WorldWideScience

Sample records for north sea region

  1. Jurassic domes in the North Sea - northern North Atlantic region

    Energy Technology Data Exchange (ETDEWEB)

    Surlyk, F. [Univ. of Copenhagen, Geological Inst., Copenhagen (Denmark)

    1996-12-31

    The stratigraphic and tectonic evolution of the Jurassic of East Greenland, the Norwegian Shelf and the North Sea is remarkably similar. A major Middle Jurassic unconformity occurs in all three areas. In the North Sea it is commonly termed the `Mid-Cimmerian Unconformity` and is characterized by progressive truncation of the underlying section towards a centre at the triple junction between the Central Graben, Viking Graben and Moray Firth. Strata above the unconformity show a progressive Late Aalenian-Early Kimmeridgian onlap in the same direction. These relations have been interpreted as caused by Early Jurassic uplift and of a major thermal dome in the central North Sea, followed by Medial and Late Jurassic rifting, erosion, deflation and transgression of the dome. The East Greenland unconformity shows progressive truncation of underlying strata from south to north, and Bajocian to Callovian onlap in the same direction. The same pattern seems to be developed on the conjugate Norwegian margin. This suggests the possibility that the three unconformities have similar causes for their development. It is proposed that major rift domes formed in the Central North Sea and in the Greenland-Norway seaway in Early Jurassic times. The domes were eroded and gradually deflated during Medial Jurassic times and were finally submerged by the Late Oxfordian-Kimmeridgian. They were associated with volcanism and rifting which was delayed with respect to dome initiation. Roughly contemperaneous domes were present west of Britain, north of the Porcupine Seabight, and in Scania, southern Sweden, as reflected by development of asymmetrical unconformities showing progressive truncation of underlying strata, onlap of overlying Jurassic strata, and associated intrusive and extrusive volcanism. The domes are related to impingement of the heads of transient mantle plumes at the base of the lithosphere. The associated unconformities are thus of non-eustatic nature. Domal uplift and

  2. Two centuries of extreme events over the Baltic Sea and North Sea regions

    Science.gov (United States)

    Stendel, Martin; den Besselaar Else, van; Abdel, Hannachi; Jaak, Jaagus; Elizabeth, Kent; Christiana, Lefebvre; Gudrun, Rosenhagen; Anna, Rutgersson; Frederik, Schenk; der Schrier Gerard, van; Tim, Woolings

    2017-04-01

    Two centuries of extreme events over the Baltic Sea and North Sea regions In the framework of the BACC 2 (for the Baltic Sea) and NOSCCA projects (for the North Sea region), studies of past and present variability and changes in atmospheric variables within the North Sea region over the instrumental period (roughly the past 200 years) have been investigated. Findings on trends in temperature and precipitation have already been presented. Here we focus on data homogeneity issues and examine how reliable reanalyses are in this context. Unlike most other regions in the world, there is a wealth of old observations available for the Baltic and North Sea regions, most of it in handwritten form in meteorological journals and other publications. These datasets need to be carefully digitised and homogenized. For this, a thorough quality control must be applied; otherwise the digitised datasets may prove useless or even counterproductive. We present evidence that this step cannot be conducted without human interference and thus cannot be fully automated. Furthermore, inhomogeneities due to e.g. instrumentation and station relocations need to be addressed. A wealth of reanalysis products is available, which can help detect such inhomogeneities in observed time series, but at the same time are prone to biases and/or spurious trends themselves e.g. introduced by changes in the availability and quality of the underlying assimilated data. It therefore in general remains unclear in how far we can simulate the pre-satellite era with respect to homogeneity with reanalyses based only on parts of the observing system. Extreme events and changes in extreme situations are more important and of greater (societal) significance than changes in mean climate. However, changes in extreme weather events are difficult to assess not only because they are, per definition, rare events, but also due to the homogeneity issues outlined above. Taking these into account, we present evidence for changes

  3. Regionalization of climate model results for the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Kauker, F. [Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany); Storch, H. von [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Hydrophysik

    2000-07-01

    A dynamical downscaling for the North Sea is presented. The numerical model used for the study is the coupled ice-ocean model OPYC. In a hindcast of the years 1979 to 1993 it was forced with atmospheric forcing of the ECMWF reanalysis. The models capability in simulating the observed mean state and variability in the North Sea is demonstrated by the hindcast. Two time scale ranges, from weekly to seasonal and the longer-than-seasonal time scales are investigated. Shorter time scales, for storm surges, are not captured by the model formulation. The main modes of variability of sea level, sea-surface circulation, sea-surface temperature, and sea-surface salinity are described and connections to atmospheric phenomena, like the NAO, are discussed. T106 ''time-slice'' simulations with a ''2 x CO{sub 2}'' horizon are used to estimate the effects of a changing climate on the shelf sea ''North Sea''. The ''2 x CO{sub 2}'' changes in the surface forcing are accompanied by changes in the lateral oceanic boundary conditions taken from a global coupled climate model. For ''2 x CO{sub 2}'' the time mean sea level increases up to 25 cm in the German Bight in the winter, where 15 cm are due to the surface forcing and 10 cm due to thermal expansion. This change is compared to the ''natural'' variability as simulated in the ECMWF integration and found to be not outside the range spanned by it. The variability of sea level on the weekly-to-seasonal time-scales is significantly reduced in the scenario integration. The variability on the longer-than-seasonal time-scales in the control and scenario runs is much smaller then in the ECMWF integration. This is traced back to the use of ''time-slice'' experiments. Discriminating between locally forced changes and changes induced at the lateral oceanic boundaries of the model in the circulation and

  4. Maps of mesoscale wind variability over the North Sea region

    DEFF Research Database (Denmark)

    Vincent, Claire Louise; Hahmann, Andrea N.; Badger, Jake

    Mesoscale wind fluctuations affect the operation of wind farms, particularly as the number of geographically concentrated wind farms in the North Sea increases (Akhmatov et al. 2007). The frequency and intensity of wind fluctuations could be considered as a new siting criterion, together with exi......Mesoscale wind fluctuations affect the operation of wind farms, particularly as the number of geographically concentrated wind farms in the North Sea increases (Akhmatov et al. 2007). The frequency and intensity of wind fluctuations could be considered as a new siting criterion, together...... with existing criteria such as the wind resource and proximity to grid connection points. We used the Weather Research and Forecasting (WRF) model to calculate the average wind variability over the North Sea for wind fluctuations with periods of 30 minutes to 8 hours. Modelled winds are saved every 10 minutes...... for a 1 year period. The model was run with a horizontal grid spacing of 2 km. The variability maps are created by integrating the average 24 hour spectra at every grid point over different time-scales....

  5. Two centuries of observed atmospheric variability and change over the North Sea region

    Science.gov (United States)

    Stendel, Martin; van den Besselaar, Else; Hannachi, Abdel; Kent, Elizabeth; Lefebvre, Christiana; Rosenhagen, Gudrun; Schenk, Frederik; van der Schrier, Gerard; Woollings, Tim

    2016-04-01

    In the upcoming North Sea Region Climate Change Assessment (NOSCCA), we present a synthesis of current knowledge about past, present and possible future climate change in the North Sea region. A climate change assessment from published scientific work has been conducted as a kind of regional IPCC report, and a book has been produced that will be published by Springer in 2016. In the framework of the NOSCCA project, we examine past and present studies of variability and changes in atmospheric variables within the North Sea region over the instrumental period, roughly the past 200 years, based on observations and reanalyses. The variables addressed in this presentation are large-scale circulation, pressure and wind, surface air temperature, precipitation and radiative properties (clouds, solar radiation, and sunshine duration). While air temperature over land, not unexpectedly, has increased everywhere in the North Sea region, with strongest trends in spring and in the north of the region, a precipitation increase has been observed in the north and a decrease in the south of the region. This pattern goes along with a north-eastward shift of storm tracks and is in agreement with climate model projections under enhanced greenhouse gas concentrations. For other variables, it is not obvious which part of the observed changes may be due to anthropogenic activities and which is internally forced. It remains also unclear to what extent atmospheric circulation over the North Sea region is influenced by distant factors, in particular Arctic sea-ice decline in recent decades. There are indications of an increase in the number of deep cyclones (but not in the total number of cyclones), while storminess since the late 19th century shows no robust trends. The persistence of circulation types appears to have increased over the last century, and consequently, there is an indication for 'more extreme' extreme events. However, changes in extreme weather events are difficult to assess

  6. Regional cenozoic uplift and subsidence events in the southeastern North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Jordt, H.

    1995-12-31

    The Paleocene topography of the Fennoscandian Shield is indicated by outbuilding towards the Central Trough and the Ringkoebing-Fyn High. From Eocene until Pliocene time three events of relative vertical movements are indicated by changes in outbuilding directions and reflection termination patterns in the central North Sea. The firs event of uplift was in the Eocene and resulted in relative uplift of the Mid North Sea High and contemporary subsidence east of it, indicated by a change in outbuilding from north to west. A second event of uplift is indicated to the north of the study area at the Eocene-Oligocene boundary by renewed southward outbuilding in the Norwegian-Danish Basin. In Miocene until Early Pliocene time a relatively stationary, almost east-west striking, basin margin was probably located to the north along the Tornquist Zone as indicated by the continued outbuilding towards the Ringkoebing-Fyn High. A third event of relative uplift is indicated east of the study area by changes in the Pliocene outbuilding pattern. After the first event of uplift it appears that the deepest parts of the Eocene North Sea Basin was located more easterly than the deepest part are today. Apparently the two latest uplift events north and east of the study area were related to movements of, or along the Tornquist Zone or to regional uplift of the Fennoscandian Shield finally resulting in the present-day configuration of the North Sea. (au) 11 refs.

  7. The contribution of ship emissions to air pollution in the North Sea regions

    Energy Technology Data Exchange (ETDEWEB)

    Matthias, Volker, E-mail: volker.matthias@gkss.d [GKSS Research Centre Geesthacht, Institute for Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Bewersdorff, Ines [GKSS Research Centre Geesthacht, Institute for Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Aulinger, Armin, E-mail: armin.aulinger@gkss.d [GKSS Research Centre Geesthacht, Institute for Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Quante, Markus, E-mail: markus.quante@gkss.d [GKSS Research Centre Geesthacht, Institute for Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht (Germany)

    2010-06-15

    As a consequence of the global distribution of manufacturing sites and the increasing international division of labour, ship traffic is steadily increasing and is becoming more and more important as an origin of air pollution. This study investigates the impact of ship emissions in coastal areas of the North Sea under conditions of the year 2000 by means of a regional chemistry transport model which runs on a sufficiently high resolution to study air pollution in coastal regions. It was found that northern Germany and Denmark in summer suffer from more than 50% higher sulphate, nitrate and ammonium aerosol concentrations due to contributions from ships. The implementation of a sulphur emission control area (SECA) in the North Sea, as it was implemented at the end of 2007, directly results in reduced sulphur dioxide and sulphate aerosol concentrations while nitrate aerosol concentrations are slightly increased. - Ship emissions lead to significantly enhanced air pollution by secondary inorganic aerosols in North Sea coastal areas.

  8. The contribution of ship emissions to air pollution in the North Sea regions.

    Science.gov (United States)

    Matthias, Volker; Bewersdorff, Ines; Aulinger, Armin; Quante, Markus

    2010-06-01

    As a consequence of the global distribution of manufacturing sites and the increasing international division of labour, ship traffic is steadily increasing and is becoming more and more important as an origin of air pollution. This study investigates the impact of ship emissions in coastal areas of the North Sea under conditions of the year 2000 by means of a regional chemistry transport model which runs on a sufficiently high resolution to study air pollution in coastal regions. It was found that northern Germany and Denmark in summer suffer from more than 50% higher sulphate, nitrate and ammonium aerosol concentrations due to contributions from ships. The implementation of a sulphur emission control area (SECA) in the North Sea, as it was implemented at the end of 2007, directly results in reduced sulphur dioxide and sulphate aerosol concentrations while nitrate aerosol concentrations are slightly increased.

  9. Persistent organochlorine pesticides and polychlorinated biphenyls in air of the North Sea region and air-sea exchange.

    Science.gov (United States)

    Mai, Carolin; Theobald, Norbert; Hühnerfuss, Heinrich; Lammel, Gerhard

    2016-12-01

    Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were studied to determine occurrence, levels and spatial distribution in the marine atmosphere and surface seawater during cruises in the German Bight and the wider North Sea in spring and summer 2009-2010. In general, the concentrations found in air are similar to, or below, the levels at coastal or near-coastal sites in Europe. Hexachlorobenzene and α-hexachlorocyclohexane (α-HCH) were close to phase equilibrium, whereas net atmospheric deposition was observed for γ-HCH. The results suggest that declining trends of HCH in seawater have been continuing for γ-HCH but have somewhat levelled off for α-HCH. Dieldrin displayed a close to phase equilibrium in nearly all the sampling sites, except in the central southwestern part of the North Sea. Here atmospheric deposition dominates the air-sea exchange. This region, close to the English coast, showed remarkably increased surface seawater concentrations. This observation depended neither on riverine input nor on the elevated abundances of dieldrin in the air masses of central England. A net depositional flux of p,p'-DDE into the North Sea was indicated by both its abundance in the marine atmosphere and the changes in metabolite pattern observed in the surface water from the coast towards the open sea. The long-term trends show that the atmospheric concentrations of DDT and its metabolites are not declining. Riverine input is a major source of PCBs in the German Bight and the wider North Sea. Atmospheric deposition of the lower molecular weight PCBs (PCB28 and PCB52) was indicated as a major source for surface seawater pollution.

  10. An evaluation of the North Sea circulation in global and regional models relevant for ecosystem simulations

    Science.gov (United States)

    Pätsch, Johannes; Burchard, Hans; Dieterich, Christian; Gräwe, Ulf; Gröger, Matthias; Mathis, Moritz; Kapitza, Hartmut; Bersch, Manfred; Moll, Andreas; Pohlmann, Thomas; Su, Jian; Ho-Hagemann, Ha T. M.; Schulz, Achim; Elizalde, Alberto; Eden, Carsten

    2017-08-01

    Simulations of the North Sea circulation by the global ocean model MPI-OM and the regional ocean models GETM, HAMSOM, NEMO, TRIM are compared against each other and with observational data for the period 1998-2009. The aim of the study is to evaluate the quality of the simulations in particular with respect to their suitability to drive biogeochemical shelf sea models. Our results demonstrate the benefit of the global model to avoid the specification of lateral open boundary conditions. Due to its stretched grid configuration, which provides a higher grid resolution at the Northwest European Shelf, the global model is able to reproduce the large-scale features, such as the water mass distribution and the thermal stratification in the central and northern North Sea, qualitatively similar to the regional models. The simulation of temperature and salinity near the coast however, shows large biases in almost all models because of the coarse meteorological forcing and too coarse vertical resolutions. The simulation of the Baltic Sea exchange and the spread of freshwater along the Norwegian coast proved difficult for all models except GETM, which reproduces impacts of the Baltic Sea outflow reasonably well.

  11. Towards harmonised assessment and classification of "biodiversity status" in the North Sea eco-region

    DEFF Research Database (Denmark)

    Skov, H.; Andersen, Jesper; Vinther, M.

    As one of the milestones in the HARMONY-project a demonstration of the application of the integrative indicator based biodiversity assessment tool (BEAT) was undertaken for the Greater North Sea sub-region across a range of coastal and offshore areas. The first version of the BEAT tool was applie......, the lack of a rigorous statistical approach and a balanced representation of different ecosystem components/food web categories....

  12. Sensitivity of modeled atmospheric nitrogen species and nitrogen deposition to variations in sea salt emissions in the North Sea and Baltic Sea regions

    Science.gov (United States)

    Neumann, Daniel; Matthias, Volker; Bieser, Johannes; Aulinger, Armin; Quante, Markus

    2016-03-01

    Coarse sea salt particles are emitted ubiquitously from the ocean surface by wave-breaking and bubble-bursting processes. These particles impact the atmospheric chemistry by affecting the condensation of gas-phase species and, thus, indirectly the nucleation of new fine particles, particularly in regions with significant air pollution. In this study, atmospheric particle concentrations are modeled for the North Sea and Baltic Sea regions in northwestern Europe using the Community Multiscale Air Quality (CMAQ) modeling system and are compared to European Monitoring and Evaluation Programme (EMEP) measurement data. The sea salt emission module is extended by a salinity-dependent scaling of the sea salt emissions because the salinity in large parts of the Baltic Sea is very low, which leads to considerably lower sea salt mass emissions compared to other oceanic regions. The resulting improvement in predicted sea salt concentrations is assessed. The contribution of surf zone emissions is considered separately. Additionally, the impacts of sea salt particles on atmospheric nitrate and ammonium concentrations and on nitrogen deposition are evaluated. The comparisons with observational data show that sea salt concentrations are commonly overestimated at coastal stations and partly underestimated farther inland. The introduced salinity scaling improves the predicted Baltic Sea sea salt concentrations considerably. The dates of measured peak concentrations are appropriately reproduced by the model. The impact of surf zone emissions is negligible in both seas. Nevertheless, they might be relevant because surf zone emissions were cut at an upper threshold in this study. Deactivating sea salt leads to minor increases in NH3 + NH4+ and HNO3 + NO3- and a decrease in NO3- concentrations. However, the overall effect on NH3 + NH4+ and HNO3 + NO3- concentrations is smaller than the deviation from the measurements. Nitrogen wet deposition is underestimated by the model at most

  13. Report of the Regional Co-ordination Meeting for the North Sea and Eastern Arctic (RCM NS&EA) 2014

    OpenAIRE

    Armstrong, M.; van Beek, F; DALSKOV J.; Elliott, M; Elson, J.; Griuniene, V. (Vilda); M. Hansson; Janakakis, M. (Marta); Kjems-Nilsen, H. (Henrik); Knapp, A. (Amelie); Kunzlik, P. (Phil); Lorenzo-González, J. (José); Mahe, K (Kelig); Morgado, C.; Nimmegeers, S.

    2014-01-01

    Report of the Regional Co-ordination Meeting for the North Sea and Eastern Arctic (RCM NS&EA) 2014 Swedish University of Agriculture Sciences (SLU Aqua) Lysekil, Sweden 08-12 September 2014 The RCM NS&EA met in Lysekil (Sweden) between 8-12 September 2014. The main purpose of the RCM is coordinate the National Programmes (NP) of the Member States (MS) in the North Sea region for 2015.

  14. Aspects of Remote Sensing in the GEOid and Sea level Of the North Atlantic Region (GEOSONAR) Project

    DEFF Research Database (Denmark)

    Hilger, Klaus Baggesen; Nielsen, Allan Aasbjerg; Knudsen, Per

    1999-01-01

    The general objectives of the GEOid and Sea level Of the North Atlantic Region (GEOSONAR) project are presented. These include analyses of the dynamics of the ocean and its characteristics. The analyses are mainly based on remote sensing. As an example a data set obtained by the multi-channel Sea...

  15. Regional carbon and CO2 budgets of North Sea tidal estuaries

    Science.gov (United States)

    Volta, C.; Laruelle, G. G.; Regnier, P.

    2016-07-01

    This study presents the first regional application of the generic estuarine reactive-transport model C-GEM (Carbon-Generic Estuary Model) that is here combined with high-resolution databases to produce a carbon and CO2 budget for all tidal estuaries discharging into the North Sea. Steady-state simulations are performed for yearly-averaged conditions to quantify the carbon processing in the six main tidal estuaries Elbe, Ems, Humber, Scheldt, Thames, and Weser, which show contrasted physical and biogeochemical dynamics and contribute the most to the regional filter. The processing rates derived from these simulations are then extrapolated to the riverine carbon loads of all the other North Sea catchments intercepted by smaller tidal estuarine systems. The Rhine-Meuse estuarine system is also included in the carbon budget and overall, we calculate that the export of organic and inorganic carbon from tidal estuaries to the North sea amounts to 44 and 409 Gmol C yr-1, respectively, while 41 Gmol C are lost annually through CO2 outgassing. The carbon is mostly exported from the estuaries in its inorganic form (>90%), a result that reflects the low organic/inorganic carbon ratio of the riverine waters, as well as the very intense decomposition of organic carbon within the estuarine systems. Our calculations also reveal that with a filtering capacity of 15% for total carbon, the contribution of estuaries to the CO2 outgassing is relatively small. Organic carbon dynamics is dominated by heterotrophic degradation, which also represents the most important contribution to the estuarine CO2 evasion. Nitrification only plays a marginal role in the CO2 dynamics, while the contribution of riverine oversaturated waters to the CO2 outgassing is generally significant and strongly varies across systems.

  16. Assessment of a zoomed global model for the North Sea by comparison with a conventional nested regional model

    Directory of Open Access Journals (Sweden)

    Jian Su

    2014-07-01

    Full Text Available Assessment of marine downscaling of global model simulations to the regional scale is a prerequisite for understanding ocean feedback to the atmosphere in regional climate downscaling. Major difficulties arise from the coarse grid resolution of global models, which cannot provide sufficiently accurate boundary values for the regional model. In this study, we first setup a stretched global model (MPIOM to focus on the North Sea by shifting poles. Second, a regional model (HAMSOM was performed with higher resolution, while the open boundary values were provided by the stretched global model. In general, the sea surface temperatures (SSTs in the two experiments are similar. Major SST differences are found in coastal regions (root mean square difference of SST is reaching up to 2°C. The higher sea surface salinity in coastal regions in the global model indicates the general limitation of this global model and its configuration (surface layer thickness is 16 m. By comparison, the advantage of the absence of open lateral boundaries in the global model can be demonstrated, in particular for the transition region between the North Sea and Baltic Sea. On long timescales, the North Atlantic Current (NAC inflow through the northern boundary correlates well between both model simulations (R~0.9. After downscaling with HAMSOM, the NAC inflow through the northern boundary decreases by ~10%, but the circulation in the Skagerrak is stronger in HAMSOM. The circulation patterns of both models are similar in the northern North Sea. The comparison suggests that the stretched global model system is a suitable tool for long-term free climate model simulations, and the only limitations occur in coastal regions. Regarding the regional studies focusing on the coastal zone, nested regional model can be a helpful alternative.

  17. GHRSST Level 4 DMI_OI North Sea and Baltic Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis by the Danish...

  18. Regional Evaluation of ERA-40 Reanalysis Data with Marine Atmospheric Observations in the North Sea Area

    Directory of Open Access Journals (Sweden)

    Nils H. Schade

    2013-12-01

    Full Text Available An important task of the departmental research programme KLIWAS is the evaluation and assessment of climate model results by means of a comprehensive reference data set. For validation purposes, and to create a North Sea wide maritime atmospheric and oceanographic reference database, in-situ observations of the Centre for Global Marine Meteorological Observations (GZS of the National Meteorological Service DWD have been compared to the ERA-40 reanalysis. ERA-40 is used as forcing for the hindcast runs of the ENSEMBLES regional climate models, which is used within the KLIWAS model chain. The GZS hosts a regularly updated, quality controlled, world-wide data bank of weather observations from the oceans. It includes data from all sorts of observation platforms as Voluntary Observing Ships (VOS, drifting and moored buoys, light vessels, and offshore platforms, either from real-time (RT via the Global Telecommunication System (GTS or from international exchange in delayed-mode (DM. In addition to the automated set of programs applied for high quality control, erroneous data are also manually corrected to a certain extent, if possible. To assure reliable statistics for the evaluation, the corrected observations are gridded to a resolution of 2.25 degree, so each grid box includes four ERA-40 reanalysis grid points. The temporal coverage of the grid boxes depends on shipping routes and the positions of automated systems. Observed air temperatures, covering a period of 40 years (1961?2000, show noticeable differences to the reanalysis data for all land influenced boxes, specifically in the winter months. The same differences can be found if ERA-40 data alone are compared between land- and sea facing boxes. They can not be found in GZS data. It can be assumed that the differences are not resulting from measurement errors or uncertain fraction variabilities, since they are small during the winter months. A comparison of the differences basing on the 1981

  19. Cost and time models for the evaluation of intermodal chains by using short sea shipping in the North Sea Region: the Rosyth-Zeebrugge route

    DEFF Research Database (Denmark)

    Lopez, Alba Martínez; Kronbak, Jacob; Jiang, Liping

    2015-01-01

    This paper is framed in the context of the EU Interreg IVB North Sea Region project Food Port. In line with this project, this paper aims to define mathematically cost and time models able to provide realistic information about the performances of road haulage and of intermodal chains using short...

  20. GHRSST Level 3C North Atlantic Regional (NAR) subskin Sea Surface Temperature from SNPP/VIIRS (GDS V2) produced by OSI SAF (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A regional Group for High Resolution Sea Surface Temperature (GHRSST) Level 3 Collated (L3C) dataset for the North Atlantic Region (NAR) based on retrievals from the...

  1. Bio-optical characterization in an ultra-oligotrophic region: the North central Red Sea

    KAUST Repository

    Kheireddine, Malika

    2015-04-01

    Until recently, satellite-derived ocean color observations have been the only means of evaluating optical variability of the Red Sea. During a cruise in autumn 2014, we investigated the variability of Inherent Optical Properties (IOPs) in the North Central Red Sea (NCRS) with a particular focus on the particulate backscattering coefficient, bbp, and colored dissolved organic matter, CDOM, absorption. To our knowledge, these are some of the measurements of these properties in the Red Sea. The IOPs are derived from the concentration and physical properties of suspended particles in the ocean. They provide a simple description of the influence of these particles on the light within the water column. Bio-optical relationships found for ultra-oligotrophic waters of the six stations sampled significantly depart from the mean standard relationships provided for the global ocean, showing the peculiar character of the Red Sea. These optical anomalies relate to the specific biological and environmental conditions occurring in the Red Sea ecosystem. Specifically, the surface specific phytoplankton absorption coefficients are lower than the values predicted from the global relationships due to a high proportion of relatively large sized phytoplankton. Conversely, bbp values are much higher than the mean standard values for a given chlorophyll-a concentration, Chl a. This presumably results from the influence of highly refractive submicrometer particles of Saharan origin in the surface layer of the water column.

  2. Impact of marine mercury cycling on coastal atmospheric mercury concentrations in the North- and Baltic Sea region

    Directory of Open Access Journals (Sweden)

    Johannes Bieser

    2016-06-01

    Full Text Available Abstract The cycling of mercury between ocean and atmosphere is an important part of the global Hg cycle. Here we study the regional contribution of the air-sea exchange in the North- and Baltic Sea region. We use a newly developed coupled regional chemistry transport modeling (CTM system to determine the flux between atmosphere and ocean based on the meteorological model COSMO-CLM, the ocean-ecosystem model ECOSMO, the atmospheric CTM CMAQ and a newly developed module for mercury partitioning and speciation in the ocean (MECOSMO. The model was evaluated using atmospheric observations of gaseous elemental mercury (GEM, surface concentrations of dissolved gaseous mercury (DGM, and air-sea flux (ASF calculations based on observations made on seven cruises in the western and central Baltic Sea and three cruises in the North Sea performed between 1991 and 2006. It was shown that the model is in good agreement with observations: DGM (Normalized Mean Bias NMB=-0.27 N=413, ASF (NMB=-0.32, N=413, GEM (NMB=0.07, N=2359. Generally, the model was able to reproduce the seasonal DGM cycle with the best agreement during winter and autumn (NMBWinter=-0.26, NMBSpring=-0.41, NMBSummer=-0.29, NMBAutumn=-0.03. The modelled mercury evasion from the Baltic Sea ranged from 3400 to 4000 kg/a for the simulation period 1994–2007 which is on the lower end of previous estimates. Modelled atmospheric deposition, river inflow and air-sea exchange lead to an annual net Hg accumulation in the Baltic Sea of 500 to 1000 kg/a. For the North Sea the model calculates an annual mercury flux into the atmosphere between 5700 and 6000 kg/a. The mercury flux from the ocean influenced coastal atmospheric mercury concentrations. Running CMAQ coupled with the ocean model lead to better agreement with GEM observations. Directly at the coast GEM concentrations could be increased by up to 10% on annual average and observed peaks could be reproduced much better. At stations 100km downwind

  3. GHRSST Level 2P North Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-16 satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for HIgh Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) from the Advanced Very High Resolution Radiometer (AVHRR) on...

  4. GHRSST Level 3P North Atlantic Regional Subskin Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on NOAA-19 (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for HIgh Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) from the Advanced Very High Resolution Radiometer (AVHRR) on...

  5. GHRSST Level 3C North Atlantic Regional (NAR) subskin Sea Surface Temperature from Metop/AVHRR (GDS V2) produced by OSI SAF (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) derived from the Advanced Very High Resolution Radiometer...

  6. GHRSST Level 2P North Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-17 satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) from the Advanced Very High Resolution Radiometer (AVHRR) on...

  7. GHRSST Level 3C North Atlantic Regional Subskin Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on NOAA-19 (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) from the Advanced Very High Resolution Radiometer (AVHRR) on...

  8. GHRSST Level 2P North Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-18 satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for HIgh Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) from the Advanced Very High Resolution Radiometer (AVHRR) on...

  9. Investigating the effects of a summer storm on the North Sea stratification using a regional coupled ocean-atmosphere model

    Science.gov (United States)

    Gronholz, Alexandra; Gräwe, Ulf; Paul, André; Schulz, Michael

    2017-02-01

    The influence of a summer storm event in 2007 on the North Sea and its effects on the ocean stratification are investigated using a regional coupled ocean (Regional Ocean Modeling System, ROMS)-atmosphere (Weather Research & Forecasting model, WRF) modeling system. An analysis of potential energy anomaly (PEA, Φ) and its temporal development reveals that the loss of stratification due to the storm event is dominated by vertical mixing in almost the entire North Sea. For specific regions, however, a considerable contribution of depth-mean straining is observed. Vertical mixing is highly correlated with wind induced surface stresses. However, peak mixing values are observed in combination with incoming flood currents. Depending on the phase between winds and tides, the loss of stratification differs strongly over the North Sea. To study the effects of interactive ocean-atmosphere exchange, a fully coupled simulation is compared with two uncoupled ones for the same vertical mixing parameters to identify the impact of spatial resolution as well as of SST feedback. While the resulting new mixed layer depth after the storm event in the uncoupled simulation with lower spatial and temporal resolution of the surface forcing data can still be located in the euphotic zone, the coupled simulation is capable to mix the entire water column and the vertical mixing in the uncoupled simulation with higher resolution of the surface forcing data is strongly amplified. These differences might have notable implications for ecosystem modeling since it could determine the development of new phytoplankton blooms after the storm and for sediment modeling in terms of sediment mobilization. An investigation of restratification after the extreme event illustrates the persistent effect of this summer storm.

  10. RKU North Sea. Update on the regional consequence examination concerning the petroleum industry in the North Sea; RKU-Nordsjoeen. Oppdatering av regional konsekvensutredning for petroleumsvirksomhet i Nordsjoeen

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-12-15

    An overview over prognoses for oil and gas production and the emissions related to these activities is provided for the years 2005-2025. A description of the Norwegian Continental Shelf's ecosystem, environmental technology employed, and considerations regarding the petroleum industry's effect on the ecosystem are considered. Emissions to air, planned emissions to the sea and accident emissions and spills are treated, as well as other possible environmental effects. Consequences for fishery, cultural monuments and for the society in general are also examined (ml)

  11. The North Sea - A shelf sea in the Anthropocene

    Science.gov (United States)

    Emeis, Kay-Christian; van Beusekom, Justus; Callies, Ulrich; Ebinghaus, Ralf; Kannen, Andreas; Kraus, Gerd; Kröncke, Ingrid; Lenhart, Hermann; Lorkowski, Ina; Matthias, Volker; Möllmann, Christian; Pätsch, Johannes; Scharfe, Mirco; Thomas, Helmuth; Weisse, Ralf; Zorita, Eduardo

    2015-01-01

    Global and regional change clearly affects the structure and functioning of ecosystems in shelf seas. However, complex interactions within the shelf seas hinder the identification and unambiguous attribution of observed changes to drivers. These include variability in the climate system, in ocean dynamics, in biogeochemistry, and in shelf sea resource exploitation in the widest sense by societies. Observational time series are commonly too short, and resolution, integration time, and complexity of models are often insufficient to unravel natural variability from anthropogenic perturbation. The North Sea is a shelf sea of the North Atlantic and is impacted by virtually all global and regional developments. Natural variability (from interannual to multidecadal time scales) as response to forcing in the North Atlantic is overlain by global trends (sea level, temperature, acidification) and alternating phases of direct human impacts and attempts to remedy those. Human intervention started some 1000 years ago (diking and associated loss of wetlands), expanded to near-coastal parts in the industrial revolution of the mid-19th century (river management, waste disposal in rivers), and greatly accelerated in the mid-1950s (eutrophication, pollution, fisheries). The North Sea is now a heavily regulated shelf sea, yet societal goals (good environmental status versus increased uses), demands for benefits and policies diverge increasingly. Likely, the southern North Sea will be re-zoned as riparian countries dedicate increasing sea space for offshore wind energy generation - with uncertain consequences for the system's environmental status. We review available observational and model data (predominantly from the southeastern North Sea region) to identify and describe effects of natural variability, of secular changes, and of human impacts on the North Sea ecosystem, and outline developments in the next decades in response to environmental legislation, and in response to

  12. The north Sulu Sea productivity

    Science.gov (United States)

    Xiao, Z.

    2009-12-01

    The Sulu Sea is a part of the western North Pacific. It is a closed sea for its deep water and a semi-closed sea for its upper layer. The Sulu Sea exchanges mainly surface waters with the South China Sea and the Celebes Sea. The Sulu Sea is more productive than the adjacent South China Sea (Jones, 2002). On the basis of MERIS satellite observations from 2002 to 2008, we focus on the high-chlorophyll area as an indicator of the abundance of primary productivity in the Sulu Sea. Strong chlorophyll concentration in the north Sulu Sea close to the Mindoro Strait mainly occurs from December to March and low chlorophyll concentration happens in April to November. The adjacent South China Sea on the other side of Mindoro Strait has shown persistent signs of low chlorophyll concentration. Based on 1/8° Global Navy Coastal Ocean Model, the intrusion of the South China Sea waters through the Mindoro Strait to the Sulu Sea from April to November is the main reason for the low chlorophyll concentration observed in the north Sulu Sea. During April to November, the South China Sea waters flow through the Mindoro Strait and stay on the surface of the north Sulu Sea because of their low density. The north Sulu Sea waters mix with fresher waters coming from the South China Sea without new nutrients supply. When the inflow from South China Sea to Sulu Sea ceases in December to March, the upwelling due to the summer monsoon wind becomes an important mechanism supplying deep nutrients to the surface water which lead to high chlorophyll concentration. Jones, I.S.F., 2002. Primary production in the Sulu Sea. Proceedings of the Indian Academy of Sciences-Earth and Planetary Sciences 111, 209-213.

  13. GHRSST Level 4 MUR North America Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced as a retrospective dataset at the JPL Physical...

  14. Assessment of coastal vulnerability to climate change hazards at the regional scale: the case study of the North Adriatic Sea

    Directory of Open Access Journals (Sweden)

    S. Torresan

    2012-07-01

    Full Text Available Sea level rise, changes in storms and wave climate as a consequence of global climate change are expected to increase the size and magnitude of flooded and eroding coastal areas, thus having profound impacts on coastal communities and ecosystems. River deltas, beaches, estuaries and lagoons are considered particularly vulnerable to the adverse effects of climate change, which should be studied at the regional/local scale. This paper presents a regional vulnerability assessment (RVA methodology developed to analyse site-specific spatial information on coastal vulnerability to the envisaged effects of global climate change, and assist coastal communities in operational coastal management and conservation. The main aim of the RVA is to identify key vulnerable receptors (i.e. natural and human ecosystems in the considered region and localize vulnerable hot spot areas, which could be considered as homogeneous geographic sites for the definition of adaptation strategies. The application of the RVA methodology is based on a heterogeneous subset of bio-geophysical and socio-economic vulnerability indicators (e.g. coastal topography, geomorphology, presence and distribution of vegetation cover, location of artificial protection, which are a measure of the potential harm from a range of climate-related impacts (e.g. sea level rise inundation, storm surge flooding, coastal erosion. Based on a system of numerical weights and scores, the RVA provides relative vulnerability maps that allow to prioritize more vulnerable areas and targets of different climate-related impacts in the examined region and to support the identification of suitable areas for human settlements, infrastructures and economic activities, providing a basis for coastal zoning and land use planning. The implementation, performance and results of the methodology for the coastal area of the North Adriatic Sea (Italy are fully described in the paper.

  15. Absolute sea levels and isostatic changes of the eastern North Sea to central Baltic region during the last 900 years

    DEFF Research Database (Denmark)

    Hansen, Jens Morten; Aagaard, Troels; Binderup, Merete

    2012-01-01

    in the present sea-level rise may be part of this 70-year cyclicity, and that the non-anthropogenic sea-level rise between 1700 and 1790 seems faster than the present and projected sea-level rise for the 21st century. Moreover, the conspicuous sea-level fall at the beginning of the Little Ice Age confirms......Most studies of late Holocene sea-level changes generally assume stable tectonic conditions. However, unrecognized neotectonic ‘noise’, even the small rates of passive continental margins, can severely distort sea-level reconstructions of the late Holocene. The detailed sea-level curve proposed...... here is reconstructed by identification of an area (Læsø archipelago in the Kattegat Sea) where small neotectonic level changes and other kinds of ‘background noise’ can be precisely quantified by advanced LiDAR techniques. We show that the absolute (‘eustatic’) sea level of Kattegat has risen by 110...

  16. Plastic in North Sea Fish

    NARCIS (Netherlands)

    Foekema, E.M.; Gruijter, de C.; Mergia, M.T.; Franeker, van J.A.; Murk, A.J.; Koelmans, A.A.

    2013-01-01

    To quantify the occurrence of ingested plastic in fish species caught at different geographical positions in the North Sea, and to test whether the fish condition is affected by ingestion of plastics, 1203 individual fish of seven common North Sea species were investigated: herring, gray gurnard, wh

  17. Relative sea level in the South Alligator River Region, North Australia, during the Holocene

    Energy Technology Data Exchange (ETDEWEB)

    Woodroffe, C.D.; Thom, B.G.; Chappell, J.; Wallensky, E.; Grindrod, J.; Head, J.

    Mangrove sediments are indicators of former sea level. Radiocarbon dating of fragments of mangrove wood from the sediments of the South Alligator tidal river, van Diemen Gulf, Northern Territory, indicates that sea level rose rapidly during the Postglacial Marine Transgression until about 6800 years B.P., when it was within 5 m of its present level. This is somewhat later than results from northeast and southeast Australia, which show the sea reached its present level before 6000 B.P. Further, we find no evidence for falling sea level in the last 5000 years, which has been reported from eastern and southwestern sites.

  18. An atmosphere-wave regional coupled model: improving predictions of wave heights and surface winds in the southern North Sea

    Science.gov (United States)

    Wahle, Kathrin; Staneva, Joanna; Koch, Wolfgang; Fenoglio-Marc, Luciana; Ho-Hagemann, Ha T. M.; Stanev, Emil V.

    2017-04-01

    The coupling of models is a commonly used approach when addressing the complex interactions between different components of earth systems. We demonstrate that this approach can result in a reduction of errors in wave forecasting, especially in dynamically complicated coastal ocean areas, such as the southern part of the North Sea - the German Bight. Here, we study the effects of coupling of an atmospheric model (COSMO) and a wind wave model (WAM), which is enabled by implementing wave-induced drag in the atmospheric model. The numerical simulations use a regional North Sea coupled wave-atmosphere model as well as a nested-grid high-resolution German Bight wave model. Using one atmospheric and two wind wave models simultaneously allows for study of the individual and combined effects of two-way coupling and grid resolution. This approach proved to be particularly important under severe storm conditions as the German Bight is a very shallow and dynamically complex coastal area exposed to storm floods. The two-way coupling leads to a reduction of both surface wind speeds and simulated wave heights. In this study, the sensitivity of atmospheric parameters, such as wind speed and atmospheric pressure, to the wave-induced drag, in particular under storm conditions, and the impact of two-way coupling on the wave model performance, is quantified. Comparisons between data from in situ and satellite altimeter observations indicate that two-way coupling improves the simulation of wind and wave parameters of the model and justify its implementation for both operational and climate simulations.

  19. Regional variation of caesium-137 in minke whales ¤Balaenoptera acutorostrata¤ from West Greenland, the Northeast Atlantic and the North Sea

    DEFF Research Database (Denmark)

    Born, E.W.; Dahlgaard, H.; Riget, F.F.

    2002-01-01

    Levels of radioactive caesium (Cs-137) were determined in minke whales (Balaenoptera acutorostrata) from West Greenland, the Northeast Atlantic region and the North Sea. The sample consisted of muscle tissue from 135 minke whales caught in 1998 in 7 different areas: West Greenland, n = 44; East G...

  20. Estimating regional pore pressure distribution using 3D seismic velocities in the Dutch Central North Sea Graben

    NARCIS (Netherlands)

    Winthaegen, P.L.A.; Verweij, J.M.

    2003-01-01

    The application of the empirical Eaton method to calibrated sonic well information and 3D seismic interval velocity data in the southeastern part of the Central North Sea Graben, using the Japsen (Glob. Planet. Change 24 (2000) 189) normal velocitydepth trend, resulted in the identification of an

  1. Estimating regional pore pressure distribution using 3D seismic velocities in the Dutch Central North Sea Graben

    NARCIS (Netherlands)

    Winthaegen, P.L.A.; Verweij, J.M.

    2003-01-01

    The application of the empirical Eaton method to calibrated sonic well information and 3D seismic interval velocity data in the southeastern part of the Central North Sea Graben, using the Japsen (Glob. Planet. Change 24 (2000) 189) normal velocitydepth trend, resulted in the identification of an un

  2. Current Land Subsidence and Sea Level Rise along the North American Coastal Region: Observations from 10-Year (2005-2014) Closely-Spaced GPS and Tide Gauge Stations

    Science.gov (United States)

    Yang, L.; Yu, J.; Kearns, T.; Wang, G.

    2014-12-01

    Strong evidence has proved that the global sea-level is now rising at an increased rate and it is projected to continue to rise. However the rise of the sea-level is not uniform around the world. The local or relative sea-level rise will be of great concern to the coastal regions. The combination of the land subsidence and global sea-level rise causes the relative sea-level to rise. Relative sea-level rise increases the risk of flooding and wetland loss problems in near coastal areas, which in turn have important economic, environmental, and human health consequences for the heavily populated and ecologically important coastal region. However the role played by the coastal land subsidence is commonly absent during the discussion of sea-level rise problems. The sea-level can be measured in two ways: satellite altimetry and tide gauges. The sea-level measured by satellite is called the geocentric sea-level that is relative to earth center and the one measured by tide gauges is called local sea-level that is relative to the land. The tide gauge measurements of the local sea-level do not distinguish between whether the water is rising or the land is subsiding. In some coastal areas, land subsidence is occurring at a higher rate than the geocentric sea-level is rising. This can have a great local effect. GPS technology has proven to be efficient and accurate for measuring and tracking absolute land elevation change. There are about 300 publically available Continuously Operating Reference GPS Stations (CORS) within 15 km from the coastal line along North America. In this study, we use publicly available long-history (> 5 years) CORS data to derive current (2005-2014) coastal subsidence in North America. Absolute coastal sea-level rise will be determined by combing the land subsidence and relative sea-level measurements. This study shows that the relative sea-level of the Alaska area appears to be falling because the land is uplifting; this study also shows that the

  3. An Analysis on Stability and Deposition Zones of Natural Gas Hydrate in Dongsha Region, North of South China Sea

    Directory of Open Access Journals (Sweden)

    Zuan Chen

    2010-01-01

    Full Text Available We propose several physical/chemical causes to support the seismic results which find presence of Bottom Simulating Reflector (BSR at site 1144 and site 1148 in Dongsha Region, North of South China Sea. At site 1144, according to geothermal gradient, the bottom of stability zone of conduction mode is in agreement with BSR. At site 1148, however, the stability zone of conduction mode is smaller than the natural gas presence zone predicted by the BSR. We propose three causes, that is, mixed convection and conduction thermal flow mode, multiple composition of natural gas and overpressure in deep sediment to explain the BSR presence or gas hydrate presence. Further, our numerical simulation results suggest yet another reason for the presence of BSR at site 1144 and site 1148. Because the temperatures in deep sediment calculated from the mixed convection and conduction thermal flow mode are lower than that from the single conduction mode, the bottom of gas hydrate stability zone (GHSZ is deeper than the bottom of gas hydrate deposition zone (GHDZ or BSR. The result indicates that occurrence zone of natural is decided by the condition that natural gas concentrate in the zone is greater than its solubility.

  4. CCS in the North Sea region: A comparison on the cost-effectiveness of storing CO2 in the Utsira formation at regional and national scales

    DEFF Research Database (Denmark)

    Strachan, N.; Hoefnagels, R.; Ramirez, A.

    2011-01-01

    The potential scale of carbon dioxide capture and storage (CCS) under long-term decarbonisation scenarios means that analysis on the contribution of large international CO2 storage reservoirs is critical. This paper compares the potentially key role of CCS within cost-optimizing energy systems...... modelling at the national level (ensuring country-specific technical, economic and policy detail), and the regional level (ensuring transboundary electricity and CO2 trade). Analysis at alternate model scales investigates the full range of drivers on the feasibility and trade-offs in using the Utsira...... formation as a common North Sea CO2 storage resource. A robust finding is that low carbon electricity is a primary decarbonisation pathway and that CCS plays a key role (32–40%) within this portfolio. This paper confirms that the overall driver of the amount of CCS utilized is the climate policy...

  5. Deposition of nitrogen into the North Sea

    DEFF Research Database (Denmark)

    Leeuw, G. de; Skjøth, C.A.; Hertel, O.;

    2003-01-01

    The flux of nitrogen species from the atmosphere into the ocean, with emphasis on coastal waters, was addressed during the ANICE project (Atmospheric Nitrogen Inputs into the Coastal Ecosystem). ANICE focused on quantifying the deposition of atmospheric inputs of inorganic nitrogen compounds (HNO3......, NO3-, NH3 and NH4+) into the North Sea and the processes governing this deposition. The Southern North Sea was studied as a prototype. Because the physical and chemical processes are described, as opposed to empirical relations, the results can potentially be transferred to other regional seas like...... the Mediterranean, the North Atlantic continental shelf area and the Baltic. Two intensive field experiments were undertaken, centred around the offshore tower Meetpost Noordwijk and the Weybourne Atmospheric Observatory in East Anglia (UK). Long-term measurements were made on a ferry sailing between Hamburg...

