh, E.A.A.; Blicher, M.E.; Mortensen, J.

2012-01-01

Melting of the Greenland Ice Sheet (GrIS) is accelerating and will contribute significantly to global sea level rise during the 21st century. Instrumental data on GrIS melting only cover the last few decades, and proxy data extending our knowledge into the past are vital for validating models...... these variations, because it precipitates its shell calcite in oxygen isotopic equilibrium with ambient seawater. As M. edulis shells are known to occur in raised shorelines and archaeological shell middens from previous Holocene warm periods, this species may be ideal in reconstructing past meltwater dynamics. We...

Exploring Greenland: science and technology in Cold War settings.

Science.gov (United States)

Heymann, Matthias; Knudsen, Henrik; Lolck, Maiken L; Nielsen, Henry; Nielsen, Kristian H; Ries, Christopher J

2010-01-01

This paper explores a vacant spot in the Cold War history of science: the development of research activities in the physical environmental sciences and in nuclear science and technology in Greenland. In the post-war period, scientific exploration of the polar areas became a strategically important element in American and Soviet defence policy. Particularly geophysical fields like meteorology, geology, seismology, oceanography, and others profited greatly from military interest. While Denmark maintained formal sovereignty over Greenland, research activities were strongly dominated by U.S. military interests. This paper sets out to summarize the limited current state of knowledge about activities in the environmental physical sciences in Greenland and their entanglement with military, geopolitical, and colonial interests of both the USA and Denmark. We describe geophysical research in the Cold War in Greenland as a multidimensional colonial endeavour. In a period of decolonization after World War II, Greenland, being a Danish colony, became additionally colonized by the American military. Concurrently, in a period of emerging scientific internationalism, the U.S. military "colonized" geophysical research in the Arctic, which increasingly became subject to military directions, culture, and rules.

Depositional evolution of the Melville Bay trough-mouth fan, NW Greenland

Science.gov (United States)

Knutz, Paul; Gregersen, Ulrik

2015-04-01

The continental margin of NW Greenland bordering northern Baffin Bay is characterized by major sediment accumulations, known as Trough-Mouth Fans (TMF). The fan depocentres represent intense sediment dispersal at the terminus of ice streams that during cold climate periods provided major drainage routes of the northern Greenland Ice Sheet into Baffin Bay. The imprint of paleo-icestreams is seen by erosional troughs crossing a >250 km broad shelf region, which caps a series of sedimentary basins containing thick Mesozoic-Tertiary strata packages. This presentation provides an overview of the seismic stratigraphic division, depositional architecture and examples of seismic facies of the Melville Bay TMF using a 5-10 km grid of industry-quality 2D seismic data (TGS). The focus will primarily be on the inception and early stage of glacial fan development. Comparing the present-day topography with the regional geology shows that the paleo-icestreams exploited the Cenozoic infill of former rift basins that are more conducive to erosion than the adjoining ridges and structural highs. The TMF sequence is constructed by a series of progradational seismic units that represent successive steps in location of ice stream terminus and associated depocenters. The slope fronts of the prograding units show abundant signatures of sediment instability and mass-wasting but evidence of along-slope current-driven processes is also recognized presumably linked to interglacial sea level high-stands. The topset of each unit is characterized by planar erosion that merges landward into hummocky positive geometries with low internal reflectivity. These features are generally interpreted as subglacial landforms, e.g. terminal moraines and ice-contact deposits, associated with grounding zone wedges. Unlike the most recent TMF units deposited in front of the present trough, the oldest glacigenic units have built out from a Neogene sediment prism that forms the core of modern shallow-water banks

Contribution of glacier melt to sea-level rise since AD 1865: a regionally differentiated calculation

NARCIS (Netherlands)

Zuo, Z.; Oerlemans, J.

1997-01-01

The contribution of glacier melt, including the Greenland ice-sheet, to sea-level change since AD 1865 is estimated on the basis of modelled sensitivity of glacier mass balance to climate change and historical temperature data. Calculations are done in a regionally differentiated manner to overcome

Mark report satellite tags (mrPATs) to detail large-scale horizontal movements of deep water species: First results for the Greenland shark (Somniosus microcephalus)

Science.gov (United States)

Hussey, Nigel E.; Orr, Jack; Fisk, Aaron T.; Hedges, Kevin J.; Ferguson, Steven H.; Barkley, Amanda N.