  6. Sedimentary and water column processes in the Oyster Grounds: a potentially hypoxic region of the North Sea.

    Science.gov (United States)

    Weston, K; Fernand, L; Nicholls, J; Marca-Bell, A; Mills, D; Sivyer, D; Trimmer, M

    2008-04-01

    The purpose of this research was to investigate the potential causes of low oxygen levels in the bottom water of the Oyster Grounds region of the shallow southern North Sea, an area which provides suitable conditions for low oxygen levels to develop. At the end of the summer stratified period, relevant biogeochemical processes were investigated using a combination of sedimentary and water column rate measurements. Phytoplankton nitrate and ammonium uptake was measured throughout the water column using (15)N labelled isotopes and showed ammonium uptake dominated in the upper and bottom mixed layer with a maximum 294.4 micromol N m(-3)h(-1). In the deep chlorophyll maximum at the thermocline, primary production was dominated by nitrate uptake, with an average of 35.0 micromol N m(-3)h(-1), relative to ammonium uptake, with an average of 24.6 micromol N m(-3)h(-1). This high relative nitrate uptake will in part result in exportable new production to the isolated bottom mixed layer and sediments, as opposed to regenerated ammonium driven uptake. This biomass export was indicated by significant benthic oxygen consumption rates in the stratified region (782-1275 micromol O(2)m(-2)h(-1)micromol N m(-3)h(-1)) long after the end of the spring bloom. The sediments were also an active net source of nitrate, ammonium, phosphate and silicate into the bottom mixed layer of 4.4, 8.4, 2.3 and 68.8 micromol m(-2)h(-1), respectively. The export of new production within the thermocline to the bottom mixed layer and the consequent sediment oxygen consumption in the isolated bottom mixed layer in the Oyster Grounds are expected to have contributed to the low bottom water oxygen concentrations of 2.07 mg l(-1) (64.7 micromol l(-1)) measured. The long stratified period associated with this low oxygen is predicted to occur more regularly in the future and continued monitoring of this ecologically important region is therefore essential if the causes of these potentially damaging low

  7. A synthesis of Cenozoic sedimentation in the North Sea

    DEFF Research Database (Denmark)

    Anell, Ingrid Anna Margareta; Thybo, Hans; Rasmussen, E.S.

    2012-01-01

    margins have undergone. While the North Sea has been mapped locally, we present the first regional mapping of the Cenozoic sedimentary strata. Our study provides a new regional sub-division of the main seismic units in the North Sea together with maps of depocentres, influx direction and source areas. Our......The North Sea Basin contains an almost complete record of Cenozoic sedimentation, separated by clear regional unconformities. The changes in sediment characteristics, rate and source, and expression of the unconformities reflect the tectonic, eustatic and climatic changes that the North Sea and its...... characteristics of many unconformities indicate that they were generated by eustatic sea-level fall, often in conjunction with other processes. Early Cenozoic unconformities, however, relate to tectonism associated with the opening of the North Atlantic. From observation on a regional scale, we infer...

  8. Importance of geographic origin for invasion success: A case study of the North and Baltic Seas versus the Great Lakes-St. Lawrence River region.

    Science.gov (United States)

    Casties, Isabel; Seebens, Hanno; Briski, Elizabeta

    2016-11-01

    Recently, several studies indicated that species from the Ponto-Caspian region may be evolutionarily predisposed to become nonindigenous species (NIS); however, origin of NIS established in different regions has rarely been compared to confirm these statements. More importantly, if species from certain area/s are proven to be better colonizers, management strategies to control transport vectors coming from those areas must be more stringent, as prevention of new introductions is a cheaper and more effective strategy than eradication or control of established NIS populations. To determine whether species evolved in certain areas have inherent advantages over other species in colonizing new habitats, we explored NIS established in the North and Baltic Seas and Great Lakes-St. Lawrence River regions-two areas intensively studied in concern to NIS, highly invaded by Ponto-Caspian species and with different salinity patterns (marine vs. freshwater). We compared observed numbers of NIS in these two regions to expected numbers of NIS from major donor regions. The expected numbers were calculated based on the available species pool from donor regions, frequency of shipping transit, and an environmental match between donor and recipient regions. A total of 281 NIS established in the North and Baltic Seas and 188 in the Great Lakes-St. Lawrence River. Ponto-Caspian taxa colonized both types of habitats, saltwater areas of the North and Baltic Seas and freshwater of the Great Lakes-St. Lawrence River, in much higher numbers than expected. Propagule pressure (i.e., number of introduced individuals or introduction effort) is of great importance for establishment success of NIS; however in our study, either shipping vector or environmental match between regions did not clarify the high numbers of Ponto-Caspian taxa in our study areas. Although we cannot exclude the influence of other transport vectors, our findings suggest that the origin of the species plays an important role

  9. Air-sea exchange studies at the North Sea

    NARCIS (Netherlands)

    Leeuw, G. de; Eijk, A.M.J. van; Kunz, G.J.; Veefkind, P.J.

    1996-01-01

    The North Sea can be considered as a local 'inner' sea in which many processes are quite different from these over the open ocean. The surrounding land has a major influence, being the source for man-made aerosols and gases, whereas the North Sea acts as a sink for these. At the same time the North

  10. GHRSST Level 3P North Atlantic Regional Subskin Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the MetOp-A satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for HIgh Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) from the Advanced Very High Resolution Radiometer (AVHRR) on...

  11. GHRSST Level 3C North Atlantic Regional (NAR) subskin Sea Surface Temperature from SNPP/VIIRS and Metop-A/AVHRR (GDS V2) produced by OSI SAF (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) derived from the Advanced Very High Resolution Radiometer...

  12. Impact of the North Atlantic circulation on the climate change patterns of North Sea.

    Science.gov (United States)

    Narayan, Nikesh; Mathis, Mortiz; Klein, Birgit; Klein, Holger; Mikolajewicz, Uwe

    2017-04-01

    The physical properties of the North Sea are characterized by the exchange of water masses with the North Atlantic at the northern boundary and Baltic Sea to the east. The combined effects of localized forcing, tidal mixing and advection of water masses make the North Sea a challenging study area. Previous investigations indicated a possibility that the variability of the North Atlantic circulation and the strength of the sub-polar gyre (SPG) might influence the physical properties of the North Sea. The assessment of the complex interaction between the North Atlantic and the North Sea in a climate change scenario requires regionally coupled global RCP simulations with enhanced resolution of the North Sea and the North Atlantic. In this study we analyzed result from the regionally coupled ocean-atmosphere-biogeochemistry model system (MPIOM-REMO-HAMOCC) with a hydrodynamic (HD) model. The ocean model has a zoomed grid which provides the highest resolution over the West European Shelf by shifting its poles over Chicago and Central Europe. An index for the intensity of SPG was estimated by averaging the barotropic stream function (ψ) over the North Atlantic. Various threshold values for ψ were tested to define the strength of the SPG. These SPG indices have been correlated with North Sea hydrographic parameters at various levels to identify areas affected by SPG variability. The influence of the Atlantic's eastern boundary current, contributing more saline waters to the North West European shelf area is also investigated.

  13. Sea Surface Temperature Climate Data Record for the North Sea and Baltic Sea

    DEFF Research Database (Denmark)

    Høyer, Jacob L.; Karagali, Ioanna

    2016-01-01

    A 30-yr climate data record (CDR) of sea surface temperature (SST) has been produced with daily gap-free analysis fields for the North Sea and the Baltic Sea region from 1982 to 2012 by combining the Pathfinder AVHRR satellite data record with the Along-Track Scanning Radiometer (ATSR) Reprocessing...... observations on average. Validation against independent in situ observations shows a very stable performance of the data record, with a mean difference of -0.06 °C compared to moored buoys and a 0.46 °C standard deviation of the differences. The mean annual biases of the SST CDR are small for all years......, with a negligible temporal trend when compared against drifting and moored buoys. Analysis of the SST CDR reveals that the monthly anomalies for the North Sea, the Danish straits, and the central Baltic Sea regions show a high degree of correlation for interannual and decadal time scales, whereas the monthly...

  14. North American Regional Report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-11-15

    North America is an energy community fortunate to be endowed with a rich and varied resource base. It consumes about a third of the world's energy and produces about one quarter of world energy supply. North America depends on a mix of complementary energy sources that should remain competitive but not in conflict. The current supply mix varies between Canada, the United States and Mexico, but fossil fuels are dominant across the region, leaving the three member countries vulnerable to a myriad of risks associated with traditional supply sources. Energy trade between all three countries is also a major contributor to the region's economy. Thus, the impetus for collaboration across the region has grown out of the common goals of energy security and economic prosperity. The goal of the WEC regional group was to discuss avenues for advancing North American cooperation and coordination on a range of energy issues. An additional objective was to develop policy recommendations that will facilitate effective development and use of the region's energy resources. Results and recommendtaions are summarized from three forums that focused on the pertinent issues of energy trade, energy efficiency and energy diversification. The inaugural forum (Energy Trade) was held in Washington, D.C. in the fall of 2005. The following summer, the second forum (Energy Efficiency) took place in Mexico City. The third forum (Energy Diversification) was hosted in Halifax, Nova Scotia.

  15. The Role of CO2-EOR for the Development of a CCTS Infrastructure in the North Sea Region: A Techno-Economic Model and Application

    OpenAIRE

    Mendelevitch, Roman

    2013-01-01

    Scenarios of future energy systems attribute an important role to Carbon Capture, Transport, and Storage (CCTS) in achieving emission reductions. Using captured CO2 for enhanced oil recovery (CO2-EOR) can improve the economics of the technology. This paper examines the potential for CO2-EOR in the North Sea region. UK oil fields are found to account for 47% of the estimated additional recovery potential of 3739 Mbbl (1234 MtCO2 of storage potential). Danish and Norwegian fields add 28% and 25...

  16. 15/9 Gamma gas field offshore Norway, new trap type for North Sea basin with regional structural implications

    Energy Technology Data Exchange (ETDEWEB)

    Pegrum, R.M.; Ljones, T.E.

    1984-07-01

    The 15/9 Gamma gas field lies in the central North Sea midway between Norway and the United Kingdom. The field was discovered in 1981 and, by mid-1982, 3 additional confirmation wells had been completed. The reservoir is provided by a complex of Paleocene submarine-fan sandstones. The sandstones decrease in thickness across the field from 150 m (492 ft) in the northwest to less than 50 m (164 ft) in the southeast. The sandstones pinch out entirely a few kilometers beyond the field. The volume of gas in place is on the order of 65 X 10/sup 9/ m/sup 3/ (2.3 tcf). The trap in the Paleocene sandstones is interpreted as being formed by a mid-Tertiary compressive phase which reactivated preexisting basement faults. Detailed structural analysis suggests that WNW-ESE-trending faults have suffered repeated strike-slip offset associated with Jurassic transtension and mid-Cretaceous and middle Tertiary transpression. The writers suggest that the WNW-ESEtrending basement faults represent a northwestward continuation of the Tornquist line, a fundamental fracture zone bounding the East European-Scandinavian platform, which had previously been considered as terminating at the line of the Oslo graben, about 250 km (155 mi) to the southeast.

  17. GHRSST Level 4 RTO Terra MODIS-AMSRE Day North America Regional Blended Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the JPL Physical...

  18. GHRSST Level 4 RTO Aqua MODIS-AMSRE Night North America Regional Blended Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the JPL Physical...

  19. GHRSST Level 4 RTO Terra MODIS-AMSRE Night North America Regional Blended Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the JPL Physical...

  20. GHRSST Level 4 RTO Aqua MODIS-AMSRE Day North America Regional Blended Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the JPL Physical...

  1. GHRSST Level 4 ODYSSEA North-Western Europe Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at Ifremer/CERSAT...

  2. Ecology of North Sea fish

    Science.gov (United States)

    Daan, N.; Bromley, P. J.; Hislop, J. R. G.; Nielsen, N. A.

    Fishes of the North Sea include over 200 species exhibiting widely differing ecological characteristics. There is a wealth of literature and, in this paper, we have restricted ourselves to providing generalized data on the more abundant species, with a view of highlighting those aspects which link the total fish community to the biotic and abiotic environment. There is necessarily a bias towards commercial species, because most of the pertinent information is related specifically to fish which are heavily fished. However, since there are few abundant species which are not exploited, the ecological links of the total fish community to other components of the system are well represented by the selection. Moreover, exploitation of the fish community may have indirectly affected the ecological relationships in the entire system. It follows that an understandinf of the impact of fisheries on the fish community is likely to play a key role in helping us to understand how the North Sea ecosystem functions. The paper highlights various ecological aspects of the fish fauna including population dynamics, spawning in time and space, distribution, variations in year class strength, feeding, density-dependent growth and changes in species composition. Despite long time series of quantitative biological information for individual species and the obvious impact of fisheries on longevity and productivity of the fish community, the general conclusion is that it remains very difficult to separate effects of fisheries and of the environment on reproductive success, in which the variation is the most important destabilizing factor in the regulation of exploited fish populations. Another conclusion is that the spatial heterogeneity of the fish community in the North Sea is a factor of considerable concern in trying to link fish production to other components. It would seem likely that, to improve our understanding of the ecological linkages in the entire system, the spatial differences

  3. Phytoplankton Bloom in North Sea off Scotland

    Science.gov (United States)

    2008-01-01

    The northern and western highlands of Scotland were still winter-brown and even dusted with snow in places, but the waters of the North Sea were blooming with phytoplankton on May 8, 2008, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite passed over the region and captured this image. The tiny, plant-like organisms swirled in the waters off the country's east coast, coloring the shallow coastal waters shades of bright blue and green. Phytoplankton are tiny organisms--many are just a single cell--that use chlorophyll and other pigments to capture light for photosynthesis. Because these pigments absorb sunlight, they change the color of the light reflected from the sea surface back to the satellite. Scientists have used observations of 'ocean color' from satellites for more than 20 years to track worldwide patterns in phytoplankton blooms. Phytoplankton are important to the Earth system for a host of reasons, including their status as the base of the ocean food web. In the North Sea, they are the base of the food web that supports Scotland's commercial fisheries, including monkfish and herring. As photosynthesizers, they also play a crucial role in the carbon cycle, removing carbon dioxide from the atmosphere. Some oceanographers are concerned that rising ocean temperatures will slow phytoplankton growth rates, harming marine ecosystems and causing carbon dioxide to accumulate more rapidly in the atmosphere.

  4. Alba is first heavy North Sea crude

    Energy Technology Data Exchange (ETDEWEB)

    1991-05-27

    The development of the Alba oil field will constitute two North Sea firsts: the first Eocene reservoir developed, and the first development to handle heavy crude. The field was discovered in Block 16/26 of the North Sea's U.K. sector in 1984. The Alba field is in the heart of the North Sea, about midway between the northern fields of the East Shetlands basin and the southern Fulmar and Argyll fields. About 250 million bbl of the estimated 1 billion bbl reservoir of 20{degrees} gravity crude is believed recoverable.

  5. An evaluation of satellite and in situ based sea surface temperature datasets in the North Indian Ocean region

    Digital Repository Service at National Institute of Oceanography (India)

    Sreejith, O.P.; Shenoi, S.S.C.

    measurements obtained from several drifting buoys and a moored buoy in the north Indian Ocean. The mean difference (bias) and scatter (root mean square deviation (RMSD)) were higher than the ideally expected values of less than 0.01 degrees C and 0.5 degrees C...

  6. Regional Risk Assessment for the analysis of the risks related to storm surge extreme events in the coastal area of the North Adriatic Sea.

    Science.gov (United States)

    Rizzi, Jonathan; Torresan, Silvia; Gallina, Valentina; Critto, Andrea; Marcomini, Antonio

    2013-04-01

    Europe's coast faces a variety of climate change threats from extreme high tides, storm surges and rising sea levels. In particular, it is very likely that mean sea level rise will contribute to upward trends in extreme coastal high water levels, thus posing higher risks to coastal locations currently experiencing coastal erosion and inundation processes. In 2007 the European Commission approved the Flood Directive (2007/60/EC), which has the main purpose to establish a framework for the assessment and management of flood risks for inland and coastal areas, thus reducing the adverse consequences for human health, the environment, cultural heritage and economic activities. Improvements in scientific understanding are thus needed to inform decision-making about the best strategies for mitigating and managing storm surge risks in coastal areas. The CLIMDAT project is aimed at improving the understanding of the risks related to extreme storm surge events in the coastal area of the North Adriatic Sea (Italy), considering potential climate change scenarios. The project implements a Regional Risk Assessment (RRA) methodology developed in the FP7 KULTURisk project for the assessment of physical/environmental impacts posed by flood hazards and employs the DEcision support SYstem for Coastal climate change impact assessment (DESYCO) for the application of the methodology to the case study area. The proposed RRA methodology is aimed at the identification and prioritization of targets and areas at risk from water-related natural hazards in the considered region at the meso-scale. To this aim, it integrates information about extreme storm surges with bio-geophysical and socio-economic information (e.g. vegetation cover, slope, soil type, population density) of the analyzed receptors (i.e. people, economic activities, cultural heritages, natural and semi-natural systems). Extreme storm surge hazard scenarios are defined using tide gauge time series coming from 28 tide gauge

  7. Well data summary sheets. Vol. 19. Danish North Sea and Baltic Sea

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    This nineteenth volume of Well Data Summary Sheets includes data from two North Sea wells: Gulnare-1, Eg-1 and one well from the Baltic Sea: Stina-1. Minor corrections have been made since the first edition. The `Complete index of released wells` had been updated. Volume 27, 28 and 29 are regional volumes; volume 27 includes well data from Southern Jutland; volumes 28 and 29 cover well data from Northern Jutland. All data from released Danish North Sea wells are included in volumes 17-26 and 30. Data references are made to the revised volumes and not to the original published reference. (au)

  8. Well data summary sheets. Vol. 18. Danish North Sea

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    This eighteenth volume of Well Data Summary Sheets includes data from five North Sea wells: Jeppe-1, Ravn-2, Gert-3, Elly-2, N-22/22A (Deep Gorm). Minor corrections have been made since the first edition. The `Complete index of released wells` has been updated. Volume 27, 28 and 29 are regional volumes; volume 27 includes well data from Southern Jutland; volume 28 and 29 cover well data from Northern Jutland. All data from released Danish North Sea wells are included in volumes 17-26 and 30. Data references are made to the revised volumes and not to the original published reference. (au)

  9. Decadal fluctuations in North Atlantic water inflow in the North Sea between 1958-2003: impacts on temperature and phytoplankton populations

    Directory of Open Access Journals (Sweden)

    Martin J. Attrill

    2008-03-01

    Full Text Available The circulation of Atlantic water along the European continental slope, in particular the inflow into the North Sea, influences North Sea water characteristics with consequent changes in the environment affecting plankton community dynamics. The long-term effect of fluctuating oceanographic conditions on the North Sea pelagic ecosystem is assessed. It is shown that (i there are similar regime shifts in the inflow through the northern North Sea and in Sea Surface Temperature, (ii long-term phytoplankton trends are influenced by the inflow only in some North Sea regions, and (iii the spatial variability in chemicophysical and biological parameters highlight the influence of smaller scale processes.

  10. Temporal Variation of Iodine Isotopes in the North Sea

    DEFF Research Database (Denmark)

    He, Peng; Aldahan, Ala; Possnert, Göran;

    2014-01-01

    Monitoring temporal variability of 129I in the North Sea, a relatively large reservoir of radioactive discharges from the nuclear fuel reprocessing facilities, is vital for the environmental situation in the region. New information on concentration levels and distribution of 129I and 127I and the...

  11. Geology of the North Sea and Skagerrak

    Energy Technology Data Exchange (ETDEWEB)

    Michelsen, O. [ed.

    1995-12-31

    The Marine Geology Unit of the Department of Earth Sciences organized the second Marine Geology symposium at Aarhus University, 7-8 October 1993. The intention was to bring together people working especially with the geology of the North Sea and Skagerrak. Approximately 60 people from different Danish and Norwegian institutions attended the symposium. 28 oral presentations were given and 2 posters presented. A large range of geological topics was covered, embracing biostratigraphy, sequence stratigraphy, sedimentology and structural geology. The majority of the presentations dealt with Quaternary geology and Cenozoic sequence stratigraphy, but also Jurassic and Lower Cretaceous stratigraphy was treated. Studies from the major part of the Danish sector were presented, spanning from Bornholm to the central North Sea, and further into the Norwegian North Sea sector. (au)

  12. Well data summary sheets. Vol. 30. North Sea wells

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    This thirtieth volume of the `Well Data Summary sheets` includes data from three recently released offshore wells from the North Sea. The two wells Amalie-1/1A and Skarv-1 are situated in the Danish Central Graben area. The Ida-1 well is one of a number of Danish North Sea wells situated outside the Central Graben (se also Volume 25). Minor corrections have been made since the first edition. The `Complete index of released wells` had been updated. Volume 27, 28 and 29 are regional volumes; volume 27 includes well data from Southern Jutland; volumes 28 and 29 cover well data from Northern Jutland. All data from released Danish North Sea wells are included in volumes 17-26 and 30. Data references are made to the revised volumes and not to the original published reference. (au)

  13. Education challenges in the North Sea area.

    Science.gov (United States)

    Ducrotoy, Jean Paul

    2003-01-01

    This paper introduces the North Sea as a fast evolving coastal ecosystem. The variability of natural conditions relates to the global climatic change and to human disturbances, which originate regionally. Education is an integral part of the strategy to improve environmental awareness. Considering contemporary challenges for educating the wider public about the main issues of environmental concern, attention is paid to various plans, which are being developed in North-Western Europe from primary schools to universities. "Learning for life" relies on an opening of the vocation of traditional universities and on the creation of a European university. Sharing resources in a competitive environment is one response given by British universities in the framework of a Discipline Network in Coastal Sciences and Management in 1996-2000. Networking is truly the key to a fast evolving teaching and learning context, notably in relation to ever developing information and communication technologies. The dissemination of scientific information is primordial in this context; a case study relating to the European project "Marine biodiversity in Europe" (BIOMARE) demonstrates the need for an elaborated strategy leading to socio-economic considerations. Empowering communities and governance are the main possible outcomes of such an enlarged approach to education, involving teachers, students, researchers, professionals, and volunteers. Proposals are made for amplifying the involvement of non-scientists into scientific research and its applications to management. Finally, a case is made for facilitating the mobility of all concerned, with a view to annihilate language and cultural barriers.

  14. Tender moments in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Fox, C.

    1991-04-01

    Described is tender-assisted drilling (TAD) on the UK North Sea Gannet field. The Gannet field is developed by Shell UK Exploration and Production (Shell Expro). In March 1990, Shell Expro awarded Sedco Forex the design and engineering contract to convert the semisubmersible drilling rig Sedco 704 into the Gannet TSV (Tender Support Vessel). The only semisubmersible TSV operation so far to have completed drilling in the North Sea has been in the Norwegian sector. The Odin field, operated by Esso Norge a/s, was developed using the converted drilling rig Treasure Hunter. 1 fig., 1 ill., 3 refs.

  15. Loss of sea ice during winter north of Svalbard

    Directory of Open Access Journals (Sweden)

    Ingrid H. Onarheim

    2014-06-01

    Full Text Available Sea ice loss in the Arctic Ocean has up to now been strongest during summer. In contrast, the sea ice concentration north of Svalbard has experienced a larger decline during winter since 1979. The trend in winter ice area loss is close to 10% per decade, and concurrent with a 0.3°C per decade warming of the Atlantic Water entering the Arctic Ocean in this region. Simultaneously, there has been a 2°C per decade warming of winter mean surface air temperature north of Svalbard, which is 20–45% higher than observations on the west coast. Generally, the ice edge north of Svalbard has retreated towards the northeast, along the Atlantic Water pathway. By making reasonable assumptions about the Atlantic Water volume and associated heat transport, we show that the extra oceanic heat brought into the region is likely to have caused the sea ice loss. The reduced sea ice cover leads to more oceanic heat transferred to the atmosphere, suggesting that part of the atmospheric warming is driven by larger open water area. In contrast to significant trends in sea ice concentration, Atlantic Water temperature and air temperature, there is no significant temporal trend in the local winds. Thus, winds have not caused the long-term warming or sea ice loss. However, the dominant winds transport sea ice from the Arctic Ocean into the region north of Svalbard, and the local wind has influence on the year-to-year variability of the ice concentration, which correlates with surface air temperatures, ocean temperatures, as well as the local wind.

  16. Wind fluctuations over the North Sea

    DEFF Research Database (Denmark)

    Vincent, Claire Louise; Pinson, Pierre; Giebel, Gregor

    2011-01-01

    a certain class of conditions can be found. Here, the HHT is applied to create conditional spectra which demonstrate patterns in the occurrence of severe wind variability. It is shown that wind fluctuations over the North Sea are more severe for westerly flow than for easterly flow, and that severe...

  17. Compositional Analysis of North Sea Oils

    DEFF Research Database (Denmark)

    Dandekar, Abhijit; Andersen, Simon Ivar; Stenby, Erling Halfdan

    2000-01-01

    on the paraffin-naphthene-aromatic distribution and its geographic origin. In this work we have performed the true TBP distillation of 7 stabilized North Sea oil samples. All the oils were distilled from carbon number 6 to 19 and the distillation was terminated at C20+, which was termed as the residue. We have...

  18. Extreme wind mapping over the North Sea

    DEFF Research Database (Denmark)

    Larsén, Xiaoli Guo

    Atlases of the 50-year wind over the North Sea have been created for two heights, 10 m and 100 m. The atlases have also been made for a range of temporal resolutions, from the original time resolution of the NCEP/NCAR reanalysis of 6 hours to 1 hour and further to 10 min. Two methods were used fo...

  19. North Sea Elasmobranchs: distribution, abundance and biodiversity

    NARCIS (Netherlands)

    Daan, N.; Heessen, H.J.L.; Hofstede, ter R.

    2005-01-01

    Based on data from various international and national surveys, an overview is given of the fine-scale distribution (resolution of 20¿longitude * 10¿ latitude; ¿ 10*10 nm) and trends in abundance of elasmobranch species reported from the North Sea. Presence-absence maps are produced based on 4

  20. Sediment volume in the north polar sand seas of Mars

    Energy Technology Data Exchange (ETDEWEB)

    Lancaster, N.; Greeley, R. (Arizona State Univ., Tempe (USA))

    1990-07-10

    Data from studies of the cross-sectional area of terrestrial transverse dunes have been combined with maps of dune morphometry derived from Viking orbiter images to generate new estimates of sediment thickness and dune sediment volume in the north polar sand seas of Mars. A relationship between dune spacing and equivalent sediment thickness (EST) was developed from field data on Namibian and North American dunes and was applied to data on dune spacing and dune cover measured on Viking orbiter images to generate maps of dune sediment thickness for Martian north polar sand seas. There are four major sand seas in the north polar region of Mars, covering an area of 6.8 x 10{sup 5} km{sup 2}. Equivalent sediment thickness ranges between 0.5 and 6.1 m with a mean of 1.8 m. The sand seas contain a total of 1158 km{sup 3} of dune sediment, which may have been derived by erosion of polar layered deposits and concentrated in its present location by winds that change direction seasonally.

  1. Geochemistry and petrology of Late Cretaceous subvolcanic rocks (Macka-Trabzon) in the north of the eastern Black Sea region, NE-Turkey

    Science.gov (United States)

    Aydin, Faruk

    2013-04-01

    In this study, geochronological, geochemical and isotopical data for the early Campanian subvolcanic rocks (Macka-Trabzon) in the north of the eastern Blacksea region, northeastern Turkey, have initially been presented with the aim of determining its magma source and geodynamic evolution. The subvolcanic rocks cutting the subduction-related Late Cretaceous volcano-sedimantary rocks in the region are characterized by several sills and dykes with columnar structures and they consist of amphibole-rich quartz-diorite and quartz-tonalite porphyries, with some dioritic mafic microgranular enclaves. The host rocks have a microgranular porphyritic texture, and they contain 15-25% phenocryst of plagioclase and amphibole and have a matrix that is composed primarily of fine-grained quartz, orthoclase, and plagioclase. Accessory apatite, zircon and Fe-Ti oxides are present in all of the rocks. Secondary minerals such as epidote, calcite, sericite and clays are sometimes observed in the matrix or as hydothermal alteration products of some amphibole and plagioclase phenocrysts. When compared to the host rocks, the magmatic enclaves without quartz are fine-grained, and they contain higher ferromagnesian phases and lower feldspar minerals. Ar-Ar geochronology studies on the amphibole separates reveal that the porphyries have a crystallization ages of 81±0.5 Ma. All samples show a high-K calc-alkaline differentiation trend and I-type features with metaluminous character. The rocks and magmatic enclaves are characterized by enrichment of LILE and depletion of HFSE with negative Nb, Ti, Zr and P anomalies. The chondrite-normalized REE patterns are not fractionated [(La/Yb)N = 9-11] and do not display Eu anomalies (Eu/Eu* = 0.7-0.9). The porphyritic rocks and their enclaves are almost isotopically similar. Sr-Nd isotopic data for all of the samples display initial Sr = 0.7085-0.7087, epsilon Nd (81 Ma) = -6.0 to -6.9, with TDM = 1.38-1.63 Ga. The lead isotopic ratios are (206Pb/204Pb

  2. Eastern Baltic Sea Region

    DEFF Research Database (Denmark)

    Jakobsen, Johnny Grandjean Gøgsig

    2016-01-01

    Kort over den østlige Østersøregion i middelalderen med angivelse af lokaliteter omtalt i antologien, placeret på s.8 i bogen "Church and Belief in the Middle Ages", red. Kirsi Salonen & Sari Katajala-Peltomaa (Amsterdam, 2016)....

  3. Variability of North Sea pH and CO2 in response to North Atlantic Oscillation forcing

    Science.gov (United States)

    Salt, Lesley A.; Thomas, Helmuth; Prowe, A. E. Friederike; Borges, Alberto V.; Bozec, Yann; Baar, Hein J. W.

    2013-12-01

    biological activity causes a distinct seasonality of surface water pH in the North Sea, which is a strong sink for atmospheric CO2 via an effective shelf pump. The intimate connection between the North Sea and the North Atlantic Ocean suggests that the variability of the CO2 system of the North Atlantic Ocean may, in part, be responsible for the observed variability of pH and CO2 in the North Sea. In this work, we demonstrate the role of the North Atlantic Oscillation (NAO), the dominant climate mode for the North Atlantic, in governing this variability. Based on three extensive observational records covering the relevant levels of the NAO index, we provide evidence that the North Sea pH and CO2 system strongly responds to external and internal expressions of the NAO. Under positive NAO, the higher rates of inflow of water from the North Atlantic Ocean and the Baltic outflow lead to a strengthened north-south biogeochemical divide. The limited mixing between the north and south leads to a steeper gradient in pH and partial pressure of CO2 (pCO2) between the two regions in the productive period. This is exacerbated further when coinciding with higher sea surface temperature, which concentrates the net community production in the north through shallower stratification. These effects can be obscured by changing properties of the constituent North Sea water masses, which are also influenced by NAO. Our results highlight the importance of examining interannual trends in the North Sea CO2 system with consideration of the NAO state.

  4. A brief analysis of North Sea physics

    Directory of Open Access Journals (Sweden)

    Jürgen Sündermann

    2011-09-01

    Full Text Available The current state of understanding the North Sea's physical system is presented. First, basic phenomena like astronomical tides and general circulation will be described and analysed with respect to their physical nature and respective interactions. There will be special focus on fundamental dynamic balances. Next, some specific topics relevant to the marine ecosystem, the economy and society will be considered: among them, spreading and transport processes, the fresh water budget, the heat budget and storm surges. A separate section is dedicated to the North Sea of Tomorrow, i.e. the prospective variations of the physical environment resulting from global changes in future decades. The statements are based on the long experience of the authors and their groups and include findings that are little known if at all. The review finishes with a list of open questions and the corresponding research demands.

  5. Revisiting sea level changes in the North Sea during the Anthropocene

    Science.gov (United States)

    Jensen, Jürgen; Dangendorf, Sönke; Wahl, Thomas; Niehüser, Sebastian

    2016-04-01

    The North Sea is one of the best instrumented ocean basins in the world. Here we revisit sea level changes in the North Sea region from tide gauges, satellite altimetry, hydrographic profiles and ocean reanalysis data from the beginning of the 19th century to present. This includes an overview of the sea level chapter of the North Sea Climate Change Assessment (NOSCCA) complemented by results from more recent investigations. The estimates of long-term changes from tide gauge records are significantly affected by vertical land motion (VLM), which is related to both the large-scale viscoelastic response of the solid earth to ice melting since the last deglaciation and local effects. Removing VLM (estimated from various data sources such as GPS, tide gauge minus altimetry and GIA) significantly reduces the spatial variability of long-term trends in the basin. VLM corrected tide gauge records suggest a transition from relatively moderate changes in the 19th century towards modern trends of roughly 1.5 mm/yr during the 20th century. Superimposed on the long-term changes there is a considerable inter-annual to multi-decadal variability. On inter-annual timescales this variability mainly reflects the barotropic response of the ocean to atmospheric forcing with the inverted barometer effect dominating along the UK and Norwegian coastlines and wind forcing controlling the southeastern part of the basin. The decadal variability is mostly remotely forced and dynamically linked to the North Atlantic via boundary waves in response to long-shore winds along the continental slope. These findings give valuable information about the required horizontal resolution of ocean models and the necessary boundary conditions and are therefore important for the dynamical downscaling of sea level projections for the North Sea coastlines.

  6. Impacts of offshore grid developments in the North Sea region on market values by 2050: How will offshore wind farms and transmission lines pay?

    DEFF Research Database (Denmark)

    Traber, Thure; Koduvere, Hardi; Koivisto, Matti Juhani

    2017-01-01

    market values of wind farms on hub level due to impacts of different options for grid structures. The results aim to inform the discussion on possibilities for the allocation of grid expansion costs to the different connected countries including Belgium, Denmark, Germany, the Netherlands, Norway......Increasing the integration of renewable energy in Northern and Central Europe markets is greatly influenced by the development of electricity transmission grid infrastructure. On the background of the fast development of offshore wind energy and its connection to the onshore electricity systems......, a coordinated grid development in the North Sea may not only save costs for individual wind farms, but also deliver additional benefits through the provision of increased interconnection of electricity markets. The previous studies do not include offshore wind development with high ambition in the long term...

  7. Pseudocollapse and rebuilding of North Sea mackerel (Scomber scombrus)

    DEFF Research Database (Denmark)

    Jansen, Teunis

    2014-01-01

    The largest observed change in mackerel (Scomber scombrus) abundance in the North Atlantic happened when the so-called “North Sea mackerel” collapsed due to overfishing. Despite protection, it has remained in a depleted state. Central to this interpretation was that the “North Sea mackerel...

  8. Well data summary sheets. Vol. 17. Danish North Sea and Baltic Sea

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    This seventeenth volume of Well Data Summary Sheets includes data from six North Sea wells: Gwen-2, Ravn-1, Middle Rosa Flank-1, East Rosa Flank-1, Tordenskjold-1, West Lulu-4 and one well from the Baltic Sea: Pernille-1. Minor corrections have been made since the first edition. The `Complete index of released wells` has been updated. Volume 27, 28 and 29 are regional volumes; volume 27 includes well data from Southern Jutland, volumes 28 and 29 cover well data from Northern Jutland. All data from released Danish North Sea wells are included in volumes 17-26 and 30. Data references are made to the revised volumes and not to the original published reference. (au)

  9. Observing and modelling phytoplankton community structure in the North Sea

    Science.gov (United States)

    Ford, David A.; van der Molen, Johan; Hyder, Kieran; Bacon, John; Barciela, Rosa; Creach, Veronique; McEwan, Robert; Ruardij, Piet; Forster, Rodney

    2017-03-01

    Phytoplankton form the base of the marine food chain, and knowledge of phytoplankton community structure is fundamental when assessing marine biodiversity. Policy makers and other users require information on marine biodiversity and other aspects of the marine environment for the North Sea, a highly productive European shelf sea. This information must come from a combination of observations and models, but currently the coastal ocean is greatly under-sampled for phytoplankton data, and outputs of phytoplankton community structure from models are therefore not yet frequently validated. This study presents a novel set of in situ observations of phytoplankton community structure for the North Sea using accessory pigment analysis. The observations allow a good understanding of the patterns of surface phytoplankton biomass and community structure in the North Sea for the observed months of August 2010 and 2011. Two physical-biogeochemical ocean models, the biogeochemical components of which are different variants of the widely used European Regional Seas Ecosystem Model (ERSEM), were then validated against these and other observations. Both models were a good match for sea surface temperature observations, and a reasonable match for remotely sensed ocean colour observations. However, the two models displayed very different phytoplankton community structures, with one better matching the in situ observations than the other. Nonetheless, both models shared some similarities with the observations in terms of spatial features and inter-annual variability. An initial comparison of the formulations and parameterizations of the two models suggests that diversity between the parameter settings of model phytoplankton functional types, along with formulations which promote a greater sensitivity to changes in light and nutrients, is key to capturing the observed phytoplankton community structure. These findings will help inform future model development, which should be coupled

  10. Summer monsoon rainfall variability over North East regions of India and its association with Eurasian snow, Atlantic Sea Surface temperature and Arctic Oscillation

    Science.gov (United States)

    Prabhu, Amita; Oh, Jaiho; Kim, In-won; Kripalani, R. H.; Mitra, A. K.; Pandithurai, G.

    2016-11-01

    This observational study during the 29-year period from 1979 to 2007 evaluates the potential role of Eurasian snow in modulating the North East-Indian Summer Monsoon Rainfall with a lead time of almost 6 months. This link is manifested by the changes in high-latitude atmospheric winter snow variability over Eurasia associated with Arctic Oscillation (AO). Excessive wintertime Eurasian snow leads to an anomalous cooling of the overlying atmosphere and is associated with the negative mode of AO, inducing a meridional wave-train descending over the tropical north Atlantic and is associated with cooling of this region. Once the cold anomalies are established over the tropical Atlantic, it persists up to the following summer leading to an anomalous zonal wave-train further inducing a descending branch over NE-India resulting in weak summer monsoon rainfall.

  11. Elastic behaviour of North Sea chalk

    DEFF Research Database (Denmark)

    Gommesen, Lars; Fabricius, Ida Lykke; Mukerji, T.

    2007-01-01

    We present two different elastic models for, respectively, cemented and uncemented North Sea chalk well-log data. We find that low Biot coefficients correlate with anomalously low cementation factors from resistivity measurements at low porosity and we interpret this as an indication of cementation...... to logging data than the Gassmann prediction for the far, virgin zone. We thus conclude that the Gassmann approach predicts hydrocarbons accurately in chalk in the sonic-frequency domain, but the fluid effects as recorded by the acoustic tool are significantly affected by invasion of mud filtrate...

  12. Geology of outer Horns Rev, Danish North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Joern B.; Gravesen, P.; Lomholt, S. (Geological Survey of Denmark and Greenland, Copenhagen (Denmark))

    2008-07-15

    In 2006, Dong Energy initiated the development of the Horns Rev II offshore wind farm in the North Sea. In order to evaluate and map the characteristics of the surface features of the sea bed and to characterise the subsurface in the wind farm area, the Geological Survey of Denmark and Greenland (GEUS) conducted a geophysical survey of the area. The survey utilised a variety of instruments: sparker, side-scan sonar, marine caesium magnetometer and a multibeam echo-sounder. In addition, information on the subsurface sediments was obtained by cone penetration tests (CPT) and by drilling to 30-50 m below the sea bottom. Geological correlation of the CPT results with the other survey results was extremely complicated but was required in order to understand the architecture of the ice marginal glaciotectonic complex. Information on the geology is crucial for evaluation of the geotechnical problems of the region. (au)

  13. Impact of spatial resolution of ocean models in depicting climate change patterns of the North Sea.

    Science.gov (United States)

    Narayan, Nikesh; Klein, Birgit; Mathis, Moritz; Klein, Holger; Mikolajewicz, Uwe

    2016-04-01

    The impact of enhanced spatial resolution of models in simulating large scale climate change has been of interest for the modeling community for quite some time. It has been noticed in previous studies that the pattern of Sea Surface Temperature anomalies are better captured by higher resolution models. Significant changes in simulating sea-ice loss associated with global warming was also noticed when the spatial resolution of climate models were enhanced. Spatial resolution is a particular important issue in climate change scenarios of shelf seas such as the North Sea. The North Sea is strongly influenced by its water mass exchanges with North Atlantic to the west and north and Baltic Sea to east. Furthermore, local forcing and changes in advected water masses significantly affect the thermodynamics and stratification patterns in the North Sea, making it a challenging area to study. Under the newly started RACE2 project we are looking at global simulations of Representative Concentration Pathway (RCP) scenarios 4.5 and 8.5 at lower and higher resolutions, performed using the Max Planck Institute Earth System Model (MPIESM). The model resolution is non uniform and achieves the highest resolution over the European Seas by shifting the model poles over Chicago and Central Europe. In the high resolution run, the grid reaches up to a spatial resolution of up to 4 km in part of the German Bight and close to 20 km in the Northern part of North Sea. The placement of model poles at specific locations enables the global model to obtain higher resolution at regional scales (North Sea), without the inherent complications of open boundary conditions. High and low resolution simulations will be compared to determine differences in spatial and temporal pattern of temperature anomalies, fresh water intrusion from the Baltic Sea to North Sea etc. Also taken into consideration will be the changes in simulating local sea level change and response to basin scale oscillations like NAO.

  14. Sea surface temperatures and salinities from platforms in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and the South China Sea (Nan Hai) from 1896-1950 (NODC Accession 0000506)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surface temperatures and salinities were collected in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and South China Sea (Nan Hai)...

  15. NOx Emissions from Oil and Gas Production in the North Sea

    Science.gov (United States)

    Lee, J. D.; Foulds, A.; Purvis, R.; Vaughan, A. R.; Carslaw, D.; Lewis, A. C.

    2015-12-01

    North Sea oil is a mixture of hydrocarbons, comprising liquid petroleum and natural gas, produced from petroleum reservoirs beneath the North Sea. As of January 2015, the North Sea is the world's most active offshore drilling region with 173 rigs drilling. During the summer of 2015, a series of survey flights took place on the UKs FAAM BAe 146 research aircraft with the primary aim to assess background methane (and other hydrocarbons) levels in the drilling areas of the North Sea. Also measured were Nitrogen Oxides (NO and NO2), which are emitted from almost all combustion processes and are a key air pollutant, both directly and as a precursor to ozone (O3). The oil and gas platforms in the North Sea are often manned and require significant power generation and support vessels for their continued operation, processes that potentially emit significant amounts of NOx into an otherwise relative clean environment. During these flights we were able to measure the NO­­­x (and any subsequently produced O3) emitted from specific rigs, as well as the NOx levels in the wider North Sea oil and gas production region (see figure for example). NOx mixing ratios of <10 ppbv were frequently observed in plumes, with significant perturbation to the wider North Sea background levels. NOx emissions from the rigs are point sources within the UKs National Atmospheric Emission Inventory (NAEI) and the measurements taken in plumes from individual rigs are used to assess the accuracy of these estimates.

  16. Migration waves to the Baltic Sea region.

    Science.gov (United States)

    Lappalainen, T; Laitinen, V; Salmela, E; Andersen, P; Huoponen, K; Savontaus, M-L; Lahermo, P

    2008-05-01

    In this study, the population history of the Baltic Sea region, known to be affected by a variety of migrations and genetic barriers, was analyzed using both mitochondrial DNA and Y-chromosomal data. Over 1200 samples from Finland, Sweden, Karelia, Estonia, Setoland, Latvia and Lithuania were genotyped for 18 Y-chromosomal biallelic polymorphisms and 9 STRs, in addition to analyzing 17 coding region polymorphisms and the HVS1 region from the mtDNA. It was shown that the populations surrounding the Baltic Sea are genetically similar, which suggests that it has been an important route not only for cultural transmission but also for population migration. However, many of the migrations affecting the area from Central Europe, the Volga-Ural region and from Slavic populations have had a quantitatively different impact on the populations, and, furthermore, the effects of genetic drift have increased the differences between populations especially in the north. The possible explanations for the high frequencies of several haplogroups with an origin in the Iberian refugia (H1, U5b, I1a) are also discussed.

  17. ECOSMO, a coupled ecosystem model of the North Sea and Baltic Sea: Part II. Spatial-seasonal characteristics in the North Sea as revealed by EOF analysis

    DEFF Research Database (Denmark)

    Schrum, Corinna; St. John, Michael; Alekseeva, I.

    2006-01-01

    The 3-D coupled biophysical model ECOSMO (ECOSystern MOdel) has been applied to simulate the spatial and temporal variability of primary and secondary production and biomass in the North Sea in 1984, In order to assess the spatial and temporal dynamics of these components, statistical methods based...... and production in the North Sea. Employing these techniques made it possible to separate regional and temporal variability into the annual pattern, its temporal characteristics and some basic regional modulations of the average seasonal signal. The analysis was able to identify the modulation of average seasonal...... and the end of April, with little to no diatom biomass in the second half of summer. Conversely flagellate biomass did not peak before the beginning of May and showed a relatively constant summer production and an autumn bloom. (c) 2006 Published by Elsevier B.V....

  18. Coastal zone management around the southern North Sea

    NARCIS (Netherlands)

    Hillen, R.; Van de Wetering, B.G.M.; Verhagen, H.J.

    1993-01-01

    The Southern North Sea is bordered by Great-Britain, France, Belgium, The Netherlands, Germany and Denmark. The North Sea basin and its adjacent shorelines are intensively used. Management of the basin and the coastal zone is therefore essential. Because of the small scale of the area, the dense pop

  19. GHRSST Level 2P North Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-17 satellite produced by NEODAAS (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Level 2P swath-based Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic area from the Advanced Very High Resolution...

  20. GHRSST Level 2P North Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-18 satellite produced by NEODAAS (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Level 2P swath-based Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic area from the Advanced Very High Resolution...

  1. GHRSST Level 2P North Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-19 satellite produced by NEODAAS (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Level 2P swath-based Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic area from the Advanced Very High Resolution...

  2. Elastic behaviour of North Sea chalk

    DEFF Research Database (Denmark)

    Gommesen, Lars; Fabricius, Ida Lykke; Mukerji, T.

    2007-01-01

    chalk. In the acoustic impedance–Poisson's ratio plane, we forecast variations in porosity and hydrocarbon saturation from their influence on the elastic behaviour of the chalk. The Gassmann model and the self-consistent approximation give roughly similar predictions of the effect of fluid on acoustic......We present two different elastic models for, respectively, cemented and uncemented North Sea chalk well-log data. We find that low Biot coefficients correlate with anomalously low cementation factors from resistivity measurements at low porosity and we interpret this as an indication of cementation...... impedance and Poisson's ratio, but we find that the high-frequency self-consistent approach gives a somewhat smaller predicted fluid-saturation effect on Poisson's ratio than the low-frequency Gassmann model. The Gassmann prediction for the near and potentially invaded zone corresponds more closely...

  3. Subsurface phytoplankton blooms fuel pelagic production in the North Sea

    DEFF Research Database (Denmark)

    Richardson, Kathrine; Visser, Andre; Pedersen, Flemming

    2000-01-01

    convincingly that energy fixed during the spring bloom is fueling the pelagic production occurring during summer months. We argue here that periodic phytoplankton blooms are occurring during the summer in the North Sea at depths of >25 m and that the accumulated new production [sensu (Dugdale and Goering......, Limnol. Oceanogr., 12, 196-206, 1967)] occurring in these blooms may be greater than that occurring in the spring bloom in the same regions. Thus, such blooms may explain apparent discrepancies in production yields between different temperate marine systems...

  4. Neogene dinocyst zonation for the eastern North Sea Basin, Denmark

    DEFF Research Database (Denmark)

    Dybkjær, Karen; Piasecki, Stefan

    2010-01-01

    - and sequence stratigraphy. The dinocyst zonation and the foraminifer zonation of the Danish Miocene (based upon analysis of the same boreholes) were independently calibrated with the established nannoplankton zonation. This correlation revealed a mismatch generally corresponding to one nannoplankton zone...... for the Achomosphaera andalousiensis Zone. Neogene biostratigraphy in the North Sea Basin has been problematic due to the periodically limited connection between the North Sea Basin and the North Atlantic Ocean, especially with respect to stratigraphy based on foraminifers and calcareous nannoplankton. Many...

  5. Cenozoic uplift and subsidence in the North Atlantic region

    DEFF Research Database (Denmark)

    Anell, Ingrid Anna Margareta; Thybo, Hans; Artemieva, Irina

    2009-01-01

    , time and amplitude (where possible) of topographic changes in the North Atlantic region during the Cenozoic (65-0 Ma). Our compilation is based on published results from reflection seismic studies, AFT (apatite fission track) studies, VR (vitrinite reflectance) trends, maximum burial, sediment supply...... studies, mass balance calculations and extrapolation of seismic profiles to onshore geomorphological features. The integration of about 200 published results reveal a clear pattern of topographic changes in the North Atlantic region during the Cenozoic: (1) The first major phase of Cenozoic regional...... and the surrounding areas. (2) A regional increase in subsidence in the offshore marginal areas of Norway, the northern North Sea, the northern British Isles and west Greenland took place in the Eocene (ca 57-35 Ma). (3) The Oligocene and Miocene (35-5 Ma) were characterized by regional tectonic quiescence, with only...

  6. Dynamical downscaling of warming scenarios with NEMO-Nordic setup for the North Sea and Baltic Sea

    Science.gov (United States)

    Gröger, Matthias; Almroth Rosell, Elin; Anderson, Helén; Axell, Lars; Dieterich, Christain; Edman, Moa; Eilola, Kari; Höglund, Anders; Hordoir, Robinson; Hieronymus, Jenny; Karlsson, Bengt; Liu, Ye; Meier, Markus; Pemberton, Per; Saraiva, Sofia

    2016-04-01

    The North Sea and Baltic Sea constitute one of the most complex and challenging areas in the world. The oceanographic setting ranges from quasi open ocean conditions in the northern North Sea to more brackish conditions in the Baltic Sea which is also affected by sea ice in winter. The two seas are connected by narrow straits which sporadically allow the important inflow of salt and oxygen rich bottom waters into the Baltic Sea. For this, the high resolution regional model NEMO-Nordic has recently been developed. Here, the model is applied on hindcast simulations and used to downscale several climate warming scenarios. The model can be interactively coupled to the regional atmosphere model RCA4 by exchanging air sea fluxes of mass and energy (Wang et al., 2015). Comparison with well established models and newly compiled observational data sets (Bersch et al., 2013) indicates NEMO-Nordic performs well on climate relevant time scales. Emphasis is laid on thermal dynamics. Hindcast simulations demonstrate that simulated winter temperatures in the Baltic Sea can benefit from interactive air sea coupling by allowing interactive feedback loops to take place between the ocean and the atmosphere (Gröger et al. 2015). Likewise, a more realistic dynamical behaviour makes the interactive coupled model suitable for dynamic downscaling of climate warming scenarios. Depending on the driving global climate model and IPCC representative concentration pathway scenario NEMO-Nordic shows an average warming of the North Sea between 2 and 4 K at the end of the 21st century. However the warming pattern is spatially inhomogeneous showing strong east west gradients. Involved processes such as circulation changes and changes in radiative forcing will be discussed. Bersch, M., Gouretski, V., Sadikni, R., Hinrichs, I., 2013. Hydrographic climatology of the North Sea and surrounding regions. Centre for Earth System Research and Sustainability, University of Hamburg, www

  7. Plate boundaries and evolution of the Solomon Sea region

    Science.gov (United States)

    Honza, E.; Davies, H. L.; Keene, J. B.; Tiffin, D. L.

    1987-09-01

    The Solomon Sea Plate was widely developed during late Oligocene, separating the proto-West Melanesian Arc from the proto-Trobriand Arc. Spreading in the Bismarck Sea and in the Woodlark Basin resulted from interaction between the Pacific and Australian Plates, specifically from the collision of the proto-West Melanesian Arc with north New Guinea, which occurred after arc reversal. This model explains the extensive Miocene, Pliocene, and Quaternary volcanism of the Papua New Guinea mainland as it related to southward subduction of the Trobriand Trough. Our interpreted plate motions are concordant with the geological evidence onshore and also with complex tectonic features in the Solomon Sea Basin Region.

  8. Baltic Earth - Earth System Science for the Baltic Sea Region

    Science.gov (United States)

    Meier, Markus; Rutgersson, Anna; Lehmann, Andreas; Reckermann, Marcus

    2014-05-01

    The Baltic Sea region, defined as its river catchment basin, spans different climate and population zones, from a temperate, highly populated, industrialized south with intensive agriculture to a boreal, rural north. It encompasses most of the Scandinavian Peninsula in the west; most of Finland and parts of Russia, Belarus, and the Baltic states in the east; and Poland and small parts of Germany and Denmark in the south. The region represents an old cultural landscape, and the Baltic Sea itself is among the most studied sea areas of the world. Baltic Earth is the new Earth system research network for the Baltic Sea region. It is the successor to BALTEX, which was terminated in June 2013 after 20 years and two successful phases. Baltic Earth stands for the vision to achieve an improved Earth system understanding of the Baltic Sea region. This means that the research disciplines of BALTEX continue to be relevant, i.e. atmospheric and climate sciences, hydrology, oceanography and biogeochemistry, but a more holistic view of the Earth system encompassing processes in the atmosphere, on land and in the sea as well as in the anthroposphere shall gain in importance in Baltic Earth. Specific grand research challenges have been formulated, representing interdisciplinary research questions to be tackled in the coming years. A major means will be scientific assessments of particular research topics by expert groups, similar to the BACC approach, which shall help to identify knowledge gaps and develop research strategies. Preliminary grand challenges and topics for which Working Groups have been installed include: • Salinity dynamics in the Baltic Sea • Land-Sea biogeochemical feedbacks in the Baltic Sea region • Natural hazards and extreme events in the Baltic Sea region • Understanding sea level dynamics in the Baltic Sea • Understanding regional variability of water and energy exchange • Utility of Regional Climate Models • Assessment of Scenario Simulations

  9. Isotopic niches of fin whales from the Mediterranean Sea and the Celtic Sea (North Atlantic).

    Science.gov (United States)

    Das, Krishna; Holleville, Ophélie; Ryan, Conor; Berrow, Simon; Gilles, Anita; Ody, Denis; Michel, Loïc N

    2017-06-01

    The fin whale (Balaenoptera physalus) is the most abundant and widespread mysticete species in the Mediterranean Sea, found mostly in deep, offshore waters of the western and central portion of the region. In the Mediterranean, this species is known to feed mainly on krill, in contrast to its Atlantic counterpart, which displays a more diversified diet. The International Whaling Commission recognizes several managements units in the Atlantic and the Mediterranean Sea and the connectivity between these populations is still being debated. Questions remain about inter-individual feeding strategies and trophic ecology. The goal of this study was to compare isotopic niches of fin whales from the Mediterranean Sea and the Celtic Sea (North Atlantic). δ(13)C and δ(15)N values were analysed in 136 skin biopsies from free-ranging Mediterranean fin whales sampled in 2010 and 2011 during campaigns at sea. δ(13)C and δ(15)N values ranged from -20.4 to -17.1‰ and from 5.9 to 8.9‰, respectively. These values are in good agreement with those estimated previously from baleen plates from Mediterranean and North Atlantic fin whales. The narrow isotopic niche width of the Mediterranean fin whale (Standard Ellipses area SEAc) compared to the North Atlantic fin whale raises many concerns in the context of global changes and long-term consequences. One could indeed expect that species displaying narrow niches would be more susceptible to ecosystem fragmentation and other anthropogenic impacts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Well data summary sheets. Vol. 20. Danish North Sea

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    This twentieth volume of the `Well Data Summary sheets` together with volumes twenty one and twenty two which have been prepared concurrently, includes data from wells in the Danish North Sea with Jurassic sections. With the exception of Falk-1 well in this volume, all the included wells have been released and can be found in the previous volumes (1-16). The primary purpose of producing these three volumes (20-22) has been to update the previously released wells and produce them in our new format. Additionally, this compilation brings together wells from the same geographic region (Central Graben area) with Jurassic sections. An exception to this is the Ibenholt-1 well (volume 21) and the Felicia-1/1A well (this volume). Minor corrections have been made since the first edition. The `Complete index of released wells` had been updated. Volume 27, 28 and 29 are regional volumes; volume 27 includes well data from Southern Jutland; volumes 28 and 29 cover well data from Northern Jutland. All data from released Danish North Sea wells are included in volumes 17-26 and 30. Data references are made to the revised volumes and not to the original published reference. (au)

  11. Arctic sea ice bordering on the North Atlantic and intera- nnual climate variations

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Variations of winter Arctic sea ice bordering on the North Atlantic are closely related to climate variations in the same region. When winter North Atlantic Oscillation (NAO) index is positive (negative) anomaly phase, Icelandic Low is obviously deepened and shifts northwards (southwards). Simultaneously, the Subtropical High over the North Atlantic is also intensified, and moves northwards (south-wards). Those anomalies strengthen (weaken) westerly be-tween Icelandic Low and the Subtropical High, and further result in positive (negative) sea surface temperature (SST) anomalies in the mid-latitude of the North Atlantic, and increase (decrease) the warm water transportation from the mid-latitude to the Barents Sea, which causes positive (nega-tive) mixed-layer water temperature anomalies in the south part of the Barents Sea. Moreover, the distribution of anom-aly air temperature clearly demonstrates warming (cooling) in northern Europe and the subarctic regions (including the Barents Sea) and cooling (warming) in Baffin Bay/ Davis Strait. Both of distributions of SST and air temperature anomalies directly result in sea ice decrease (increase) in the Barents/Kara Seas, and sea ice increase (decrease) in Baffin Bay/Davis Strait.

  12. The impacts of physical processes on oxygen variations in the North Sea-Baltic Sea transition zone

    OpenAIRE

    Jonasson, L.; Wan, Z.; J. H. S. Hansen; J. She

    2011-01-01

    The bottom water of the North Sea-Baltic Sea transition zone suffers from seasonal hypoxia, usually during late summer and autumn. These hypoxic events are critical for the benthic ecosystems and the concentration of dissolved oxygen is an important measure of the water quality. However, to model the subsurface dissolved oxygen is a major challenge, especially in estuaries and coastal regions. In this study a simple oxygen consumption model is coupled to a 3-D hydrodynamical model in order to...

  13. Assessments of the lesser sandeel ( Ammodytes marinus ) in the North Sea based on revised stock divisions

    DEFF Research Database (Denmark)

    Pedersen, S.A.; Lewy, Peter; Wright, P.

    1999-01-01

    for the different aggregations. Based on a geographical division of the North Sea in a number of proposed assessment regions, regional as well as whole North Sea sandeel assessments are presented based on revised data (e.g, catch in numbers at age and effort). The assessments suggest regional differences in fishing...... effort, catch per unit effort, yield, fishing and natural mortality. A better understanding of sandeel growth is important for stock and catch predictions because previous studies indicate that the variability of mean weight-at-age is one of the most important factors influencing the precision...

  14. The microbiome of North Sea copepods

    Science.gov (United States)

    Gerdts, G.; Brandt, P.; Kreisel, K.; Boersma, M.; Schoo, K. L.; Wichels, A.

    2013-12-01

    Copepods can be associated with different kinds and different numbers of bacteria. This was already shown in the past with culture-dependent microbial methods or microscopy and more recently by using molecular tools. In our present study, we investigated the bacterial community of four frequently occurring copepod species, Acartia sp., Temora longicornis, Centropages sp. and Calanus helgolandicus from Helgoland Roads (North Sea) over a period of 2 years using DGGE (denaturing gradient gel electrophoresis) and subsequent sequencing of 16S-rDNA fragments. To complement the PCR-DGGE analyses, clone libraries of copepod samples from June 2007 to 208 were generated. Based on the DGGE banding patterns of the two years survey, we found no significant differences between the communities of distinct copepod species, nor did we find any seasonality. Overall, we identified 67 phylotypes (>97 % similarity) falling into the bacterial phyla of Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. The most abundant phylotypes were affiliated to the Alphaproteobacteria. In comparison with PCR-DGGE and clone libraries, phylotypes of the Gammaproteobacteria dominated the clone libraries, whereas Alphaproteobacteria were most abundant in the PCR-DGGE analyses.

  15. Regionalization in the Black Sea Area: a Comparative Study

    Directory of Open Access Journals (Sweden)

    Diana Rusu

    2011-06-01

    Full Text Available The post-Cold War period in Europe was favourable for the development of new regionalization projects which surrounded the EU. The Baltic Sea, the Mediterranean Sea and the Black Sea became the centre of new European sub-regions. Each project stands out now through a certain image that it received mirroring its type and level of regionalization emerged at the junction of regional dynamics and external influences. While the Nordic region is addressed as a model of multi-level, locally driven cooperation, the Mediterranean region is embedded in the North- South developmental division approach with little cooperation and strong external influences. The Black Sea’s position is debated between the two models mentioned above. Thus, I propose a comparative analysis of these three cases aiming to trace down the similarities and differences between them with the focus on the Black Sea Region. The conclusion of the study places the Black Sea Region in between the cases with a genuine potential to follow the Nordic model but with its future evolution hanging on the EU’s policies toward the area.

  16. Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian Sea and White Sea from R/Vs Artemovsk, Atlantida, Okeanograf, Professor Rudovits, and ice observations, 1957 - 1995 (NODC Accession 0073674)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian...

  17. Phytoplankton of the North Sea and its dynamics: A review

    Science.gov (United States)

    Reid, P. C.; Lancelot, C.; Gieskes, W. W. C.; Hagmeier, E.; Weichart, G.

    microscopic observations has been documented by measurements of taxon-specific pigments such as chlorophyll b (green algae), alloxanthin (Cryptophyceae) and 19' - hexanolyloxyfucoxanthin (Prymnesiophyceae or Haptophyceae). Analysis of time series of satellite images is a promising way to assess in a quantitative and, more important, synoptic way the patchy distribution of phytoplankton over large regions. Growth processes of the phytoplankton respond according to variables amenable to such satellite remote sensing. Empirical and theoretical relationships that can be established between chlorophyll a, 14C uptake, turbidity, stratification, suspended sediment type, irradiance and temperature in some well-investigated areas make remote sensing a potential tool to obtain reliable estimates of primary production in the whole North Sea. The 14C method for estimates of the rate of algal growth processes appears to agree reasonably well with other methods, both involving incubation of samples and in situ measurements of temporal changes of oxygen and pH. The level of net primary production is 250 g C.m -2.a -1 in the central North Sea, 150 to 200 g C.m -2.a -1 in the northern North Sea, and 200 g in the South. The main metabolic processes involved in phytoplankton growth have been modelled mathematically in terms of the most important controlling environmental parameters. Such parameters comprise not only those of a chemical signature (micro- and macronutrients, both inorganic and organic) but also physical effects of vertical mixing and sinking, and biological effects including allelopathic interactions, antibiotic excretions, vertical migration, and mortality due to grazing and parasitism. The balance between primary production and consumption of organic matter appears to vary both geographically and seasonally. The process of regeneration of primary products both in the water column and in and near the bottom seems to be of major importance. Future research should center around a

  18. Virulence Profiles of Vibrio vulnificus in German Coastal Waters, a Comparison of North Sea and Baltic Sea Isolates

    Directory of Open Access Journals (Sweden)

    Nadja Bier

    2015-12-01

    Full Text Available Vibrio vulnificus is a halophilic bacterium of coastal environments known for sporadically causing severe foodborne or wound infections. Global warming is expected to lead to a rising occurrence of V. vulnificus and an increasing incidence of human infections in Northern Europe. So far, infections in Germany were exclusively documented for the Baltic Sea coast, while no cases from the North Sea region have been reported. Regional variations in the prevalence of infections may be influenced by differences in the pathogenicity of V. vulnificus populations in both areas. This study aimed to compare the distribution of virulence-associated traits and genotypes among 101 V. vulnificus isolates from the Baltic Sea and North Sea in order to assess their pathogenicity potential. Furthermore, genetic relationships were examined by multilocus sequence typing (MLST. A high diversity of MLST sequences (74 sequence types and differences regarding the presence of six potential pathogenicity markers were observed in the V. vulnificus populations of both areas. Strains with genotypes and markers associated with pathogenicity are not restricted to a particular geographic region. This indicates that lack of reported cases in the North Sea region is not caused by the absence of potentially pathogenic strains.

  19. Analysis of North Sea Offshore Wind Power Variability

    Directory of Open Access Journals (Sweden)

    Aymeric Buatois

    2014-05-01

    Full Text Available This paper evaluates, for a 2030 scenario, the impact on onshore power systems in terms of the variability of the power generated by 81 GW of offshore wind farms installed in the North Sea. Meso-scale reanalysis data are used as input for computing the hourly power production for offshore wind farms, and this total production is analyzed to identify the largest aggregated hourly power variations. Based on publicly available information, a simplified representation of the coastal power grid is built for the countries bordering the North Sea. Wind farms less than 60 km from shore are connected radially to the mainland, while the rest are connected to a hypothetical offshore HVDC (High-Voltage Direct Current power grid, designed such that wind curtailment does not exceed 1% of production. Loads and conventional power plants by technology and associated cost curves are computed for the various national power systems, based on 2030 projections. Using the MATLAB-based MATPOWER toolbox, the hourly optimal power flow for this regional hybrid AC/DC grid is computed for high, low and medium years from the meso-scale database. The largest net load variations are evaluated per market area and related to the extra load-following reserves that may be needed from conventional generators.

  20. The North Atlantic Oscillation: variability and interactions with the North Atlantic ocean and Artic sea ice

    Energy Technology Data Exchange (ETDEWEB)

    Jung, T.

    2000-07-01

    The North Atlantic oscillation (NAO) represents the dominant mode of atmospheric variability in the North Atlantic region and describes the strengthening and weakening of the midlatitude westerlies. In this study, variability of the NAO during wintertime and its relationship to the North Atlantic ocean and Arctic sea ice is investigated. For this purpose, observational data are analyzed along with integrations of models for the Atlantic ocean, Arctic sea ice, and the coupled global climate system. From a statistical point of view, the observed NAO index shows unusually high variance on interdecadal time scales during the 20th century. Variability on other time scales is consistent with realizations of random processes (''white noise''). Recurrence of wintertime NAO anomalies from winter-to-winter with missing signals during the inbetween nonwinter seasons is primarily associated with interdecadal variability of the NAO. This recurrence indicates that low-frequency changes of the NAO during the 20th century were in part externally forced. (orig.)

  1. Sea surface height variability in the North East Atlantic from satellite altimetry

    Science.gov (United States)

    Sterlini, Paul; de Vries, Hylke; Katsman, Caroline

    2016-08-01

    Data from 21 years of satellite altimeter measurements are used to identify and understand the major contributing components of sea surface height variability (SSV) on monthly time-scales in the North East Atlantic. A number of SSV drivers is considered, which are categorised into two groups; local (wind and sea surface temperature) and remote (sea level pressure and the North Atlantic oscillation index). A multiple linear regression model is constructed to model the SSV for a specific target area in the North Sea basin. Cross-correlations between candidate regressors potentially lead to ambiguity in the interpretation of the results. We therefore use an objective hierarchical selection method based on variance inflation factors to select the optimal number of regressors for the target area and accept these into the regression model if they can be associated to SSV through a direct underlying physical forcing mechanism. Results show that a region of high SSV exists off the west coast of Denmark and that it can be represented well with a regression model that uses local wind, sea surface temperature and sea level pressure as primary regressors. The regression model developed here helps to understand sea level change in the North East Atlantic. The methodology is generalised and easily applied to other regions.

  2. Sea turtles sightings in North Carolina

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sea turtles sightings are reported to the NMFS Beaufort Laboratory sea turtle program by the general public as they are fishing, boating, etc. These sightings...

  3. Air-Sea Exchange of Legacy POPs in the North Sea Based on Results of Fate and Transport, and Shelf-Sea Hydrodynamic Ocean Models

    Directory of Open Access Journals (Sweden)

    Kieran O'Driscoll

    2014-04-01

    Full Text Available The air-sea exchange of two legacy persistent organic pollutants (POPs, γ-HCH and PCB 153, in the North Sea, is presented and discussed using results of regional fate and transport and shelf-sea hydrodynamic ocean models for the period 1996–2005. Air-sea exchange occurs through gas exchange (deposition and volatilization, wet deposition and dry deposition. Atmospheric concentrations are interpolated into the model domain from results of the EMEP MSC-East multi-compartmental model (Gusev et al, 2009. The North Sea is net depositional for γ-HCH, and is dominated by gas deposition with notable seasonal variability and a downward trend over the 10 year period. Volatilization rates of γ-HCH are generally a factor of 2–3 less than gas deposition in winter, spring and summer but greater in autumn when the North Sea is net volatilizational. A downward trend in fugacity ratios is found, since gas deposition is decreasing faster than volatilization. The North Sea is net volatilizational for PCB 153, with highest rates of volatilization to deposition found in the areas surrounding polluted British and continental river sources. Large quantities of PCB 153 entering through rivers lead to very high local rates of volatilization.

  4. Potential Impacts of Offshore Wind Farms on North Sea Stratification.

    Science.gov (United States)

    Carpenter, Jeffrey R; Merckelbach, Lucas; Callies, Ulrich; Clark, Suzanna; Gaslikova, Lidia; Baschek, Burkard

    2016-01-01

    Advances in offshore wind farm (OWF) technology have recently led to their construction in coastal waters that are deep enough to be seasonally stratified. As tidal currents move past the OWF foundation structures they generate a turbulent wake that will contribute to a mixing of the stratified water column. In this study we show that the mixing generated in this way may have a significant impact on the large-scale stratification of the German Bight region of the North Sea. This region is chosen as the focus of this study since the planning of OWFs is particularly widespread. Using a combination of idealised modelling and in situ measurements, we provide order-of-magnitude estimates of two important time scales that are key to understanding the impacts of OWFs: (i) a mixing time scale, describing how long a complete mixing of the stratification takes, and (ii) an advective time scale, quantifying for how long a water parcel is expected to undergo enhanced wind farm mixing. The results are especially sensitive to both the drag coefficient and type of foundation structure, as well as the evolution of the pycnocline under enhanced mixing conditions-both of which are not well known. With these limitations in mind, the results show that OWFs could impact the large-scale stratification, but only when they occupy extensive shelf regions. They are expected to have very little impact on large-scale stratification at the current capacity in the North Sea, but the impact could be significant in future large-scale development scenarios.

  5. Causes for contemporary regional sea level changes.

    Science.gov (United States)

    Stammer, Detlef; Cazenave, Anny; Ponte, Rui M; Tamisiea, Mark E

    2013-01-01

    Regional sea level changes can deviate substantially from those of the global mean, can vary on a broad range of timescales, and in some regions can even lead to a reversal of long-term global mean sea level trends. The underlying causes are associated with dynamic variations in the ocean circulation as part of climate modes of variability and with an isostatic adjustment of Earth's crust to past and ongoing changes in polar ice masses and continental water storage. Relative to the coastline, sea level is also affected by processes such as earthquakes and anthropogenically induced subsidence. Present-day regional sea level changes appear to be caused primarily by natural climate variability. However, the imprint of anthropogenic effects on regional sea level-whether due to changes in the atmospheric forcing or to mass variations in the system-will grow with time as climate change progresses, and toward the end of the twenty-first century, regional sea level patterns will be a superposition of climate variability modes and natural and anthropogenically induced static sea level patterns. Attribution and predictions of ongoing and future sea level changes require an expanded and sustained climate observing system.

  6. NCEP North American Regional Reanalysis (NARR)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NARR dataset is an extension of the NCEP Global Reanalysis which is run over the North American Region. The NARR model uses the very high resolution NCEP Eta...

  7. Seasonal distribution and relationship of water mass and suspended load in North Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    LI Zhen; BAO Xianwen; WANG Yongzhi; LI Na; QIAO Lulu

    2009-01-01

    The concentration of suspended load can be determined by its linear relationship to turbidity. Our results present the basic distribution of suspended load in North Yellow Sea. In summer, the suspended load concentration is high along the coast and low in the center of the sea. There are four regions of high concentration in the surface layer: Penglai and Chengshantou along the north of the Shandong Peninsula, and the coastal areas of Lüshun and Changshan Islands. There is a 2 mg/L contour at 124°E that separates the North Yellow Sea from regions of lower concentrations in the open sea to the west. And there is a 2 mg/L contour at 124°E that separates the North Yellow Sea from regions of lower concentrations in the open sea to the west. The distribution features in the 10 m and bottom layer are similar to the surface layer, however, the suspended load concentration declines in the 10 m layer while it increases in the bottom layer. And in the bottom layer there is a low suspended load concentration water mass at the region south of 38°N and east of 123°E extending to the southeast. In general, the lowest suspended load concentration in a vertical profile is at a depth of 10 to 20 m, the highest suspended load concentration is in the bottom near Chengshantou area. In winter, the distribution of suspended load is similar to summer, but the average concentrations are three times higher. There are two tongue-shaped high suspended load concentration belt, one occurring from surface to seafloor, extends to the north near Chengshantou and the other invades north to south along the east margin of Dalian Bay. They separate the low suspended load concentration water masses in the center of North Yellow Sea into east and west parts. Vertical distribution is quite uniform in the whole North Yellow Sea because of the cooling effect and strong northeast winds. The distribution of suspended load has a very close relationship to the current circulation and wind-induced waves

  8. Geodynamic Evolution of the Banda Sea Region

    Science.gov (United States)

    Kaymakci, N.; Decker, J.; Orange, D.; Teas, P.; Van Heiningen, P.

    2013-12-01

    We've carried out a large on- and offshore study in Eastern Indonesia to characterize the major structures and to provide constraints on the Neogene geodynamic evolution of the Banda Sea region. The onshore portion utilized remote sensing data and published geology. We tied the onshore to the offshore using recently acquired high resolution bathymetric data (16m and 25m bin size) and 2D seismic profiles that extend from Sulawesi in the west to Irian Jaya in the east across the northern part of the Banda Arc. We interpret the northern boundary of the 'Birds Head' (BH) of Papua, the Sorong Fault, to be a sinistral strike-slip fault zone with a minimum of 48 km displacement over the last few million years. The western boundary fault of Cendrawasih Basin defines the eastern boundary of BH and corresponds to the Wandamen Peninsula which comprises high pressure metamorphic rocks, including eclogite and granulite facies rocks, with exhumation ages from 4 to 1 Ma. Earthquake focal mechanism solutions indicate that the eastern boundary of BH is linked with a large scale offshore normal fault which we suggest may be related to the exhumation of the Wandamen Peninsula. The eastern boundary of Cendrawasih Basin is defined by a large transpressive belt along which BH is decoupled from the rest of Papua / Irian Jaya. This interpretation is supported by recent GPS studies. We propose that the BH and the Pacific plate are coupled, and therefore the Birds Head is therefore completely detached from Irian Jaya. Furthermore, Aru Basin, located at the NE corner of Banda Arc, is a Fault-Fault-Transform (FFT) type triple junction. According to available literature information the Banda Sea includes three distinct basins with different geologic histories; the North Banda Sea Basin (NBSB) was opened during 12-7 Ma, Wetar-Damar Basin (WDB) during 7-3.5 Ma and Weber Basin (WB) 3-0 Ma. Our bathymetric and seismic data indicated that the NBSB and Weber Basin lack normal oceanic crust and are

  9. Mapping cumulative human impacts in the eastern North Sea

    DEFF Research Database (Denmark)

    Stock, A.; Andersen, Jesper; Heinänen, S.

    of the MSFD; and 3) to deepen the understanding of how errors in expert judgment affect the resulting cumulative human impact maps by means of Monte Carlo simulations. We combined existing data sets on the spatial distribution of 33 anthropogenic stressors (linked to the MSFD pressures) and 28 key habitats....... In contrast, the predicted impacts for much of the Norwegian EEZ and areas far offshore were lower. The Monte Carlo simulations confirmed earlier findings that mapping cumulative impacts is generally "robust", but also showed that specific combinations of errors can seriously change local and regional...... on marine ecosystems have only recently been developed. The aims of our study were: 1) to develop a map of cumulative human impacts for the Danish, Swedish, Norwegian and German parts of the Greater North Sea; 2) to adjust the existing methods for mapping cumulative human impacts to fit the requirements...

  10. Relating Regional Arctic Sea Ice and climate extremes over Europe

    Science.gov (United States)

    Ionita-Scholz, Monica; Grosfeld, Klaus; Lohmann, Gerrit; Scholz, Patrick

    2016-04-01

    of cold nights, cold days, ice days and consecutive frost days over the western part of Europe. In the opposite case of low sea ice concentration over the Barents/Kara Seas an increase of up to 8 days/winter of cold nights and days is observed over the whole Europe and an increase of up to 4 days/winter in the number of ID and CFD is observed over the same regions. The cold winters over Europe (low sea ice years) are associated with anomalous anticyclone and the downstream development of a mid-latitude trough, which in turn favours the advection of cold air from the north, providing favourable conditions for severe winters over Europe. We suggest that these results can help to improve the seasonal predictions of winter extreme events over Europe. Due to the non-linear response to high vs. low sea ice years, the skill of the predictions might depend on the sign and amplitude of the anomalies.

  11. Spatial and temporal variability of late Holocene sea-level changes in the North Atlantic (Invited)

    Science.gov (United States)

    Kemp, A.; Kopp, R. E.; Horton, B.; Cahill, N.

    2013-12-01

    Proxy sea-level reconstructions spanning the last ~2000 years capture multiple phases of climate and sea level behavior for model calibration, provide a pre-anthropogenic background against which to compare recent trends, and characterize patterns of natural spatial and temporal variability. In the western North Atlantic basin, salt-marsh sediment is an archive for reconstructing sea level with the decimeter and multi-decadal resolution necessary to characterize subtle changes. New and existing salt-marsh reconstructions from northern Florida, North Carolina, New Jersey, Connecticut, and Massachusetts provide a dataset for investigating spatial and temporal sea-level variability during the late Holocene. The reconstructions were developed using foraminifera, plants, and bulk sediment δ13C values as sea-level proxies. The age of sediment deposition was estimated from composite chronologies of radiocarbon and chronohorizons of regional pollution and land-use change that were combined in age depth models. We used a spatio-temporal Gaussian process model to identify and characterize persistent phases of sea level behavior during the late Holocene in the western North Atlantic Ocean. The results indicate an acceleration in global mean sea level from the early 19th century through the early 20th century. The rate of sea-level rise increased significantly in the late 19th century. The timing and magnitude of this rise varied among sites even after accounting for differences in glacio-isostatic adjustment. Sea level in North Carolina rose faster than in New Jersey sea-level during the Medieval Climate Optimum, while sea level in New Jersey rose faster during the Little Ice Age. Spatially variable sea-level rise on the Atlantic coast of North America can be caused by dynamic oceanographic processes and/or melting of the Greenland Ice Sheet. Our analysis suggests that plausible levels of meltwater input from Greenland would be inadequate to explain the reconstructed pattern

  12. The Potential for Wave Energy in the North Sea

    DEFF Research Database (Denmark)

    Sørensen, H. C.; Chozas, Julia Fernandez

    2010-01-01

    the North Sea are expected to change the priority in favour of utilising wave energy from the North Sea. The paper describes the opportunities for power production in the North Sea considering the competition for space and the synergy with offshore wind. Two approaches are used: a traditional national......The North Sea has not yet been regarded as prime area for wave energy development in Europe except in Denmark, Benelux and Germany. The reason is the relatively low intensity of waves (12-17kW/m) compared to the Atlantic with a wave climate of 24-48kW/m. Further on the design wave load is almost...... as in the Atlantic and the distance to shore relatively long compared to sites with good wave climate like Ireland, Portugal, Spain and the west coast of UK. The increasing activities within offshore wind in the North Sea and the attempt to build a super grid connecting the wind sites with the major consumers around...

  13. Subsurface low pH and carbonate saturation state of aragonite on China side of the North Yellow Sea: combined effects of global atmospheric CO2 increase, regional environmental changes, and local biogeochemical processes

    Directory of Open Access Journals (Sweden)

    J.-Y. Wang

    2013-02-01

    Full Text Available Based upon seven field surveys conducted between May 2011 and January 2012, we investigated pH, carbonate saturation state of aragonite (Ωarag, and ancillary parameters on the Chinese side of the North Yellow Sea, a western North Pacific continental margin of major economic importance. Subsurface waters were nearly in equilibrium with air in May and June. From July to October, the fugacity of CO2 (fCO2 of bottom water gradually increased to 697 ± 103 μatm and pH decreased to 7.83 ± 0.07 due to respiration/remineralization processes of primary production induced biogenic particles. In November and January, bottom water fCO2 decreased and pH gradually returned to an air-equilibrated level due to cooling enhanced vertical mixing. The corresponding bottom water Ωarag was 1.74 ± 0.17 (May, 1.77 ± 0.26 (June, 1.70 ± 0.26 (July, 1.72 ± 0.33 (August, 1.32 ± 0.31 (October, 1.50 ± 0.28 (November, and 1.41 ± 0.12 (January. Critically low Ωarag values of 1.0 to 1.2 were mainly observed in subsurface waters in a salinity range of 31.5–32.5 psu in October and November, accounting for ~ 10% of the North Yellow Sea area. Water mass derived from the adjacent Bohai Sea had a typical water salinity of 30.5–31.5 psu, and bottom water Ωarag values ranged mostly between 1.6 and 2.4. This study showed that the carbonate system in the North Yellow Sea was substantially influenced by global atmospheric CO2 increase. The community respiration/remineralization rates in typical North Yellow Sea bottom water mass were estimated at 0.55–1.0 μmol O2 kg−1 d−1 in warm seasons, leading to seasonal drops in subsurface pH and Ωarag. Outflow of the Bohai Sea water mass counteracted the subsurface Ωarag reduction in the North Yellow Sea.

  14. Population genetic structure of North Atlantic, Mediterranean Sea and Sea of Cortez fin whales, Balaenoptera physalus (Linnaeus 1758) : Analysis of mitochondrial and nuclear loci

    NARCIS (Netherlands)

    Bérubé, Martine; Aguilar, Alex; Dendanto, Dan; Larsen, Finn; Notarbartolo di Sciara, Guiseppe; Sears, Richard; Sigurjónsson8, Johan; Urban-R, Jorge; Palsboll, Per

    1998-01-01

    Samples were collected from 407 fin whales, Balaenoptera physalus, at four North Atlantic and one Mediterranean Sea summer feeding area as well as the Sea of Cortez in the Pacific Ocean. For each sample, the sex, the sequence of the first 288 nucleotides of the mitochondrial (mt) control region and

  15. How Changing Human Lifestyles are Shaping Europe's Regional Seas

    Science.gov (United States)

    Mee, L. D.; Lowe, C. D.; Langmead, O.; McQuatters-Gollop, A.; Attrill, M.; Cooper, P.; Gilbert, A.; Knudsen, S.; Garnacho, E.

    2007-05-01

    European society is experiencing unprecedented changes triggered by expansion of the European Union, the fall of Communism, economic growth and the onset of globalisation. Europe's regional seas, the Baltic, Black Sea, Mediterranean and North-East Atlantic (including the North Sea), provide key goods and services to the human population but have suffered from severe degradation in past decades. Their integrity as coupled social and ecological systems depends on how humanity will anticipate potential problems and deal with its ecological footprint in the future. We report the outcome of an EU-funded 15-country, 28 institution project entitled European Lifestyles and Marine Ecosystems (ELME). Our studies were designed to inform new EU policy and legislation that incorporates Ecosystem-Based Management. ELME has modelled the key relationships between economic and social drivers (D), environmental pressures (P) and changes in the state of the environment (S) in Europe's regional seas. We examined four key issues in each sea: habitat change, eutrophication, chemical pollution and fisheries. We developed conceptual models for each regional sea and employed a novel stochastic modelling technique to examine the interrelationship between key components of the conceptual models. We used the models to examine 2-3 decade projections of current trends in D, P and S and how a number of alternative development scenarios might modify these trends. These simulations demonstrate the vulnerability of Europe's seas to human pressure. As affluence increases in countries acceding to the EU, so does the demand for marine goods and services. There are `winners' and `losers' amongst marine species; the winners are often species that are opportunistic invaders or those with low economic value. In the case of eutrophication, semi-enclosed seas such as the Baltic or Black Sea are already affected by the `legacy of the past'; nutrients that have accumulated in soils, ground waters and

  16. North Pacific High Seas Squid Jig Logbook

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a federally mandated logbook program high seas squid jig fishing, and it is required to be mailed in to PIFSC after a fishing trip. Fishing occurs in the...

  17. Sea Surface Temperature (14 KM North America)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Product shows local sea surface temperatures (degrees C). It is a composite gridded-image derived from 8-km resolution SST Observations. It is generated every 48...

  18. Quantifying pelagic-benthic coupling in the North Sea: Are we asking the right question?

    DEFF Research Database (Denmark)

    Richardson, K.; Cedhagen, T.

    2002-01-01

    fished region such as the North Sea where deployment of sediment traps or bottom mounted cameras or samplers is difficult. Thus, there are relatively few sites in the North Sea for which good data are available for describing pelagic-benthic (or near shore-offsbore) coupling and considerable effort...... of energy and nutrients. We argue that foraminiferans may deserve more study in this respect. Their large numbers in combination with structural and physiological adaptations suggest that these organisms may be of greater importance than other meiofaunal organisms of comparative size and abundance....

  19. Modelling marine ecosystem response to climate change and trawling in the North Sea

    NARCIS (Netherlands)

    van der Molen, J.; Aldridge, J.N.; Coughlan, C.; Parker, E.R.; Stephens, D; Ruardij, P.

    2013-01-01

    The marine ecosystem response to climate change and demersal trawling was investigated using the coupled hydrodynamic-biogeochemical water column model GOTM-ERSEM-BFM for three contrasting sites in the North Sea. Climate change forcing was derived from the HadRM3-PPE-UK regional climate model for

  20. The phytoplankton spring bloom in Dutch coaqtal waters of the North Sea

    NARCIS (Netherlands)

    Gieskes, W.W.C.; Kraay, G.W.

    1975-01-01

    In the eastern part of the Southern Bight of the North Sea several sub areas could be distinguished, each with a characteristic spring bloom and species succession pattern. Regional differences in spring bloom timing were in accord with theoretical considerations in which (on the assumption of a ver

  1. Impacts of the north and tropical Atlantic Ocean on the Antarctic Peninsula and sea ice.

    Science.gov (United States)

    Li, Xichen; Holland, David M; Gerber, Edwin P; Yoo, Changhyun

    2014-01-23

    In recent decades, Antarctica has experienced pronounced climate changes. The Antarctic Peninsula exhibited the strongest warming of any region on the planet, causing rapid changes in land ice. Additionally, in contrast to the sea-ice decline over the Arctic, Antarctic sea ice has not declined, but has instead undergone a perplexing redistribution. Antarctic climate is influenced by, among other factors, changes in radiative forcing and remote Pacific climate variability, but none explains the observed Antarctic Peninsula warming or the sea-ice redistribution in austral winter. However, in the north and tropical Atlantic Ocean, the Atlantic Multidecadal Oscillation (a leading mode of sea surface temperature variability) has been overlooked in this context. Here we show that sea surface warming related to the Atlantic Multidecadal Oscillation reduces the surface pressure in the Amundsen Sea and contributes to the observed dipole-like sea-ice redistribution between the Ross and Amundsen-Bellingshausen-Weddell seas and to the Antarctic Peninsula warming. Support for these findings comes from analysis of observational and reanalysis data, and independently from both comprehensive and idealized atmospheric model simulations. We suggest that the north and tropical Atlantic is important for projections of future climate change in Antarctica, and has the potential to affect the global thermohaline circulation and sea-level change.

  2. Gravity and magnetic modelling of North Sea basins[Marine and Onshore North Sea Acquisition for Lithospheric Seismic Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lyngsie, S.B.; Thybo, H. [Copenhagen Univ., Geological Inst. (Denmark)

    2003-07-01

    One of the primary sources of information for interpretation of subsurface geology and large scale tectonic features is potential field data. Gravity and magnetic data may reveal large and small scale features such as basement type, intrusions into the crust, volcanic roks, basement furface, faults and salt structures. As such, this type of data provides an invaluable source of information, which is cimplimentary to seismic data. We are currently conducting a project on interpretation of basins in the North Sea Based on potential field data, constrained by the wealth of existing seismic data. High resolution modelling of gravimetric and magnetic anomalies constrained by seismic P-wave velocity models and normal incidence reflection seismic data may reveal intrinsic details of upper- and lower Palaeozoic basin formation and changes in crustal domains in the Danish North Sea area. The MONA LISA (Marine and Onshore North Sea Acquisition for Lithospheric Seismic Analysis) data set from the south-eastern North Sea (MONA LISA Working Group, 1997) consists of four deep seismic normal incidence reflection profiles recorded to 26 s (twt) and coincident wide-angle reflection/refraction data recorded on 26 onshore mobile seismometers and 29 ocean bottom hydrophones (OBH's) placed along profiles 1,2 and 3. The east-west trending MONA LISA profile 3 traverses the basement high of the Mid North Sea - Ringkoebing Fyn High (MSRFH) and crosses the N-S striking Central Graben (CG) and Horn Graven (HG). (au)

  3. CHASE assessment of the North Sea – a pilot study

    DEFF Research Database (Denmark)

    Green, N.; Andersen, Jesper; Høgåsen, T.;

    In this pilot study, hazardous substances in the North Sea were assessed and classified using the HELCOM Chemical Substances Status Assessment Tool (CHASE). The study was based on monitoring by Belgium, Denmark, France, Germany, the Netherlands, Norway, Sweden and the United Kingdom. Together, 1350...... assessment and classification of “hazardous substances status”. This can be in particular advantageous for use in remedial action plan and, in particular, for the sciencebased evaluation of whether the North Sea is undisturbed by hazardous substances....... locations (1155 for sediment and 195 for biota) were used resulting in 966 matrices sampled in the open-sea and 506 in coastal areas. CHASE is a multi-metric indicator-based tool developed for the HELCOM integrated thematic assessment of hazardous substances in the Baltic Sea. CHASE produces an integrated...

  4. Regional métier definition: A comparative investigation of statistical methods using a workflow applied to the international otter trawl fisheries in the North Sea

    DEFF Research Database (Denmark)

    Deporte, Nicolas; Ulrich, Clara; Mahévas, Stephanie

    2012-01-01

    The European Common Fisheries Policy recognizes the importance of accounting for heterogeneity in fishing practices, and métier-based sampling is now at the core of the EU Data Collection Framework. The implementation of such an approach would require Member States to agree on the standard region...

  5. North Alaska petroleum analysis: the regional map compilation

    Science.gov (United States)

    Saltus, Richard W.; Bird, Kenneth J.

    2003-01-01

    The U.S. Geological Survey initiated an effort to model north Alaskan petroleum systems. The geographic and geologic basis for modeling systems is provided by a set of regional digital maps that allow evaluation of the widest possible extent of each system. Accordingly, we laid out a rectangular map grid 1300 km (800 miles) east-west and 600 km (375 miles) north-south. The resulting map area extends from the Yukon Territory of Canada on the east to the Russian-U.S. Chukchi Sea on the west and from the Brooks Range on the south to the Canada basin-Chukchi borderland on the north. Within this map region, we combined disparate types of publicly available data to produce structure contour maps. Data types range from seismic-based mapping as in the National Petroleum Reserve to well penetrations in areas of little or no seismic data where extrapolation was required. With these types of data, we produced structure contour maps on three horizons: top of pre-Mississippian (basement), top of Triassic (Ellesmerian sequence), and top of Neocomian (Beaufortian sequence). These horizons, when combined with present-day topography and bathymetry, provide the bounding structural/stratigraphic surfaces of the north Alaskan petroleum province that mark major defining moments of the region's geologic history and allow regional portrayal of preserved sediment accumulations.

  6. Dynamic and static elastic moduli of North Sea and deep sea chalk

    DEFF Research Database (Denmark)

    Gommesen, Lars; Fabricius, Ida Lykke

    2001-01-01

    We have established an empirical relationship between the dynamic and the static mechanical properties of North Sea and deep sea chalk for a large porosity interval with respect to porosity, effective stress history and textural composition. The chalk investigated is from the Tor and Hod Formations...

  7. Remotely sensed seasonality in the spatial distribution of sea-surface suspended particulate matter in the southern North Sea

    Science.gov (United States)

    Eleveld, Marieke A.; Pasterkamp, Reinold; van der Woerd, Hendrik J.; Pietrzak, Julie D.

    2008-10-01

    An algorithm is presented for estimating near-surface SPM concentrations in the turbid Case 2 waters of the southern North Sea. The single band algorithm, named POWERS, was derived by parameterising Gordon's approximation of the radiative transfer model with measurements of Belgian and Dutch inherent optical properties. The algorithm was used to calculate near-surface SPM concentration from 491 SeaWiFS datasets for 2001. It was shown to be a robust algorithm for estimating SPM in the southern North Sea. Regression of annual geometric mean SPM concentration derived from remote sensing (SPM rs), against in situ (SPM is) data from 19 Dutch monitoring stations was highly significant with an r2 of 0.87. Further comparison and statistical testing against independent datasets for 2000 confirmed the consistency of this relationship. Moreover, time series of SPM rs concentrations derived from the POWERS algorithm, were shown to follow the same temporal trends as individual SPM is data recorded during 2001. Composites of annual, winter and summer SPM rs for 2001 highlight the three dominant water masses in the southern North Sea, as well as their winter-fall and spring-summer variability. The results indicate that wind induced wave action and mixing cause high surface SPM signals in winter in regions where the water column becomes well mixed, whereas in summer stratification leads to a lower SPM surface signal. The presented algorithm gives accurate near-surface SPM concentrations and could easily be adapted for other water masses and seas.

  8. Historical marine ecology: examining the role of fisheries in changes in North Sea benthos.

    Science.gov (United States)

    Robinson, Leonie A; Frid, Chris L J

    2008-07-01

    The organisms living on and in the sea floor, the benthos, represent an important ecological group. Although some (shellfish) have an economic value, most do not, and so little long-term data are available. We have identified three sources of historic benthic data for the North Sea, a regional sea that has been subjected to multiple human impacts for at least several hundred years. Each dataset has its limitations, but by their use together some issues emerge. Wider community shifts were observed in the shorter term and a number of extirpations at the scale of the North Sea were seen over longer time scales. The extirpated taxa share a number of characteristics consistent with an effect of fisheries such as fragile morphology. We must concentrate now on furthering our understanding of the ecological significance of shifts in dominance of particular functional units and protecting those habitats and species most vulnerable to fisheries-driven extirpation.