2018-04-01

The deep-sea is increasingly viewed as a lucrative environment for the growth of resource extraction industries. To date, our ability to study deep-sea species lags behind that of those inhabiting the photic zone limiting scientific data available for management. In particular, knowledge of horizontal movements is restricted to two locations; capture and recapture, with no temporal information on absolute animal locations between endpoints. To elucidate the horizontal movements of a large deep-sea fish, a novel tagging approach was adopted using the smallest available prototype satellite tag - the mark-report pop-up archival tag (mrPAT). Five Greenland sharks (Somniosus microcephalus) were equipped with multiple mrPATs as well as a standard archival satellite tag (miniPAT) that were programmed to release in sequence at 8-10 day intervals. The performance of the mrPATs was quantified. The tagging approach provided multiple locations per individual and revealed a previously unknown directed migration of Greenland sharks from the Canadian high Arctic to Northwest Greenland. All tags reported locations, however, the accuracy and time from expected release were variable among tags (average time to an accurate location from expected release = 30.8 h, range: 4.9-227.6 h). Average mrPAT drift rate estimated from best quality messages (LQ1,2,3) was 0.37 ± 0.09 m/s indicating tags were on average 41.1 ± 63.4 km (range: 6.5-303.1 km) from the location of the animal when they transmitted. mrPATs provided daily temperature values that were highly correlated among tags and with the miniPAT (70.8% of tag pairs were significant). In contrast, daily tilt sensor data were variable among tags on the same animal (12.5% of tag pairs were significant). Tracking large-scale movements of deep-sea fish has historically been limited by the remote environment they inhabit. The current study provides a new approach to document reliable coarse scale horizontal movements to understand

Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins

Science.gov (United States)

Cronin, Thomas M.; O'Regan, Matt; Pearce, Christof; Gemery, Laura; Toomey, Michael; Semiletov, Igor; Jakobsson, Martin

2017-09-01

Deglacial (12.8-10.7 ka) sea level history on the East Siberian continental shelf and upper continental slope was reconstructed using new geophysical records and sediment cores taken during Leg 2 of the 2014 SWERUS-C3 expedition. The focus of this study is two cores from Herald Canyon, piston core SWERUS-L2-4-PC1 (4-PC1) and multicore SWERUS-L2-4-MC1 (4-MC1), and a gravity core from an East Siberian Sea transect, SWERUS-L2-20-GC1 (20-GC1). Cores 4-PC1 and 20-GC were taken at 120 and 115 m of modern water depth, respectively, only a few meters above the global last glacial maximum (LGM; ˜ 24 kiloannum or ka) minimum sea level of ˜ 125-130 meters below sea level (m b.s.l.). Using calibrated radiocarbon ages mainly on molluscs for chronology and the ecology of benthic foraminifera and ostracode species to estimate paleodepths, the data reveal a dominance of river-proximal species during the early part of the Younger Dryas event (YD, Greenland Stadial GS-1) followed by a rise in river-intermediate species in the late Younger Dryas or the early Holocene (Preboreal) period. A rapid relative sea level rise beginning at roughly 11.4 to 10.8 ka ( ˜ 400 cm of core depth) is indicated by a sharp faunal change and unconformity or condensed zone of sedimentation. Regional sea level at this time was about 108 m b.s.l. at the 4-PC1 site and 102 m b.s.l. at 20-GC1. Regional sea level near the end of the YD was up to 42-47 m lower than predicted by geophysical models corrected for glacio-isostatic adjustment. This discrepancy could be explained by delayed isostatic adjustment caused by a greater volume and/or geographical extent of glacial-age land ice and/or ice shelves in the western Arctic Ocean and adjacent Siberian land areas.

Large-scale evolution of the central-east Greenland margin: New insights to the North Atlantic glaciation history

Science.gov (United States)