  9. Last glacial dynamics of the Vale of York and North Sea lobes of the British and Irish Ice Sheet.

    OpenAIRE

    Bateman, M.D.; Evans, D.J.A.; Buckland, P. C.; Connell, E.R.; Friend, R. J.; Hartmann, D. (Dominic); Moxon, H.; Fairburn, W.A.; Panagiotakopulu, E.; Ashurst, R. A.

    2015-01-01

    During the Last Glacial Maximum, the Vale of York and North Sea lobes of the British and Irish Ice Sheet extended to within 10 km of each other, impounding a series of pro-glacial lakes. Such an interplay of ice lobes provides a useful analogue for elsewhere in the North Sea basin. This paper focusses on reconstructing the Vale of York and North Sea Ice lobes using a regional suite of 25 luminescence ages in combination with stratigraphical and geomorphic evidence. Results extend and revise t...

  10. Deglacial and Holocene sea-ice variability north of Iceland and response to ocean circulation changes

    Science.gov (United States)

    Xiao, Xiaotong; Zhao, Meixun; Knudsen, Karen Luise; Sha, Longbin; Eiríksson, Jón; Gudmundsdóttir, Esther; Jiang, Hui; Guo, Zhigang

    2017-08-01

    Sea-ice conditions on the North Icelandic shelf constitute a key component for the study of the climatic gradients between the Arctic and the North Atlantic Oceans at the Polar Front between the cold East Icelandic Current delivering Polar surface water and the relatively warm Irminger Current derived from the North Atlantic Current. The variability of sea ice contributes to heat reduction (albedo) and gas exchange between the ocean and the atmosphere, and further affects the deep-water formation. However, lack of long-term and high-resolution sea-ice records in the region hinders the understanding of palaeoceanographic change mechanisms during the last glacial-interglacial cycle. Here, we present a sea-ice record back to 15 ka (cal. ka BP) based on the sea-ice biomarker IP25, phytoplankton biomarker brassicasterol and terrestrial biomarker long-chain n-alkanols in piston core MD99-2272 from the North Icelandic shelf. During the Bølling/Allerød (14.7-12.9 ka), the North Icelandic shelf was characterized by extensive spring sea-ice cover linked to reduced flow of warm Atlantic Water and dominant Polar water influence, as well as strong meltwater input in the area. This pattern showed an anti-phase relationship with the ice-free/less ice conditions in marginal areas of the eastern Nordic Seas, where the Atlantic Water inflow was strong, and contributed to an enhanced deep-water formation. Prolonged sea-ice cover with occasional occurrence of seasonal sea ice prevailed during the Younger Dryas (12.9-11.7 ka) interrupted by a brief interval of enhanced Irminger Current and deposition of the Vedde Ash, as opposed to abruptly increased sea-ice conditions in the eastern Nordic Seas. The seasonal sea ice decreased gradually from the Younger Dryas to the onset of the Holocene corresponding to increasing insolation. Ice-free conditions and sea surface warming were observed for the Early Holocene, followed by expansion of sea ice during the Mid-Holocene.

  11. Pliocene pre-glacial North Atlantic: A coupled sea surface-deep ocean circulation climate response

    Energy Technology Data Exchange (ETDEWEB)

    Ishman, S.E.; Dowsett, H.J. (Geological Survey, Reston, VA (United States). National Center)

    1992-01-01

    A latitudinal transect of North Atlantic Deep Sea Drilling Project Holes from the equatorial region to 56 N in the 2,300- to 3,000-meter depth range was designed for a high-resolution study of coupled sea surface and deep ocean response to climate change. Precise age control was provided using magnetostratigraphic and biostratigraphic data from the cores to identify the 4.0 to 2.2 Ma interval, a period of warm-to-cool climatic transitions in the North Atlantic. The objective is to evaluate incremental (10 kyr) changes in sea surface temperatures (SST) and deep North Atlantic circulation patterns between 4.0 and 2.2 Ma to develop a coupled sea surface-deep ocean circulation response model. Sea surface temperature (SST) estimates are based on planktic foraminifer-based factor-analytic transfer functions. Oxygen isotopic data from paired samples provide tests of the estimated temperature gradients between localities. Benthic foraminifer assemblage data and [partial derivative]O-18 and [partial derivative]C-13 Isotopic data are used to quantitatively determine changes in deep North Atlantic circulation. These data are used to determine changes in source area (North Atlantic Deep Water (NADW) or Antarctic Bottom Water) and (or) in the components of NADW that were present (Upper or Lower NADW). These paired paleoceanographic sea surface and deep circulation interpretations over a 1.8 my interval form the basis for a coupled sea surface-deep circulation response model for the Pliocene North Atlantic Ocean.

  12. Diel feeding pattern of whiting in the North Sea

    DEFF Research Database (Denmark)

    Rindorf, Anna

    2003-01-01

    Though numerous studies have analysed the feeding periodicity of North Sea gadoids, no general diel pattern has been found. The lack of agreement between studies may be related to differences, in prey composition and behaviour, but it has not been attempted to link the diel intake pattern directly...... to intake of individual prey. This study presents an analysis of the round the clock occurrence of several prey types in the stomachs of whiting Merlangius merlangus, a major predator on fish and crustaceans in the North Sea. Generalised linear models were used to determine if the occurrence of different...

  13. Wind Stress Forcing of the North Sea "Pole Tide"

    Science.gov (United States)

    OConnor, William P.; Chao, Benjamin Fong; Zheng, Dawei; Au, Andrew Y.

    1998-01-01

    We conducted numerical simulations of the wind-forcing of the sea level variations in the North Sea using a barotropic ocean model with realistic geography, bathymetry, and boundary conditions, to examine the forcing of the 14-month "pole tide" which is known to be strong along the Denmark- Netherlands coast. The simulation input is the monthly-mean surface wind stress field from the National Centers for Environmental Prediction (NCEP) reanalysis for the 40-year period 1958-1997. The output sea level response was then compared with 10 coastal tide gauge records from the Permanent Service for Mean Sea Level (PSMSL). Besides the strong seasonal variations, several prominent quasi-periodicities exist at around 7 years, 3 years, 14 months, 9 months, and 6.5 months. Correlation and spectral analyses show remarkable agreement between the model output and the observations, particularly in the 14-month, or Chandler period band. The latter indicates that the enhanced pole tide found in the North Sea along the Denmark-Netherlands coast is actually the coastal setup response to wind stress forcing with a periodicity of 14 months. We find no need to invoke a geophysical explanation involving resonance-enhancement of pole tide in the North Sea to explain the observations.

  14. Seamount physiography and biology in the north-east Atlantic and Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    T. Morato

    2013-05-01

    Full Text Available This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (north-east Atlantic Ocean and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (north-east Atlantic and in the Mediterranean Sea is large with around 557 and 101 seamount-like features, respectively. Similarly, seamounts occupy large areas of about 616 000 km2 in the OSPAR region and of about 89 500 km2 in the Mediterranean Sea. The presence of seamounts in the north-east Atlantic has been known since the late 19th century, but overall knowledge regarding seamount ecology and geology is still relatively poor. Only 37 seamounts in the OSPAR area (3.5% of all seamounts in the region, 22 in the Mediterranean Sea (9.2% of all seamounts in the region and 25 in the north-east Atlantic south of the OSPAR area have in situ information. Seamounts mapped in both areas are in general very heterogeneous, showing diverse geophysical characteristics. These differences will likely affect the biological diversity and production of resident and associated organisms.

  15. Regional sea level change in the Thailand-Indonesia region

    Science.gov (United States)

    Fenoglio-Marc, L.; Becker, M. H.; Buchhaupt, C.

    2013-12-01

    It is expected that the regional sea level rise will strongly affect particular regions with direct impacts including submergence of coastal zones, rising water tables and salt intrusion into groundwaters. It can possibly also exacerbate other factors as floodings, associated to storms and hurricanes, as well as ground subsidence of anthropogenic nature. The Thailand-Vietnam-Indonesian region is one of those zones. On land, the Chao-Praya and Mekong Delta are fertile alluvial zones. The potential for sea level increases and extreme floodings due to global warming makes the Deltas a place where local, regional, and global environmental changes are converging. We investigate the relative roles of regional and global mechanisms resulting in multidecadal variations and inflections in the rate of sea level change. Altimetry and GRACE data are used to investigate the variation of land floodings. The land surface water extent is evaluated at 25 km sampling intervals over fifteen years (1993-2007) using a multisatellite methodology which captures the extent of episodic and seasonal inundations, wetlands, rivers, lakes, and irrigated agriculture, using passive and active (microwaves and visible observations. The regional sea level change is analysed during the period 1993-2012 using satellite altimetry, wind and ocean model data, tide gauge data and GPS. The rates of absolute eustatic sea level rise derived from satellite altimetry through 19-year long precise altimeter observations are in average higher than the global mean rate. Several tide gauge records indicate an even higher sea level rise relative to land. We show that the sea level change is closely linked to the ENSO mode of variability and strongly affected by changes in wind forcing and ocean circulation. We have determined the vertical crustal motion at a given tide gauge location by differencing the tide gauge sea level time-series with an equivalent time-series derived from satellite altimetry and by computing

  16. Segregation of herring larvae from inshore and offshore spawning grounds in the north-western North Sea — Implications for stock structure

    Science.gov (United States)

    Heath, M.

    Herring larvae hatching from spawning sites around the Scottish coast are dispersed by water currents during the weeks following hatching. Hydrographic data, observations on the distribution of caesium-137 and measurements of current velocities by moored meters and drifting buoys, suggest that larvae from offshore spawning sites around the north of Scotland should be more rapidly dispersed than those hatching in inshore areas. This has been confirmed by direct observations on the advection of herring larvae in different regions of the north western North Sea. The conclusion is that larvae hatching in inshore areas, especially in the Moray Firth, are most likely to contribute to nearby juvenile populations, whereas larvae from offshore spawning sites should be widely dispersed over the North Sea. Tagging and parasitology investigations have shown that adult herring spawning in the north-western North Sea have been widely dispersed in the North Sea and adjacent waters as juveniles (six months — one and a half years old). However, a high proportion of adult fish caught at inshore spawning sites and in the Moray Firth were found to have been recruited from more local areas. Taken together with the observations on larval drift, these observations suggest that the stock structure of herring in the northern North Sea may in part be a consequence of the physical oceanography of the area.

  17. Regional ocean-colour chlorophyll algorithms for the Red Sea

    KAUST Repository

    Brewin, Robert J.W.

    2015-05-18

    The Red Sea is a semi-enclosed tropical marine ecosystem that stretches from the Gulf of Suez and Gulf of Aqaba in the north, to the Gulf of Aden in the south. Despite its ecological and economic importance, its biological environment is relatively unexplored. Satellite ocean-colour estimates of chlorophyll concentration (an index of phytoplankton biomass) offer an observational platform to monitor the health of the Red Sea. However, little is known about the optical properties of the region. In this paper, we investigate the optical properties of the Red Sea in the context of satellite ocean-colour estimates of chlorophyll concentration. Making use of a new merged ocean-colour product, from the European Space Agency (ESA) Climate Change Initiative, and in situ data in the region, we test the performance of a series of ocean-colour chlorophyll algorithms. We find that standard algorithms systematically overestimate chlorophyll when compared with the in situ data. To investigate this bias we develop an ocean-colour model for the Red Sea, parameterised to data collected during the Tara Oceans expedition, that estimates remote-sensing reflectance as a function of chlorophyll concentration. We used the Red Sea model to tune the standard chlorophyll algorithms and the overestimation in chlorophyll originally observed was corrected. Results suggest that the overestimation was likely due to an excess of CDOM absorption per unit chlorophyll in the Red Sea when compared with average global conditions. However, we recognise that additional information is required to test the influence of other potential sources of the overestimation, such as aeolian dust, and we discuss uncertainties in the datasets used. We present a series of regional chlorophyll algorithms for the Red Sea, designed for a suite of ocean-colour sensors, that may be used for further testing.

  18. The Holocene palaeogeography and relative sea level for two tidal basins of the German North Sea coast

    Science.gov (United States)

    Bungenstock, Friederike; Wartenberg, Wolfram; Mauz, Barbara; Freund, Holger; Frechen, Manfred; Weerts, Henk J. T.; Berner, Heinrich

    2014-05-01

    The response of coasts to global sea-level rise is highly variable. Knowledge of driving coastal parameters alongside the regional sea-level history is therefore indispensable when the response to global sea-level rise is to be assessed. Here, we study the Holocene relative sea-level of the south coast of the North Sea which is controlled by a number of very local parameters, as well as by regional glacio-isostatic adjustments. It is therefore crucial to restrict the data acquisition and evaluation to small coastal sections, ideally to single tidal basins, to minimize the sources of uncertainties (Bungenstock & Weerts 2010, 2012). We present data from two tidal basins, Langeoog and Jade Bay. For Langeoog a database derived from 600 cores, 68 km of Boomer seismic data, 33 radiocarbon ages and 8 OSL dates is available. (Bungenstock & Schäfer 2009, Mauz & Bungenstock 2007). For the Jade bay, the database comprises sedimentary markers, pollen and macro remains derived from 68 cores. The sedentary chronology is based on 54 radiocarbon ages and pollen constraints (Wartenberg & Freund 2011, Wartenberg et al. 2013). For both tidal basins the sedimentological record was interpreted in terms of the local paleogeographical development since about 7000 cal BP and its influence on the local relative sea-level curve. While the trend of the relative sea level is similar for both tidal basins, it shows a different altitude. The timing of the main marine transgression within the Langeoog area takes place ~3000 cal. BP whereas the sedimentological record of the Jade Bay shows two prominent transgressions, one for ~5000 cal. BP and one for ~3000 cal. BP. The Langeoog palaeo-environment is continuously characterised by marine influence. Within the Jade Bay two different palaeo-environments could be identified, documenting that from the West to the centre the landscape development in the Jade Bay was drainage driven feeding the associated fen peat with minerogenic water but being

  19. Evolutionary impact assessment of the north sea plaice fishery

    NARCIS (Netherlands)

    Mollet, Fabian M.; Poos, Jan Jaap; Dieckmann, Ulf; Rijnsdorp, Adriaan D.

    2016-01-01

    There is growing evidence that fishing causes evolution in life-history traits that affect the productivity of fish stocks. Here we explore the impact of fisheries-induced evolution (FIE) on the productivity of North Sea plaice (Pleuronectes platessa) using an ecogenetic, individual-based model b

  20. The Potential for Wave Energy in the North Sea

    DEFF Research Database (Denmark)

    Sørensen, H. C.; Chozas, Julia Fernandez

    2010-01-01

    The North Sea has not yet been regarded as prime area for wave energy development in Europe except in Denmark, Benelux and Germany. The reason is the relatively low intensity of waves (12-17kW/m) compared to the Atlantic with a wave climate of 24-48kW/m. Further on the design wave load is almost ...

  1. Analysis of North Sea Offshore Wind Power Variability

    NARCIS (Netherlands)

    Buatois, A.; Gibescu, M.; Rawn, B.G.; Van der Meijden, M.A.M.M.

    2014-01-01

    This paper evaluates, for a 2030 scenario, the impact on onshore power systems in terms of the variability of the power generated by 81 GW of offshore wind farms installed in the North Sea. Meso-scale reanalysis data are used as input for computing the hourly power production for offshore wind farms

  2. Analysis of North Sea Offshore Wind Power Variability

    NARCIS (Netherlands)

    Buatois, A.; Gibescu, M.; Rawn, B.G.; Van der Meijden, M.A.M.M.

    2014-01-01

    This paper evaluates, for a 2030 scenario, the impact on onshore power systems in terms of the variability of the power generated by 81 GW of offshore wind farms installed in the North Sea. Meso-scale reanalysis data are used as input for computing the hourly power production for offshore wind

  3. The internal consistency of the North Sea carbonate system

    NARCIS (Netherlands)

    Salt, S.; Thomas, H.; Bozec, Y.; Borges, A.V.; de Baar, H.J.W

    2016-01-01

    In 2002 (February) and 2005 (August), the full suite of carbonate system parameters (total alkalinity (AT), dissolved inorganic carbon (DIC), pH, and partial pressure of CO2 (pCO2) were measured on two re-occupations of the entire North Sea basin, with three paramete

  4. Predicting the occurrence of sand banks in the North Sea

    NARCIS (Netherlands)

    Veen, van der Henriët H.; Hulscher, Suzanne J.M.H.

    2009-01-01

    Sand banks have a wavelength between 1 and 10 km, and they are up to several tens of meters high. Also, sand banks may have an impact on large-scale human activities that take place in the North Sea like sand mining, shipping, offshore wind farms, etc. Therefore, it is important to know where sand b

  5. Modelling the advection of herring larvae in the North Sea

    Science.gov (United States)

    Bartsch, J.; Brander, K.; Heath, M.; Munk, P.; Richardson, K.; Svendsen, E.

    1989-08-01

    THE number of fish at the age of first capture in a fishery (recruitment) is dependent on the production of eggs by the parent stock and the survival of early life stages (eggs, larvae and juveniles). In many pelagic fish species the survival of larvae depends on transport from spawning to nursery areas1. To investigate larval transport processes for North Sea herring (Clupea harengus L.) we have modelled in three dimensions the advection of autumn-spawned larvae during the winter of 1987-1988 and compared the results with sequential field data on the actual distribution of larvae. Circulation in the North Sea is pre-dominantly wind-driven during the winter, and in 1987-1988 anomalous atmospheric conditions caused a reduction in cyclonic circulation and unusual transport of larvae from northern North Sea and west of Scotland spawning areas. Predicting variations in recruitment in advance of fishery legislation has always been difficult and the collapse of North Sea herring populations during the mid-1970s is believed to have been due to a period of several years of low recruitment coupled with high fishing activity2. Our results suggest that a better understanding can be achieved with the aid of environmental modelling.

  6. Stratigraphic guide to the Rogaland Group, Norwegian North Sea

    NARCIS (Netherlands)

    Brunstad, H.; Gradstein, F.; Lie, J.E.; Hammer, O.; Munsterman, D.K.; Ogg, G.; Hollerbach, M.

    2013-01-01

    This guide provides a major revision and update of the lithostratigraphy of the Rogaland Group for the Norwegian North Sea. An abundance of recent well and seismic data sheds new light on lithology, biostratigraphy, provenance, geographic distribution and terminology of all Rogaland rock units, used

  7. Analysis of North Sea Offshore Wind Power Variability

    NARCIS (Netherlands)

    Buatois, A.; Gibescu, M.; Rawn, B.G.; Van der Meijden, M.A.M.M.

    2014-01-01

    This paper evaluates, for a 2030 scenario, the impact on onshore power systems in terms of the variability of the power generated by 81 GW of offshore wind farms installed in the North Sea. Meso-scale reanalysis data are used as input for computing the hourly power production for offshore wind farms

  8. Competitive interactions between two fishing fleets in the North Sea

    NARCIS (Netherlands)

    Sys, Klaas; Poos, Jan Jaap; Meensel, van Jef; Polet, Hans; Buysse, Jeroen

    2016-01-01

    We examine whether the landing rates of Belgian beam trawlers in the Southern Bight of the North Sea were affected through competitive interactions with the Dutch beam trawler fleet and whether the development of a pulse trawler fleet has altered competitive interactions between both fleets. Effe

  9. North Sea palaeogeographical reconstructions for the last 1 Ma

    NARCIS (Netherlands)

    Cohen, K.M.; Gibbard, P.L.; Weerts, H.J.T.

    2014-01-01

    The landscape evolution of the southern North Sea basin is complex and has left a geographically varying record of marine, lacustrine, fluvial and glacial sedimentation and erosion. Quaternary climatic history, which importantly included glaciation, combined with tectonics gave rise to cyclic and

  10. Sleep and Alertness in North Sea Helicopter Operations

    NARCIS (Netherlands)

    Simons, M.; Wilschut, E.S.; Valk, P.J.L.

    2011-01-01

    Introduction : Dutch North Sea helicopter operations are characterized by multiple sector flights to offshore platforms under difficult environmental conditions. In the context of a Ministry of Transport program to improve safety levels of helicopter operations, we assessed effects of pre-duty

  11. Quaternary evolution of the North Sea and the English Channel

    NARCIS (Netherlands)

    Gibbard, P.L.; Cohen, K.M.

    2015-01-01

    The island of Britain is surrounded by a ‘moat’ of water, of which the English Channel and the North Sea are two major components. This talk described some major events that occurred to shape these seaways and, in particular, the evidence preserved on the Channel seabed. Here a system of valleys occ

  12. Nine decades of North Sea sole and plaice distribution

    NARCIS (Netherlands)

    Engelhard, G.H.; Pinnegar, J.K.; Kell, L.T.; Rijnsdorp, A.D.

    2011-01-01

    Recent studies based mainly on research survey data suggest that within the North Sea, sole Solea solea and plaice Pleuronectes platessa have exhibited distribution shifts in recent decades—on average southward for sole and northward to deeper waters for plaice. Various hypotheses may account for su

  13. CHASE assessment of the North Sea – a pilot study

    DEFF Research Database (Denmark)

    Green, N.; Andersen, Jesper; Høgåsen, T.

    In this pilot study, hazardous substances in the North Sea were assessed and classified using the HELCOM Chemical Substances Status Assessment Tool (CHASE). The study was based on monitoring by Belgium, Denmark, France, Germany, the Netherlands, Norway, Sweden and the United Kingdom. Together, 1350...

  14. North Sea development action brisk; plays expand elsewhere off Europe

    Energy Technology Data Exchange (ETDEWEB)

    Knott, D.J.

    1996-08-19

    The North Sea may be a mature play, but operators are continually searching for new ways to develop small finds near existing infrastructure and to develop discoveries in new areas at low cost. As they fill in gaps in the North Sea oil and gas infrastructure, companies are also exploring and planning developments in new plays such as the U.K.`s West of Shetlands area, the Irish Sea, and the Atlantic Margin from off western Ireland to northern Norway. Floating production systems and subsea technology are vital parts of many of Northwest Europe`s recently sanctioned field developments, for both large and small reservoirs. The paper discusses the dominant role of floating production units, the niche for subsea developments, new production, the Harding field, the Schieballion and Clair fields (UK), Norway`s plans, the Elgin/Franklin field, small fields, frontier work, in-field projects, flexible floating platforms, deepwater technology, a gas monotower, and subsea control.

  15. Tectonic Evolution of the North Depression of the South Yellow Sea Basin Since Late Cretaceous

    Institute of Scientific and Technical Information of China (English)

    LI Nan; LI Weiran; LONG Haiyan

    2016-01-01

    On the basis of subsidence history analysis and balanced cross-section analysis, the vertical uplift/subsidence history and horizontal extension/compression history of the north depression of the south Yellow Sea basin are quantitatively studied. The results show that the tectonic evolution of the north depression of the south Yellow Sea basin since late Cretaceous can be divided into a rifting phase (late Cretaceous to Paleogene) and a post-rifting phase (Neogene to Quaternary). The rifting phase can be further subdivided into an initial rifting stage (late Cretaceous), an intensive rifting stage (Paleocene), a rifting termination stage (Eocene), and an inversion-uplifting stage (Oligocene). Together, this division shows the characteristics of an episodic-evolved intracontinental rift-depression basin. The deformation of the north depression of the south Yellow Sea basin since late Cretaceous was mainly fault-related. The horizontal extension and tectonic subsidence were controlled by the activity of faults. The differential evolution of faults also caused variations in local uplift/subsidence movements and the regional heterogeneity in extension. The late Cretaceous initial rifting of the north depression of the south Yellow Sea basin is related to the Pacific-Eurasia convergence. From the Paleocene intensive rifting stage to present, the Pacific-Eurasia convergence and India-Eurasia convergence have played important roles in the evolution of this region.

  16. Tectonic evolution of the north depression of the south Yellow Sea basin since late Cretaceous

    Science.gov (United States)

    Li, Nan; Li, Weiran; Long, Haiyan

    2016-12-01

    On the basis of subsidence history analysis and balanced cross-section analysis, the vertical uplift/subsidence history and horizontal extension/compression history of the north depression of the south Yellow Sea basin are quantitatively studied. The results show that the tectonic evolution of the north depression of the south Yellow Sea basin since late Cretaceous can be divided into a rifting phase (late Cretaceous to Paleogene) and a post-rifting phase (Neogene to Quaternary). The rifting phase can be further subdivided into an initial rifting stage (late Cretaceous), an intensive rifting stage (Paleocene), a rifting termination stage (Eocene), and an inversion-uplifting stage (Oligocene). Together, this division shows the characteristics of an episodic-evolved intracontinental rift-depression basin. The deformation of the north depression of the south Yellow Sea basin since late Cretaceous was mainly fault-related. The horizontal extension and tectonic subsidence were controlled by the activity of faults. The differential evolution of faults also caused variations in local uplift/subsidence movements and the regional heterogeneity in extension. The late Cretaceous initial rifting of the north depression of the south Yellow Sea basin is related to the Pacific-Eurasia convergence. From the Paleocene intensive rifting stage to present, the Pacific-Eurasia convergence and India-Eurasia convergence have played important roles in the evolution of this region.

  17. 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.

  18. Hierarchical modeling of bycatch rates of sea turtles in the western North Atlantic

    Science.gov (United States)

    Gardner, B.; Sullivan, P.J.; Epperly, S.; Morreale, S.J.

    2008-01-01

    Previous studies indicate that the locations of the endangered loggerhead Caretta caretta and critically endangered leatherback Dermochelys coriacea sea turtles are influenced by water temperatures, and that incidental catch rates in the pelagic longline fishery vary by region. We present a Bayesian hierarchical model to examine the effects of environmental variables, including water temperature, on the number of sea turtles captured in the US pelagic longline fishery in the western North Atlantic. The modeling structure is highly flexible, utilizes a Bayesian model selection technique, and is fully implemented in the software program WinBUGS. The number of sea turtles captured is modeled as a zero-inflated Poisson distribution and the model incorporates fixed effects to examine region-specific differences in the parameter estimates. Results indicate that water temperature, region, bottom depth, and target species are all significant predictors of the number of loggerhead sea turtles captured. For leatherback sea turtles, the model with only target species had the most posterior model weight, though a re-parameterization of the model indicates that temperature influences the zero-inflation parameter. The relationship between the number of sea turtles captured and the variables of interest all varied by region. This suggests that management decisions aimed at reducing sea turtle bycatch may be more effective if they are spatially explicit. ?? Inter-Research 2008.

  19. Variability of North Sea pH and CO2 in response to North Atlantic Oscillation forcing

    DEFF Research Database (Denmark)

    Salt, Lesley A.; Thomas, Helmuth; Prowe, Friederike;

    2013-01-01

    observational records covering the relevant levels of the NAO index, we provide evidence that the North Sea pH and CO2 system strongly responds to external and internal expressions of the NAO. Under positive NAO, the higher rates of inflow of water from the North Atlantic Ocean and the Baltic outflow lead......[1] High biological activity causes a distinct seasonality of surface water pH in the North Sea, which is a strong sink for atmospheric CO2 via an effective shelf pump. The intimate connection between the North Sea and the North Atlantic Ocean suggests that the variability of the CO2 system...... of the North Atlantic Ocean may, in part, be responsible for the observed variability of pH and CO2 in the North Sea. In this work, we demonstrate the role of the North Atlantic Oscillation (NAO), the dominant climate mode for the North Atlantic, in governing this variability. Based on three extensive...

  20. AoA Region: South Asian Seas

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.

    sea surface temperature, any change in river run-off is likely to provide a feedback to climate change. 7. CAPACITY OF THE REGION TO UNDERTAKE FUTURE ASSESSMENTS Even though there is adequate technical expertise and infrastructure in a few South...

  1. Palaeoenvironmental changes across the Danian–Selandian boundary in the North Sea Basin

    DEFF Research Database (Denmark)

    Clemmensen, Anne; Thomsen, Erik

    2005-01-01

    and eastern part of the North Sea Basin resulted in a huge influx of reworked Cretaceous chalk and an almost complete stop of carbonate production. Finally, later in the early Selandian, in connection to a general sea-level rise and a reduction in the gateway between the North Sea Basin and the Tethys Sea...

  2. Earthquake Activity in the North Greenland Region

    Science.gov (United States)

    Larsen, Tine B.; Dahl-Jensen, Trine; Voss, Peter H.

    2017-04-01

    Many local and regional earthquakes are recorded on a daily basis in northern Greenland. The majority of the earthquakes originate at the Arctic plate boundary between the Eurasian and the North American plates. Particularly active regions away from the plate boundary are found in NE Greenland and in northern Baffin Bay. The seismograph coverage in the region is sparse with the main seismograph stations located at the military outpost, Stations Nord (NOR), the weather station outpost Danmarkshavn (DAG), Thule Airbase (TULEG), and the former ice core drilling camp (NEEM) in the middle of the Greenland ice sheet. Furthermore, data is available from Alert (ALE), Resolute (RES), and other seismographs in northern Canada as well as from a temporary deployment of BroadBand seismographs along the north coast of Greenland from 2004 to 2007. The recorded earthquakes range in magnitude from less than 2 to a 4.8 event, the largest in NE Greenland, and a 5.7 event, the largest recorded in northern Baffin Bay. The larger events are recorded widely in the region allowing for focal mechanisms to be calculated. Only a few existing focal mechanisms for the region can be found in the ISC bulletin. Two in NE Greenland representing primarily normal faulting and one in Baffin Bay resulting from reverse faulting. New calculations of focal mechanisms for the region will be presented as well as improved hypocenters resulting from analysis involving temporary stations and regional stations that are not included in routine processing.

  3. Correcting North Atlantic sea surface salinity biases in the Kiel Climate Model: influences on ocean circulation and Atlantic Multidecadal Variability

    Science.gov (United States)

    Park, T.; Park, W.; Latif, M.

    2016-10-01

    A long-standing problem in climate models is the large sea surface salinity (SSS) biases in the North Atlantic. In this study, we describe the influences of correcting these SSS biases on the circulation of the North Atlantic as well as on North Atlantic sector mean climate and decadal to multidecadal variability. We performed integrations of the Kiel Climate Model (KCM) with and without applying a freshwater flux correction over the North Atlantic. The quality of simulating the mean circulation of the North Atlantic Ocean, North Atlantic sector mean climate and decadal variability is greatly enhanced in the freshwater flux-corrected integration which, by definition, depicts relatively small North Atlantic SSS biases. In particular, a large reduction in the North Atlantic cold sea surface temperature bias is observed and a more realistic Atlantic Multidecadal Variability simulated. Improvements relative to the non-flux corrected integration also comprise a more realistic representation of deep convection sites, sea ice, gyre circulation and Atlantic Meridional Overturning Circulation. The results suggest that simulations of North Atlantic sector mean climate and decadal variability could strongly benefit from alleviating sea surface salinity biases in the North Atlantic, which may enhance the skill of decadal predictions in that region.

  4. Impacts of Sea Surface Salinity Bias Correction on North Atlantic Ocean Circulation and Climate Variability in the Kiel Climate Model

    Science.gov (United States)

    Park, Taewook; Park, Wonsun; Latif, Mojib

    2016-04-01

    We investigated impacts of correcting North Atlantic sea surface salinity (SSS) biases on the ocean circulation of the North Atlantic and on North Atlantic sector mean climate and climate variability in the Kiel Climate Model (KCM). Bias reduction was achieved by applying a freshwater flux correction over the North Atlantic to the model. The quality of simulating the mean circulation of the North Atlantic Ocean, North Atlantic sector mean climate and decadal variability is greatly enhanced in the freshwater flux-corrected integration which, by definition, depicts relatively small North Atlantic SSS biases. In particular, a large reduction in the North Atlantic cold sea surface temperature (SST) bias is observed and a more realistic Atlantic Multidecadal Variability (AMV) simulated. Improvements relative to the non-flux corrected integration also comprise a more realistic representation of deep convection sites, sea ice, gyre circulation and Atlantic Meridional Overturning Circulation (AMOC). The results suggest that simulations of North Atlantic sector mean climate and decadal variability could strongly benefit from alleviating sea surface salinity biases in the North Atlantic, which may enhance the skill of decadal predictions in that region.

  5. Cenozoic structures and the tectonic evolution of the eastern North Sea

    DEFF Research Database (Denmark)

    Clausen, O.R.; Nielsen, S.B.; Egholm, D.L.

    2011-01-01

    Abundant seismic sections and well data from the Cenozoic succession in the eastern North Sea area generally reveal normal faulting, salt tectonics and localized tectonic inversion. However, inferences on the Cenozoic dynamic evolution of the region require thorough analysis of interactions between...... or cover tectonism took place. Our objectives are thus 1) to analyze the interaction between basement and cover structures, and if possible 2) to relate the structures to the regional tectonic evolution. The Zechstein evaporites pinch out onto the Ringkøbing-Fyn High, which in the eastern North Sea...... influencede.g. Miocene deposition and controlled the generation of second order faults. The latter detached along the top Chalk Group due to the topography generated during faulting, i.e. they are second order detachment surfaces. We conclude that the regional tectonic significance of the Cenozoic structures...

  6. The changing North Sea: knowledge, speculation and new challenges

    Directory of Open Access Journals (Sweden)

    Jürgen Sündermann

    2003-06-01

    Full Text Available Synthesis and New Conception of North Sea Research (SYCON is the title of a German project carried out from 1998-2000 under the leadership of Hamburg University 1. It was accompanied by an international advisory board and covered North Sea issues as well as the general challenges to shelf sea research and sustainable management under global change. Particular emphasis was placed on the interdisciplinary analysis of comprehensive areas of knowledge: the data situation, understanding of processes, model development, instruments and methods, understanding of the system. Based onthis, perspectives for future North Sea research were developed. The project produced a synthesis report, eleven monodisciplinaryreports and an illustrated brochure for the general public (see Annex 1, this paper, p. 258.1The SYCON Project was carried out with support of the German Federal Ministry of Education and Research under GrantNo. 03F0215A. This article is based on the SYCON Synthesis Report (Südermann et al. 2001.

  7. Regional variability in sea ice melt in a changing Arctic.

    Science.gov (United States)

    Perovich, Donald K; Richter-Menge, Jacqueline A

    2015-07-13

    In recent years, the Arctic sea ice cover has undergone a precipitous decline in summer extent. The sea ice mass balance integrates heat and provides insight on atmospheric and oceanic forcing. The amount of surface melt and bottom melt that occurs during the summer melt season was measured at 41 sites over the time period 1957 to 2014. There are large regional and temporal variations in both surface and bottom melting. Combined surface and bottom melt ranged from 16 to 294 cm, with a mean of 101 cm. The mean ice equivalent surface melt was 48 cm and the mean bottom melt was 53 cm. On average, surface melting decreases moving northward from the Beaufort Sea towards the North Pole; however interannual differences in atmospheric forcing can overwhelm the influence of latitude. Substantial increases in bottom melting are a major contributor to ice losses in the Beaufort Sea, due to decreases in ice concentration. In the central Arctic, surface and bottom melting demonstrate interannual variability, but show no strong temporal trends from 2000 to 2014. This suggests that under current conditions, summer melting in the central Arctic is not large enough to completely remove the sea ice cover. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  8. Tourism Profile Danish North Sea Coast

    DEFF Research Database (Denmark)

    Hergesell, Anja; Blichfeldt, Bodil Stilling

    2007-01-01

    in the major source markets. On the other hand, the domestic demand grew in importance while the German market, especially due to the continuous shortening of holiday stays, has declined in terms of overnights but has slightly recovered in the geographically closer southern part of Jutland. Despite the latter...... observations, the Germans continue to account for most of all overnights and remain the dominant segment in the southern parts of the peninsula, while the domestic demand prevails in the north. Despite the above described changes and the differences among origin markets regarding their preferred type...... star qualification, there are various systems based on the type of business, themes and environmental friendliness. As these quality schemes predominantly apply technical criteria, they are of limited use in the assessment of supply quality. The tourism labour force plays a crucial role in the delivery...

  9. Cenozoic evolution of the eastern Danish North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Huuse, M.; Lykke-Andersen, H.; Michelsen, O.

    2003-12-01

    This paper provides a review of recent high-resolution and conventional seismic investigations in the eastern Danish North Sea and destribes their implications for the development of the eastern North Sea Basin. The results tomprise detailed timestructure maps of four major unconformities in the eastern Danish North Sea: the Top Chalk surface (mid-Paleogene), near top Oligocene, the mid-Miocene unconformity, and base Quatemary. The maps show that the eastem Danish North Sea has been affected by fauldng and salt diapirism throughout the Cenozoic. Carbonate mounds, erosional valleys and pockmark- or karstlike struttures were identitied at the top of the Upper Cretaceous-Danian Chalk Group. Strike-parallel erosional features and depositional geometries observed at near top Oligocene and at the mid-Miocene unconformity indicate that these major sequence boundarics tan be attributed to large-scale lateral changes in sediment supply directions. Increases in sediment flux to the southeastern North Sea at the Eocene/Oligocene transition and in the post-Middle Miocene appear to correlate with similar events world wide and with long term {delta} {sup 18} O increases, indicating forting by global factors, i.e. eustasy and climate. Stratal geometries observed on the seismic data indicate that the socalled `Neogene uplift' of the Bastern Danish North Sea may have been hundreds of metres less than previously suggested. lt is argued that late Cenozoic uplift of the basin margin and of mountain peaks in southern Norway may have been caused entirely by isostatic uplift of the trust in response to accelerated late Cenozoic denudation and dissection of topography created in the Paleogene. The late Cenozoic periods of accelerated denudation and incision rates were most likely driven by climatic deterioration and long term eustatic lowering rather than active late Cenozoic tectonics, the cause of which is conjectural. A series of shallow thrust struttures and an associated system

  10. Regional warming chnages fish species richness in the eastern North Atlantic Ocean

    NARCIS (Netherlands)

    Hofstede, ter R.; Hiddink, J.G.; Rijnsdorp, A.D.

    2010-01-01

    Regional warming causes changes in local communities due to species extinctions and latitudinal range shifts. We show that the species richness of fish in 3 regional seas in the eastern North Atlantic Ocean has changed over time (1997 to 2008), and we relate this to higher water temperatures and the

  11. The Netherlands' environmental policy for the North Sea and Wadden Sea.

    Science.gov (United States)

    Beukema, A A; Hekstra, G P; Venema, C

    1986-09-01

    The water quality management of The Netherlands' part of the North Sea (57 000 km(2) continental shelf of which 7600 km(2) is territorial sea to 12 miles) and the Wadden Sea (a wetland area behind the northern coastal islands), is described on the basis of recent scientific studies and governmental policy documents. The links with international conventions and treaties are mentioned. The overall water quality in these areas has significantly deteriorated over the last century, notably since the post-war industrial revival, due to a great number of emissions of heavy metals and organochlorine substances. A dramatic decline of seals and porpoises has occurred. However, over the last few years some emissions have been reduced. A national ecological research programme for the North Sea is developing. Monitoring is concentrated on levels of pollutants as well as on effects upon biota. Baseline standards are now being developed as references for further action against pollution. If the recent trend towards improvement is to continue, it requires that the increased economic activities (notably the mining of oil and gas, petrochemical production, and incineration and dumping of chemical wastes) be kept sufficiently under control. A need is felt for a continued rational harmonization and planning of all activities on the North Sea. An even more stringent planning is required for the Wadden Sea which is now an international nature reserve under the Wetland Convention and is eligible for designation as a Biosphere Reserve under the UNESCO-MAB-programme. The river Rhine as greatest polluter of the North Sea and Wadden Sea urgently needs a clean-up.

  12. Temperature, salinity, and nutrients data collected from North Atlantic Ocean, White Sea, Mediterranean Sea, Black Sea, and Sea of Azov from 1924-03-19 to 1989-11-19 by multiple Soviet Union institutes (NODC Accession 0077413)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, and nutrients data collected from North Atlantic Ocean, White Sea, Mediterranean Sea, Black Sea, and Sea of Azov from 1924-03-19 to 1989-11-19...

  13. Spatial sensitivity of inorganic carbon to model setup: North Sea and Baltic Sea with ECOSMO

    Science.gov (United States)

    Castano Primo, Rocio; Schrum, Corinna; Daewel, Ute

    2015-04-01

    In ocean biogeochemical models it is critical to capture the key processes adequately so they do not only reproduce the observations but that those processes are reproduced correctly. One key issue is the choice of parameters, which in most cases are estimates with large uncertainties. This can be the product of actual lack of detailed knowledge of the process, or the manner the processes are implemented, more or less complex. In addition, the model sensitivity is not necessarily homogenous across the spatial domain modelled, which adds another layer of complexity to biogeochemical modelling. In the particular case of the inorganic carbon cycle, there are several sets of carbonate constants that can be chosen. The calculated air-sea CO2 flux is largely dependent on the parametrization chosen. In addition, the different parametrizations all the underlying processes that in some way impact the carbon cycle beyond the carbonate dissociation and fluxes give results that can be significantly different. Examples of these processes are phytoplankton growth rates or remineralization rates. Despite their geographical proximity, the North and Baltic Seas exhibit very different dynamics. The North Sea receives important inflows of Atlantic waters, while the Baltic Sea is an almost enclosed system, with very little exchange from the North Sea. Wind, tides, and freshwater supply act very differently, but dominantly structure the ecosystem dynamics on spatial and temporal scales. The biological community is also different. Cyanobacteria, which are important due to their ability to fix atmospheric nitrogen, and they are only present in the Baltic Sea. These differentiating features have a strong impact in the biogeochemical cycles and ultimately shape the variations in the carbonate chemistry. Here the ECOSMO model was employed on the North Sea and Baltic Sea. The model is set so both are modelled at the same time, instead of having them run separately. ECOSMO is a 3-D coupled

  14. How does the SST variability over the western North Atlantic Ocean control Arctic warming over the Barents–Kara Seas?

    Science.gov (United States)

    Jung, Ok; Sung, Mi-Kyung; Sato, Kazutoshi; Lim, Young-Kwon; Kim, Seong-Joong; Baek, Eun-Hyuk; Jeong, Jee-Hoon; Kim, Baek-Min

    2017-03-01

    Arctic warming over the Barents–Kara Seas and its impacts on the mid-latitude circulations have been widely discussed. However, the specific mechanism that brings the warming still remains unclear. In this study, a possible cause of the regional Arctic warming over the Barents–Kara Seas during early winter (October–December) is suggested. We found that warmer sea surface temperature anomalies over the western North Atlantic Ocean (WNAO) modulate the transient eddies overlying the oceanic frontal region. The altered transient eddy vorticity flux acts as a source for the Rossby wave straddling the western North Atlantic and the Barents–Kara Seas (Scandinavian pattern), and induces a significant warm advection, increasing surface and lower-level temperature over the Eurasian sector of the Arctic Ocean. The importance of the sea surface temperature anomalies over the WNAO and subsequent transient eddy forcing over the WNAO was also supported by both specially designed simple model experiments and general circulation model experiments.

  15. Ecology of the North Sea: Problems, successes, failures, future needs

    Science.gov (United States)

    Kinne, O.

    1995-03-01

    After defining ‘ecology’, outlining the basic categories of ecological research and listing examples of modern ecological investigations, this introductory paper focusses on basic considerations; it is, in essence, a programmatic contribution. Research details on the ecology of the North Sea are the subject of the following papers. The problems of ecological North Sea research are formidable. Hydrological and biological fluctuations and variabilities are pronounced. Exchange patterns with the Atlantic are complex, and the inputs of rivers and rain defy exact measurement and prediction. Season, weather, climate—and as yet insufficiently known and controlled human-caused impacts—further complicate the situation. All this results in an unusually high degree of uncertainty. New questions and problems arise before the old ones can be answered or solved. Nevertheless, ecological North Sea research has achieved many successes. The North Sea is the most intensively investigated sea area on our planet. Generations of zoologists, botanists and hydrographers — and more recently microbiologists, meteorologists, climatologists, chemists, pathologists and toxicologists — have produced an impressive body of knowledge. Slowly we are beginning to understand the forces that govern energy budgets and balances, material fluxes, and the factors that control and direct ecosystem dynamics. Essential driving forces of ecosystem dynamics result from microbial, especially bacterial, activities. Ecological modelling has paved the way for new theories and insights, and holds promise for progress towards a predictive ecology. Failures and shortcomings include insufficient long-term research, inadequately designed experiments, and misconceptions in environmental protection. Net changes in ecological processes of an heterogeneous and intensely varying environment such as the North Sea can only be comprehended adequately against the background of sustained measurements over decades

  16. NEMO-Nordic : A NEMO based ocean modelling configuration for Baltic & North Seas

    Science.gov (United States)

    Hordoir, Robinson; Schimanke, Semjon; Axell, Lars; Gröger, Matthias; Dieterich, Christian; Liu, Ye; Höglund, Anders; Kuznetsov, Ivan; Ljungemyr, Patrik; Nygren, Petter; Jönsson, Anette; Meier, Markus

    2015-04-01

    Based on the NEMO ocean engine, three regional setups for the North Sea and Baltic Sea domain have been developed : the NEMO-Nordic configuration is declined in an operational setup, a stand-alone version used for climate and process studies, and a NEMO-Nordic-RCA4 atmosphere/ocean coupled configuration used for downscalling climate scenarios. We give a brief overview of the options chosen within the NEMO engine to design the configurations. Based on the results provided by each of the three configurations, we also provide an assessment of the strengths and weaknesses of NEMO-Nordic. Finally, a validation of the configurations is provided based on an extensive comparison between in-situ measurements and model results for temperature, salinity, sea-ice extent, sea level and mean circulation.

  17. Shallow gas in Cenozoic sediments of the Southern North Sea

    Science.gov (United States)

    Trampe, Anna F.; Lutz, Rüdiger; Franke, Dieter; Thöle, Hauke; Arfai, Jashar

    2013-04-01

    Shallow petroleum systems in the southern North Sea are known for several decades but they were not actively explored for a long time. In recent years these unconventional shallow petroleum systems are studied in greater detail and one shallow gas field (A-12) is in production in the Netherlands. Additionally, oil was encountered in Miocene sandstones in the southern Danish North Sea (Lille John well) just north of the Danish-German border. Seismic amplitude anomalies are an indication for hydrocarbons in sediments. Therefore we have mapped the occurrence of seismic amplitude anomalies in the German North Sea based on more than 25.000 km of 2D seismic data and around 4.000 km2 of 3D seismic data. Amplitude anomalies are ubiquitous phenomena in the study area. These anomalies are not only caused by hydrocarbons but also by changing lithologies e.g. peat or fluid migration. Therefore several classes of seismic anomalies, e.g. bright spots, chimneys, blanking areas and velocity pull-down were mapped. Examples for these classes were studied with AVO (amplitude variation with offset) analyses to verify the existence or non-existence of gas in the sediments. Shallow gas can be produced and transported through the dense pipeline grid of the southern and central North Sea or it could be burned offshore close to wind parks in small power plants and the electric energy then transported through the existing power connections of the wind parks. Thus enabling a continuous energy supply during calm wind periods. This study is carried out within the framework of the project "Geoscientific Potential of the German North Sea (GPDN)" in which the Cenozoic sedimentary system was mapped in great detail. A detailed model of delta evolution (Baltic river system) was developed which serves as a structural framework. The studied interval is time equivalent to the Utsira formation which is used offshore Norway for sequestration of CO2. These different possibilities of using or exploiting

  18. Report on ICDP workshop CONOSC (COring the NOrth Sea Cenozoic)

    Science.gov (United States)

    Westerhoff, Wim; Donders, Timme; Luthi, Stefan

    2016-08-01

    ICDP workshop COring the NOrth Sea Cenozoic focused on the scientific objectives and the technical aspects of drilling and sampling. Some 55 participants attended the meeting, ranging from climate scientists, drilling engineers, and geophysicists to stratigraphers and public outreach experts. Discussion on the proposed research sharpened the main research lines and led to working groups and the necessary technical details to compile a full proposal that was submitted in January 2016.

  19. Cenozoic structures and the tectonic evolution of the eastern North Sea

    DEFF Research Database (Denmark)

    Clausen, O.R.; Nielsen, S.B.; Egholm, D.L.

    2011-01-01

    Abundant seismic sections and well data from the Cenozoic succession in the eastern North Sea area generally reveal normal faulting, salt tectonics and localized tectonic inversion. However, inferences on the Cenozoic dynamic evolution of the region require thorough analysis of interactions between....... These structures have in the last decades been an integrated part of the discussions about subsidence and uplift of not only the interior of the basin but also of the basin margin. Abundant 2D and 3D seismic data and new depositional models enable detailed analysis and reinterpretation of where and when basement...... or cover tectonism took place. Our objectives are thus 1) to analyze the interaction between basement and cover structures, and if possible 2) to relate the structures to the regional tectonic evolution. The Zechstein evaporites pinch out onto the Ringkøbing-Fyn High, which in the eastern North Sea...

  20. Regional higher education co-operation: a research proposal to compare the Baltic Sea and the Black Sea regions

    Directory of Open Access Journals (Sweden)

    Stefan Ewert

    2011-12-01

    Full Text Available While the Baltic Sea Region is considered to be a pioneer region in the development of regional integration and identity, the Black Sea Region is regarded to be a laggard in terms of regionali¬zation and region building. My paper summarizes the role of regional higher education co-operation in the Baltic Sea regionalization process in theory and analyzes the empirical background of these assumptions. Yet, inasmuch an evaluation of the regions` status as a pioneer is possible only in a comparative perspective, I propose to compare the Black Sea and the Baltic Sea Region regarding their higher education networks systematically. My paper asks for the transferability of arguments in favor of a strong regional higher education co-operation in the Baltic Sea Region since the 1990s to today’s situation of the Black Sea Region. It concludes with some fundamental considerations on a comparative research project.

  1. Airborne gravity survey of Lincoln Sea and Wandel Sea, north Greenland

    DEFF Research Database (Denmark)

    Olesen, Arne Vestergaard; Forsberg, René; Keller, K.

    2000-01-01

    In June 1998 National Survey and Cadastre Denmark (KMS) carried out an airborne gravity survey over the Polar Sea to the north of Greenland. A Twin Otter from Greenlandair, equipped with autopilot and additional fuel tanks, was employed for the survey. A modified marine LaCoste & Romberg gravimeter...

  2. Geopolitical Interests in the Black Sea / Caspian Region

    Science.gov (United States)

    2011-03-21

    conquest was focused on reaching step by step the Carpathian Mountains and the Baltic Sea in the west and northwest, the Black Sea and Caspian Sea in...Plain, Ural Mountains and the Barents Sea in the North), determined an offensive and aggressive political stance towards the neighboring countries...the south, then, the Tien Shan and Pamir Mountains range in the south east, and later the Pacific Ocean coast in the Far East (natural boundaries).9

  3. Quantifying the impact of the major driving mechanisms of inter-annual variability of salinity in the North Sea

    Science.gov (United States)

    Núñez-Riboni, Ismael; Akimova, Anna

    2017-05-01

    New 67-year long (1948-2014) gridded time series of salinity in the North Sea at all depths allowed to quantify, spatially resolved, the amount of inter-annual salinity variability explained by each of its driving mechanisms: sea level pressure (SLP), precipitation, river run-off, zonal and meridional winds and currents over the eastern North Atlantic. For the current data, not only annual averages but also their deviations, as measure of turbulence, were considered. Our results summarize and expand the knowledge gathered in the last 50 years about the mechanisms driving inter-annual variability of salinity in the North Sea. Three mechanisms, uncorrelated with each other and acting over separate regions of the North Sea, arise as most important: (1) River run-off from continental Europe explains 50-80% of inter-annual salinity variations at lag 0 in the Southern and German Bights and the Norwegian Trench up to the connection with the North Atlantic, down to the seabed near the coasts and to the deep Norwegian Trench (100 m); (2) Remote variations of salinity in the Rockall Trough explain 70% of salinity variations of the tongue of high salinity in the northwestern North Sea with a lag of one year and down the water column; (3) The Neva discharge explains 60% of salinity changes in Skagerrak and southern Norwegian trench at lag 0. An explanation for this correlation might be the Baltic freshwater outflow being modulated by the Neva discharge through intensification of the estuarine gravitational circulation. We confirmed known relations between river run-off, precipitation over continental Europe, SLP over northern Europe and zonal wind over western Europe. Linked to these changes, we found also changes of meridional wind north of Scotland favoring eastward Ekman transport of salty North Atlantic waters into the North Sea off the Norwegian coast. Excluding this only case, we found no significant correlation between wind-driven currents and North Sea salinity changes

  4. Sea-ice evaluation of NEMO-Nordic 1.0: a NEMO–LIM3.6-based ocean–sea-ice model setup for the North Sea and Baltic Sea

    Directory of Open Access Journals (Sweden)

    P. Pemberton

    2017-08-01

    Full Text Available The Baltic Sea is a seasonally ice-covered marginal sea in northern Europe with intense wintertime ship traffic and a sensitive ecosystem. Understanding and modeling the evolution of the sea-ice pack is important for climate effect studies and forecasting purposes. Here we present and evaluate the sea-ice component of a new NEMO–LIM3.6-based ocean–sea-ice setup for the North Sea and Baltic Sea region (NEMO-Nordic. The setup includes a new depth-based fast-ice parametrization for the Baltic Sea. The evaluation focuses on long-term statistics, from a 45-year long hindcast, although short-term daily performance is also briefly evaluated. We show that NEMO-Nordic is well suited for simulating the mean sea-ice extent, concentration, and thickness as compared to the best available observational data set. The variability of the annual maximum Baltic Sea ice extent is well in line with the observations, but the 1961–2006 trend is underestimated. Capturing the correct ice thickness distribution is more challenging. Based on the simulated ice thickness distribution we estimate the undeformed and deformed ice thickness and concentration in the Baltic Sea, which compares reasonably well with observations.

  5. Sea-ice evaluation of NEMO-Nordic 1.0: a NEMO-LIM3.6-based ocean-sea-ice model setup for the North Sea and Baltic Sea

    Science.gov (United States)

    Pemberton, Per; Löptien, Ulrike; Hordoir, Robinson; Höglund, Anders; Schimanke, Semjon; Axell, Lars; Haapala, Jari

    2017-08-01

    The Baltic Sea is a seasonally ice-covered marginal sea in northern Europe with intense wintertime ship traffic and a sensitive ecosystem. Understanding and modeling the evolution of the sea-ice pack is important for climate effect studies and forecasting purposes. Here we present and evaluate the sea-ice component of a new NEMO-LIM3.6-based ocean-sea-ice setup for the North Sea and Baltic Sea region (NEMO-Nordic). The setup includes a new depth-based fast-ice parametrization for the Baltic Sea. The evaluation focuses on long-term statistics, from a 45-year long hindcast, although short-term daily performance is also briefly evaluated. We show that NEMO-Nordic is well suited for simulating the mean sea-ice extent, concentration, and thickness as compared to the best available observational data set. The variability of the annual maximum Baltic Sea ice extent is well in line with the observations, but the 1961-2006 trend is underestimated. Capturing the correct ice thickness distribution is more challenging. Based on the simulated ice thickness distribution we estimate the undeformed and deformed ice thickness and concentration in the Baltic Sea, which compares reasonably well with observations.

  6. Temperature and salinity profile data collected by bottle on multiple cruises in the Baltic Sea, Baffin Bay, Davis Strait, the North Atlantic Ocean, and the North Sea from 02 January 1985 to 13 November 1989 (NODC Accession 0000056)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and nutrients data were collected using bottle casts from DANA and other platforms in Baffin Sea, Baltic Sea, Davis Strait, North Sea, and North...

  7. Response of the Baltic and North Seas to river runoff from the Baltic watershed - Physical and biological changes

    Science.gov (United States)

    Hänninen, Jari; Vuorinen, Ilppo; Rajasilta, Marjut; Reid, Philip C.

    2015-11-01

    Selected Baltic Sea watershed River Runoff (BSRR) events during 1970-2000 were used as predictor in Generalised Linear Mixed Models (GLIMMIX) for evidence of simultaneous changes/chain of events (including possible time lags) in some chemical, physical and biological variables in the Baltic and North Sea ecosystems. Our aim was to explore for climatic-based explanation for ecological regime shifts that were documented semi-simultaneously in both ecosystems. Certain similarities were identified in the North Sea and the Baltic Sea salinity, oxygen concentration, temperature and phyto- and zooplankton parameters. These findings suggest that BSRR events which originate in the Baltic Sea catchment area modify and contribute to large scale ecosystem changes not only in the Baltic Sea, but also in the adjacent parts of the North Sea. However, the Baltic Sea inter-annual and inter-decadal variabilities of physical and biological parameters are driven by direct atmospheric forcing, typically with a relatively short lag. In contrast, such changes in the North Sea are influenced by both local and direct atmospheric forcing, typically with a longer lag than in the Baltic, and a more regional, indirect forcing from changes in the North Atlantic. We suggest that this interactive system partially is behind large scale ecosystem regime shifts found in both Seas. During our study period two such shifts have been identified independently from us in a study earlier in the Southern and Central Baltic in 1980s and 1990s and a later one in 2001/2002 in the North Sea. As a post hoc test we compared the 0+ year class strength of the North Sea herring with BSRR intensity, and found evidence for higher herring production in high BSRR periods, which further corroborates the idea of a remote effect from the large watershed area of the Baltic. Regime shifts as well as their semi-synchronous appearance in two neighbouring sea areas could be identified. GLIMMIX models provide opportunities for

  8. Tourism Profile Danish North Sea Coast

    DEFF Research Database (Denmark)

    Hergesell, Anja; Blichfeldt, Bodil Stilling

    2007-01-01

    and learning structures, the review of innovative projects and evaluation of the region's innovativeness, and the identification of actors shaping tourism related policies and development strategies. Overall, tourism demand and supply in the Danish NSR has hardly changed in the last five years. However, while...... the basis for the development of off-season products. Changes in the information and booking behaviour such as the rising importance of the internet and differences among the segments related to the timing of destination choice have to receive further consideration. Tourism supply is at a consolidated stage...... of satisfying tourist experiences. The high turnover, large share of insufficiently skilled staff and shortage in tourism employees lessen the quality provided; these issues are thus identified as challenges to tourism development. An assessment of tourism's sustainability in the Danish NSR turned out...

  9. Hourly to Decadal variability of sea surface carbon parameters in the north western Mediteranean Sea

    Science.gov (United States)

    Boutin, Jacqueline; Merlivat, Liliane; Antoine, David; Beaumont, Laurence; Golbol, Melek; Velluci, Vincenzo

    2017-04-01

    Sea surface CO2 fugacity, fCO2, is recorded hourly in the north western Mediterranean Sea since 2013 by two CARIOCA (Carbon Interface Ocean Atmosphere) sensors installed on the BOUSSOLE (Buoy for the acquisition of long term optical time series, http://www.obs-vlfr.fr/Boussole/html/project/introduction.php) mooring at 3m and 10m depth. fCO2 exhibits a large seasonal cycle, about 150 microatm peak to peak, very consistent with earlier CARIOCA measurements taken in 1995-1999 at the DYFAMED site (located 6km apart from the BOUSSOLE mooring) (Hood and Merlivat, JMR, 2001; Copin-Montegut et al., Mar. Chem., 2004): this seasonal cycle is driven primarily by intense mixing in Winter, biological uptake during Spring and warming during Summer. Interannual variability of these processes leads to interannual variability of monthly mean fCO2 that can reach more than 20 microatm. The short term variability (1 hour to 1 week) is large, especially during Summer 2014 (more than 40 microatm) due to a very strong vertical stratification and to the influence of internal waves. The hourly CARIOCA measurements allow to correctly filter out the high frequency variability while the three year long time series allow to smooth out interannual variability. Hence, for the first time, we get a precise estimate of the change of fCO2 in surface waters within 20 years. Over the 1995-2015 interval, we estimate an increase of fCO2 computed at a constant temperature of 13˚ C equal to 1.8 microatm per year. Given the alkalinity/salinity relationship in this region, we estimate mean annual rates of change of -0.0023+/-0.0001 pH unit and of +1.47+/-0.03 μmol kg-1 for pH and DIC respectively. These results give a quantitative estimate of the penetration of anthropogenic carbon in the surface waters of the northwestern Mediterranean Sea, about 80% via air-sea exchange and 20% via transport of carbon from the Atlantic across the Strait of Gibraltar as suggested by Palmieri et al (BG, 2015). We estimate

  10. The first occurrence of the ctenophore Mnemiopsis leidyi in the North Sea

    Science.gov (United States)

    Boersma, Maarten; Malzahn, Arne M.; Greve, Wulf; Javidpour, Jamileh

    2007-06-01

    After the discovery of large densities of Mnemiopsis leidyi in the Baltic Sea near Kiel by Javidpour et al. (First record of Mnemiopsis leidyi A. Agassiz 1865 in the Baltic Sea, 2006) in October 2006, we investigated the gelatinous zooplankton in the North Sea near Helgoland and recorded Mnemiopsis leidyi for the first time in the North Sea, albeit in much lower densities than those recorded in the Baltic Sea.

  11. Beached bird surveys indicate decline in chronic oil pollution in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Camphuysen, K.C.J. [Netherlands Institute for Sea Research, Texel (Netherlands)

    1998-12-31

    Strandings of oiled seabirds have been a signal of the ongoing problem of chronic oil pollution in the North Sea since the beginning of the twentieth century. Overall numbers of beached birds are subject to enormous fluctuations, being the result, for example, of changes in the amount of oil spilled in the marine environment, currents, the frequency of onshore winds and variations in the numbers of seabirds in a given region. In contrast, oil rates, being the fraction of oiled birds of the total stranded, appeared to be relatively constant while specific for different species and regions. A power analysis of the results of beached bird surveys demonstrated the sensitivity of these data as a tool to monitor trends in oil rates of stranded birds. Rather subtle changes in oil rates could be demonstrated, indicating positive results of attempts to protect certain sea areas (e.g. the Wadden Sea) and a decline in oil rates over time. (author)

  12. Marine environment protection for the North and Baltic Seas. Special Report - February 2004

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The marine environment of the North Sea and Baltic Sea is still heavily polluted. The marine ecosystems are under severe stress from overfishing, water pollution, raw materials production and tourism. Environmental protection in this region necessitates decisive political initiatives and strict corrections especially in fishery policy, agricultural policy and chemical substances control. This is the balance of the special expert opinion of the Council of Environmental Experts. The publication specifies the main problem areas, the current pollution situation, the fields where action is most urgently required - especially in fishery, chemical substances, agricultural and sea travel policies - and presents suggestions for an integrated European and national marine protection policy including a regional development concept for the marine environment. (orig.)

  13. Modeling the buoyancy-driven Black Sea Water outflow into the North Aegean Sea

    Directory of Open Access Journals (Sweden)

    Nikolaos Kokkos

    2016-04-01

    Full Text Available A three-dimensional numerical model was applied to simulate the Black Sea Water (BSW outflux and spreading over the North Aegean Sea, and its impact on circulation and stratification–mixing dynamics. Model results were validated against satellite-derived sea surface temperature and in-situ temperature and salinity profiles. Further, the model results were post-processed in terms of the potential energy anomaly, ϕ, analyzing the factors contributing to its change. It occurs that BSW contributes significantly on the Thracian Sea water column stratification, but its signal reduces in the rest of the North Aegean Sea. The BSW buoyancy flux contributed to the change of ϕ in the Thracian Sea by 1.23 × 10−3 W m−3 in the winter and 7.9 × 10−4 W m−3 in the summer, significantly higher than the corresponding solar heat flux contribution (1.41 × 10−5 W m−3 and 7.4 × 10−5 W m−3, respectively. Quantification of the ϕ-advective term crossing the north-western BSW branch (to the north of Lemnos Island, depicted a strong non-linear relation to the relative vorticity of Samothraki Anticyclone. Similar analysis for the south-western branch illustrated a relationship between the ϕ-advective term sign and the relative vorticity in the Sporades system. The ϕ-mixing term increases its significance under strong winds (>15 m s−1, tending to destroy surface meso-scale eddies.

  14. Warming in the Nordic Seas, North Atlantic storms and thinning Arctic sea ice

    Science.gov (United States)

    Alexeev, Vladimir A.; Walsh, John E.; Ivanov, Vladimir V.; Semenov, Vladimir A.; Smirnov, Alexander V.

    2017-08-01

    Arctic sea ice over the last few decades has experienced a significant decline in coverage both in summer and winter. The currently warming Atlantic Water layer has a pronounced impact on sea ice in the Nordic Seas (including the Barents Sea). More open water combined with the prevailing atmospheric pattern of airflow from the southeast, and persistent North Atlantic storms such as the recent extremely strong Storm Frank in December 2015, lead to increased energy transport to the high Arctic. Each of these storms brings sizeable anomalies of heat to the high Arctic, resulting in significant warming and slowing down of sea ice growth or even melting. Our analysis indicates that the recently observed sea ice decline in the Nordic Seas during the cold season around Svalbard, Franz Joseph Land and Novaya Zemlya, and the associated heat release from open water into the atmosphere, contributed significantly to the increase in the downward longwave radiation throughout the entire Arctic. Added to other changes in the surface energy budget, this increase since the 1960s to the present is estimated to be at least 10 W m-2, which can result in thinner (up to at least 15-20 cm) Arctic ice at the end of the winter. This change in the surface budget is an important contributing factor accelerating the thinning of Arctic sea ice.

  15. Complex molecules in W51 North region

    CERN Document Server

    Rong, Jialei; Zapata, Luis A; Wu, Yuefang; Liu, Tie; Zhang, Chengpeng; Peng, Yaping; Zhang, Li; Liu, Ying

    2015-01-01

    We present Submillimeter Array (SMA) molecular line observations in two 2 GHz-wide bands centered at 217.5 and 227.5 GHz, toward the massive star forming region W51 North. We identified 84 molecular line transitions from 17 species and their isotopologues. The molecular gas distribution of these lines mainly peaks in the continuum position of W51 North, and has a small tail extending to the west, probably associated with W51 d2. In addition to the commonly detected nitrogen and oxygen-bearing species, we detected a large amount of transitions of the Acetone (CH$_3$COCH$_3$) and Methyl Formate (CH$_3$OCHO), which may suggest that these molecules are present in an early evolutionary stage of the massive stars. We also found that W51 North is an ethanol-rich source. There is no obvious difference in the molecular gas distributions between the oxygen-bearing and nitrogen-bearing molecules. Under the assumption of Local Thermodynamic Equilibrium (LTE), with the XCLASS tool, the molecular column densities, and rota...

  16. Climate impacts on the structures of the North Pacific air-sea CO2 flux variability

    Directory of Open Access Journals (Sweden)

    Y. Nojiri

    2011-05-01

    Full Text Available Some dominant spatial and temporal structures of the North Pacific air-sea CO2 fluxes in response to the Pacific Decadal Oscillation (PDO are identified in four data products from four independent sources: an assimilated CO2 flux product, two forward model solutions, and a gridded pCO2 dataset constructed with a neural network approach. The interannual variability of CO2 flux is found to be an order of magnitude weaker compared to the seasonal cycle of CO2 flux in the North Pacific. A statistical approach is employed to quantify the signal-to-noise ratio in the reconstructed dataset to delineate the representativity errors. The dominant variability with a signal-to-noise ratio above one is identified and its correlations with PDO are examined. A tentative four-box structure in the North Pacific air-sea CO2 flux variability linked to PDO emerges in which two positively correlated boxes are oriented in the northwest and southeast directions and contrarily, the negatively correlated boxes are oriented in the northeast and southwest directions. This pattern is verified with the CO2 and pCO2 from four products and its relations to the interannual El Niño-Southern Oscillation (ENSO and lower-frequency PDO are separately identified. A combined EOF analysis between air-sea CO2 flux and key variables representing ocean-atmosphere interactions is carried out to elicit robust oscillations in the North Pacific CO2 flux in response to the PDO. The proposed spatial and temporal structures of the North Pacific CO2 fluxes are insightful since they separate the secular trends of the surface ocean carbon from the interannual variability. The regional characterization of the North Pacific in terms of PDO and CO2 flux variability is also instructive for determining the homogeneous oceanic domains for the Regional Carbon Cycle and Assessment Processes (RECCAP.

  17. Modes of sedimentary basin formation in the north-eastern Black Sea

    Science.gov (United States)

    Stephenson, Randell; Starostenko, Vitaly; Sydorenko, Grygoriy; Yegorova, Tamara

    2016-04-01

    The Greater Caucasus and Black Sea sedimentary basins developed in a Mesozoic back-arc setting, the former older than the latter (Jurassic v. Cretaceous). Compressional shortening of the former and accompanying ongoing development of marginal basin depocentres in the north-eastern Black Sea - which is closely tied to the formation of the Crimea-Greater Caucasus orogen - is a Cenozoic phenomenon, starting in the Eocene and proceeding until the present day. Recently, the sedimentary basin/crust/lithosphere geometry of the study area has been characterised across a range of scales using regional seismic reflection profiling, long-offset refraction/wide-angle reflection profiling and local earthquake tomography. These provide a new integrated image of the present-day crustal structure and sedimentary basin architecture of the northern margin of the eastern Black Sea, north across the Azov Sea and provide evidence of the deeper expression of sedimentary basins and the processes controlling the geometry of their inversion during the Cenozoic. It is inferred that the Greater Caucasus paleo-Basin, lying stratigraphically below the Black Sea and younger sedimentary successions, extends further to the west than previously known. This basin has significant thickness in the area between the Azov and Black seas and probably forms the deeper core of the Crimea-Caucasus inversion zone. The Crimea-Greater Caucasus orogenic belt is the expression of "basin inversion" of the Jurassic Greater Caucasus paleo-Basin, the degree of inversion of which varies along strike. The Greater Caucasus foredeep basins - Indolo-Kuban and Sorokin-Tuapse troughs -represent syn-inversional marginal troughs to the main inversion zone. The Shatsky Ridge - the northern flank of the main East Black Sea Basin - may also be mainly a syn-inversional structure, underlain by a blind thrust zone expressed as a northward dipping zone of seismicity on the northern margin of the eastern Black Sea.

  18. Rapid decline of the CO2 buffering capacity in the North Sea and implications for the North Atlantic Ocean

    NARCIS (Netherlands)

    Thomas, Helmuth; Prowe, A. E. Friederike; van Heuven, Steven; Bozec, Yann; de Baar, Hein J. W.; Schiettecatte, Laure-Sophie; Suykens, Kim; Kone, Mathieu; Borges, Alberto V.; Lima, Ivan D.; Doney, Scott C.

    2007-01-01

    New observations from the North Sea, a NW European shelf sea, show that between 2001 and 2005 the CO2 partial pressure (pCO(2)) in surface waters rose by 22 mu atm, thus faster than atmospheric pCO(2), which in the same period rose approximately 11 matm. The surprisingly rapid decline in air-sea par

  19. Rapid decline of the CO2 buffering capacity in the North Sea and implications for the North Atlantic Ocean

    NARCIS (Netherlands)

    Thomas, Helmuth; Prowe, A. E. Friederike; van Heuven, Steven; Bozec, Yann; de Baar, Hein J. W.; Schiettecatte, Laure-Sophie; Suykens, Kim; Kone, Mathieu; Borges, Alberto V.; Lima, Ivan D.; Doney, Scott C.

    2007-01-01

    New observations from the North Sea, a NW European shelf sea, show that between 2001 and 2005 the CO2 partial pressure (pCO(2)) in surface waters rose by 22 mu atm, thus faster than atmospheric pCO(2), which in the same period rose approximately 11 matm. The surprisingly rapid decline in air-sea

  20. Well data summary sheets. Vol. 25. North Sea Wells from outside the Central Graben area

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    This twenty-fifth volume of the `Well Data Summary sheets` together with volumes twenty-three, twenty-four and twenty-six which have been prepared concurrently, includes data from wells in the Danish North Sea. With the exception of Alma-1x well in volume 26 and the Gert-4 well in volume 23, all the included wells have been released and can be found in the previous volumes (1-16). The primary purpose of producing these four volumes (23-26) has been to update the previously released wells and produce them in our new format. With the new volumes 23, 24, and 26 together with well data from volumes 17, 18, and 19, all released wells from the Danish Central Graben are updated in our new format. Volume 25 includes Danish North sea wells from outside the Central Graben area. The Ibenholt-1 well and the Felicia-1/1A well included in this regional volume were previously included in volumes 21 and 20 respectively. Minor corrections have been made since the first edition. The `Complete index of released wells` had been updated. Volume 27, 28 and 29 are regional volumes; volume 27 includes well data from Southern Jutland; volumes 28 and 29 cover well data from Northern Jutland. All data from released Danish North Sea wells are included in volumes 17-26 and 30. Data references are made to the revised volumes and not to the original published reference. (au)

  1. Spatio-temporal variability of the North Sea cod recruitment in relation to temperature and zooplankton.

    Directory of Open Access Journals (Sweden)

    Delphine Nicolas

    Full Text Available The North Sea cod (Gadus morhua, L. stock has continuously declined over the past four decades linked with overfishing and climate change. Changes in stock structure due to overfishing have made the stock largely dependent on its recruitment success, which greatly relies on environmental conditions. Here we focus on the spatio-temporal variability of cod recruitment in an effort to detect changes during the critical early life stages. Using International Bottom Trawl Survey (IBTS data from 1974 to 2011, a major spatio-temporal change in the distribution of cod recruits was identified in the late 1990s, characterized by a pronounced decrease in the central and southeastern North Sea stock. Other minor spatial changes were also recorded in the mid-1980s and early 1990s. We tested whether the observed changes in recruits distribution could be related with direct (i.e. temperature and/or indirect (i.e. changes in the quantity and quality of zooplankton prey effects of climate variability. The analyses were based on spatially-resolved time series, i.e. sea surface temperature (SST from the Hadley Center and zooplankton records from the Continuous Plankton Recorder Survey. We showed that spring SST increase was the main driver for the most recent decrease in cod recruitment. The late 1990s were also characterized by relatively low total zooplankton biomass, particularly of energy-rich zooplankton such as the copepod Calanus finmarchicus, which have further contributed to the decline of North Sea cod recruitment. Long-term spatially-resolved observations were used to produce regional distribution models that could further be used to predict the abundance of North Sea cod recruits based on temperature and zooplankton food availability.

  2. Quarter-Century Offshore Winds from SSM/I and WRF in the North Sea and South China Sea

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Astrup, Poul; Zhu, Rong;

    2016-01-01

    We study the wind climate and its long-term variability in the North Sea and South China Sea, areas relevant for offshore wind energy development, using satellite-based wind data, because very few reliable long-term in-situ sea surface wind observations are available. The Special Sensor Microwave...

  3. Regional and interannual variability of sea ice mass balance

    Science.gov (United States)

    Richter-Menge, J. A.; Perovich, D. K.; Nghiem, S. V.; Overland, J. E.

    2006-12-01

    The Arctic sea ice cover is undergoing significant climate-induced changes, affecting both its extent and thickness. The ice mass balance provides key insights into the nature of these changes by attributing them to variations in growth, surface melt, and bottom ablation. Ice mass balance buoys (IMB) autonomously monitor snow accumulation and ablation, ice growth and melt, and internal ice temperature. These buoys have been deployed in many locations, with an emphasis on the Beaufort Sea and the North Pole Environmental Observatory (NPEO). At the NPEO, the IMB sites are complemented by web cams which provide photographs showing changing surface conditions and the evolution of melt ponds in summer. IMB results indicate that there is significant regional and interannual variability in the mass balance. North Pole buoys, in particular, have recorded significant interannual variability in surface ablation, with values ranging from 0 to 35 cm from 2000 to 2005. There is good agreement determining the onset of melt and freezeup dates at the sites from both IMB results and from QuikScat satellite data. Results suggest that the total amount of surface melting is most significantly influenced by the date of the onset of summer melt. Quikscat results indicated that melt onset occurs concurrently over hundreds of kilometers providing a thermodynamic length scale, which may then be used to extrapolate the point measurements from the IMBs to larger scales.

  4. The North Sea Andrea storm and numerical simulations

    Science.gov (United States)

    Bitner-Gregersen, E. M.; Fernandez, L.; Lefèvre, J. M.; Monbaliu, J.; Toffoli, A.

    2014-06-01

    A coupling of a spectral wave model with a nonlinear phase-resolving model is used to reconstruct the evolution of wave statistics during a storm crossing the North Sea on 8-9 November 2007. During this storm a rogue wave (named the Andrea wave) was recorded at the Ekofisk field. The wave has characteristics comparable to the well-known New Year wave measured by Statoil at the Draupner platform 1 January 1995. Hindcast data of the storm at the nearest grid point to the Ekofisk field are here applied as input to calculate the evolution of random realizations of the sea surface and its statistical properties. Numerical simulations are carried out using the Euler equations with a higher-order spectral method (HOSM). Results are compared with some characteristics of the Andrea wave record measured by the down-looking lasers at Ekofisk.

  5. Digenea trematodes in fish of the North Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Vesna PARADIŽNIK

    2007-12-01

    Full Text Available The paper gives an overview of trematodes that have been isolated from the north Adriatic Sea , during a 10-year research program. A total of 63 marine fish species of pelagic and benthic of the classes Chondrichthyes and Osteichthyes were analyzed. We found that 21 fish species ted digenean trematodes (33.33% prevalence, and 12 fish species are reported as hosts for the t time. During our research, 63 species of fish (total of 2659 fish were examined and 25.16 % e found invaded by endohelminths, belonging to 22 digeneans species.

  6. A wasted resource: cod discards in the North Sea

    DEFF Research Database (Denmark)

    Feekings, Jordan P.; Poos, Jan Jaap; Aarts, Geert

    2012-01-01

    The public, political, and stakeholder perception of fisheries discards is that they are a waste of a valuable resource. In the North Sea, fisheries discards are some of the highest in the world. Cod (Gadus morhua) has contributed considerably to the amount discarded. The declining cod stock with......, spatially and temporally, in discarding over the past decade while pinpointing the major reasons to why it occurs. We discuss how such information can be used to improve future fishing activities and their subsequent catch compositions under a discard...

  7. Changes in extreme regional sea level under global warming

    Science.gov (United States)

    Brunnabend, S.-E.; Dijkstra, H. A.; Kliphuis, M. A.; Bal, H. E.; Seinstra, F.; van Werkhoven, B.; Maassen, J.; van Meersbergen, M.

    2017-01-01

    An important contribution to future changes in regional sea level extremes is due to the changes in intrinsic ocean variability, in particular ocean eddies. Here, we study a scenario of future dynamic sea level (DSL) extremes using a high-resolution version of the Parallel Ocean Program and generalized extreme value theory. This model is forced with atmospheric fluxes from a coupled climate model which has been integrated under the IPCC-SRES-A1B scenario over the period 2000-2100. Changes in 10-year return time DSL extremes are very inhomogeneous over the globe and are related to changes in ocean currents and corresponding regional shifts in ocean eddy pathways. In this scenario, several regions in the North Atlantic experience an increase in mean DSL of up to 0.4 m over the period 2000-2100. DSL extremes with a 10-year return time increase up to 0.2 m with largest values in the northern and eastern Atlantic.

  8. Phase equilibrium of North Sea oils with polar chemicals: Experiments and CPA modeling

    DEFF Research Database (Denmark)

    Frost, Michael Grynnerup; Kontogeorgis, Georgios M.; von Solms, Nicolas;

    2016-01-01

    This work consists of a combined experimental and modeling study for oil - MEG - water systems, of relevance to petroleum applications. We present new experimental liquid-liquid equilibrium data for the mutual solubility of two North Sea oils + MEG and North Sea oils + MEG + water systems...... in the temperature range 303.15-323.15 K and at atmospheric pressure. These new data are for North Sea oils which are substantially heavier and with higher aromatic/naphthenic content compared to previous studies. The new data compare favorably with previously reported measurements for other North Sea oils. The data...

  9. Sea Ice Variability in the Northern North Atlantic during the Last 14 Kyr BP

    Science.gov (United States)

    Cabedo-Sanz, P.; Belt, S. T.

    2014-12-01

    Sea ice plays an important role on the Earth's climate system by controlling fluxes of heat and moisture across the ocean-atmosphere interface and changes in the Earth's albedo, as well as oceanic circulation processes (e.g. the thermohaline circulation). Thus, reconstruction of Arctic sea ice is necessary to understand past sea ice variability and help improve the accuracy of model-based estimates of future changes in climate. Recently, the presence of the sea ice diatom biomarker IP25in Arctic marine sediments has been used as a proxy for past spring sea ice occurrence and as an indicator of wider palaeoenvironmental conditions for different regions of the Arctic over various timescales (e.g. Belt and Müller, 2013). Here, we present and compare new and existing biomarker data from different sediment cores along a S-N transect on the Norwegian - Svalvard continental margin from ca. 69 ºN to 78.5 ºN, northern North Atlantic. The presence and abundances of the sea ice biomarker IP25, a related HBI Diene and various sterols (e.g. brassicasterol, 24-methylenecholesterol) were used to infer past variations of sea ice/open-water conditions in the study area during the last 14 kyr BP. In addition, a comparison with other commonly used proxies for reconstructing different palaeoenvironmental conditions (e.g. planktic and benthic foraminiferal fauna, SST, IRD) was used to enable a more comprehensive reconstruction of climatic variations. References Belt, S.T., Müller, J., 2013. The Arctic sea ice biomarker IP25: a review of current understanding, recommendations for future research and applications in palaeo sea ice reconstructions. Quaternary Science Reviews 79, 9-25.

  10. Projected impact of climate change in the North and Baltic Sea. Results from dynamical downscaling of global CMIP climate scenarios

    Science.gov (United States)

    Gröger, Matthias; Maier-Reimer, Ernst; Mikolajewicz, Uwe; Sein, Dmitry

    2013-04-01

    Climate models have predicted strongest climate change impact for the mid/high lattiude areas. Despite their importance, shelves seas (which are supposed to account for more than 20% of global marine primary production and for up to 50% of total marine carbon uptake) are not adequately resolved in climate models. In this study, the global ocean general circulation and biogeochemistry model MPIOM/HAMOCC has been setup with an enhanced resolution over the NW European shelf (~10 km in the southern North Sea). For a realistic representation of atmosphere-ocean interactions the regional model REMO has been implemented. Thus, this model configuration allows a physically consistent simulation of climate signal propagation from the North Atlantic over the North Sea into the Baltic Sea since it interactively simulates mass and energy fluxes between the three basins. The results indicate substantial changes in hydrographic and biological conditions for the end of the 21st Century. A freshening by about 0.75 psu together with a surface warming of ~2.0 K and associated circulation changes in and outside the North Sea reduce biological production on the NW European shelf by ~35%. This reduction is twice as strong as the reduction in the open ocean. The underlying mechanism is a spatially well confined stratification feedback along the shelf break and the continental slope which reduces the winter mixed layer by locally more than 200 m compared to current conditions. As a consequence winter nutrient supply from the deep Atlantic declines between 40 and 50%. In addition to this, the volume transport of water and salt into the North Sea will slightly reduce (~10%) during summer. At the end of the 21st Century the North Sea appears nearly decoupled from the deep Atlantic. The projected decline in biological productivity and subsequent decrease of phytoplankton (by averaged 25%) will probably negatively affect the local fish stock in the North Sea. In the Baltic Sea the climate

  11. Regional Sea Level Variation: California Coastal Subsidence (Invited)

    Science.gov (United States)

    Blewitt, G.; Hammond, W. C.; Nerem, R.

    2013-12-01

    Satellite altimetry over the last two decades has measured variations in geocentric sea level (GSL), relative to the Earth system center of mass, providing valuable data to test models of physical oceanography and the effects of global climate change. The societal impacts of sea level change however relate to variations in local sea level (LSL), relative to the land at the coast. Therefore, assessing the impacts of sea level change requires coastal measurements of vertical land motion (VLM). Indeed, ΔLSL = ΔGSL - ΔVLM, with subsidence mapping 1:1 into LSL. Measurements of secular coastal VLM also allow tide-gauge data to test models of GSL over the last century in some locations, which cannot be provided by satellite data. Here we use GPS geodetic data within 15 km of the US west coast to infer regional, secular VLM. A total of 89 GPS stations met the criteria that time series span >4.5 yr, and do not have obvious non-linear variation, as may be caused by local instability. VLM rates for the GPS stations are derived in the secular reference frame ITRF2008, which aligns with the Earth system center of mass to ×0.5 mm/yr. We find that regional VLM has different behavior north and south of the Mendocino Triple Junction (MTJ). The California coast has a coherent regional pattern of subsidence averaging 0.5 mm/yr, with an increasing trend to the north. This trend generally matches GIA model predictions. Around San Francisco Bay, the observed coastal subsidence of 1.0 mm/yr coherently decreases moving away from the Pacific Ocean to very small subsidence on the east shores of the bay. This gradient is likely caused by San Andreas-Hayward Fault tectonics, and possibly by differential surface loading across the bay and Sacramento-San Joachim River Delta. Thus in addition to the trend in subsidence from GIA going northward along the California coast, tectonics may also play a role where the plate boundary fault system approaches the coast. In contrast, we find that VLM

  12. Organophosphorus flame retardants and plasticizers in the atmosphere of the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Axel, E-mail: axel.moeller@hzg.de [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Coastal Research, Department for Environmental Chemistry, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Xie Zhiyong; Caba, Armando; Sturm, Renate; Ebinghaus, Ralf [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Coastal Research, Department for Environmental Chemistry, Max-Planck-Strasse 1, 21502 Geesthacht (Germany)

    2011-12-15

    Air samples collected in the German part of the North Sea from March to July 2010 were investigated for organophosphorus compounds (OPs) being applied as flame retardants and plasticizers. The {Sigma}{sub 8}OPs concentration ranged from 110 to 1400 pg m{sup -3} while tris(2-chloroisopropyl) phosphate (TCPP) dominated all samples with individual concentrations up to 1200 pg m{sup -3}. The highest concentrations were observed in continental air masses showing the high influence of industrialized regions including production sites on atmospheric emissions and concentrations. The occurrence of OPs even in oceanic/Arctic air masses shows that OPs can undergo long-range atmospheric transport. Dry particle-bound deposition fluxes from 9 to 240 ng m{sup -2} d{sup -1} for {Sigma}{sub 8}OPs were estimated leading to a minimum annual flux of 710 {+-} 580 kg y{sup -1} OPs into the German North Sea. This study presents the first occurrence of OPs in the marine atmosphere together with important information on their long-range transport potential. - Highlights: > Organophosphorus flame retardants are detected for the first time in the marine atmosphere. > Organophosphorus compounds can undergo medium to long-range atmospheric transport. > Western Europe emits organophosphorus compounds to the marine atmosphere. > Marine air levels of organophosphorus flame retardants range up to 1 ng/m{sup 3}. - Organophosphorus flame retardants, in particular tris(2-chloroisopropyl) phosphate, are emitted into the North Sea atmosphere by Western European countries.

  13. Formation of Barents Sea Branch Water in the north-eastern Barents Sea

    Directory of Open Access Journals (Sweden)

    Vidar S. Lien

    2013-09-01

    Full Text Available The Barents Sea throughflow accounts for approximately half of the Atlantic Water advection to the Arctic Ocean, while the other half flows through Fram Strait. Within the Barents Sea, the Atlantic Water undergoes considerable modifications before entering the Arctic Ocean through the St. Anna Trough. While the inflow area in the south-western Barents Sea is regularly monitored, oceanographic data from the outflow area to the north-east are very scarce. Here, we use conductivity, temperature and depth data from August/September 2008 to describe in detail the water masses present in the downstream area of the Barents Sea, their spatial distribution and transformations. Both Cold Deep Water, formed locally through winter convection and ice-freezing processes, and Atlantic Water, modified mainly through atmospheric cooling, contribute directly to the Barents Sea Branch Water. As a consequence, it consists of a dense core characterized by a temperature and salinity maximum associated with the Atlantic Water, in addition to the colder, less saline and less dense core commonly referred to as the Barents Sea Branch Water core. The denser core likely constitutes a substantial part of the total flow, and it is more saline and considerably denser than the Fram Strait branch as observed within the St. Anna Trough. Despite the recent warming of the Barents Sea, the Barents Sea Branch Water is denser than observed in the 1990s, and the bottom water observed in the St. Anna Trough matches the potential density at 2000 m depth in the Arctic Ocean.

  14. Reevaluation of mid-Pliocene North Atlantic sea surface temperatures

    Science.gov (United States)

    Robinson, Marci M.; Dowsett, Harry J.; Dwyer, Gary S.; Lawrence, Kira T.

    2008-01-01

    Multiproxy temperature estimation requires careful attention to biological, chemical, physical, temporal, and calibration differences of each proxy and paleothermometry method. We evaluated mid-Pliocene sea surface temperature (SST) estimates from multiple proxies at Deep Sea Drilling Project Holes 552A, 609B, 607, and 606, transecting the North Atlantic Drift. SST estimates derived from faunal assemblages, foraminifer Mg/Ca, and alkenone unsaturation indices showed strong agreement at Holes 552A, 607, and 606 once differences in calibration, depth, and seasonality were addressed. Abundant extinct species and/or an unrecognized productivity signal in the faunal assemblage at Hole 609B resulted in exaggerated faunal-based SST estimates but did not affect alkenone-derived or Mg/Ca–derived estimates. Multiproxy mid-Pliocene North Atlantic SST estimates corroborate previous studies documenting high-latitude mid-Pliocene warmth and refine previous faunal-based estimates affected by environmental factors other than temperature. Multiproxy investigations will aid SST estimation in high-latitude areas sensitive to climate change and currently underrepresented in SST reconstructions.

  15. Development of a coupled physical-biological ecosystem model ECOSMO - Part I: Model description and validation for the North Sea

    DEFF Research Database (Denmark)

    Schrum, Corinna; Alekseeva, I.; St. John, Michael

    2006-01-01

    forcing at temporal scale of 6 h using atmospheric re-analysis data. The model was integrated for 1984 and 1986. The simulated fields for 1984 were used to investigate the annual spatial distribution of phytoplankton and zooplankton biomass and their production in the North Sea. A detailed validation...... showed that the model, based on consideration of limiting processes, is able to reproduce the observed spatial and seasonal variability of the North Sea ecosystem e.g. the spring bloom, summer sub-surface production and the fall bloom. Distinct differences in regional characteristics of diatoms...

  16. Spring distribution and density of minke whale Balaenoptera acutorostrata along an offshore bank in the central North Sea

    NARCIS (Netherlands)

    Boer, de M.N.

    2010-01-01

    Minke whales were recorded in the central North Sea in an area characterised by frontal features and high productivity northeast of the Dogger Bank (4677 km2). Survey efforts were carried out from 28 March to 2 July 2007, at a finer scale than in earlier studies in the region, using 2 vessels as pla

  17. Spring distribution and density of minke whale Balaenoptera acutorostrata along an offshore bank in the central North Sea

    NARCIS (Netherlands)

    Boer, de M.N.

    2010-01-01

    Minke whales were recorded in the central North Sea in an area characterised by frontal features and high productivity northeast of the Dogger Bank (4677 km2). Survey efforts were carried out from 28 March to 2 July 2007, at a finer scale than in earlier studies in the region, using 2 vessels as

  18. Modelling climate change effects on benthos: Distributional shifts in the North Sea from 2001 to 2099

    Science.gov (United States)

    Weinert, Michael; Mathis, Moritz; Kröncke, Ingrid; Neumann, Hermann; Pohlmann, Thomas; Reiss, Henning

    2016-06-01

    In the marine realm, climate change can affect a variety of physico-chemical properties with wide-ranging biological effects, but the knowledge of how climate change affects benthic distributions is limited and mainly restricted to coastal environments. To project the response of benthic species of a shelf sea (North Sea) to the expected climate change, the distributions of 75 marine benthic species were modelled and the spatial changes in distribution were projected for 2099 based on modelled bottom temperature and salinity changes using the IPCC scenario A1B. Mean bottom temperature was projected to increase between 0.15 and 5.4 °C, while mean bottom salinity was projected to moderately increase by 1.7. The spatial changes in species distribution were modelled with Maxent and the direction and extent of these changes were assessed. The results showed a latitudinal northward shift for 64% of the species (maximum 109 km; brittle star Ophiothrix fragilis) and a southward shift for 36% (maximum 101 km; hermit crab Pagurus prideaux and the associated cloak anemone Adamsia carciniopados; 105 km). The relatively low rates of distributional shifts compared to fish or plankton species were probably influenced by the regional topography. The environmental gradients in the central North Sea along the 50 m depth contour might act as a 'barrier', possibly resulting in a compression of distribution range and hampering further shifts to the north. For 49 species this resulted in a habitat loss up to 100%, while only 11 species could benefit from the warming in terms of habitat gain. Particularly the benthic communities of the southern North Sea, where the strongest temperature increase was projected, would be strongly affected by the distributional changes, since key species showed northward shifts and high rates of habitat loss, with potential ramifications for the functioning of the ecosystem.

  19. Subduction erosion and accretion in the Solomon Sea region

    Science.gov (United States)

    Honza, Eiichi; Miyazaki, Teruki; Lock, Jo

    1989-03-01

    The Solomon Sea region is an area of intense tectonic activity characterized by structural complexity, a high level of seismicity and volcanism, and rapid evolution of plate boundaries. There is little accretion in the eastern New Britain Trench. Accretion gradually increases westward with thick accretion in the western New Britain Trench and in the Trobriand Subduction System. The thick accretion in the western part of the New Britain Trench may be a result of collision from the north of Finisterre-Huon block with New Guinea mainland. The present boundary of the collision is along the Ram-Markham fault. Deformation structures and present day seismicity suggest that the northern block is under compression. Accretion has occurred in the sediment filled trenches in the Solomon Sea. The scale of the accretionary wedge depends on the amount of trench-fill sediment available. It is unlikely that there is no sediment supply to the eastern part of the New Britain Trench where no accretion is observed and subduction erosion may be occurring. There are two possible mechanisms for subduction erosion of sediment; either a rapid rate of subduction relative to the supply of sediment inhibiting sediment accumulation in the trench; or horizontal tensional force superimposed on both the forearc and backarc regions of the arc. Seafloor spreading in both the Manus and Woodlark basins is fan-like with nearby poles in the western margins of the basins. This may be a reflection of a horizontally compressional field in the western part and a tensional field in the eastern part of the Solomon Sea. Therefore it is possible to conclude that the consumption of sediment in the eastern New Britain Trench is related to the horizontal tensional field superimposed on both the forearc and backarc regions of the subduction system. Imbricated thrust and overthrust faults in the western New Britain Trench and Trobriand Trough are not linear over long distance, but form wavy patterns in blocks with

  20. The internal consistency of the North Sea carbonate system

    Science.gov (United States)

    Salt, Lesley A.; Thomas, Helmuth; Bozec, Yann; Borges, Alberto V.; de Baar, Hein J. W.