Pérez, Lara F.; Nielsen, Tove; Knutz, Paul C.; Kuijpers, Antoon; Damm, Volkmar

2018-04-01

The continental shelf of central-east Greenland is shaped by several glacially carved transverse troughs that form the oceanward extension of the major fjord systems. The evolution of these troughs through time, and their relation with the large-scale glaciation of the Northern Hemisphere, is poorly understood. In this study seismostratigraphic analyses have been carried out to determine the morphological and structural development of this important sector of the East Greenland glaciated margin. The age of major stratigraphic discontinuities has been constrained by a direct tie to ODP site 987 drilled in the Greenland Sea basin plain off Scoresby Sund fan system. The areal distribution and internal facies of the identified seismic units reveal the large-scale depositional pattern formed by ice-streams draining a major part of the central-east Greenland ice sheet. Initial sedimentation along the margin was, however, mainly controlled by tectonic processes related to the margin construction, continental uplift, and fluvial processes. From late Miocene to present, progradational and erosional patterns point to repeated glacial advances across the shelf. The evolution of depo-centres suggests that ice sheet advances over the continental shelf have occurred since late Miocene, about 2 Myr earlier than previously assumed. This cross-shelf glaciation is more pronounced during late Miocene and early Pliocene along Blosseville Kyst and around the Pliocene/Pleistocene boundary off Scoresby Sund; indicating a northward migration of the glacial advance. The two main periods of glaciation were separated by a major retreat of the ice sheet to an inland position during middle Pliocene. Mounded-wavy deposits interpreted as current-related deposits suggest the presence of changing along-slope current dynamics in concert with the development of the modern North Atlantic oceanographic pattern.

Characterization of household waste in Greenland

International Nuclear Information System (INIS)

Eisted, Rasmus; Christensen, Thomas H.

2011-01-01

The composition of household waste in Greenland was investigated for the first time. About 2 tonnes of household waste was sampled as every 7th bag collected during 1 week along the scheduled collection routes in Sisimiut, the second largest town in Greenland with about 5400 inhabitants. The collection bags were sorted manually into 10 material fractions. The household waste composition consisted primarily of biowaste (43%) and the combustible fraction (30%), including anything combustible that did not belong to other clean fractions as paper, cardboard and plastic. Paper (8%) (dominated by magazine type paper) and glass (7%) were other important material fractions of the household waste. The remaining approximately 10% constituted of steel (1.5%), aluminum (0.5%), plastic (2.4%), wood (1.0%), non-combustible waste (1.8%) and household hazardous waste (1.2%). The high content of biowaste and the low content of paper make Greenlandic waste much different from Danish household waste. The moisture content, calorific value and chemical composition (55 elements, of which 22 were below detection limits) were determined for each material fraction. These characteristics were similar to what has been found for material fractions in Danish household waste. The chemical composition and the calorific value of the plastic fraction revealed that this fraction was not clean but contained a lot of biowaste. The established waste composition is useful in assessing alternative waste management schemes for household waste in Greenland.

The right of indigenous peoples to education in their own language – Greenlanders in Denmark and in Greenland

DEFF Research Database (Denmark)

Næsborg-Andersen, Ayo; Khalaf, Bassah

2018-01-01

Both language and culture are interdependent pillars on which the identity of a people is maintained, including indigenous peoples. Without the appropriate linguistic terminology available to express indigenous philosophies and concepts, indigenous peoples lose some of their ability to accurately...... and in Denmark. As a part of this examination the paper also gives an overview of history of the Greenlandic school system. Finally the paper compares the current situation of Greenlanders in Denmark with the Sami peoples in Norway....

Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and non-ortho-PCBs in eggs of white-tailed sea eagles collected along the Swedish coast in the Baltic Sea.

Science.gov (United States)

Nordlöf, Ulrika; Helander, Björn; Zebühr, Yngve; Bignert, Anders; Asplund, Lillemor

2012-11-01

Concentrations of polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), and dioxin-like non-ortho-PCBs were measured in white-tailed sea eagle (WTSE) eagle eggs collected along the Swedish coast of the Baltic Sea during the period 1992-2004. The eggs represent two different subpopulations with significantly different nestling brood sizes; the Baltic Proper (BP) with an approximately normal nestling brood size (1.62), and the south Bothnian Sea (sBS) with reduced nestling brood size (1.22) combined with a significantly higher rate of dead eggs. The aim was to investigate if this difference in reproductive outcome was linked to differences in exposure to dioxin-like compounds. Three eggs collected in Greenland in 2000 were included in the study to provide a reference sea eagle population outside of the Baltic Sea region. The concentrations of ∑PCDD, ∑PCDF and ∑non-ortho-PCB in the two subpopulations from the Baltic Sea (BS) region ranged from 0.41-4.1, 1.2-5.3 and 180-970 ng/g lipids, respectively, while in the Greenland population the ranges were 0.11-0.16, 0.22-0.33 and 57-83 ng/g lipid, respectively. 2,3,4,7,8-PCDF was the predominant congener in all areas and accounted for on average 31-49% of the total ∑PCDD/F concentrations. The total toxic equivalents (TEQ) in sBS WTSEs were higher (approximately 39 ng TEQ/g lipid) than reported in eggs for many other birds, and the major contributors to the TEQ in the Baltic Sea were the non-ortho-PCBs. A principal component analysis (PCA) showed a difference in congener pattern between the two Baltic regions that was statistically significant (Hotelling's T(2) test). We found no significant differences in the total TEQ between the two populations (sBS-BP) and thus no evidence was found linking the reproductive impairment in WTSE in sBS to the concentrations of PCDD/Fs or non-ortho-PCBs in the eggs. Copyright © 2012 Elsevier B.V. All rights reserved.