    2016-05-01

    In 2002 (February) and 2005 (August), the full suite of carbonate system parameters (total alkalinity (AT), dissolved inorganic carbon (DIC), pH, and partial pressure of CO2 (pCO2) were measured on two re-occupations of the entire North Sea basin, with three parameters (AT, DIC, pCO2) measured on four additional re-occupations, covering all four seasons, allowing an assessment of the internal consistency of the carbonate system. For most of the year, there is a similar level of internal consistency, with AT being calculated to within ± 6 μmol kg- 1 using DIC and pH, DIC to ± 6 μmol kg- 1 using AT and pH, pH to ± 0.008 using AT and pCO2, and pCO2 to ± 8 μatm using DIC and pH, with the dissociation constants of Millero et al. (2006). In spring, however, we observe a significant decline in the ability to accurately calculate the carbonate system. Lower consistency is observed with an increasing fraction of Baltic Sea water, caused by the high contribution of organic alkalinity in this water mass, not accounted for in the carbonate system calculations. Attempts to improve the internal consistency by accounting for the unconventional salinity-borate relationships in freshwater and the Baltic Sea, and through application of the new North Atlantic salinity-boron relationship (Lee et al., 2010), resulted in no significant difference in the internal consistency.

  1. Sea surface temperature variability in the North Western Mediterranean Sea (Gulf of Lion) during the Common Era

    Science.gov (United States)

    Sicre, Marie-Alexandrine; Jalali, Bassem; Martrat, Belen; Schmidt, Sabine; Bassetti, Maria-Angela; Kallel, Nejib

    2016-12-01

    This study investigates the multidecadal-scale variability of sea surface temperatures (SSTs) in the convection region of the Gulf of Lion (NW Mediterranean Sea) over the full past 2000 yr (Common Era) using alkenone biomarkers. Our data show colder SSTs by 1.7 °C over most of the first millennium (200-800 AD) and by 1.3 °C during the Little Ice Age (LIA; 1400-1850 AD) than the 20th century mean (17.9 °C). Although on average warmer, those of the Medieval Climate Anomaly (MCA) (1000-1200 AD) were lower by 1 °C. We found a mean SST warming of 2 °C/100 yr over the last century in close agreement with the 0.22 and 0.26 °C/decade values calculated for the western Mediterranean Sea from in situ and satellite data, respectively. Our results also reveal strongly fluctuating SSTs characterized by cold extremes followed by abrupt warming during the LIA. We suggest that the coldest decades of the LIA were likely caused by prevailing negative EA states and associated anticyclone blocking over the North Atlantic resulting in cold continental northeasterly winds to blow over Western Europe and the Mediterranean region.

  2. The impact of regional Arctic sea ice loss on atmospheric circulation and the NAO

    Science.gov (United States)

    Anker Pedersen, Rasmus; Cvijanovic, Ivana; Langen, Peter Lang; Vinther, Bo

    2016-04-01

    Reduction of the Arctic sea ice cover can affect the atmospheric circulation, and thus impact the climate beyond the Arctic. The atmospheric response may, however, vary with the geographical location of sea ice loss. The atmospheric sensitivity to the location of sea ice loss is studied using a general circulation model in a configuration that allows combination of a prescribed sea ice cover and an active mixed layer ocean. This hybrid setup makes it possible to simulate the isolated impact of sea ice loss and provides a more complete response compared to experiments with fixed sea surface temperatures. Three investigated sea ice scenarios with ice loss in different regions all exhibit substantial near-surface warming which peaks over the area of ice loss. The maximum warming is found during winter, delayed compared to the maximum sea ice reduction. The wintertime response of the mid-latitude atmospheric circulation shows a non-uniform sensitivity to the location of sea ice reduction. While all three scenarios exhibit decreased zonal winds related to high-latitude geopotential height increases, the magnitudes and locations of the anomalies vary between the simulations. Investigation of the North Atlantic Oscillation reveals a high sensitivity to the location of the ice loss. The northern center of action exhibits clear shifts in response to the different sea ice reductions. Sea ice loss in the Atlantic and Pacific sectors of the Arctic cause westward and eastward shifts, respectively.

  3. A high-resolution hindcast of wind and waves for The North Sea, The Norwegian Sea and The Barents Sea

    CERN Document Server

    Reistad, Magnar; Haakenstad, Hilde; Aarnes, Ole Johan; Furevik, Birgitte R; Bidlot, Jean-Raymond; 10.1029/2010JC006402

    2011-01-01

    A combined high-resolution atmospheric downscaling and wave hindcast based on the ERA-40 reanalysis covering the Norwegian Sea, the North Sea and the Barents Sea is presented. The period covered is from September 1957 to August 2002. The dynamic atmospheric downscaling is performed as a series of short prognostic runs initialized from a blend of ERA-40 and the previous prognostic run to preserve the fine-scale surface features from the high-resolution model while maintaining the large-scale synoptic field from ERA-40. The nested WAM wave model hindcast consists of a coarse 50 km model covering the North Atlantic forced with ERA-40 winds and a nested 10-11 km resolution model forced with downscaled winds. A comparison against in situ and satellite observations of wind and sea state reveals significant improvement in mean values and upper percentiles of wind vectors and the significant wave height over ERA-40. Improvement is also found in the mean wave period. ERA-40 is biased low in wind speed and significant ...

  4. Estimating decadal variability in sea level from tide gauge records: An application to the North Sea

    Science.gov (United States)

    Frederikse, Thomas; Riva, Riccardo; Slobbe, Cornelis; Broerse, Taco; Verlaan, Martin

    2016-03-01

    One of the primary observational data sets of sea level is represented by the tide gauge record. We propose a new method to estimate variability on decadal time scales from tide gauge data by using a state space formulation, which couples the direct observations to a predefined state space model by using a Kalman filter. The model consists of a time-varying trend and seasonal cycle, and variability induced by several physical processes, such as wind, atmospheric pressure changes and teleconnection patterns. This model has two advantages over the classical least-squares method that uses regression to explain variations due to known processes: a seasonal cycle with time-varying phase and amplitude can be estimated, and the trend is allowed to vary over time. This time-varying trend consists of a secular trend and low-frequency variability that is not explained by any other term in the model. As a test case, we have used tide gauge data from stations around the North Sea over the period 1980-2013. We compare a model that only estimates a trend with two models that also remove intra-annual variability: one by means of time series of wind stress and sea level pressure, and one by using a two-dimensional hydrodynamic model. The last two models explain a large part of the variability, which significantly improves the accuracy of the estimated time-varying trend. The best results are obtained with the hydrodynamic model. We find a consistent low-frequency sea level signal in the North Sea, which can be linked to a steric signal over the northeastern part of the Atlantic.

  5. Insight into the Pacific Sea Surface Temperature- North American Hydroclimate Connection from an Eastern Tropical North Pacific Coral Record

    Science.gov (United States)

    Sanchez, S. C.; Charles, C. D.; Carriquiry, J. D.

    2015-12-01

    The last few years of record-breaking climate anomalies across North America--a resilient atmospheric ridge and extreme drought over the West Coast, and severe winters across the Midwest and East Coast regions--have been linked to anomalous Pacific sea surface temperatures (Seager et al. 2014, Wang et al. 2014, Hartmann 2015). The synoptic associations prompt important questions on the relation between these unusual phenomena and extreme expressions of known Pacific decadal modes, such as the North Pacific Gyre Oscillation (NPGO). These questions motivate our pursuit to document multiple realizations of decadal variability in the Pacific-North American region through periods of varied radiative forcing. Here we introduce a 178 year, seasonally resolved Porites coral record from Clarion Island (18N, 115W), the westernmost island of the Revillagigedo Archipelago, a region both highly influenced by NPGO SST and SSS variability and critical for NPGO tropical-extratropical communication via the Seasonal Footprinting Mechanism (Vimont et al. 2003). When coupled with tree ring records from the western United States (Griffin and Anchukaitis 2014, MacDonald and Case 2005) and coral records from the central tropical Pacific (Cobb et al. 2001), the δ18O signal from the Clarion coral offers an extended framework of coherent continental hydroclimate and oceanic variability across the Pacific basin beyond the instrumental record. Over the last 200 years, we find clear commonality in the timing, magnitude and spatial expression of variability (illustrated through the NADA Atlas, Cook et al. 2004) amongst the proxy records. The strong relationship between Northeastern Pacific Clarion and the Central Pacific Palmyra record with the North American hydroclimate records can be viewed within the mechanistic framework of the NPGO; this framework is then explored over the last millennium across intervals of varied radiative forcing.

  6. Distribution patterns of wintering sea ducks in relation to the North Atlantic Oscillation and local environmental characteristics

    Science.gov (United States)

    Zipkin, Elise F.; Gardner, Beth; Gilbert, Andrew T.; O'Connell, Allan F.; Royle, J. Andrew; Silverman, Emily D.

    2010-01-01

    Twelve species of North American sea ducks (Tribe Mergini) winter off the eastern coast of the United States and Canada. Yet, despite their seasonal proximity to urbanized areas in this region, there is limited information on patterns of wintering sea duck habitat use. It is difficult to gather information on sea ducks because of the relative inaccessibility of their offshore locations, their high degree of mobility, and their aggregated distributions. To characterize environmental conditions that affect wintering distributions, as well as their geographic ranges, we analyzed count data on five species of sea ducks (black scoters Melanitta nigra americana, surf scoters M. perspicillata, white-winged scoters M. fusca, common eiders Somateria mollissima, and long-tailed ducks Clangula hyemalis) that were collected during the Atlantic Flyway Sea Duck Survey for ten years starting in the early 1990s. We modeled count data for each species within ten-nautical-mile linear survey segments using a zero-inflated negative binomial model that included four local-scale habitat covariates (sea surface temperature, mean bottom depth, maximum bottom slope, and a variable to indicate if the segment was in a bay or not), one broad-scale covariate (the North Atlantic Oscillation), and a temporal correlation component. Our results indicate that species distributions have strong latitudinal gradients and consistency in local habitat use. The North Atlantic Oscillation was the only environmental covariate that had a significant (but variable) effect on the expected count for all five species, suggesting that broad-scale climatic conditions may be directly or indirectly important to the distributions of wintering sea ducks. Our results provide critical information on species-habitat associations, elucidate the complicated relationship between the North Atlantic Oscillation, sea surface temperature, and local sea duck abundances, and should be useful in assessing the impacts of climate

  7. Atmospheric concentrations and air-sea exchanges of nonylphenol, tertiary octylphenol and nonylphenol monoethoxylate in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Xie Zhiyong [Institute for Coastal Research, GKSS Research Centre, Max-Planck-Street 1, D-21502 Geesthacht (Germany) and Institute of Ecology and Environmental Chemistry, University of Lueneburg, Scharnhorst Street 1, D-21335 Lueneburg (Germany)]. E-mail: zhiyong.xie@gkss.de; Lakaschus, Soenke [Institute for Coastal Research, GKSS Research Centre, Max-Planck-Street 1, D-21502 Geesthacht (Germany); Ebinghaus, Ralf [Institute for Coastal Research, GKSS Research Centre, Max-Planck-Street 1, D-21502 Geesthacht (Germany); Caba, Armando [Institute for Coastal Research, GKSS Research Centre, Max-Planck-Street 1, D-21502 Geesthacht (Germany); Ruck, Wolfgang [Institute of Ecology and Environmental Chemistry, University of Lueneburg, Scharnhorst Street 1, D-21335 Lueneburg (Germany)

    2006-07-15

    Concentrations of nonylphenol isomers (NP), tertiary octylphenol (t-OP) and nonylphenol monoethoxylate isomers (NP1EO) have been simultaneously determined in the sea water and atmosphere of the North Sea. A decreasing concentration profile appeared following the distance increasing from the coast to the central part of the North Sea. Air-sea exchanges of t-OP and NP were estimated using the two-film resistance model based upon relative air-water concentrations and experimentally derived Henry's law constant. The average of air-sea exchange fluxes was -12 {+-} 6 ng m{sup -2} day{sup -1} for t-OP and -39 {+-} 19 ng m{sup -2} day{sup -1} for NP, which indicates a net deposition is occurring. These results suggest that the air-sea vapour exchange is an important process that intervenes in the mass balance of alkylphenols in the North Sea. - Air-sea vapour exchanges of estrogenic alkylphenols are studied in the North Sea and it is shown that a net deposition is occurring.

  8. On estimating the intensity of oil-pollution in the North-Sea

    NARCIS (Netherlands)

    Helmers, R.

    1995-01-01

    In a project, commissioned by the North Sea Directorate, Ministry of Transport and Public Works (RWS), the problem is to estimate the intensity of oil pollution in the Dutch part of the North Sea. A planar inhomogeneous Poisson point process with an intensity function, which is parametrized by a fin

  9. A legal framework for a transnational offshore grid in the North Sea

    NARCIS (Netherlands)

    Müller, Hannah Katharina

    2015-01-01

    A legal framework for a transnational offshore grid in the North Sea Most North Sea states consider offshore wind energy as a substantial contributor towards reaching their renewable energy targets. With the increasing number of offshore wind farms and the increasing distance from shore, the questio

  10. Management options for brown shrimp (Crangon crangon) fisheries in the North Sea

    NARCIS (Netherlands)

    Steenbergen, J.; Kooten, van T.; Wolfshaar, van de K.E.; Trapman, B.K.; Reijden, van der K.J.

    2015-01-01

    Fisheries targeting brown shrimp (Crangon crangon) in the North Sea in European waters are largely unregulated in terms of landings and effort. A license system exists, but this did not prevent the current situation of overcapacity of the shrimp fleet. The governments of the North Sea brown shrimp f

  11. Management options for brown shrimp (Crangon crangon) fisheries in the North Sea

    NARCIS (Netherlands)

    Steenbergen, J.; Kooten, van T.; Wolfshaar, van de K.E.; Trapman, B.K.; Reijden, van der K.J.

    2015-01-01

    Fisheries targeting brown shrimp (Crangon crangon) in the North Sea in European waters are largely unregulated in terms of landings and effort. A license system exists, but this did not prevent the current situation of overcapacity of the shrimp fleet. The governments of the North Sea brown shrimp

  12. Save the North Sea fulmar-litter-ecoQO manual Part 1 :collection and dissection procedures

    NARCIS (Netherlands)

    Franeker, van J.A.

    2004-01-01

    This manual describes standard procedures for the collection and dissection of beachwashed Fulmars used in the Save the North Sea (SNS)'-Fulmar study. Save the North Sea is an international project which aims to reduce marine litter through increased awareness. Fulmars ingest marine litter and accum

  13. Micro contaminants in surface sediments and macrobenthic invertebrates of the North Sea

    NARCIS (Netherlands)

    Everaarts, J.M.; Fischer, C.V.

    1989-01-01

    Trace metal concentrations (copper, zinc, cadmium and lead) were measured in the silt fraction (grainsize < 63 µm) of surface sediment of the North Sea. The concentrations varied in different areas of the Dutch continental shelf of the North Sea. The trace metal concentrations were highly related wi

  14. The effects of regional economic integration in Europe of the pattern north-north and north-south

    Directory of Open Access Journals (Sweden)

    Antevski Miroslav

    2007-01-01

    Full Text Available This paper examines the effects of regional economic integration in Europe, especially the North-North and North-South integration patterns, and how the benefits and costs of integration are divided between countries. Outcomes depend on: comparative advantages, factor endowments, factor intensities, competitive advantages, FDI flows, transfers of technology, knowledge spillovers, economies of scale, transport costs, industry/GDP ratios, and agglomeration forces. The North-North integration between high income countries tends to lead to convergence of country incomes. Contrary, the South-South integration between low income countries causes divergence. Low income countries are likely to be better served by the North-South integration.

  15. Investigation of sea level trends and the effect of the north atlantic oscillation (NAO) on the black sea and the eastern mediterranean sea

    Science.gov (United States)

    Ozgenc Aksoy, Aysegul

    2017-07-01

    The North Atlantic Oscillation (NAO) has significant effects on sea levels, weather, and climate. In this study, the sea level trends and the effects of the North Atlantic Oscillation Indices (NAOI) on annual mean sea level data were assessed for the Black Sea and the Eastern Mediterranean Sea. The trends of sea level and NAOI were determined using Mann-Kendall dimensionless z statistics. Generally, upward sea level trends were detected for the Black Sea and the Eastern Mediterranean Sea. In the Black Sea, significant and continuous upward trends were detected after the year 1950. Weaker trends were detected for the Eastern part of the Mediterranean Sea. Sea level trends were correlated with trends in NAO indices; negative correlations were detected for the Black Sea, whereas positive correlations were found for the Eastern Mediterranean Sea. Paired t tests were performed to determine the turning points for all sea level data sets. The value of t was positive for all data sets, which means that the mean value of the data set before the turning point was smaller than the mean value of the data set after the turning point.

  16. Shallow Drilling In The Salton Sea Region, The Thermal Anomaly

    Energy Technology Data Exchange (ETDEWEB)

    Newmark, R. L.; Kasameyer, P. W.; Younker, L. W.

    1987-01-01

    During two shallow thermal drilling programs, thermal measurements were obtained in 56 shallow (76.2 m) and one intermediate (457.3 m) depth holes located both onshore and offshore along the southern margin of the Salton Sea in the Imperial Valley, California. These data complete the surficial coverage of the thermal anomaly, revealing the shape and lateral extent of the hydrothermal system. The thermal data show the region of high thermal gradients to extend only a short distance offshore to the north of the Quaternary volcanic domes which are exposed along the southern shore of the Salton Sea. The thermal anomaly has an arcuate shape, about 4 km wide and 12 km long. Across the center of the anomaly, the transition zone between locations exhibiting high thermal gradients and those exhibiting regional thermal gradients is quite narrow. Thermal gradients rise from near regional (0.09 C/m) to extreme (0.83 C/m) in only 2.4 km. The heat flow in the central part of the anomaly is >600 mW/m{sup 2} and in some areas exceeds 1200 mW/m{sup 2}. The shape of the thermal anomaly is asymmetric with respect to the line of volcanoes previously thought to represent the center of the field, with its center line offset south of the volcanic buttes. There is no broad thermal anomaly associated with the magnetic high that extends offshore to the northeast from the volcanic domes. These observations of the thermal anomaly provide important constraints for models of the circulation of the hydrothermal system. Thermal budgets based on a simple model for this hydrothermal system indicate that the heat influx rate for local ''hot spots'' in the region may be large enough to account for the rate of heat flux from the entire Salton Trough.

  17. Late Eocene sea surface cooling of the western North Atlantic (ODP Site 647A)

    Science.gov (United States)

    Sliwinska, Kasia K.; Coxall, Helen K.; Schouten, Stefan

    2016-04-01

    The initial shift out of the early Cenozoic greenhouse and into a glacial icehouse climate occurred during the middle to late Eocene and culminated in the abrupt growth of a continental-scale ice cap on Antarctica, during an episode known as the Oligocene Isotope Event 1 (Oi-1) ˜33.7 Ma. Documenting the patterns of global and regional cooling prior to Oi-1 is crucial for understanding the driving force and feedback behind the switch in climate mode. Well-dated high-resolution temperature records, however, remain sparse and the climatic response in some of the most climatically sensitive regions of the Earth, including the high latitude North Atlantic (NA), where today large amounts of ocean heat are exchanged, are poorly known. Here we present a sea surface palaeotemperature record from the late Eocene to the early Oligocene (32.5 Ma to 35 Ma) of ODP Hole 647A based on archaeal tetraether lipids (TEX86H). The site is located in the western North Atlantic (Southern Labrador Sea) and is the most northerly located (53° N) open ocean site with a complete Eocene-Oligocene sequence which yields both calcareous and organic microfossils suitable for detailed proxy reconstructions. Our record agrees with the magnitude of temperature decrease (˜3 ° C sea surface cooling) recorded by alkenones and pollen data from the Greenland Sea, but our higher resolution study reveals that the high latitude NA cooling step occurred about 500 kyrs prior to the Oi-1 Antarctic glaciation, at around ˜34.4 Ma. This cooling can be explained by regional effects related to local NA tectonics including ocean gateways, known to have changed at the time, with potential to effect NA overturning circulation due to adjustments in the thermohaline density balance. Alternatively, the cooling itself may be due to changes in NA circulation, suggesting that global ocean circulation played a role in pre-conditioning the Earth for Antarctic glaciation.

  18. Regional air quality modeling: North American and European perspectives

    NARCIS (Netherlands)

    Steyn, D.; Builtjes, P.; Schaap, M.; Yarwood, G.

    2013-01-01

    An overview of regional-scale quality modeling practices and perspectives in North America and Europe, highlighting the differences and commonalities in how regional-scale air quality modeling systems are being used and evaluated across both continents

  19. Trace elements in a North Sea drill core

    DEFF Research Database (Denmark)

    Kunzendorf, Helmar; Gwozdz, R.; Svendsen, N.

    1986-01-01

    space is filled mainly by hydrocarbons. A significant decrease of Mn with depth probably suggests diagenesis of chalk prior to, or with, hydrocarbon emplacement. Investigations of drilling fluids and cuttings reveal a strong contamination of the latter, mainly by Ba. Chalk data from comparable onshore......Chalk samples, systematically taken along a drill core from one of the hydrocarbon producing fields of the North Sea (Tyra field), were analysed by a neutron activation technique involving measurement of radioisotopes with relatively short half-lives. Elements determined include Na, Al, Cl, Ca, Mn......, V, Sr, Dy, Mg, Ti, Ba and Eu. The major elements Ca and Al could be related to petrophysical parameters, particularly Al which shows a correlation with the silicification/argillaceous content. Na (and Cl) has a low content in the hydrocarbon-bearing section of the drill core suggesting that the pore...

  20. Well data summary sheets. Vol. 33: North sea wells

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    This 33rd volume of the `Well Data Summary sheets` includes data from seven recently released offshore wells from the North Sea. The wells Baron-2, S.E. Adda-1 and Skjold Flank-1 were presented in our `Well Data Summary Sheets, special volume`, published May 1, 1997. In volume 33, the wells Baron-2 and Skjold Flank-1 are updated with respect to information on sidewall cores. Information regarding all released well data, included in our well data summary sheets, are available on GEUS homepage: http://www.geus.dk/ or the departments homepage: http://www.geus.dk/departments/geol-info-data-centre/geoldata.htm/. A complete index of releases wells in volumes 17-33 is included. (au)

  1. Rock-physics modelling of the North Sea greensand

    DEFF Research Database (Denmark)

    Hossain, Zakir

    Greensands are composed of a mixture of stiff clastic quartz grains and soft glauconite grains. Glauconites are porous and composed of aggregates of ironbearing clay. Greensands from the two formations in the Nini field of the North Sea were studied in this thesis. Hermod Formation is weakly...... from NMR measurements were correlated with measurements from core analysis. NMR underestimates the total porosity due to the presence of iron bearing clay minerals in greensand. Permeability may be predicted from NMR by using Kozeny’s equation when surface relaxivity is known. The surface area measured...... by the BET method is associated with the micro-porous glauconite grains. The effective specific surface area as calculated from Kozeny’s equation is associated with macro-pores. Capillary pressure drainage curves may be predicted from NMR T2 distribution when pore size distribution within a sample...

  2. Conoco schedules new subsea system in North Sea

    Energy Technology Data Exchange (ETDEWEB)

    1978-08-21

    Continental Oil Co. Ltd. is to introduce a new concept in satellite subsea wells for development of the Murchison oil field in the E. Shetlands Basin of the North Sea. The Conoco system will allow 3 subsea wells--2 oil and one water injection--to be serviced with tools hydraulically controlled through flow lines from the main steel platform instead of from a drilling rig. Basis of the system is 4 small hydraulic control lines encased with two 3-1/2-in. main flow lines in a 12-3/4-in. protective pipe. If the tubing removal safety valves in the tubing strings fail, new pump-down safety valves can be installed through the flow lines. Other servicing operations, similar to those done with wire-line units on land or platform wells, can be performed with pump-down tools through the flow lines.

  3. Exergetic assessment of energy systems on North Sea oil and gas platforms

    DEFF Research Database (Denmark)

    Nguyen, Tuong-Van; Pierobon, Leonardo; Elmegaard, Brian

    2013-01-01

    Oil and gas platforms in the North Sea region are associated with high power consumption and large CO2-emissions, as the processing and utility plants suffer from significant changes in production rates and performance losses over the field lifespan. In this paper, a generic model of the overall...... destruction of an offshore platform is attributable to the power generation and waste heat recovery system, and 35 e38% to the oil and gas processing. The variability of the feed composition has little effect on the split of the thermodynamic irreversibilities between both plants. The rejection of high...

  4. Assessment and classification of eutrophication status in the Eastern North Sea

    DEFF Research Database (Denmark)

    Axe, P.; Andersen, Jesper; Murray, Ciarán

    This contribution describes the first eutrophication assessment of the eastern North Sea using a harmonized quantitative assessment tool, so as to describe recent environmental status in response to nutrient loading pressures. The assessment tool HEAT (Andersen et al., 2010) was developed......) eutrophication status was presented as single values covering large assessment units (often national Exclusive Economic Zones) with no indication of status gradients within these regions. The present assessment resolves status variation within and across these assessment units. The eutrophication assessment...... highlighted limitations of some eutrophication indicators, differences in assumptions about eutrophication status between countries and also between the OSPAR COMP, Water Framework Directive and Marine Strategy approaches....

  5. Distribution, partitioning and sources of dissolved and particulate nitrogen and phosphorus in the north Yellow Sea

    Science.gov (United States)

    Duan, Li-Qin; Song, Jin-Ming; Yuan, Hua-Mao; Li, Xue-Gang; Li, Ning

    2016-11-01

    Little is known about characteristics of dissolved and particulate N and P forms in the north Yellow Sea (NYS). In this study, water and particulate samples were collected from the NYS to understand the biogeochemical behaviors, interactions and sources of dissolved and particulate N and P. Among the various N and P forms, dissolved organic N (DON) and P (DOP) were the predominant forms, accounting for 64% and 65% of total N (TN) and P (TP). Dissolved and particulate inorganic N and P displayed a decreasing trend from northwest region to the middle region, which was mainly influenced by riverine input along the Liaodong Peninsula coast. However, dissolved and particulate organic N and P showed higher values at northwest region and southern region, which were dominantly affected by biological activities and the Bohai Sea input. Vertical distribution patterns of dissolved and particulate N and P generally displayed the higher values at surface and bottom waters, which was the combined result of the influences by thermocline, the Yellow Sea Cold Water Mass (YC), biological activities and sediment resuspension. There were significant correlations between dissolved and particulate pools and between inorganic and organic forms, indicating their transformations through phytoplankton and bacteria activities and adsorption/desorption processes. Budgets suggested that net sink of dissolved inorganic N and P in the NYS could be mainly removed from water column. Particulate N and P were mainly from phytoplankton productivity, contributing to 84% and 74% of total particulate N (TPN) and P (TPP) influx.

  6. Simulating Dust Regional Impact on the Middle East Climate and the Red Sea

    Science.gov (United States)

    Osipov, Sergey; Stenchikov, Georgiy

    2017-04-01

    Dust is one of the most abundant aerosols, however, currently only a few regional climate downscalings account for dust. This study focuses on the Middle East and the Red Sea regional climate response to the dust aerosol radiative forcing. The Red Sea is located between North Africa and Arabian Peninsula, which are first and third largest source regions of dust, respectively. MODIS and SEVIRI satellite observations show extremely high dust optical depths in the region, especially over the southern Red Sea during the summer season. The significant north-to-south gradient of the dust optical depth over the Red Sea persists throughout the entire year. Modeled atmospheric radiative forcing at the surface, top of the atmosphere and absorption in the atmospheric column indicate that dust significantly perturbs radiative balance. Top of the atmosphere modeled forcing is validated against independently derived GERB satellite product. Due to strong radiative forcing at the sea surface (daily mean forcing during summer reaches -32 Wm-2 and 10 Wm-2 in SW and LW, respectively), using uncoupled ocean model with prescribed atmospheric boundary conditions would result in an unrealistic ocean response. Therefore, here we employ the Regional Ocean Modeling system (ROMS) fully coupled with the Weather Research and Forecasting (WRF) model to study the impact of dust on the Red Sea thermal regime and circulation. The WRF was modified to interactively account for the radiative effect of dust. Daily spectral optical properties of dust are computed using Mie, T-matrix, and geometric optics approaches, and are based on the SEVIRI climatological optical depth. The WRF model parent and nested domains are configured over the Middle East and North Africa (MENA) region and over the Red Sea with 30 and 10 km resolution, respectively. The ROMS model over the Red Sea has 2 km grid spacing. The simulations show that, in the equilibrium response, dust causes 0.3-0.5 K cooling of the Red Sea surface

  7. Last Interglacial transgression rates and high stand duration in the near-field Eemian North Sea

    NARCIS (Netherlands)

    Cohen, K.M.; Peeters, J.; Sier, M.J.; Busschers, F.S.; Hijma, M.P.

    2015-01-01

    The sea-level history of the Eemian transgression and high stand in the Southern North Sea (The Netherlands), first described by Zagwijn (1983), features in many Last Interglacial sea-level and GIA studies. The reconstruction is based on sedimentary contacts in coastal deposits (transgressed tidal-m

  8. Triassic rift-raft tectonics in the German Southern North Sea; Flosstektonik in der Trias der Deutschen Suedlichen Nordsee

    Energy Technology Data Exchange (ETDEWEB)

    Thieme, B.; Rockenbauch, K. [BEB Erdgas und Erdoel GmbH, Hannover (Germany)

    2001-12-01

    This paper discusses extensional structures in the German Southern North Sea which were formed during Triassic rifting. Recent salt tectonic concepts and palinspastic methods provided the basis for structural interpretation. The results were compared with examples of the adjacent North Sea sectors and other raft provinces worldwide. Rifting in the German Southern North Sea began in Early Triassic times causing faulting and subsequent lateral movements and rotations of rigid Bunter blocks on the ductile Zechstein salinar substrate. This process, called >>raft-tectonics<<, exerted important controls on the further tectonic and sedimentary evolution during Triassic (and Early Jurassic) times. The structures created were formed by a complex interaction of basin extension, halokinesis and deposition of syn- and post-raft sediments. Variations in the controlling factors led to the different morphologies and styles observed. The German Southern North Sea did not undergo any inversion. As a consequence, the extensional rift-raft features remained without compressional overprint, allowing therefore a detailed interpretation of the deformation history. Main characteristics of the raft features in the German Southern North Sea are: raft structures represent an initial stage of development (extension and translation), rift-raft features within the Triassic interval are genetically related to basement extension (Triassic rifting), Triassic rifting was polyphase, rift-raft features are associated with reactive salt diapirs and/or syn- and post-rift depocenters, both of which developed syn-tectonically in the gaps created between the rafts, controlling factors on the morphologies observed are: moderate extension, low angle detachment (gentle regional dip and low strain rates), thick detachment layer (salt thickness of the Zechstein salinar), and lithology (sediment thickness and competence) of the raft- and post-raft Mesozoic sequences. Finally, the impact of raft tectonics on

  9. Extant Rhabdosphaeraceae (coccolithophorids, class Prymnesiophyceae) from the Indian Ocean, Red Sea, Mediterranean Sea and North Atlantic Ocean

    NARCIS (Netherlands)

    Kleijne, A.

    1992-01-01

    Rhabdosphaerids were consistently present as a minor constituent of the 1985 summer coccolithophorid flora in surface waters of the Indian Ocean, Red Sea, Mediterranean Sea and North Atlantic. Sixteen taxa are identified, belonging to seven genera, including the two new combinations Cyrtosphaera acu

  10. The influence of riverine nitrogen on the dynamics of the North Sea oxygen minimum zone

    Science.gov (United States)

    Große, Fabian; Kreus, Markus; Lenhart, Hermann; Pätsch, Johannes

    2016-04-01

    The mitigation of eutrophication and its concomitants, like oxygen deficiency in bottom waters, is one of the major aspects of the ecological management of coastal marine ecosystems. In the past, biogeochemical models helped to significantly improve the understanding of the interaction of the physical and biological processes driving eutrophication. Anthropogenic river input of nitrogen (N) and phosphorus (P) is the main driver for eutrophication. Nevertheless, the quantification of their influence in a specific region remains an important issue, since it is as crucial for an efficient management as it is difficult to obtain. During the past decade, a quantitative method applicable to biogeochemical models - often referred to as `trans-boundary nutrient transports' (TBNT) - became more and more popular in the context of marine ecosystem management. This method allows for the tracing of elements from various sources, e.g., nitrogen (N) from different rivers, throughout the whole process chain of the applied model. By this, it provides valuable information about the contributions from different sources to the overall amount and turnover of an element in different areas of the model domain. This information constitutes the basis for the quantification, evaluation and optimisation of river input reduction targets for the tributaries, which are defined in relation to their ecological consequences in the marine environment. In existing studies, the TBNT method has been applied to a variety of biogeochemical models, e.g. to quantify the atmospheric contribution to total N in the North Sea (Troost et al., 2013). This study presents a novel approach to link the TBNT method applied to N to the biological processes driving the oxygen dynamics in the bottom layer of the North Sea. For this purpose, simulations from the biogeochemical model ECOHAM (ECOlogical model HAMburg) are analysed for the years 2002 and 2010, with the focus on the southern central North Sea, the region of

  11. Produced Water Treatment Methods and Regulations: Lessons from the Gulf of Mexico and North Sea for Nigeria

    Directory of Open Access Journals (Sweden)

    Adaobi Stephenie Nwosi-Anele

    2016-12-01

    Full Text Available Discharge specifications are allowable effluent limits of constituents in produced water before being discharged into the environment. Environmental regulatory agencies in the North Sea, Gulf of Mexico, and Niger Delta regions have specified effluent limits for the constituents of produced water. These PW discharge limits may be specified for metals, solids, bacteria, oil/grease content, PH, temperature, process chemicals and dispersed hydrocarbon constituents. Recent environmental impact assessments show that contrary to the trend in Niger Delta, North Sea and Gulf of Mexico have continued to modify their effluent limits pursuant to ZERO effluent discharge. This contrasts sharply with the Niger Delta which has maintained its effluent discharge limits for a long time without review. This has left the region with discharged effluents that may fall short of the needed environmental friendliness level. This paper investigates produced water treatment methods used in North Sea and Gulf of Mexico and how these could be useful for produced water treatment in Niger Delta. Critical comparative evaluations of treatment processes used in North Sea and Gulf of Mexico are carried out considering the terrain, PW constituents and regulatory specifications analogous to the Niger Delta. Results show that these treatment processes may be adopted based on terrain similarities. Effluent discharge limits may be met and exceeded with a view to achieving ZERO discharge effluent in Niger Delta.

  12. New insights into the earliest Quaternary environments in the Central North Sea from 3D seismic

    Science.gov (United States)

    Lamb, Rachel; Huuse, Mads; Stewart, Margaret; Brocklehurst, Simon H.

    2014-05-01

    In the past the transition between an unconformable surface in the south to a conformable horizon towards the north has made identification and mapping the base-Quaternary in the central North Sea difficult (Sejrup et al 1991; Gatliff et al 1994). However recent integration of biostratigraphy, pollen analysis, paleomagnetism and amino acid analysis in the Dutch and Danish sectors (Rasmussen et al 2005; Kuhlmann et al 2006) has allowed greater confidence in the correlation to the region 3D seismic datasets and thus has allowed the base-Quaternary to be mapped across the entire basin. The base-Quaternary has been mapped using the PGS MegaSurvey dataset from wells in the Danish Sector along the initially unconformable horizon and down the delta front into the more conformable basin giving a high degree of confidence in the horizon pick. The revised base-Quaternary surface reaches a depth of 1248 ms TWT with an elongate basin shape which is significantly deeper than the traditionally mapped surface. Using RMS amplitudes and other seismic attributes the revised base-Quaternary has been investigated along the horizon and in time slice to interpret the environments of the earliest Quaternary prior to the onset of glaciation. Combined with analysis of aligned elongate furrows over 10 km long, 100 m wide and 100 m deep suggest a deep marine environment in an almost enclosed basin with persistent strong NW-SE bottom currents in the deepest parts. Pockmarks were formed by the escape of shallow gas on the sides of a small delta in the eastern part of the basin. The progradation of large deltas from both the north and south into the basin make up the majority of the deposition of sediment into the basin. Key Words: base-Quaternary; seismic interpretation; paleoenvironments References: Gatliff, R.W, Richards, P.C, Smith, K, Graham, C.C, McCormac, M, Smith, N.J.P, Long, D, Cameron, T.D.J, Evans, D, Stevenson, A.G, Bulat, J, Ritchie, J.D, (1994) 'United Kingdom offshore regional

  13. Seasonal and Interannual Variability of the North-Western Black Sea Ecosystem

    Directory of Open Access Journals (Sweden)

    Joanna Staneva

    2010-01-01

    Full Text Available This study describes the coupling between physical and biogeochemical models and analyses the response of the ecosystem in the north-western Black Sea to nutrient loads and climate changes. The basic physical and biological dynamics of the upper north-western Black Sea is illustrated as well. The physical model is based on the Princeton Ocean Model (POM; additionally, a parameterisation of mixed layer is included. The biogeochemical model is based on the European Regional Sea Ecosystem Model (ERSEM and consists of five modules: (1 primary producers, (2 microbial loop, (3 mesozooplankton, (4 benthic nutrients, and (5 benthic biology. The ecosystem in ERSEM is subdivided into three functional types, producers (phytoplankton, decomposers (pelagic and benthic bacteria and consumers (zooplankton and zoobenthos. Model-data comparisons have been performed for both calibrating and verifying coupled model simulations. We address here the impact of nutrient discharge from the Danube River on the functioning of the biological system. The evolution of the mixed layer, as well as the response of the biological system to variability of the nutrient discharge from the Danube River is described in detail. Several scenarios have been developed to study the impact which nutrient reduction has on the coastal marine system. The model predictions indicate that the biological system is very sensitive to the changes in nutrient concentrations, as well as to their ratios.

  14. Lithospheric Thermal Isostasy of North Continental Margin of the South China Sea

    Institute of Scientific and Technical Information of China (English)

    Chen Shi; Zhang Jian; Sun Yujun; Shi Yaolin

    2009-01-01

    Accompanied with rifting and detaching of the north continental margin of the South China Sea,the ernst and the lithosphere become thinner away from the continental margin resulting from the tectonic activities,such as tensile deformation,thermal uplift,and cooling subsidence,etc..Integrated with thermal,gravimetric,and isostatic analysis techniques,based on the seismic interpretation of the deep penetration seismic soundings across the northern margin of the South China Sea,we reconstructed the lithospheric thermal structure and derived the variation of the crust boundary in the east and west parts of the seismic profde by using gravity anomaly data.We mainly studied the thermal isostasy problems using the bathymetry of the profiles and calculated the crust thinning effect due to the thermal variety in the rifting process.The results Indicate that the thermal isostasy may reach 2.5 kin,and the compositional variations in the ilthospheric density and thickness may produce a variation of 4.0 kin.Therefore,the compositional isostatic correction is very important to recover the relationship between surface heat flow and topography.Moreover,because of the high heat flow characteristic of the continental margin,building the model of lithospheric geotherm in this region is of great importan for studying the Cenozoic tectonic thermal evolution of the north passive continental margin of the South China Sea.

  15. Projecting twenty-first century regional sea-level changes

    NARCIS (Netherlands)

    Slangen, A.B.A.; Carson, M.; Katsman, C.A.; van de Wal, R.S.W.; Köhl, A.; Vermeersen, L.L.A.; Stammer, D.

    2014-01-01

    We present regional sea-level projections and associated uncertainty estimates for the end of the 21 (st) century. We show regional projections of sea-level change resulting from changing ocean circulation, increased heat uptake and atmospheric pressure in CMIP5 climate models. These are combined wi

  16. Projecting twenty-first century regional sea-level changes

    NARCIS (Netherlands)

    Slangen, A. B A; Carson, M.; Katsman, C. A.; van de Wal, R. S W; Köhl, A.; Vermeersen, L. L A; Stammer, D.

    2014-01-01

    We present regional sea-level projections and associated uncertainty estimates for the end of the 21st century. We show regional projections of sea-level change resulting from changing ocean circulation, increased heat uptake and atmospheric pressure in CMIP5 climate models. These are combined with

  17. Continuous measurements of atmospheric oxygen and carbon dioxide on a North Sea gas platform

    Directory of Open Access Journals (Sweden)

    I. T. Luijkx

    2009-07-01

    Full Text Available A new atmospheric measurement station has been established on the North Sea oil and gas production platform F3, 200 km north off the Dutch coast (54°51' N, 4°44' E. Atmospheric mixing ratios of O2 and CO2 are continuously measured using fuel cell technology and compact infrared absorption instruments, respectively. Furthermore, the station includes an automated air flask sampler for laboratory analysis of the atmospheric mixing ratios of CO2, CH4, CO and O2 and isotope measurements of δ13C, δ18O and Δ14C from CO2. This station is – to our knowledge – the first fixed sea based station with on-site continuous O2 and CO2 measurements and therefore yields valuable additional information about the CO2 uptake in coastal marine regions, specifically the North Sea. This paper presents the measurement station and the used methodologies in detail. Additionally, the first data is presented showing the seasonal cycle as expected during August 2008 through June 2009. In comparison to land-based stations, the data show low day-to-day variability, as they are practically free of nightly inversions. Therefore, the data set collected at this measurement station serves directly as background data for the coastal northwest European region. Additionally, some short-term O2 and CO2 signals are presented, including very large (over 200 per meg and fast negative atmospheric O2 excursions.

  18. Changes in size and trends of North American sea duck populations associated with North Pacific oceanic regime shifts

    Science.gov (United States)

    Flint, Paul L.

    2013-01-01

    Broad-scale multi-species declines in populations of North American sea ducks for unknown reasons is cause for management concern. Oceanic regime shifts have been associated with rapid changes in ecosystem structure of the North Pacific and Bering Sea. However, relatively little is known about potential effects of these changes in oceanic conditions on marine bird populations at broad scales. I examined changes in North American breeding populations of sea ducks from 1957 to 2011 in relation to potential oceanic regime shifts in the North Pacific in 1977, 1989, and 1998. There was strong support for population-level effects of regime shifts in 1977 and 1989, but little support for an effect of the 1998 shift. The continental-level effects of these regime shifts differed across species groups and time. Based on patterns of sea duck population dynamics associated with regime shifts, it is unclear if the mechanism of change relates to survival or reproduction. Results of this analysis support the hypothesis that population size and trends of North American sea ducks are strongly influenced by oceanic conditions. The perceived population declines appear to have halted >20 years ago, and populations have been relatively stable or increasing since that time. Given these results, we should reasonably expect dramatic changes in sea duck population status and trends with future oceanic regime shifts.

  19. Persistent influence of tropical North Atlantic wintertime sea surface temperature on the subsequent Atlantic hurricane season

    Science.gov (United States)

    Wang, Xidong; Liu, Hailong; Foltz, Gregory R.

    2017-08-01

    This study explores the seasonally lagged impact of wintertime sea surface temperature (SST) in the Atlantic main development region (MDR) on the subsequent Atlantic hurricane season. It is found that wintertime SST anomalies in the MDR can persist into the summer, explaining 42% of the variance in the subsequent hurricane season's SST during 1951-2010. An anomalously warm wintertime in the MDR is usually followed by an anomalously active hurricane season. Analysis shows an important constraint on the seasonal evolution of the MDR SST by the water vapor feedback process, in addition to the well-known wind-evaporation-SST and cloud-SST feedback mechanisms over the tropical North Atlantic. The water vapor feedback influences the seasonal evolution of MDR SST by modulating seasonal variations of downward longwave radiation. This wintertime thermal control of hurricane activity has significant implications for seasonal predictions and long-term projections of hurricane activity over the North Atlantic.

  20. Climate change facilitated range expansion of the non-native angular crab Goneplax rhomboides into the North Sea

    NARCIS (Netherlands)

    Neumann, H.; Boois, de I.J.; Kroncke, I.; Reiss, H.

    2013-01-01

    The angular crab Goneplax rhomboides is native to the north-eastern Atlantic and Mediterranean Sea. It has rarely been reported from the North Sea, with no evidence of sustainable populations. Compiled survey data, however, revealed an increasing abundance of this species in the North Sea since

  1. Climate change facilitated range expansion of the non-native angular crab Goneplax rhomboides into the North Sea

    NARCIS (Netherlands)

    Neumann, H.; Boois, de I.J.; Kroncke, I.; Reiss, H.

    2013-01-01

    The angular crab Goneplax rhomboides is native to the north-eastern Atlantic and Mediterranean Sea. It has rarely been reported from the North Sea, with no evidence of sustainable populations. Compiled survey data, however, revealed an increasing abundance of this species in the North Sea since 2000

  2. Anthropogenic {sup 129}I in the North Pacific, Bering and Chukchi Seas, and Arctic Ocean in 2012–2013

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, H., E-mail: hnagai@chs.nihon-u.ac.jp [Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo 156-8550 (Japan); Hasegawa, A. [Graduate School of Integrated Basic Sciences, Nihon University, Tokyo 156-8550 (Japan); Yamagata, T. [Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo 156-8550 (Japan); Kumamoto, Y.; Nishino, S. [Japan Agency for Marine-Earth Science and Technology, Kanagawa 237-0061 (Japan); Matsuzaki, H. [Department of Nuclear Engineering and Management, The University of Tokyo, Tokyo 113-0032 (Japan)

    2015-10-15

    Most of anthropogenic {sup 129}I in marine environment are due to discharge from the nuclear fuel reprocessing facilities at Sellafield (U.K.) and La Hague (France) for past few decades. The discharge raised {sup 129}I concentration in seawaters in the North Atlantic and Arctic Oceans to more than 10{sup 9} atoms L{sup −1}, which is two orders of magnitude higher than that in other region. Recently, in March 2011, a large quantity of {sup 129}I was released into the western North Pacific due to the Fukushima Daiichi Nuclear Power Plant (F1NPP) accident. To evaluate the influence of these events, we have measured {sup 129}I concentration in seawaters in the northern North Pacific Ocean, Bering and Chukchi Seas, and Arctic Ocean in 2012–2013. The {sup 129}I concentrations were 1.0–1.8 × 10{sup 7} atoms L{sup −1} in the surface waters in the vicinity of 47°N 150°E–130°W North Pacific Ocean, Bering Sea, and Chukchi Sea (<74°N), which are equal to or lower than the {sup 129}I concentration level in surface water in the North Pacific Ocean before the F1NPP accident. The vertical profiles in the North Pacific were almost same as that observed in the western North Pacific before the F1NPP accident. The {sup 129}I distribution in seawater in the North Pacific to the Chukchi Sea revealed no significant increase of {sup 129}I concentration caused by the F1NPP accident. The {sup 129}I concentrations were 13–14 × 10{sup 7} atoms L{sup −1} in surface waters and 80 × 10{sup 7} atoms L{sup −1} at depths of 300 and 800 m in the Arctic Ocean.