SeaWinds - Oceans, Land, Polar Regions

Science.gov (United States)

1999-01-01

The SeaWinds scatterometer on the QuikScat satellite makes global radar measurements -- day and night, in clear sky and through clouds. The radar data over the oceans provide scientists and weather forecasters with information on surface wind speed and direction. Scientists also use the radar measurements directly to learn about changes in vegetation and ice extent over land and polar regions.This false-color image is based entirely on SeaWinds measurements obtained over oceans, land, and polar regions. Over the ocean, colors indicate wind speed with orange as the fastest wind speeds and blue as the slowest. White streamlines indicate the wind direction. The ocean winds in this image were measured by SeaWinds on September 20, 1999. The large storm in the Atlantic off the coast of Florida is Hurricane Gert. Tropical storm Harvey is evident as a high wind region in the Gulf of Mexico, while farther west in the Pacific is tropical storm Hilary. An extensive storm is also present in the South Atlantic Ocean near Antarctica.The land image was made from four days of SeaWinds data with the aid of a resolution enhancement algorithm developed by Dr. David Long at Brigham Young University. The lightest green areas correspond to the highest radar backscatter. Note the bright Amazon and Congo rainforests compared to the dark Sahara desert. The Amazon River is visible as a dark line running horizontally though the bright South American rain forest. Cities appear as bright spots on the images, especially in the U.S. and Europe.The image of Greenland and the north polar ice cap was generated from data acquired by SeaWinds on a single day. In the polar region portion of the image, white corresponds to the largest radar return, while purple is the lowest. The variations in color in Greenland and the polar ice cap reveal information about the ice and snow conditions present.NASA's Earth Science Enterprise is a long-term research and technology program designed to examine Earth

Small-scale fisheries in Greenlandic planning

DEFF Research Database (Denmark)

Jacobsen, Rikke Becker

2013-01-01

This article analyses an ongoing planning process in Greenlandic fisheries governance aiming to reform the coastal Greenland halibut fishery. It examines the way certain truths about this fishery and the need for reform are produced up to and in the final policy document ‘regulation concerning...... could also be understood as primarily a problem to a certain ‘governmentality’ mode of governance. Whereas some fishery studies document how governmentality modes of governance in fisheries succeeds in transforming subjectivities, this study offers a view into the process that might go before successful...

The Intra-Americas Sea low-level jet: overview and future research.

Science.gov (United States)

Amador, Jorge A

2008-12-01

A relevant climate feature of the Intra-Americas Sea (IAS) is the low-level jet (IALLJ) dominating the IAS circulation, both in summer and winter; and yet it is practically unknown with regard to its nature, structure, interactions with mid-latitude and tropical phenomena, and its role in regional weather and climate. This paper updates IALLJ current knowledge and its contribution to IAS circulation-precipitation patterns and presents recent findings about the IALLJ based on first in situ observations during Phase 3 of the Experimento Climático en las Albercas de Agua Cálida (ECAC), an international field campaign to study IALLJ dynamics during July 2001. Nonhydrostatic fifth-generation Pennsylvania State University National Center for Atmospheric Research Mesoscale Model (MM5) simulations were compared with observations and reanalysis. Large-scale circulation patterns of the IALLJ northern hemisphere summer and winter components suggest that trades, and so the IALLJ, are responding to land-ocean thermal contrasts during the summer season of each continent. The IALLJ is a natural component of the American monsoons as a result of the continent's approximate north-south land distribution. During warm (cold) El Niño-Southern Oscillation phases, winds associated with the IALLJ core (IALLJC) are stronger (weaker) than normal, so precipitation anomalies are positive (negative) in the western Caribbean near Central America and negative (positive) in the central IAS. During the ECAC Phase 3, strong surface winds associated with the IALLJ induced upwelling, cooling down the sea surface temperature by 1-2 degrees C. The atmospheric mixed layer height reached 1 km near the surface wind maximum below the IALLJC. Observations indicate that primary water vapor advection takes place in a shallow layer between the IALLJC and the ocean surface. Latent heat flux peaked below the IALLJC. Neither the reanalysis nor MM5 captured the observed thermodynamic and kinematic IALLJ

Coastal Freshening Prevents Fjord Bottom Water Renewal in Northeast Greenland: A Mooring Study From 2003 to 2015

Science.gov (United States)

Boone, Wieter; Rysgaard, Søren; Carlson, Daniel F.; Meire, Lorenz; Kirillov, Sergei; Mortensen, John; Dmitrenko, Igor; Vergeynst, Leendert; Sejr, Mikael K.