  3. Exchanges between the open Black Sea and its North West shelf

    Science.gov (United States)

    Shapiro, Georgy; Wobus, Fred; Zhou, Feng

    2014-05-01

    and North Sea. NATO ASI Series, Vol. 27, Kluwer Academic Publishers, 253-264. Shapiro, G.I. , S.V. Stanichny, R.R. Stanychna, 2010. Anatomy of shelf-deep sea exchanges by a mesoscale eddy in the North West Black Sea as derived from remotely sensed data. Remote Sensing of Environment, 114 , 867-875. Shapiro, G., Luneva, M., Pickering, J., and Storkey, D., 2013. The effect of various vertical discretization schemes and horizontal diffusion parameterization on the performance of a 3-D ocean model: the Black Sea case study, Ocean Science, 9, 377-390. Staneva, J. V. and E. V. Stanev, 1997. Cold water mass formation in the Black Sea. Analysis on numerical model simulations. In: E. Ozsoy and A. Mikaelyan (eds.), Sensitivity to change: Black Sea, Baltic Sea and North Sea. NATO ASI Series, Vol. 27, Kluwer Academic Publishers, 375-393. Zaitsev Yu.P., B.G. Alexandrov, N.A. Berlinsky, A. Zenetos, 2001. Europe's biodiversity - biogeographical regions and seas. The Black Sea. European Environment Agency.

  4. The SeaDataNet data products: regional temperature and salinity historical data collections

    Science.gov (United States)

    Simoncelli, Simona; Coatanoan, Christine; Bäck, Orjan; Sagen, Helge; Scoy, Serge; Myroshnychenko, Volodymyr; Schaap, Dick; Schlitzer, Reiner; Iona, Sissy; Fichaut, Michele

    2016-04-01

    Temperature and Salinity (TS) historical data collections covering the time period 1900-2013 were created for each European marginal sea (Arctic Sea, Baltic Sea, Black Sea, North Sea, North Atlantic Ocean and Mediterranean Sea) within the framework of SeaDataNet2 (SDN) EU-Project and they are now available as ODV collections through the SeaDataNet web catalog at http://sextant.ifremer.fr/en/web/seadatanet/. Two versions have been published and they represent a snapshot of the SDN database content at two different times: V1.1 (January 2014) and V2 (March 2015). A Quality Control Strategy (QCS) has been developped and continuously refined in order to improve the quality of the SDN database content and to create the best product deriving from SDN data. The QCS was originally implemented in collaboration with MyOcean2 and MyOcean Follow On projects in order to develop a true synergy at regional level to serve operational oceanography and climate change communities. The QCS involved the Regional Coordinators, responsible of the scientific assessment, the National Oceanographic Data Centers (NODC) and the data providers that, on the base of the data quality assessment outcome, checked and eventually corrected anomalies in the original data. The QCS consists of four main phases: 1) data harvesting from the central CDI; 2) file and parameter aggregation; 3) quality check analysis at regional level; 4) analysis and correction of data anomalies. The approach is iterative to facilitate the upgrade of SDN database content and it allows also the versioning of data products with the release of new regional data collections at the end of each QCS loop. SDN data collections and the QCS will be presented and the results summarized.

  5. Variability of mesozooplankton spatial distribution in the North Aegean Sea, as influenced by the Black Sea waters outflow

    Science.gov (United States)

    Siokou-Frangou, Ioanna; Zervoudaki, Soultana; Christou, Epaminondas D.; Zervakis, Vassilis; Georgopoulos, Dimitrios

    2009-11-01

    The North Aegean Sea constitutes an important region of the Mediterranean Sea since in its eastern part the mesotrophic, low salinity and relatively cold water from the Black Sea (outflowing from the Dardanelles strait) meets the oligotrophic, warm and very saline water of Levantine origin, thus forming a thermohaline front. Mesozooplankton samples were collected at discrete layers according to the hydrology of the upper 100 m, during May 1997 and September 1998. In May highest biomass and abundance values (up to 66.82 mg m - 3 and 14,157 ind m - 3 ) were detected in the 10-20 m layer (within the halocline) of the stations positioned close to the Dardanelles strait. The front moved slightly southwards in September, characterized by high biomass and abundance values within the halocline layer. The areas moderately or non influenced by Black Sea water revealed lower standing stock values than the frontal area in both cruises and maxima were detected in the uppermost low salinity layer. Samples collected at the stations and/or layers more influenced by Black Sea water were distinguished from those collected at layers and/or stations more affected by Levantine waters in both periods. In May the former samples were characterized by the copepods Acartia clausi, Centropages typicus, Paracalanus parvus. The abundance of the above species decreased gradually with increasing salinity, in the horizontal and/or in the vertical dimension, with a parallel increase of the copepods Oithona plumifera, Oithona copepodites, Oncaea media, Ctenocalanus vanus, Farranula rostrata. During September the frontal area as well as that covered by the modified Black Sea water, were highly dominated by the cladoceran Penilia avirostris and doliolids. For both seasons, MDS plots, issued from the combination of mesozooplankton and water-type data, revealed the gradual differentiation of zooplankton composition from the frontal area towards the area covered by Levantine water, following the

  6. Budgets for total and bioavailable nitrogen in the North Sea-Baltic Sea transition zone

    DEFF Research Database (Denmark)

    Jørgensen, L.; Markager, Stiig; Maar, Marie

    Budget calculations show that bioavailability of dissolved organic nitrogen (DON) is a key factor in management of eutrophication in open marine areas as it governs the importance of local loadings versus nitrogen received from adjacent seas and hence if eutrophication is a local or regional...... problem. Nitrogen is the limiting nutrient in the Belt Sea and the Kattegat. At the same time the area is heavily affected by eutrophication. Hence, a number of abatement measures have been implanted in Denmark, Sweden and Germany in order to reduce the anthropogenic nitrogen loadings. In this context...... it is essential to know how much of the nitrogen comes from local sources and how much is imported for the adjacent seas. We have therefore made nitrogen budgets for both total nitrogen and bioavailable nitrogen covering the area. Bioavailable nitrogen consists of inorganic N, particulate organic N...

  7. Comparison of numerical hindcasted severe waves with Doppler radar measurements in the North Sea

    Science.gov (United States)

    Ponce de León, Sonia; Bettencourt, João H.; Dias, Frederic

    2017-01-01

    Severe sea states in the North Sea present a challenge to wave forecasting systems and a threat to offshore installations such as oil and gas platforms and offshore wind farms. Here, we study the ability of a third-generation spectral wave model to reproduce winter sea states in the North Sea. Measured and modeled time series of integral wave parameters and directional wave spectra are compared for a 12-day period in the winter of 2013-2014 when successive severe storms moved across the North Atlantic and the North Sea. Records were obtained from a Doppler radar and wave buoys. The hindcast was performed with the WAVEWATCH III model (Tolman 2014) with high spectral resolution both in frequency and direction. A good general agreement was obtained for integrated parameters, but discrepancies were found to occur in spectral shapes.

  8. Smart Specialization and Capabilities for Offshore Wind Services around the North Sea

    DEFF Research Database (Denmark)

    Piirainen, Kalle; Tanner, Anne Nygaard; Alkærsig, Lars;

    2014-01-01

    This paper addresses a growing gap between the policy practice of “Smart Specialization strategies” and its theoretical base. The concept of Smart specialization has attracted a high level of policy interest and has been adopted widely in policy circles in Europe. However, Smart Specialization...... lacks an empirical and theoretical foundation that can help guide its application in practice. This paper develops a framework based on two strings of literature, namely the fields of evolutionary economic geography and innovation systems. Subsequently the framework is applied on a regional mapping...... exercise conducted in an EU funded ‘Regions of Knowledge’-project that focuses on the Offshore Wind Service sector in four regions around the North Sea. The purpose is to illustrate how a strategy-making process can be guided by a few theory based principles in pursuing the goals of smart specialization...

  9. Synchronous response of marine plankton ecosystems to climate in the Northeast Atlantic and the North Sea

    Science.gov (United States)

    Goberville, Eric; Beaugrand, Gregory; Edwards, Martin

    2014-01-01

    Over the last few decades, global warming has accelerated both the rate and magnitude of changes observed in many functional units of the Earth System. In this context, plankton are sentinel organisms because they are sensitive to subtle levels of changes in temperature and might help in identifying the current effects of climate change on pelagic ecosystems. In this paper, we performed a comparative approach in two regions of the North Atlantic (i.e. the Northeast Atlantic and the North Sea) to explore the relationships between changes in marine plankton, the regional physico-chemical environment and large-scale hydro-climatic forcing using four key indices: the North Atlantic Oscillation (NAO), the Atlantic Multidecadal Oscillation (AMO), the East Atlantic (EA) pattern and Northern Hemisphere Temperature (NHT) anomalies. Our analyses suggest that long-term changes in the states of the two ecosystems were synchronous and correlated to the same large-scale hydro-climatic variables: NHT anomalies, the AMO and to a lesser extent the EA pattern. No significant correlation was found between long-term ecosystem modifications and the state of the NAO. Our results suggest that the effect of climate on these ecosystems has mainly occurred in both regions through the modulation of the thermal regime.

  10. Extended late Holocene relative sea-level histories for North Carolina, USA

    Science.gov (United States)

    Kemp, Andrew C.; Kegel, Jessica J.; Culver, Stephen J.; Barber, Donald C.; Mallinson, David J.; Leorri, Eduardo; Bernhardt, Christopher E.; Cahill, Niamh; Riggs, Stanley R.; Woodson, Anna L.; Mulligan, Ryan P.; Horton, Benjamin P.

    2017-03-01

    We produced ∼3000-year long relative sea-level (RSL) histories for two sites in North Carolina (USA) using foraminifera preserved in new and existing cores of dated salt-marsh sediment. At Cedar Island, RSL rose by ∼2.4 m during the past ∼3000 years compared to ∼3.3 m at Roanoke Island. This spatial difference arises primarily from differential GIA that caused late Holocene RSL rise to be 0.1-0.2 mm/yr faster at Roanoke Island than at Cedar Island. However, a non-linear difference in RSL between the two study regions (particularly from ∼0 CE to ∼1250 CE) indicates that additional local- to regional-scale processes drove centennial-scale RSL change in North Carolina. Therefore, the Cedar Island and Roanoke Island records should be considered as independent of one another. Between-site differences on sub-millennial timescales cannot be adequately explained by non-stationary tides, sediment compaction, or local sediment dynamics. We propose that a period of accelerating RSL rise from ∼600 CE to 1100 CE that is present at Roanoke Island (and other sites north of Cape Hatteras at least as far as Connecticut), but absent at Cedar Island (and other sites south of Cape Hatteras at least as far as northeastern Florida) is a local-to regional-scale effect of dynamic ocean and/or atmospheric circulation.

  11. Impacts of the local environment on recruitment: a comparative study of North Sea and Baltic Sea fish stocks

    DEFF Research Database (Denmark)

    Pécuchet, Lauréne; Nielsen, J. Rasmus; Christensen, Asbjørn

    2015-01-01

    of other fish stocks are regularly significant in the models. This study shows the importance of the local environment on the dynamics of SR. The results provide evidence of the necessity of including environmental variables in stock assessment for a realistic and efficient management of fisheries.......While the impact of environmental forcing on recruitment variability in marine populations remains largely elusive, studies spanning large spatial areas and many stocks are able to identify patterns common to different regions and species. In this study, we investigate the effects...... of the environment on the residuals of a Ricker stock-recruitment (SR) model, used as a proxy of prerecruits' survival, of 18 assessed stocks in the Baltic and North Seas. A probabilistic principal components (PCs) analysis permits the identification of groups of stocks with shared variability in the prerecruits...

  12. A probabilistic storm surge risk model for the German North Sea and Baltic Sea coast

    Science.gov (United States)

    Grabbert, Jan-Henrik; Reiner, Andreas; Deepen, Jan; Rodda, Harvey; Mai, Stephan; Pfeifer, Dietmar

    2010-05-01

    The German North Sea coast is highly exposed to storm surges. Due to its concave bay-like shape mainly orientated to the North-West, cyclones from Western, North-Western and Northern directions together with astronomical tide cause storm surges accumulating the water in the German bight. Due to the existence of widespread low-lying areas (below 5m above mean sea level) behind the defenses, large areas including large economic values are exposed to coastal flooding including cities like Hamburg or Bremen. The occurrence of extreme storm surges in the past like e.g. in 1962 taking about 300 lives and causing widespread flooding and 1976 raised the awareness and led to a redesign of the coastal defenses which provide a good level of protection for today's conditions. Never the less the risk of flooding exists. Moreover an amplification of storm surge risk can be expected under the influence of climate change. The Baltic Sea coast is also exposed to storm surges, which are caused by other meteorological patterns. The influence of the astronomical tide is quite low instead high water levels are induced by strong winds only. Since the exceptional extreme event in 1872 storm surge hazard has been more or less forgotten. Although such an event is very unlikely to happen, it is not impossible. Storm surge risk is currently (almost) non-insurable in Germany. The potential risk is difficult to quantify as there are almost no historical losses available. Also premiums are difficult to assess. Therefore a new storm surge risk model is being developed to provide a basis for a probabilistic quantification of potential losses from coastal inundation. The model is funded by the GDV (German Insurance Association) and is planned to be used within the German insurance sector. Results might be used for a discussion of insurance cover for storm surge. The model consists of a probabilistic event driven hazard and a vulnerability module, furthermore an exposure interface and a financial

  13. Hydrographic responses to regional covariates across the Kara Sea

    Science.gov (United States)

    Mäkinen, Jussi; Vanhatalo, Jarno

    2016-12-01

    The Kara Sea is a shelf sea in the Arctic Ocean which has a strong spatiotemporal hydrographic variation driven by river discharge, air pressure, and sea ice. There is a lack of information about the effects of environmental variables on surface hydrography in different regions of the Kara Sea. We use a hierarchical spatially varying coefficient model to study the variation of sea surface temperature (SST) and salinity (SSS) in the Kara Sea between years 1980 and 2000. The model allows us to study the effects of climatic (Arctic oscillation index (AO)) and seasonal (river discharge and ice concentration) environmental covariates on hydrography. The hydrographic responses to covariates vary considerably between different regions of the Kara Sea. River discharge decreases SSS in the shallow shelf area and has a neutral effect in the northern Kara Sea. The responses of SST and SSS to AO show the effects of different wind and air pressure conditions on water circulation and hence on hydrography. Ice concentration has a constant effect across the Kara Sea. We estimated the average SST and SSS in the Kara Sea in 1980-2000. The average August SST over the Kara Sea in 1995-2000 was higher than the respective average in 1980-1984 with 99.9% probability and August SSS decreased with 77% probability between these time periods. We found a support that the winter season AO has an impact on the summer season hydrography, and temporal trends may be related to the varying level of winter season AO index.

  14. Seasonal thickness changes of Arctic sea ice north of Svalbard and implications for satellite remote sensing, ecosystem, and environmental management

    Science.gov (United States)

    Gerland, S.; Rösel, A.; King, J.; Spreen, G.; Divine, D.; Eltoft, T.; Gallet, J. C.; Hudson, S. R.; Itkin, P.; Krumpen, T.; Liston, G. E.; Merkouriadi, I.; Negrel, J.; Nicolaus, M.; Polashenski, C.; Assmy, P.; Barber, D. G.; Duarte, P.; Doulgeris, A. P.; Haas, C.; Hughes, N.; Johansson, M.; Meier, W.; Perovich, D. K.; Provost, C.; Richter-Menge, J.; Skourup, H.; Wagner, P.; Wilkinson, J.; Granskog, M. A.; Steen, H.

    2016-12-01

    Sea-ice thickness is a crucial parameter to consider when assessing the status of Arctic sea ice, whether for environmental management, monitoring projects, or regional or pan-arctic assessments. Modern satellite remote sensing techniques allow us to monitor ice extent and to estimate sea-ice thickness changes; but accurate quantifications of sea-ice thickness distribution rely on in situ and airborne surveys. From January to June 2015, an international expedition (N-ICE2015) took place in the Arctic Ocean north of Svalbard, with the Norwegian research vessel RV Lance frozen into drifting sea ice. In total, four drifts, with four different floes were made during that time. Sea-ice and snow thickness measurements were conducted on all main ice types present in the region, first year ice, multiyear ice, and young ice. Measurement methods included ground and helicopter based electromagnetic surveys, drillings, hot-wire installations, snow-sonde transects, snow stakes, and ice mass balance and snow buoys. Ice thickness distributions revealed modal thicknesses in spring between 1.6 and 1.7 m, which is lower than reported for the region from comparable studies in 2009 (2.4 m) and 2011 (1.8 m). Knowledge about the ice thickness distribution in a region is crucial to the understanding of climate processes, and also relevant to other disciplines. Sea-ice thickness data collected during N-ICE2015 can also give us insights into how ice and snow thicknesses affect ecosystem processes. In this presentation, we will explore the influence of snow cover and ocean properties on ice thickness, and the role of sea-ice thickness in air-ice-ocean interactions. We will also demonstrate how information about ice thickness aids classification of different sea ice types from SAR satellite remote sensing, which has real-world applications for shipping and ice forecasting, and how sea ice thickness data contributes to climate assessments.

  15. Revisiting the Submerged Paleo Elbe Valley (S North Sea) with High-Resolution Shallow Seismics

    Science.gov (United States)

    Papenmeier, S.; Hass, H. C.

    2014-12-01

    The Elbe paleo valley is the most prominent subsurface structure in the southern North Sea (~10,000 km²) and constitutes an important part of Germany's largest marine Natura 2000-Reserve "Sylter Außenriff" (European environmental protection area). It is supposed that the valley was formed by epeirogenic movement during the Tertiary. The depression developed to its present form during the Weichselian sea-level lowstand (-130 m below present). Melt waters that discharged in north-westerly directions fed the paleo Elbe at that time. During the Holocene the valley drowned in the rising sea. A narrow raster of new shallow seismic data combined with high resolution sidescan sonar data is used to shed new light on the Holocene development of the paleo Elbe valley and its adjacent regions in detail. Cross sections distributed with transect distances of 400 and 800 m, respectively, over a length of 100 km (approximately one third of the total valley length) enable a good comprehensive analysis of the historical process of sedimentary valley infill and coastal evolution with the successive Holocene sea level rise. The eastern flank of the valley is characterized by a relatively steep slope with one or more terraces, representing moraine deposits which are today still present at the seafloor surface, partly covered with Holocene marine deposits. The western slip-off slope of the valley is much smoother than the eastern undercut slope. West of the valley, sediment cores show peat and tidal flat sediments. Shallow seismic data show the base of the valley. There are conspicuous internal seismic reflectors above the base, inclined in northeastern direction. They indicate a sedimentary infill of the valley from the southwest when the southern part of the Dogger Bank was flooded during the early Holocene sea-level rise. In this process the steeper eastern slope acted as a natural barrier towards the northeast, averted sediment transport beyond the eastern boundary of the paleo

  16. Modelling transport and reproduction of the invasive comb jelly Mnemiopsis leidyi in the North Sea

    Science.gov (United States)

    van der Molen, Johan

    2014-05-01

    Mnemiopsis leidyi is an invasive comb jelly fish species that originates from the Gulf of Mexico and the US east coast. It has high bloom potential, and can survive in a wide variety of environmental conditions. It was first introduced in Europe through ballast water discharges in the Black Sea, where it was associated with the anchovis stock collapse in the 1990's. From there, it has spread through the Mediterranean Sea. Since the mid 2000's it has been observed in ports and estuaries along the English Channel, the North Sea and the Baltic Sea. In the North Sea, M. leidyi blooms occur in the Scheldt estuaries, the Wadden Sea, and in ports and canals. In winter, M. Leidyi has been observed at sea in the German Bight. A particle tracking model was modified to include a simple reproduction mechanism, using food fields from the coupled hydrodynamics-ecosystem model GETM-ERSEM. The model was used to study the potential spreading and bloom potential of M. Leidyi in the southern North Sea under present and increased temperature conditions. Under present conditions, the model suggested that M. Leidyi can survive in the North Sea, and can be transported over distances of several hundreds of km, enabling connectivity between estuarine populations. It could not, however, bloom at open sea because of temperature constraints. These constraints were lifted for increased temperature scenarios, suggesting increased bloom potential under climate change conditions.

  17. Coastal Erosion and Flooding Hazards on the North Sea Coast at Thyboron, Denmark

    DEFF Research Database (Denmark)

    Sørensen, Per; Sørensen, Carlo Sass; Nielsen, Peter

    Since a breach of the coastal barrier in 1862, the Thyboron Channel connecting the North Sea and the Lim Fiord has been artificially maintained by construction of breakwaters and groins on the North Sea coast and inside the channel, respectively. Sand nourishment schemes have since the 1980s...... counteracted the natural erosion in the upper profile on the North Sea coast where the alongshore sediment transport converges towards the channel and deposits up to 1 million m3/y on the flood tidal delta inside the fiord, Figure 1....

  18. Evaluating Financial Model Performance: An Empirical Analysis of Some North Sea Investments

    CERN Document Server

    Croll, Grenville J; Lawal, Ola

    2010-01-01

    Fifty North Sea oil & gas investment transactions were analysed using traditional spreadsheet based financial modelling methods. The purpose of the analysis was to determine if there was a statistically significant relationship between the price paid for an oil & gas asset and the actual or expected financial return over the asset's economically useful life. Several interesting and statistically significant relationships were found which reveal useful information about financial modelling performance, the premia paid to acquire North Sea assets, the contribution oil and gas price uncertainty has on estimates of future financial returns and the median financial return of these North Sea Investments.

  19. Warm Greenland during the last interglacial: the role of regional changes in sea ice cover

    Science.gov (United States)

    Merz, Niklaus; Born, Andreas; Raible, Christoph C.; Stocker, Thomas F.

    2016-10-01

    The last interglacial, also known as the Eemian, is characterized by warmer than present conditions at high latitudes. This is implied by various Eemian proxy records as well as by climate model simulations, though the models mostly underestimate the warming with respect to proxies. Simulations of Eemian surface air temperatures (SAT) in the Northern Hemisphere extratropics further show large variations between different climate models, and it has been hypothesized that this model spread relates to diverse representations of the Eemian sea ice cover. Here we use versions 3 and 4 of the Community Climate System Model (CCSM3 and CCSM4) to highlight the crucial role of sea ice and sea surface temperatures changes for the Eemian climate, in particular in the North Atlantic sector and in Greenland. A substantial reduction in sea ice cover results in an amplified atmospheric warming and thus a better agreement with Eemian proxy records. Sensitivity experiments with idealized lower boundary conditions reveal that warming over Greenland is mostly due to a sea ice retreat in the Nordic Seas. In contrast, sea ice changes in the Labrador Sea have a limited local impact. Changes in sea ice cover in either region are transferred to the overlying atmosphere through anomalous surface energy fluxes. The large-scale spread of the warming resulting from a Nordic Seas sea ice retreat is mostly explained by anomalous heat advection rather than by radiation or condensation processes. In addition, the sea ice perturbations lead to changes in the hydrological cycle. Our results consequently imply that both temperature and snow accumulation records from Greenland ice cores are sensitive to sea ice changes in the Nordic Seas but insensitive to sea ice changes in the Labrador Sea. Moreover, the simulations suggest that the uncertainty in the Eemian sea ice cover accounts for 1.6 °C of the Eemian warming at the NEEM ice core site. The estimated Eemian warming of 5 °C above present day

  20. Comparative SWOT analysis of strategic environmental assessment systems in the Middle East and North Africa region.

    Science.gov (United States)

    Rachid, G; El Fadel, M

    2013-08-15

    This paper presents a SWOT analysis of SEA systems in the Middle East North Africa region through a comparative examination of the status, application and structure of existing systems based on country-specific legal, institutional and procedural frameworks. The analysis is coupled with the multi-attribute decision making method (MADM) within an analytical framework that involves both performance analysis based on predefined evaluation criteria and countries' self-assessment of their SEA system through open-ended surveys. The results show heterogenous status with a general delayed progress characterized by varied levels of weaknesses embedded in the legal and administrative frameworks and poor integration with the decision making process. Capitalizing on available opportunities, the paper highlights measures to enhance the development and enactment of SEA in the region.

  1. Mapping the North Sea base-Quaternary: using 3D seismic to fill a gap in the geological record

    Science.gov (United States)

    Lamb, Rachel; Huuse, Mads; Stewart, Margaret; Brocklehurst, Simon H.

    2014-05-01

    The identification and mapping of the base-Quaternary boundary in the central parts of the North Sea is problematic due to the change from an unconformable transition between Pliocene and Pleistocene deltaic deposits in the southern North Sea to a conformable one further north (Sejrup et al 1991; Gatliff et al 1994). The best estimates of the transition use seismic reflection data to identify a 'crenulated reflector' (Buckley 2012), or rely on correlating sparse biostratigraphy (Cameron et al 1987). Recent integration of biostratigraphy, pollen analysis, paleomagnetism and amino acid analysis in the Dutch and Danish sectors (Rasmussen et al 2005; Kuhlmann et al 2006) allows greater confidence in the correlation to a regional 3D seismic dataset and show that the base-Quaternary can be mapped across the entire basin. The base-Quaternary has been mapped using the PGS MegaSurvey dataset from wells in the Danish Sector along the initially unconformable horizon and down the delta front into the more conformable basin giving a high degree of confidence in the horizon pick. The mapped horizon is presented here alongside the difference between this new interpretation and the previously interpreted base-Quaternary (Buckley 2012). The revised base-Quaternary surface reaches a depth of 1248 ms TWT or approximately 1120 m (assuming average velocity of 1800 m/s) showing an elongate basin shape that follows the underlying structure of the Central Graben. The difference between the revised base-Quaternary and the traditional base-Quaternary reaches a maximum of over 600 ms TWT or approximately 540 m in the south-west with over 300 ms TWT or approximately 270 m at the Josephine well (56° 36.11'N, 2° 27.09'E) in the centre of the basin. Mapping this new base-Quaternary allows for the interpretation of the paleo-envionrment during the earliest Quaternary. Seismic attribute analysis indicates a deep water basin with sediment deposition from multiple deltas and redistribution by deep

  2. Tertiary paleomagnetism of regions around the South China Sea

    Science.gov (United States)

    Fuller, M.; Haston, R.; Lin, Jin-Lu; Richter, B.; Schmidtke, E.; Almasco, J.

    Paleomagnetic data from the Philippine Sea Plate (PSP) reveal a history of plate-wide clockwise (CW) rotation and northerly translation since the late Eocene about a nearby pole to the east. The motion has generated left lateral oblique convergence between the Philippine Sea Plate and S.E. Asia. Paleomagnetic data from Luzon in the northern Philippines show early Miocene CCW rotation followed by late Miocene CW rotation. In contrast, the Southern and Central Philippines display early Miocene CW rotation and unrotated late Miocene directions. These results define two different paleomagnetic domains with distinct post early Miocene histories. Pre-Miocene CCW rotation is suggested by data from Zambales, the Visayas and the Celebes Sea. In Borneo, a history of Tertiary CCW rotation has been found in Sarawak, and Sabah. Conflicting results have been reported from Kalimantan, some show no rotation with respect to Eurasia, while others give CCW rotations. In the Malaysian peninsula, the Segamat basalts and Kuantan dykes, of probable late Cretaceous early Tertiary age show CCW rotations similar to those seen in Sarawak. To the north peninsular Thailand, CW rotations have been found in two Miocene non-marine basins. Late Tertiary basalts from Northern and Central Thailand yield similar CW rotations while coeval flows on the Khorat plateau in Eastern Thailand are unrotated. The tectonic implications of the results remain problematical. In particular, the relative importance of true plate rotations and localized rotation of upper crustal blocks in distributed shear zones is unclear. The substantial region of CCW rotation in Borneo, the Celebes Sea and the Philippines is consistent with the broad features of the Holloway model, although the timing of the rotations precludes simple coherent rotation. The model must also be modified to include the effect of the left lateral oblique convergence between the PSP and Eurasia. The CW rotations seen in peninsular Thailand and Malaysia

  3. North Atlantic teleconnection patterns signature on sea level from satellite altimetry

    Science.gov (United States)

    Iglesias, Isabel; Lázaro, Clara; Joana Fernandes, M.; Bastos, Luísa

    2015-04-01

    Presently, satellite altimetry record is long enough to appropriately study inter-annual signals in sea level anomaly and ocean surface circulation, allowing the association of teleconnection patterns of low-frequency variability with the response of sea level. The variability of the Atlantic Ocean at basin-scale is known to be complex in space and time, with the dominant mode occurring on annual timescales. However, interannual and decadal variability have already been documented in sea surface temperature. Both modes are believed to be linked and are known to influence sea level along coastal regions. The analysis of the sea level multiannual variability is thus essential to understand the present climate and its long-term variability. While in the open-ocean sea level anomaly from satellite altimetry currently possesses centimetre-level accuracy, satellite altimetry measurements become invalid or of lower accuracy along the coast due to the invalidity of the wet tropospheric correction (WTC) derived from on-board microwave radiometers. In order to adequately analyse long-term changes in sea level in the coastal regions, satellite altimetry measurements can be recovered by using an improved WTC computed from recent algorithms that combine wet path delays from all available observations (remote sensing scanning imaging radiometers, GNSS stations, microwave radiometers on-board satellite altimetry missions and numerical weather models). In this study, a 20-year (1993-2013) time series of multi-mission satellite altimetry (TOPEX/Poseidon, Jason-1, OSTM/Jason-2, ERS-1/2, ENVISAT, CryoSat-2 and SARAL), are used to characterize the North Atlantic (NA) long-term variability on sea level at basin-scale and analyse its response to several atmospheric teleconnections known to operate on the NA. The altimetry record was generated using an improved coastal WTC computed from either the GNSS-derived path Delay or the Data Combination methodologies developed by University of

  4. Can regional climate engineering save the summer Arctic sea ice?

    Science.gov (United States)

    Tilmes, S.; Jahn, Alexandra; Kay, Jennifer E.; Holland, Marika; Lamarque, Jean-Francois

    2014-02-01

    Rapid declines in summer Arctic sea ice extent are projected under high-forcing future climate scenarios. Regional Arctic climate engineering has been suggested as an emergency strategy to save the sea ice. Model simulations of idealized regional dimming experiments compared to a business-as-usual greenhouse gas emission simulation demonstrate the importance of both local and remote feedback mechanisms to the surface energy budget in high latitudes. With increasing artificial reduction in incoming shortwave radiation, the positive surface albedo feedback from Arctic sea ice loss is reduced. However, changes in Arctic clouds and the strongly increasing northward heat transport both counteract the direct dimming effects. A 4 times stronger local reduction in solar radiation compared to a global experiment is required to preserve summer Arctic sea ice area. Even with regional Arctic dimming, a reduction in the strength of the oceanic meridional overturning circulation and a shut down of Labrador Sea deep convection are possible.

  5. Regional Military Security Cooperation in North America

    Science.gov (United States)

    2009-12-11

    Forward for North American Integration by Dr. Stephen Blank, Dr. Stephanie Golob, and Dr. Guy Stanley is a Pace University, Lubin School of Business...States are “the countries that ring the Gap – Mexico, Brazil, South Africa, Morocco, Algeria, Greece, Turkey, Pakistan, Thailand, Malaysia , the... vernacular regarding globalization, I will examine the impact of globalization on the world in terms of population, natural resources, and connectivity

  6. NCEP North American Regional Reanalysis (NARR), for 1979 to Present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The North America Regional Reanalysis (NARR) Project is a reanalysis of historical observations using a 32-km version of the National Centers for Environmental...

  7. Thermocline bulk shear analysis in the northern North Sea

    Science.gov (United States)

    Chen, Shengli; Polton, Jeff A.; Hu, Jianyu; Xing, Jiuxing

    2016-04-01

    Thermocline bulk shear is investigated in the northern North Sea using historical observations. The conventional bulk shear is modified to define a thermocline bulk shear (TBS), in order to better represent the shear across the thermocline. The TBS computed by observed currents is decomposed into components at different frequency bands. The near-inertial TBS is the largest component. Its dominance is significant during the period of high wind. It is formed by the wind-driven near-inertial current which has a distinct phase shift (˜180°) across the thermocline. A linear model is presented, which well simulates the observed near-inertial TBS, especially during the period of relatively strong wind. The semidiurnal TBS makes a secondary contribution to the total TBS. It is only slightly smaller than the near-inertial TBS when the wind is relatively weak. The large values of semidiurnal TBS are associated with semidiurnal currents which have a phase shift (˜30-40°) or a magnitude difference (˜5 cm/s) across the thermocline. The low-frequency (<0.7 cpd) TBS also makes an episodic contribution to the total. Its variation coincides with the Ekman transport during the period of relatively strong wind. The low-frequency TBS is mainly formed by an Ekman-like clockwise spiraling of velocity with depth or a distinct magnitude difference in velocities between upper and lower layers.

  8. Flight crew fatigue III: North Sea helicopter air transport operations.

    Science.gov (United States)

    Gander, P H; Barnes, R M; Gregory, K B; Graeber, R C; Connell, L J; Rosekind, M R

    1998-09-01

    We studied 32 helicopter pilots before, during, and after 4-5 d trips from Aberdeen, Scotland, to service North Sea oil rigs. On duty days, subjects awoke 1.5 h earlier than pretrip or posttrip, after having slept nearly an hour less. Subjective fatigue was greater posttrip than pretrip. By the end of trip days, fatigue was greater and mood more negative than by the end of pretrip days. During trips, daily caffeine consumption increased 42%, reports of headache doubled, reports of back pain increased 12-fold, and reports of burning eyes quadrupled. In the cockpits studied, thermal discomfort and high vibration levels were common. Subjective workload during preflight, taxi, climb, and cruise was related to the crewmembers' ratings of the quality of the aircraft systems. During descent and approach, workload was affected by weather at the landing site. During landing, it was influenced by the quality of the landing site and air traffic control. Beginning duty later, and greater attention to aircraft comfort and maintenance, should reduce fatigue in these operations.

  9. Cost Overruns and Cost Estimation in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Emhjellen, Magne; Emhjellen, Kjetil; Osmundsen, Petter

    2001-10-01

    Recently, a Norwegian government report on the cost overruns of projects in the North Sea was presented (NOU 1999:11). It concluded that there was a 25% increase in development costs from project sanction (POD, Plan for Operation and Development) to last CCE (Capital Cost Estimate) for the 11 oil field projects investigated. Many reasons like unclear project assumptions in early phase, optimistic interpolation of previous project assumptions, too optimistic estimates, and underestimation of uncertainty were given as reasons for overruns. In this article we highlight the possibility that the cost overruns are not necessarily all due to the reasons given, but also to an error in the estimation and reporting of the capital expenditure cost (CAPEX). Usually the CAPEX is given by a single cost figure, with some indication of its probability distribution. The oil companies report, and are required to do so by government authorities, the estimated 50/50 (median) cost estimate instead of the estimated expected value cost estimate. We demonstrate how the practice of using a 50/50 (median) CAPEX estimate for the 11 projects when the cost uncertainty distributions are asymmetric, may explain at least part of the ''overruns''. Hence, we advocate changing the practice of using 50/50 cost estimates instead of expected value cost estimates for project management and decision purposes. (author)

  10. [Vegetation landscape health assessment in Changshan Archipelago, North Yellow Sea].

    Science.gov (United States)

    Suo, An-ning; Sun, Yong-guang; Li, Bin-yong; Lin, Yong; Zhang, Yong-hua

    2015-04-01

    Island vegetation is an important component of island ecosystem. Multi-targets of island ecosystem health integrated with landscape ecology theory were employed to construct the index system for island vegetation health assessment in terms of landscape vigor, landscape stressing intensity and landscape stability. The Changshan Archipelago in the North Yellow Sea was chosen as a case to apply the island vegetation health assessment index system. The results showed that the overall vegetation health status in Changshan Archipelago was good and had a big island variation. The vegetation health index for Haiyang Island and Zhangzi Island was above 0.80, belonging to first eco-health level area, whereas that for Dachangshan Island, Xiaochangshan Island and Dawangjia Island ranged from 0.70 to 0.80, which could be categorized as the second eco-health level area. Guanglu Island and Shichen Island could be termed as the third eco-health level area with the vegetation health index below 0.70. The distance of island to mainland, area of island together with industrial structure were the main driving forces for the variation of vegetation landscape heath between different islands.

  11. Rock physics model of glauconitic greensand from the North Sea

    DEFF Research Database (Denmark)

    Hossain, Zakir; Mukerji, Tapan; Dvorkin, Jack

    2011-01-01

    The objective of this study was to establish a rock physics model of North Sea Paleogene greensand. The Hertz-Mindlin contact model is widely used to calculate elastic velocities of sandstone as well as to calculate the initial sand-pack modulus of the soft-sand, stiff-sand, and intermediate......-stiff-sand models. When mixed minerals in rock are quite different, e.g., mixtures of quartz and glauconite in greensand, the Hertz-Mindlin contact model of single type of grain may not be enough to predict elastic velocity. Our approach is first to develop a Hertz-Mindlin contact model for a mixture of quartz...... and glauconite. Next, we use this Hertz-Mindlin contact model of two types of grains as the initial modulus for a soft-sand model and a stiff-sand model. By using these rock physics models, we examine the relationship between elastic modulus and porosity in laboratory and logging data and link rock...

  12. Transport and hydraulically-induced recycling of phosphorus in the North Sea-Baltic Sea transition zone

    Directory of Open Access Journals (Sweden)

    Christian Christiansen

    2006-06-01

    Full Text Available Bottom-mounted acoustic Doppler current profiler measurementsindicate that the net transport of water (844 m3 s-1 in theLittle Belt makes up only 6% of the total transport betweenthe Baltic Sea and the North Sea. This is a smaller percentagethan the 9% commonly found in the literature. Owing to barotropicand tidal currents the gross transport is 5 times larger. Thenet transport is directed towards the North Sea mainly in thetop 32 m of the water column but towards the Baltic Sea it occursin the lower 5 m of the water column. The resulting transportof phosphorus is strongly affected by vertical mixing in an areaof hydraulic control in the narrow part of the Little Belt. Comparisonsof phosphorus profiles in stratified waters and in the mixingarea indicate a yearly entrainment of 15 tonnes P from the bottomwater to the surface layer. This vertical transport of P formspart of an internal loop in the general transport between theBaltic Sea and the North Sea. Compared to the transport observed15-16 years ago, the present net phosphorus transport of 163tonnes yr-1 from the Baltic Sea through the Little Belt is substantiallylower.

  13. Species of Thaumatomastix (Thaumatomastigidae, Protista incertae sedis) from the Arctic sea ice biota (North-East Water Polynya, NE Greenland)

    Science.gov (United States)

    Thomsen, Helge Abildhauge; Ikävalko, Johanna

    1997-01-01

    The sea ice biota of polar regions contains numerous heterotrophic flagellates very few of which have been properly identified. The whole mount technique for transmission electron microscopy enables the identification of loricate and scaly forms. A survey of Arctic ice samples (North-East Water Polynya, NE Greenland) revealed the presence of ca. 12 taxa belonging to the phagotrophic genus Thaumatomastix (Protista incertae sedis). Species of Thaumatomastix possess siliceous body scales and one naked and one scale-covered flagellum. The presence in both Arctic samples and sea ice material previously examined from the Antarctic indicates that this genus is most likely ubiquitous in polar sea ice and may be an important component in sea ice biota microbial activities.

  14. Changes in extreme regional sea surface height due to an abrupt weakening of the Atlantic MOC

    Directory of Open Access Journals (Sweden)

    S.-E. Brunnabend

    2014-04-01

    Full Text Available As an extreme scenario of dynamical sea level changes, regional sea surface height (SSH changes that occur in the North Atlantic due to an abrupt weakening of the Atlantic Meridional Overturning Circulation (AMOC are simulated. Two versions of the same ocean-only model are used to study the effect of ocean model resolution on these SSH changes: a high-resolution (HR strongly eddying version and a low-resolution (LR version in which the effect of eddies are parameterized. The weakening of the AMOC is induced in both model versions by applying strong freshwater perturbations around Greenland. A rapid decrease of the AMOC in the HR version induces much shorter return times of several specific regional and coastal extremes in North Atlantic SSH than in the LR version. This effect is caused by a change in main eddy pathways associated with a change in separation latitude of the Gulf Stream.

  15. Elemental (C, H, N) composition of zooplankton from north Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Matondkar, S.G.P.; Bhat, K.L.; Ansari, Z.A.; Parulekar, A.H.

    Zooplankton samples collected from north Arabian Sea during March 1992 were analysed for elemental (C,H,N) composition. Estimated carbon, hydrogen and nitrogen concentrations displayed variations among different groups but their ratios were nearly...

  16. Variability of shelf sea pH and surface water CO2 in response to North Atlantic Oscillation forcing

    Science.gov (United States)

    Salt, L.; Thomas, H.; Prowe, A. E. F.; Borges, A. V.; de Baar, H. J. W.

    2012-04-01

    High biological activity causes a distinct seasonality of surface water pH in the North Sea, which has been identified as a strong sink for atmospheric CO2 via a particularly effective shelf pump. The intimate connection between the North Sea and the North Atlantic suggests that the variability of the CO2 system of the North Atlantic Ocean may in part be responsible for the observed, but hitherto poorly understood variability of pH and CO2 in the North Sea. Here we investigate the role of the North Atlantic Oscillation (NAO), the dominant climate mode for the North Atlantic hemisphere in governing this variability. Based on three extensive observational records covering the relevant levels of the NAO index, we provide evidence that the North Sea pH and CO2 system strongly responds to external and internal expressions of the NAO. We argue that under NAO+ conditions higher rates of inflow of water from the North Atlantic Ocean limits seasonal shoaling of the summer mixed layer in the northern North Sea, diminishing the biological potential to lower pCO2 and raise pH. In addition the faster circulation of the North Sea enhances the shelf pump efficiency. These clear patterns are obscured by changing properties of the North Sea waters, masking or enforcing these effects on various time scales. Such controls indicate that inter-annual trends in the North Sea CO2 system must be carefully examined with consideration to the North Atlantic Oscillation.

  17. The Digital North Denmark Programme -Promoting Regional Change?

    DEFF Research Database (Denmark)

    Østergaard, Christian Richter

    2007-01-01

    The Digital North Denmark (DDN) was an IT programme running from 2000 to 2003 in the North Jutland County in Denmark with national government support of € 23 million. The Danish government initiated the programme with the aim of further strengthening regions with an already proven ICT capability...... (Dybkjær and Lindegaard, 1999, p.96-100). The declared approach was to build on the existing competencies in industry as well as at universities. The national government chose two regions – Ørestaden, a new concentration of knowledge-based institutions near Copenhagen Airport, and North Jutland...

  18. Plastic ingestion by pelagic and demersal fish from the North Sea and Baltic Sea.

    Science.gov (United States)

    Rummel, Christoph D; Löder, Martin G J; Fricke, Nicolai F; Lang, Thomas; Griebeler, Eva-Maria; Janke, Michael; Gerdts, Gunnar

    2016-01-15

    Plastic ingestion by marine biota has been reported for a variety of different taxa. In this study, we investigated 290 gastrointestinal tracts of demersal (cod, dab and flounder) and pelagic fish species (herring and mackerel) from the North and Baltic Sea for the occurrence of plastic ingestion. In 5.5% of all investigated fishes, plastic particles were detected, with 74% of all particles being in the microplastic (ingestion was recorded, showing a significantly higher ingestion frequency in the pelagic feeders. The condition factor K was calculated to test differences in the fitness status between individuals with and without ingested plastic, but no direct effect was detected. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Improving the assessment and management of the plaice stock complex between the North Sea and the Baltic Sea

    DEFF Research Database (Denmark)

    Ulrich, Clara; Boje, Jesper; Cardinale, Massimiliano

    2012-01-01

    a stock unit and is proposed to be assessed and managed as such. Pragmatic options are suggested for empirical harvest control rules accounting for the dynamic of local abundance, using a survey‐based biomass indicator. For the future, new scientific analyses should be developed to better inform......Plaice in Kattegat and Skagerrak have traditionally been considered as one stock unit. However the collected information on biology and fishery in areas between the North and Baltic Seas suggest changes are needed in assessment units as well as in management areas. Plaice in Skagerrak (Division 20......) is now considered to be closely associated with plaice in the North Sea and is proposed to be included in the North Sea plaice stock assessment, although it is recognized that local populations are present in the area. Therefore, specific management of the Skagerrak plaice is suggested. Plaice...

  20. Protected areas in the North Sea: An absolute need for future marine research

    Science.gov (United States)

    Lindeboom, H. J.

    1995-03-01

    There are many signals that different human activities affect the marine ecosystem on local and sometimes regional scales. There is evidence that in the Dutch sector of the North Sea at least 25 species have decreased tremendously in numbers or have totally disappeared. But what has caused their disappearance: fisheries, pollution, eutrophication, climatic changes, or a combination of causes? On the Dutch Continental Shelf, the fisheries are now so intensive that every square metre is trawled, on an average, once to twice a year. Furthermore, it has been shown that trawling causes direct damage to the marine ecosystem. This indicates that the “natural” North Sea ecosystem we are studying is already a heavily influenced system. And what is the value of data on the diversity and production of benthic animals, if the research area has been raked by beamtrawl gear an unknown amount of times before sampling? To be able to study the natural trends in the marine ecosystem, or to answer the question which human activity has most influenced the ecosystem, there is an absolute and immediate need for protected areas to be established. The size of the protected areas must be determined by the behaviour of that species characteristic for the area. In such areas, where fisheries and local pollution would be forbidden or very limited, scientific research into the species composition and age distribution of different populations should be carried out and trends should be established.

  1. Evolution of marine storminess in the Belgian part of the North Sea

    Directory of Open Access Journals (Sweden)

    D. Van den Eynde

    2012-02-01

    Full Text Available Severe storms have affected European coast lines in the past but knowledge on changes in storminess for the last decades is still sparse. Climate change is assumed to be a main driving factor with the potential to induce changes on the intensity, duration and frequency of powerful marine storms, including a long-term influence on peak wind speeds, surges and waves. It is, therefore, important to investigate whether in the last decades changes in the magnitude of storms, their duration and frequency could be observed. Understanding trends in storminess in the last decades will help to better prepare coastal managers for future events, taking into account potential changes on storm occurrence and magnitude to improve planning of mitigation and adaptation strategies. The purpose of this study was to focus on the evolution of extreme wind conditions, wave height and storm surge levels in the North Sea Region, especially in the Belgian part of the North Sea (BPNS. Based on the analysis performed it is concluded that no clear trend can be observed for the occurrence of significant increasing extreme wind speeds over the BPNS. Furthermore, one can conclude that not enough scientific evidence is available to support scenarios with increased wave height or storminess.