2018-03-01

The freshwater content of the Arctic Ocean and its bordering seas has recently increased. Observing freshening events is an important step toward identifying the drivers and understanding the effects of freshening on ocean circulation and marine ecosystems. Here we present a 13 year (2003-2015) record of temperature and salinity in Young Sound-Tyrolerfjord (74°N) in Northeast Greenland. Our observations show that strong freshening occurred from August 2005 to August 2007 (-0.92 psu or -0.46 psu yr-1) and from August 2009 to August 2013 (-0.66 psu or -0.17 psu yr-1). Furthermore, temperature-salinity analysis from 2004 to 2014 shows that freshening of the coastal water ( range at sill depth: 33.3 psu in 2005 to 31.4 psu in 2007) prevented renewal of the fjord's bottom water. These data provide critical observations of interannual freshening rates in a remote fjord in Greenland and in the adjacent coastal waters and show that coastal freshening impacts the fjord hydrography, which may impact the ecosystem dynamics in the long term.

Continuity and discontinuity in the Inuit culture of Greenland

NARCIS (Netherlands)

Kylstra, Hans P.

1977-01-01

In november 1976 the Arctic Centre of the University of Gronlngen organized its third symposium. The third symposium was a Dutch-Danish one on the Greenlandic Inuit: 'Continuity and Discontinuity In Greenlandic Arctic Culture'. As on the two previous occasions, an exhibition was organized.

Climate Change and Baleen Whale Trophic Cascades in Greenland

Science.gov (United States)

2009-09-30

DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. Climate Change and Baleen Whale Trophic Cascades in Greenland...SUBTITLE Climate Change And Baleen Whale Trophic Cascades In Greenland 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S

Detailed Sea Level Record from Barbados Spanning 13,000 to 11,000 Years Before Present

Science.gov (United States)

Abdul, N. A.; Mortlock, R. A.; Wright, J. D.; Fairbanks, R. G.

2013-12-01

Th/U dated reef-crest corals (Acropora palmata) obtained from new Barbados offshore drill cores provide a local sea level reconstruction in unprecedented detail. The time interval, 13,000 to 11,000 years before present (BP), spans the well-studied Younger Dryas pollen zone, a period that has given rise to more than three decades of sensational climate interpretations and popular press. Widely described as a time when Earth's climate reverted to "glacial-like conditions" the various hypotheses that attempt to explain the "cause" of the Younger Dryas climate event have their staunch supporters as well as their critics but there remains little consensus. The Barbados sea level record for this time interval shows that sea level continued to rise during the Younger Dryas, albeit at a slower rate than prior to 13,000 or following 11,000 years BP. The decrease in the rate of sea level rise can simply be explained by the slow expansion of the Fennoscandian Ice Sheet beginning 12,800 years BP followed by its faster demise contributing to a period of rapid sea level increase known as Melt Water Pulse 1B. We calculate the ice volume history of the Fennoscandian Ice Sheet and it compares favorably to the moraine history and ice models. The Younger Dryas climate event is most often defined by the rapid shifts in atmospheric proxies measured in ice cores from Greenland. The ice core proxies shift into and out of the Younger Dryas climate event in only a few years to a few decades. Abrupt shifts in the climate state associated with the onset and termination of the Younger Dryas as revealed in Greenland Ice cores are not expressed in the smooth Barbados deglacial sea level record. We make the case that these Greenland atmospheric records mark regional atmospheric frontal shifts and changes in air mass sources over an ice sheet that largely did not participate in the deglaciation or sea level change. As proposed decades ago, the warming of the North Atlantic between 14,000 and 13

Interannual variability of the Equatorial Jets in the Indian Ocean from the merged altimetry data

Digital Repository Service at National Institute of Oceanography (India)

Somayajulu, Y.K.; Murty, V.S.N.; Neelima, C.; Jagadeesh, P.S.V.

The merged ERS-1/2, TOPEX/Poseidon and Jason-1 altimeter weekly sea level anomalies (SLAs) for the period 1997- 2005 were analyzed to study the variability of sea level and computed geostrophic currents in relation to the equatorial jets...