  2. Organophosphorus flame retardants and plasticizers in the atmosphere of the North Sea.

    Science.gov (United States)

    Möller, Axel; Xie, Zhiyong; Caba, Armando; Sturm, Renate; Ebinghaus, Ralf

    2011-12-01

    Air samples collected in the German part of the North Sea from March to July 2010 were investigated for organophosphorus compounds (OPs) being applied as flame retardants and plasticizers. The ∑(8)OPs concentration ranged from 110 to 1400 pg m(-3) while tris(2-chloroisopropyl) phosphate (TCPP) dominated all samples with individual concentrations up to 1200 pg m(-3). The highest concentrations were observed in continental air masses showing the high influence of industrialized regions including production sites on atmospheric emissions and concentrations. The occurrence of OPs even in oceanic/Arctic air masses shows that OPs can undergo long-range atmospheric transport. Dry particle-bound deposition fluxes from 9 to 240 ng m(-2) d(-1) for ∑(8)OPs were estimated leading to a minimum annual flux of 710 ± 580 kg y(-1) OPs into the German North Sea. This study presents the first occurrence of OPs in the marine atmosphere together with important information on their long-range transport potential. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. The developmental biogeography of hawksbill sea turtles in the North Pacific.

    Science.gov (United States)

    Van Houtan, Kyle S; Francke, Devon L; Alessi, Sarah; Jones, T Todd; Martin, Summer L; Kurpita, Lauren; King, Cheryl S; Baird, Robin W

    2016-04-01

    High seas oceanic ecosystems are considered important habitat for juvenile sea turtles, yet much remains cryptic about this important life-history period. Recent progress on climate and fishery impacts in these so-called lost years is promising, but the developmental biogeography of hawksbill sea turtles (Eretmochelys imbricata) has not been widely described in the Pacific Ocean. This knowledge gap limits the effectiveness of conservation management for this globally endangered species. We address this with 30 years of stranding observations, 20 years of bycatch records, and recent simulations of natal dispersal trajectories in the Hawaiian Archipelago. We synthesize the analyses of these data in the context of direct empirical observations, anecdotal sightings, and historical commercial harvests from the insular Pacific. We find hawksbills 0-4 years of age, measuring 8-34 cm straight carapace length, are found predominantly in the coastal pelagic waters of Hawaii. Unlike other species, we find no direct evidence of a prolonged presence in oceanic habitats, yet satellite tracks of passive drifters (simulating natal dispersal) and our small sample sizes suggest that an oceanic phase for hawksbills cannot be dismissed. Importantly, despite over 600 million hooks deployed and nearly 6000 turtle interactions, longline fisheries have never recorded a single hawksbill take. We address whether the patterns we observe are due to population size and gear selectivity. Although most sea turtle species demonstrate clear patterns of oceanic development, hawksbills in the North Pacific may by contrast occupy a variety of ecosystems including coastal pelagic waters and shallow reefs in remote atolls. This focuses attention on hazards in these ecosystems - entanglement and ingestion of marine debris - and perhaps away from longline bycatch and decadal climate regimes that affect sea turtle development in oceanic regions.

  4. An Operational Search and Rescue Model for the Norwegian Sea and the North Sea

    CERN Document Server

    Breivik, Øyvind; 10.1016/j.jmarsys.2007.02.010

    2011-01-01

    A new operational, ensemble-based search and rescue model for the Norwegian Sea and the North Sea is presented. The stochastic trajectory model computes the net motion of a range of search and rescue objects. A new, robust formulation for the relation between the wind and the motion of the drifting object (termed the leeway of the object) is employed. Empirically derived coefficients for 63 categories of search objects compiled by the US Coast Guard are ingested to estimate the leeway of the drifting objects. A Monte Carlo technique is employed to generate an ensemble that accounts for the uncertainties in forcing fields (wind and current), leeway drift properties, and the initial position of the search object. The ensemble yields an estimate of the time-evolving probability density function of the location of the search object, and its envelope defines the search area. Forcing fields from the operational oceanic and atmospheric forecast system of The Norwegian Meteorological Institute are used as input to th...

  5. Lithospheric strength and elastic thickness of the Barents Sea and Kara Sea region

    Science.gov (United States)

    Gac, Sébastien; Klitzke, Peter; Minakov, Alexander; Faleide, Jan Inge; Scheck-Wenderoth, Magdalena

    2016-11-01

    Interpretation of tomography data indicates that the Barents Sea region has an asymmetric lithospheric structure characterized by a thin and hot lithosphere in the west and a thick and cold lithosphere in the east. This suggests that the lithosphere is stronger in the east than in the west. This asymmetric lithosphere strength structure may have a strong control on the lithosphere response to tectonic and surface processes. In this paper, we present computed strength and effective elastic thickness maps of the lithosphere of the Barents Sea and Kara Sea region. Those are estimated using physical parameters from a 3D lithospheric model of the Barents Sea and Kara Sea region. The lithospheric strength is computed assuming a temperature-dependent ductile and brittle rheology for sediments, crust and mantle lithosphere. Results show that lithospheric strength and elastic thickness are mostly controlled by the lithosphere thickness. The model generally predicts much larger lithospheric strength and elastic thickness for the Proterozoic parts of the East Barents Sea and Kara Sea. Locally, the thickness and lithology of the continental crust disturb this general trend. At last, the gravitational potential energy (GPE) is computed. Our results show that the difference in GPE between the Barents Sea and the Mid-Atlantic Ridge provides a net horizontal force large enough to cause contraction in the western and central Barents Sea.

  6. Evolution of physical and biological characteristics of mesoscale eddy in north-central Red Sea

    Science.gov (United States)

    Zarokanellos, Nikolaos; Jones, Burton

    2015-04-01

    Eddies appear to be important to both the physical and biogeochemical dynamics of the Red Sea. Numerical simulations of physical dynamics and remote sensing studies of chlorophyll concentration and sea surface height in the Red Sea indicate their importance to the upper portions of the sea (Raitsos et al., 2013; Yao et al., 2014; Zhan et al., 2014). Despite their apparent importance, process studies of these eddies have been lacking. In March 2013 we began an extended observational study of the north-central Red Sea (NCRS) where anticyclonic eddies have been observed. The study began with a ship-based characterization of the eddy and was followed by a three-month observational time series using an autonomous glider equipped with a CTD, oxygen sensor, and optical sensors for chlorophyll, CDOM and optical backscatter. The ship-based study captured an initial snapshot of an anticyclonic eddy and it's associated biological and bio-optical distributions. Initially, chlorophyll distributions tended to mirror the density distribution, with deeper isopycnals and chlorophyll maximum depth in the anticyclonic eddy center. The anticyclone eddy in March had an along basin diameter of 150 km, penetrated vertically less than 150 m and elevated near surface chlorophyll concentrations appeared along its outer boundary. The shallowing of the pycnocline of the outer boundaries of the anticyclone eddy on March may elevate nutrients into the lower euphotic zone, contributing to phytoplankton productivity and biomass within the eddy. This eddy contains most of the kinetic energy of the region with the maximum velocities up to 30 - 35 cm/s. The eddy appeared to interact with the coastal reefs where exchange particulate and dissolved matter may occur. The autonomous glider provided the spring-to-summer progression of the system with increasing stratification, shallowing of the subsurface chlorophyll maximum, and fluctuations in the position and intensity of the eddy. Our glider effort

  7. Evolution of physical and biological characteristics of mesoscale eddy in north-central Red Sea

    KAUST Repository

    Zarokanellos, Nikolaos

    2015-04-01

    Eddies appear to be important to both the physical and biogeochemical dynamics of the Red Sea. Numerical simulations of physical dynamics and remote sensing studies of chlorophyll concentration and sea surface height in the Red Sea indicate their importance to the upper portions of the sea (Raitsos et al., 2013; Yao et al., 2014; Zhan et al., 2014). Despite their apparent importance, process studies of these eddies have been lacking. In March 2013 we began an extended observational study of the north-central Red Sea (NCRS) where anticyclonic eddies have been observed. The study began with a ship-based characterization of the eddy and was followed by a three-month observational time series using an autonomous glider equipped with a CTD, oxygen sensor, and optical sensors for chlorophyll, CDOM and optical backscatter. The ship-based study captured an initial snapshot of an anticyclonic eddy and it\\'s associated biological and bio-optical distributions. Initially, chlorophyll distributions tended to mirror the density distribution, with deeper isopycnals and chlorophyll maximum depth in the anticyclonic eddy center. The anticyclone eddy in March had an along basin diameter of 150 km, penetrated vertically less than 150 m and elevated near surface chlorophyll concentrations appeared along its outer boundary. The shallowing of the pycnocline of the outer boundaries of the anticyclone eddy on March may elevate nutrients into the lower euphotic zone, contributing to phytoplankton productivity and biomass within the eddy. This eddy contains most of the kinetic energy of the region with the maximum velocities up to 30 - 35 cm/s. The eddy appeared to interact with the coastal reefs where exchange particulate and dissolved matter may occur. The autonomous glider provided the spring-to-summer progression of the system with increasing stratification, shallowing of the subsurface chlorophyll maximum, and fluctuations in the position and intensity of the eddy. Our glider effort

  8. Advancing Sentinel-1 use in Coastal Climate Impact Assessments and Adaptation – A Case Study from the Danish North Sea

    DEFF Research Database (Denmark)

    Sørensen, Carlo Sass; Marinkovic, Petar; Larsen, Yngvar

    Low-lying coastal communities face increasing challenges from rise in sea level, more extreme storm surge levels and floods. In addition, changing groundwater levels and precipitation patterns may further exacerbate the water-related impacts of climate change on society. Approximately 40,000 km2...... of Europe’s North Sea region is already flood prone. Storm surges pose a real and substantial risk to this area, especially the densely populated areas. Climate and sea level research seek to provide robust regional projections of change and to address uncertainties and errors inherent in climate models....... It is a challenge for coastal communities to transform this information in order to provide for local impact assessments and to implement adaptive measures. To this end, information about potential subsidence, its magnitudes and causes is important: subsidence may adversely affect the probability, extent and depths...

  9. Interannual and regional variability of ecosystem dynamics in the Black Sea

    Science.gov (United States)

    Fach, Bettina A.; Cannaby, Heather; Dorofeyev, Viktor L.; Kubryakov, Alexander I.; Salihoglu, Baris; Korotaev, Gennady K.; Oguz, Temel; Kideys, Ahmet E.

    2013-04-01

    A three-dimensional hydrodynamic ecosystem model developed for the Black Sea was used to investigate the influence of anthropogenic drivers on marine ecosystem functioning in the Black Sea with a special focus on regional differences. Data from the ECMWF 40 Year Re-analysis global atmospheric circulation model (ERA-40) were used to force a coupled hydrodynamic ecosystem model (BIMS) for a hindcast simulation from 1980-2000. Model skill was assessed by model comparisons with SeaWiFS surface chlorophyll distributions. We study the regional differences the introduction of invasive comb jelly Mnemiopsis leidyi has on modeled ecosystem dynamics as well as the regional influence of changing river nutrient loads on ecosystem dynamics. We can demonstrate clearly that the appearance of M. Leidyi changes ecosystem functioning through exerting grazing pressure on zooplankton and thereby changing the seasonal cycle of phytoplankton and zooplankton species significantly. On the north-western shelf this effect is less pronounced than in the southeast Black Sea, where zooplankton is grazed down more heavily, allowing for higher phytoplankton biomass. In addition, the Black Sea ecosystem shows strong regional nitrate limitation, and high sensitivity to increased eutrophication: A 50% increase in nutrient loading causes a 48% increase in primary production in the eastern regions of the Black Sea, while the north-western shelf reacts more moderately. Despite an increase in primary production, chlorophyll-a concentrations typically respond weakly to changes in nitrate availability. This indicates that increased grazing closely mirrors an increase in productivity. This is confirmed by an increase in zooplankton biomass. It is important to note that for this reason simulated chlorophyll concentration is not a good indicator of eutrophication in the Black Sea. The reduction in the productivity of the entire Black Sea system associated with a reduction in riverine nutrient loadings is

  10. Chemical and temperature profile data from CTD casts in the East China Sea, Sea of Japan, and North Pacific Ocean (NODC Accession 9700022)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical and temperature profile data were collected from CTD casts in the East China Sea, Sea of Japan, and North Pacific Ocean. Data were submitted by the Japan...

  11. Assessment of the processes controlling seasonal variations of dissolved inorganic carbon in the North Sea

    NARCIS (Netherlands)

    Bozec, Yann; Thomas, Helmuth; Schiettecatte, Laure-Sophie; Borges, Alberto V.; Elkalay, Khalid; Baar, Hein J.W. de

    2006-01-01

    We used a seasonal North Sea data set comprising dissolved inorganic carbon (DIC), partial pressure of CO2 (pCO2), and inorganic nutrients to assess the abiotic and biological processes governing the monthly variations of DIC. During winter, advection and air–sea exchange of CO2 control and increase

  12. Wettability Improvement with Enzymes: Application to Enhanced Oil Recovery under Conditions of the North Sea Reservoirs

    DEFF Research Database (Denmark)

    Khusainova, Alsu; Shapiro, Alexander; Stenby, Erling Halfdan

    2012-01-01

    , proteases and oxidoreductases, provided by Novozymes, have been investigated. Two commercial mixtures containing enzymes: Apollo-GreenZyme™ and EOR-ZYMAX™ have also been applied. The North Sea dead oil and the synthetic sea water were used as test fluids. Internal surface of a carbonate rock has been...

  13. Transport, preservation and accumulation of organic carbon in the North Sea

    NARCIS (Netherlands)

    de Haas, H.

    1997-01-01

    This thesis contains the results of the research on the burial of organic carbon in the North Sea as it was carried out at the Netherlands Institute for Sea Research in the period 1993-1997. Carbon in the form of carbon dioxide (CO2 ) is one of the major contributors to the natural greenhouse

  14. Transport, preservation and accumulation of organic carbon in the North Sea

    NARCIS (Netherlands)

    Haas, H. de

    1997-01-01

    This thesis contains the results of the research on the burial of organic carbon in the North Sea as it was carried out at the Netherlands Institute for Sea Research in the period 1993-1997. Carbon in the form of carbon dioxide (C02 ) is one of the major contributors to the natural greenhouse

  15. Transport, preservation and accumulation of organic carbon in the North Sea

    NARCIS (Netherlands)

    Haas, H. de

    1997-01-01

    This thesis contains the results of the research on the burial of organic carbon in the North Sea as it was carried out at the Netherlands Institute for Sea Research in the period 1993-1997. Carbon in the form of carbon dioxide (C02 ) is one of the major contributors to the natural greenhouse effect

  16. Transport, preservation and accumulation of organic carbon in the North Sea

    NARCIS (Netherlands)

    de Haas, H.

    1997-01-01

    This thesis contains the results of the research on the burial of organic carbon in the North Sea as it was carried out at the Netherlands Institute for Sea Research in the period 1993-1997. Carbon in the form of carbon dioxide (CO2 ) is one of the major contributors to the natural greenhouse effect

  17. Transport, preservation and accumulation of organic carbon in the North Sea

    NARCIS (Netherlands)

    de Haas, H.

    1997-01-01

    This thesis contains the results of the research on the burial of organic carbon in the North Sea as it was carried out at the Netherlands Institute for Sea Research in the period 1993-1997. Carbon in the form of carbon dioxide (CO2 ) is one of the major contributors to the natural greenhouse effect

  18. Transport, preservation and accumulation of organic carbon in the North Sea

    NARCIS (Netherlands)

    Haas, H. de

    1997-01-01

    This thesis contains the results of the research on the burial of organic carbon in the North Sea as it was carried out at the Netherlands Institute for Sea Research in the period 1993-1997. Carbon in the form of carbon dioxide (C02 ) is one of the major contributors to the natural greenhouse effect

  19. An Ichthyophonus hoferi epizootic in herring in the North Sea, the Skagerrak, the Kattegat and the Baltic Sea

    DEFF Research Database (Denmark)

    Mellergaard, Stig; Spanggaard, Bettina

    1997-01-01

    An epizootic caused by the internal parasite Ichthyophonus hoferi in herring Clupea harengus was recorded from 1991 to 1993 in the waters around Denmark. A surveillance programme from research vessels and commercial fishing boats was conducted in the North Sea, Skagerrak, Kattegat and Baltic Sea....... A total of 15769 hearts of adult herring were examined macroscopically for evidence of infection. The prevalence of the infection in this period decreased from 10.6 to 2.0% in the North Sea, from 8.0 to 5.6% in the Skagerrak, from 12.0 to 1.1% in the Kattegat and from 4.5 to 0.4% in the Baltic Sea...... Sea and the Skagerrak. The majority of the infected fish belonged to the age groups 2+, 3+ and 4+ except in the commercial catches from the North Sea where most of the affected fish belonged to the age groups 5+, 6+ and 7+. Annual mortality in the different areas, based on the observed prevalences...

  20. North-West Iowa Groundwater Vulnerability Regions

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — The regions on this map represent areas with similar hydro-geologic characteristics thought to represent similar potentials for contamination of groundwater and/or...

  1. North-East Iowa Groundwater Vulnerability Regions

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — The regions on this map represent areas with similar hydro-geologic characteristics thought to represent similar potentials for contamination of groundwater and/or...

  2. Quarter-Century Offshore Winds from SSM/I and WRF in the North Sea and South China Sea

    Directory of Open Access Journals (Sweden)

    Charlotte Bay Hasager

    2016-09-01

    Full Text Available We study the wind climate and its long-term variability in the North Sea and South China Sea, areas relevant for offshore wind energy development, using satellite-based wind data, because very few reliable long-term in-situ sea surface wind observations are available. The Special Sensor Microwave Imager (SSM/I ocean winds extrapolated from 10 m to 100 m using the Charnock relationship and the logarithmic profile method are compared to Weather Research and Forecasting (WRF model results in both seas and to in-situ observations in the North Sea. The mean wind speed from SSM/I and WRF differ only by 0.1 m/s at Fino1 in the North Sea, while west of Hainan in the South China Sea the difference is 1.0 m/s. Linear regression between SSM/I and WRF winds at 100 m show correlation coefficients squared of 0.75 and 0.67, standard deviation of 1.67 m/s and 1.41 m/s, and mean difference of −0.12 m/s and 0.83 m/s for Fino1 and Hainan, respectively. The WRF-derived winds overestimate the values in the South China Sea. The inter-annual wind speed variability is estimated as 4.6% and 4.4% based on SSM/I at Fino1 and Hainan, respectively. We find significant changes in the seasonal wind pattern at Fino1 with springtime winds arriving one month earlier from 1988 to 2013 and higher winds in June; no yearly trend in wind speed is observed in the two seas.

  3. Space weather effects on drilling accuracy in the North Sea

    Directory of Open Access Journals (Sweden)

    S. J. Reay

    2005-11-01

    Full Text Available The oil industry uses geomagnetic field information to aid directional drilling operations when drilling for oil and gas offshore. These operations involve continuous monitoring of the azimuth and inclination of the well path to ensure the target is reached and, for safety reasons, to avoid collisions with existing wells. Although the most accurate method of achieving this is through a gyroscopic survey, this can be time consuming and expensive. An alternative method is a magnetic survey, where measurements while drilling (MWD are made along the well by magnetometers housed in a tool within the drill string. These MWD magnetic surveys require estimates of the Earth's magnetic field at the drilling location to correct the downhole magnetometer readings. The most accurate corrections are obtained if all sources of the Earth's magnetic field are considered. Estimates of the main field generated in the core and the local crustal field can be obtained using mathematical models derived from suitable data sets. In order to quantify the external field, an analysis of UK observatory data from 1983 to 2004 has been carried out. By accounting for the external field, the directional error associated with estimated field values at a mid-latitude oil well (55° N in the North Sea is shown to be reduced by the order of 20%. This improvement varies with latitude, local time, season and phase of the geomagnetic activity cycle. By accounting for all sources of the field, using a technique called Interpolation In-Field Referencing (IIFR, directional drillers have access to data from a "virtual" magnetic observatory at the drill site. This leads to an error reduction in positional accuracy that is close to matching that of the gyroscopic survey method and provides a valuable independent technique for quality control purposes.

  4. Space weather effects on drilling accuracy in the North Sea

    Science.gov (United States)

    Reay, S. J.; Allen, W.; Baillie, O.; Bowe, J.; Clarke, E.; Lesur, V.; MacMillan, S.

    2005-11-01

    The oil industry uses geomagnetic field information to aid directional drilling operations when drilling for oil and gas offshore. These operations involve continuous monitoring of the azimuth and inclination of the well path to ensure the target is reached and, for safety reasons, to avoid collisions with existing wells. Although the most accurate method of achieving this is through a gyroscopic survey, this can be time consuming and expensive. An alternative method is a magnetic survey, where measurements while drilling (MWD) are made along the well by magnetometers housed in a tool within the drill string. These MWD magnetic surveys require estimates of the Earth's magnetic field at the drilling location to correct the downhole magnetometer readings. The most accurate corrections are obtained if all sources of the Earth's magnetic field are considered. Estimates of the main field generated in the core and the local crustal field can be obtained using mathematical models derived from suitable data sets. In order to quantify the external field, an analysis of UK observatory data from 1983 to 2004 has been carried out. By accounting for the external field, the directional error associated with estimated field values at a mid-latitude oil well (55° N) in the North Sea is shown to be reduced by the order of 20%. This improvement varies with latitude, local time, season and phase of the geomagnetic activity cycle. By accounting for all sources of the field, using a technique called Interpolation In-Field Referencing (IIFR), directional drillers have access to data from a "virtual" magnetic observatory at the drill site. This leads to an error reduction in positional accuracy that is close to matching that of the gyroscopic survey method and provides a valuable independent technique for quality control purposes.

  5. Regionally coupled atmosphere-ocean-sea ice-marine biogeochemistry model ROM: 1. Description and validation

    Science.gov (United States)

    Sein, Dmitry V.; Mikolajewicz, Uwe; Gröger, Matthias; Fast, Irina; Cabos, William; Pinto, Joaquim G.; Hagemann, Stefan; Semmler, Tido; Izquierdo, Alfredo; Jacob, Daniela

    2015-03-01

    The general circulation models used to simulate global climate typically feature resolution too coarse to reproduce many smaller-scale processes, which are crucial to determining the regional responses to climate change. A novel approach to downscale climate change scenarios is presented which includes the interactions between the North Atlantic Ocean and the European shelves as well as their impact on the North Atlantic and European climate. The goal of this paper is to introduce the global ocean-regional atmosphere coupling concept and to show the potential benefits of this model system to simulate present-day climate. A global ocean-sea ice-marine biogeochemistry model (MPIOM/HAMOCC) with regionally high horizontal resolution is coupled to an atmospheric regional model (REMO) and global terrestrial hydrology model (HD) via the OASIS coupler. Moreover, results obtained with ROM using NCEP/NCAR reanalysis and ECHAM5/MPIOM CMIP3 historical simulations as boundary conditions are presented and discussed for the North Atlantic and North European region. The validation of all the model components, i.e., ocean, atmosphere, terrestrial hydrology, and ocean biogeochemistry is performed and discussed. The careful and detailed validation of ROM provides evidence that the proposed model system improves the simulation of many aspects of the regional climate, remarkably the ocean, even though some biases persist in other model components, thus leaving potential for future improvement. We conclude that ROM is a powerful tool to estimate possible impacts of climate change on the regional scale.

  6. Phosphorus binding by poorly crystalline iron oxides in North Sea sediments

    NARCIS (Netherlands)

    Slomp, C.P.; Gaast, S. J. van der; Raaphorst, W. van

    1996-01-01

    Differential X-ray powder diffraction (DXRD) and extraction procedures were used to characterize the iron oxides present in four sediments from contrasting environments in the North Sea. Stations were located in depositional areas on the southern shelf (German Bight) and on the north-eastern

  7. Phosphorus binding by poorly crystalline iron oxides in North Sea sediments

    NARCIS (Netherlands)

    Slomp, C.P.; Gaast, S. J. van der; Raaphorst, W. van

    1996-01-01

    Differential X-ray powder diffraction (DXRD) and extraction procedures were used to characterize the iron oxides present in four sediments from contrasting environments in the North Sea. Stations were located in depositional areas on the southern shelf (German Bight) and on the north-eastern shelf-s

  8. Continuous measurements of atmospheric oxygen and carbon dioxide on a North Sea gas platform

    NARCIS (Netherlands)

    Laan-Luijkx, I.T. van der; Neubert, R.E.M.; Laan, S. van der; Meijer, H.A.J.; Toohey, D.

    2010-01-01

    A new atmospheric measurement station has been established on the North Sea oil and gas production platform F3, 200 km north off the Dutch coast (54 degrees 51' N, 4 degrees 44' E). Atmospheric concentrations of O(2) and CO(2) are continuously measured using fuel cell technology and compact infrared

  9. Continuous measurements of atmospheric oxygen and carbon dioxide on a North Sea gas platform

    NARCIS (Netherlands)

    Laan-Luijkx, van der I.T.; Neubert, R.E.M.; Laan, van der S.; Meijer, H.A.J.

    2010-01-01

    A new atmospheric measurement station has been established on the North Sea oil and gas production platform F3, 200 km north off the Dutch coast (54°51' N, 4°44' E). Atmospheric concentrations of O2 and CO2 are continuously measured using fuel cell technology and compact infrared absorption instrume

  10. Oil Spill Monitoring in North Sea and Bohai Sea Using High Resolution X-Band SAR Imagery

    Science.gov (United States)

    Velotto, Domenico; Lehner, Susanne

    2013-01-01

    Offshore crude oil production has grown regularly since its beginning in the early 1940s, it accounts today for almost one-third of the world’s production. This growth goes along with the production plateau reached in the last decades by onshore installations. As a direct consequence also the sea oil pollution caused by operational offshore activities has increased. In this paper results of oil spill monitoring using X-band SAR imagery are shown. North Sea and Bohai Sea are two hot spots because they are reach of oil fields.

  11. Improving sea level simulation in Mediterranean regional climate models

    Science.gov (United States)

    Adloff, Fanny; Jordà, Gabriel; Somot, Samuel; Sevault, Florence; Arsouze, Thomas; Meyssignac, Benoit; Li, Laurent; Planton, Serge

    2017-08-01

    For now, the question about future sea level change in the Mediterranean remains a challenge. Previous climate modelling attempts to estimate future sea level change in the Mediterranean did not meet a consensus. The low resolution of CMIP-type models prevents an accurate representation of important small scales processes acting over the Mediterranean region. For this reason among others, the use of high resolution regional ocean modelling has been recommended in literature to address the question of ongoing and future Mediterranean sea level change in response to climate change or greenhouse gases emissions. Also, it has been shown that east Atlantic sea level variability is the dominant driver of the Mediterranean variability at interannual and interdecadal scales. However, up to now, long-term regional simulations of the Mediterranean Sea do not integrate the full sea level information from the Atlantic, which is a substantial shortcoming when analysing Mediterranean sea level response. In the present study we analyse different approaches followed by state-of-the-art regional climate models to simulate Mediterranean sea level variability. Additionally we present a new simulation which incorporates improved information of Atlantic sea level forcing at the lateral boundary. We evaluate the skills of the different simulations in the frame of long-term hindcast simulations spanning from 1980 to 2012 analysing sea level variability from seasonal to multidecadal scales. Results from the new simulation show a substantial improvement in the modelled Mediterranean sea level signal. This confirms that Mediterranean mean sea level is strongly influenced by the Atlantic conditions, and thus suggests that the quality of the information in the lateral boundary conditions (LBCs) is crucial for the good modelling of Mediterranean sea level. We also found that the regional differences inside the basin, that are induced by circulation changes, are model-dependent and thus not

  12. Evaluation of hematology and serum biochemistry of cold-stunned green sea turtles (Chelonia mydas) in North Carolina, U.S.A.

    Science.gov (United States)

    Anderson, Eric T; Harms, Craig A; Stringer, Elizabeth M; Cluse, Wendy M

    2011-06-01

    Hypothermia or cold-stunning is a condition in which the body temperature of an animal decreases below normal physiologic range and which has been linked to severe morbidity in sea turtles. Reports have focused on the physiologic changes caused by cold-stunning in Kemp's Ridley sea turtles (Lepidochelys kempii) and loggerhead sea turtles (Caretta caretta), but few have evaluated the green sea turtle (Chelonia mydas). This study evaluated hematologic and serum biochemical profiles of cold-stunned green sea turtles in North Carolina, USA. When compared with healthy, free-ranging juvenile green turtles from the same region, cold-stunned turtles exhibited hypoglycemia, hypocalcemia (both total and ionized calcium), hyponatremia, hypokalemia, hypoproteinemia, hypoalbuminemia, hyperphosphatemia, and elevations in uric acid and blood urea nitrogen. These findings contrast with some previously reported changes in cold-stunned Kemp's Ridley and loggerhead sea turtles. These results emphasize the importance of basing therapeutic regimens on biochemical analyses in cold-stunned sea turtles.

  13. Projected changes in regional climate extremes arising from Arctic sea ice loss

    Science.gov (United States)

    Screen, James A.; Deser, Clara; Sun, Lantao

    2015-08-01

    The decline in Arctic sea ice cover has been widely documented and it is clear that this change is having profound impacts locally. An emerging and highly uncertain area of scientific research, however, is whether such Arctic change has a tangible effect on weather and climate at lower latitudes. Of particular societal relevance is the open question: will continued Arctic sea ice loss make mid-latitude weather more extreme? Here we analyse idealized atmospheric general circulation model simulations, using two independent models, both forced by projected Arctic sea ice loss in the late twenty-first century. We identify robust projected changes in regional temperature and precipitation extremes arising solely due to Arctic sea ice loss. The likelihood and duration of cold extremes are projected to decrease over high latitudes and over central and eastern North America, but to increase over central Asia. Hot extremes are projected to increase in frequency and duration over high latitudes. The likelihood and severity of wet extremes are projected to increase over high latitudes, the Mediterranean and central Asia; and their intensity is projected to increase over high latitudes and central and eastern Asia. The number of dry days over mid-latitude Eurasia and dry spell duration over high latitudes are both projected to decrease. There is closer model agreement for projected changes in temperature extremes than for precipitation extremes. Overall, we find that extreme weather over central and eastern North America is more sensitive to Arctic sea ice loss than over other mid-latitude regions. Our results are useful for constraining the role of Arctic sea ice loss in shifting the odds of extreme weather, but must not be viewed as deterministic projections, as they do not account for drivers other than Arctic sea ice loss.

  14. Local adaptation and oceanographic connectivity patterns explain genetic differentiation of a marine diatom across the North Sea-Baltic Sea salinity gradient.

    Science.gov (United States)

    Sjöqvist, C; Godhe, A; Jonsson, P R; Sundqvist, L; Kremp, A

    2015-06-01

    Drivers of population genetic structure are still poorly understood in marine micro-organisms. We exploited the North Sea-Baltic Sea transition for investigating the seascape genetics of a marine diatom, Skeletonema marinoi. Eight polymorphic microsatellite loci were analysed in 354 individuals from ten locations to analyse population structure of the species along a 1500-km-long salinity gradient ranging from 3 to 30 psu. To test for salinity adaptation, salinity reaction norms were determined for sets of strains originating from three different salinity regimes of the gradient. Modelled oceanographic connectivity was compared to directional relative migration by correlation analyses to examine oceanographic drivers. Population genetic analyses showed distinct genetic divergence of a low-salinity Baltic Sea population and a high-salinity North Sea population, coinciding with the most evident physical dispersal barrier in the area, the Danish Straits. Baltic Sea populations displayed reduced genetic diversity compared to North Sea populations. Growth optima of low salinity isolates were significantly lower than those of strains from higher native salinities, indicating local salinity adaptation. Although the North Sea-Baltic Sea transition was identified as a barrier to gene flow, migration between Baltic Sea and North Sea populations occurred. However, the presence of differentiated neutral markers on each side of the transition zone suggests that migrants are maladapted. It is concluded that local salinity adaptation, supported by oceanographic connectivity patterns creating an asymmetric migration pattern between the Baltic Sea and the North Sea, determines genetic differentiation patterns in the transition zone.

  15. 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...... of the Irish Sea) to Spitsbergen. 241Am found in Arctic waters probably originates from the decay of fallout 241Pu and, like Pu, tentatively has a residence time of the order of several years. Americium from Sellafield has an estimated mean residence time of 4–6 months in Scottish waters....

  16. Crustal model for the Middle East and North Africa region: implications for the isostatic compensation mechanism

    Science.gov (United States)

    Seber, Dogan; Sandvol, Eric; Sandvol, Christine; Brindisi, Carrie; Barazangi, Muawia

    2001-12-01

    We present a new 3-D crustal model for the Middle East and North Africa region that includes detailed topography, sediment thickness, and Moho depth values. The model is obtained by collecting, integrating, and interpolating reliable, published sedimentary rock thickness and Moho depth measurements in the Middle East and North Africa region. To evaluate the accuracy of the model, the 3-D gravity response of the model is calculated and compared with available observed Bouguer gravity anomalies in the region. The gravity modelling shows that the new crustal model predicts large portions of the observed Bouguer anomalies. However, in some regions, such as the Red Sea and Caspian Sea regions, where crustal structure is relatively well-determined, the residual anomalies are of the order of a few hundred milligals. Since the new crustal model results in large residual anomalies in regions where reasonably good constraints exist for the model, these large residuals cannot simply be explained by inaccuracies in the model. To analyse the cause of these residuals further we developed an isostatically compensated (Airy-type) Moho-depth model and calculated its gravity response. Isostatic gravity anomalies are in nearly perfect agreement with the observed gravity values. However, the isostatic model differs significantly from the new (3-D) crustal model. If isostasy is to be maintained, crustal and/or upper mantle lateral density variations are needed to explain the large observed gravity residuals.

  17. Atmospheric forcing of sea ice anomalies in the Ross Sea Polynya region

    Science.gov (United States)

    Dale, Ethan; McDonald, Adrian; Rack, Wolfgang

    2016-04-01

    Despite warming trends in global temperatures, sea ice extent in the southern hemisphere has shown an increasing trend over recent decades. Wind-driven sea ice export from coastal polynyas is an important source of sea ice production. Areas of major polynyas in the Ross Sea, the region with largest increase in sea ice extent, have been suggested to produce the vast amount of the sea ice in the region. We investigate the impacts of strong wind events on polynyas and the subsequent sea ice production. We utilize Bootstrap sea ice concentration (SIC) measurements derived from satellite based, Special Sensor Microwave Imager (SSM/I) brightness temperature images. These are compared with surface wind measurements made by automatic weather stations of the University of Wisconsin-Madison Antarctic Meteorology Program. Our analysis focusses on the winter period defined as 1st April to 1st November in this study. Wind data was used to classify each day into characteristic regimes based on the change of wind speed. For each regime, a composite of SIC anomaly was formed for the Ross Sea region. We found that persistent weak winds near the edge of the Ross Ice Shelf are generally associated with positive SIC anomalies in the Ross Sea polynya area (RSP). Conversely we found negative SIC anomalies in this area during persistent strong winds. By analyzing sea ice motion vectors derived from SSM/I brightness temperatures, we find significant sea ice motion anomalies throughout the Ross Sea during strong wind events. These anomalies persist for several days after the strong wing event. Strong, negative correlations are found between SIC within the RSP and wind speed indicating that strong winds cause significant advection of sea ice in the RSP. This rapid decrease in SIC is followed by a more gradual recovery in SIC. This increase occurs on a time scale greater than the average persistence of strong wind events and the resulting Sea ice motion anomalies, highlighting the production

  18. Size Scaling in Western North Atlantic Loggerhead Turtles Permits Extrapolation between Regions, but Not Life Stages.

    Directory of Open Access Journals (Sweden)

    Nina Marn

    Full Text Available Sea turtles face threats globally and are protected by national and international laws. Allometry and scaling models greatly aid sea turtle conservation and research, and help to better understand the biology of sea turtles. Scaling, however, may differ between regions and/or life stages. We analyze differences between (i two different regional subsets and (ii three different life stage subsets of the western North Atlantic loggerhead turtles by comparing the relative growth of body width and depth in relation to body length, and discuss the implications.Results suggest that the differences between scaling relationships of different regional subsets are negligible, and models fitted on data from one region of the western North Atlantic can safely be used on data for the same life stage from another North Atlantic region. On the other hand, using models fitted on data for one life stage to describe other life stages is not recommended if accuracy is of paramount importance. In particular, young loggerhead turtles that have not recruited to neritic habitats should be studied and modeled separately whenever practical, while neritic juveniles and adults can be modeled together as one group. Even though morphometric scaling varies among life stages, a common model for all life stages can be used as a general description of scaling, and assuming isometric growth as a simplification is justified. In addition to linear models traditionally used for scaling on log-log axes, we test the performance of a saturating (curvilinear model. The saturating model is statistically preferred in some cases, but the accuracy gained by the saturating model is marginal.

  19. A Reanalysis of North Pacific Sea Surface Temperatures Using State-Space Techniques: The PDO In A New Light

    CERN Document Server

    Mendelssohn, Roy

    2012-01-01

    North Pacific sea surface temperatures (SST), as used in estimating the PDO, are reanalyzed using state-space decomposition and subspace identification techniques. The reanalysis presents a very different picture of SST in this region. The first common trend reflects a global warming signal. The second common trend modifies this for areas that underwent a sharper warming (cooling) starting in the early 1970's. This trend is also related to dynamics in the tropics and in Arctic sea ice extent. The third common trend is a superposition of changes in pressure centers on the long-term global warming signal. The fourth common trend is the trend that is contained in the original PDO series if analyzed by state-space techniques, and is identical to the trend in the North Pacific High. The first two common stochastic cycles capture the original PDO and so-called "Victoria mode", showing that these series are dominated by stationary behavior..

  20. Potential and challenges for the Black Sea regional cooperation

    Directory of Open Access Journals (Sweden)

    Galya VLADOVA

    2014-06-01

    Full Text Available Since the early nineties, the Black Sea region has witnessed fundamental geopolitical changes and significant shifts in its regional context and dynamics. In an attempt to react to the altered circumstances after the collapse of the Soviet Union and to address an increasing number of common challenges, the Black Sea states have jointed efforts in various regional cooperation activities. Throughout the years, the Black Sea cooperation has evolved with different speed and success, reflecting the difficult regional circumstances and attracting increasing external involvement. Today, more than twenty years after the first cooperation activities have been launched, the Black Sea cooperation is still shadowed by persisting historical rivalries, unrecognized territorial entities, ‘frozen conflicts’ and security threats. As a result, despite the many pressing problems of regional character, the cooperation efforts are currently showing rather limited outcomes. Seen against this background, the current paper presents a study of the main challenges and the existing potential for further development of the Black Sea regional cooperation.

  1. High oxygen consumption rates in the deep layers of the North Aegean Sea (eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    E. SOUVERMEZOGLOU

    2002-06-01

    Full Text Available Severe winter meteorological conditions promote dense water formation over the shelves of the North Aegean Sea. The newly formed dense water fills the deep basins of the North Aegean Sea, contributing to their ventilation and the downward transport of organic and inorganic material. The great bathymetric variability imposes limitations on the deep circulation and the communication between the various basins and makes the North Aegean Sea an appropriate area for the monitoring of oxygen consumption in the deep layers. Historical hydrographic data suggest that there was extensive production of dense water in the North Aegean Sea on two occasions during the last decade, the winters of 1987 and 1992-1993. Our data series from August 1986 to September 1989 and from March 1997 to February 1999, permitted us to follow, step by step, the oxygen consumption and the nutrient regeneration in the deep basins of the northern Aegean Sea during these periods of isolation. The organic matter reaching the bottom layer just after the deep water formation event is rich in labile and easily oxidizable material and its decomposition leads to a significant oxygen uptake during the first year of stagnation. The further decomposition of the remaining semi-labile and refractory material turns over on greater time scales, by consuming lesser amounts of oxygen. A more significant oxygen decrease is recorded in the eastern basin (Lemnos Basin of the North Aegean Trough, than in the central (Athos Basin and the western (North Sporades Basin ones and is attributed to the irregular contribution of the Black Sea Water (BSW to the water masses formed on the different shelves of the North Aegean Sea. Our results and the existing data on the Turkish straits showed that dissolved organic matter is the major constituent responsible for this high oxygen consumption. The slightly different particulate organic carbon fluxes to these depressions play a secondary role.

  2. High oxygen consumption rates in the deep layers of the North Aegean Sea (eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    E. SOUVERMEZOGLOU

    2012-12-01

    Full Text Available Severe winter meteorological conditions promote dense water formation over the shelves of the North Aegean Sea. The newly formed dense water fills the deep basins of the North Aegean Sea, contributing to their ventilation and the downward transport of organic and inorganic material. The great bathymetric variability imposes limitations on the deep circulation and the communication between the various basins and makes the North Aegean Sea an appropriate area for the monitoring of oxygen consumption in the deep layers. Historical hydrographic data suggest that there was extensive production of dense water in the North Aegean Sea on two occasions during the last decade, the winters of 1987 and 1992-1993. Our data series from August 1986 to September 1989 and from March 1997 to February 1999, permitted us to follow, step by step, the oxygen consumption and the nutrient regeneration in the deep basins of the northern Aegean Sea during these periods of isolation. The organic matter reaching the bottom layer just after the deep water formation event is rich in labile and easily oxidizable material and its decomposition leads to a significant oxygen uptake during the first year of stagnation. The further decomposition of the remaining semi-labile and refractory material turns over on greater time scales, by consuming lesser amounts of oxygen. A more significant oxygen decrease is recorded in the eastern basin (Lemnos Basin of the North Aegean Trough, than in the central (Athos Basin and the western (North Sporades Basin ones and is attributed to the irregular contribution of the Black Sea Water (BSW to the water masses formed on the different shelves of the North Aegean Sea. Our results and the existing data on the Turkish straits showed that dissolved organic matter is the major constituent responsible for this high oxygen consumption. The slightly different particulate organic carbon fluxes to these depressions play a secondary role.

  3. Brominated flame retardant trends in aquatic birds from the Salish Sea region of the west coast of North America, including a mini-review of recent trends in marine and estuarine birds

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Aroha [Department of Applied Biology, University of British Columbia, 2357 Main Mall, Vancouver, BC (Canada); Elliott, John E., E-mail: John.Elliott@ec.gc.ca [Science and Technology, Environment Canada, Delta, BC V4K 3N2 (Canada); Elliott, Kyle H.; Guigueno, Mélanie F. [Department of Biology, University of Western Ontario, 1151 Richmond Street, London, ON N6A 3K7 (Canada); Wilson, Laurie K. [Canadian Wildlife Service, Pacific Wildlife Research Centre, Environment Canada, Delta, BC V4K 3N2 (Canada); Lee, Sandi [Science and Technology, Environment Canada, Delta, BC V4K 3N2 (Canada); Idrissi, Abde [Environment Canada, National Wildlife Research Centre, Ottawa, ON K1A 0H3 (Canada)

    2015-01-01

    Polybrominated diphenyl ethers (PBDEs) increased in many matrices during the 1990s and early 2000s. Since voluntary restrictions and regulations on PBDEs were implemented in North America circa early 2000s, decreases in PBDEs have occurred in many of these same matrices. To examine temporal trends in the North Pacific, we retrospectively analysed PBDEs and eight non-PBDE flame retardants (FR) in eggs of two aquatic bird species, great blue herons, Ardea herodias, and double-crested cormorants, Phalacrocorax auritus, collected along the British Columbia coast, Canada from 1979 to 2012. Increasing PBDE concentrations were observed in both species followed by significant decreases post-2000 for all dominant congeners and ΣPBDE. Non-PBDE FRs were generally undetected in cormorant eggs, or detected at very low levels in heron eggs, except for hexabromocyclododecane (HBCDD). HBCDD, currently unregulated in North America, was not detected in early sampling years; however low concentrations were observed in both species in recent sampling years (2003–2012). Dietary tracers (δ{sup 13}C and δ{sup 15}N) did not change significantly over time, indicating that temporal changes in PBDEs are likely caused by implemented regulations. A comparison with recently published temporal trends of ΣPBDE in marine birds from North America and Europe is given. - Highlights: • Seabird eggs have been used to monitor POPs on the west coast of Canada since 1979. • Samples of these eggs were analysed retrospectively for PBDEs and HBCDD. • Regulations exist in North America to control PBDEs, but not HBCDD. • PBDEs decreased significantly since regulations were applied. • HBCDD was not detected pre-2003, but is now found in low concentrations.

  4. Holocene sea-level changes along the North Carolina Coastline and their implications for glacial isostatic adjustment models

    Science.gov (United States)

    Horton, B.P.; Peltier, W.R.; Culver, S.J.; Drummond, R.; Engelhart, S.E.; Kemp, A.C.; Mallinson, D.; Thieler, E.R.; Riggs, S.R.; Ames, D.V.; Thomson, K.H.

    2009-01-01

    We have synthesized new and existing relative sea-level (RSL) data to produce a quality-controlled, spatially comprehensive database from the North Carolina coastline. The RSL database consists of 54 sea-level index points that are quantitatively related to an appropriate tide level and assigned an error estimate, and a further 33 limiting dates that confine the maximum and minimum elevations of RSL. The temporal distribution of the index points is very uneven with only five index points older than 4000 cal a BP, but the form of the Holocene sea-level trend is constrained by both terrestrial and marine limiting dates. The data illustrate RSL rapidly rising during the early and mid Holocene from an observed elevation of -35.7 ?? 1.1 m MSL at 11062-10576 cal a BP to -4.2 m ?? 0.4 m MSL at 4240-3592 cal a BP. We restricted comparisons between observations and predictions from the ICE-5G(VM2) with rotational feedback Glacial Isostatic Adjustment (GIA) model to the Late Holocene RSL (last 4000 cal a BP) because of the wealth of sea-level data during this time interval. The ICE-5G(VM2) model predicts significant spatial variations in RSL across North Carolina, thus we subdivided the observations into two regions. The model forecasts an increase in the rate of sea-level rise in Region 1 (Albemarle, Currituck, Roanoke, Croatan, and northern Pamlico sounds) compared to Region 2 (southern Pamlico, Core and Bogue sounds, and farther south to Wilmington). The observations show Late Holocene sea-level rising at 1.14 ?? 0.03 mm year-1 and 0.82 ?? 0.02 mm year-1 in Regions 1 and 2, respectively. The ICE-5G(VM2) predictions capture the general temporal trend of the observations, although there is an apparent misfit for index points older than 2000 cal a BP. It is presently unknown whether these misfits are caused by possible tectonic uplift associated with the mid-Carolina Platform High or a flaw in the GIA model. A comparison of local tide gauge data with the Late Holocene RSL

  5. Unusual forest growth decline in boreal North America covaries with the retreat of Arctic sea ice.

    Science.gov (United States)

    Girardin, Martin P; Guo, Xiao Jing; De Jong, Rogier; Kinnard, Christophe; Bernier, Pierre; Raulier, Frédéric

    2014-03-01

    The 20th century was a pivotal period at high northern latitudes as it marked the onset of rapid climatic warming brought on by major anthropogenic changes in global atmospheric composition. In parallel, Arctic sea ice extent has been decreasing over the period of available satellite data records. Here, we document how these changes influenced vegetation productivity in adjacent eastern boreal North America. To do this, we used normalized difference vegetation index (NDVI) data, model simulations of net primary productivity (NPP) and tree-ring width measurements covering the last 300 years. Climatic and proxy-climatic data sets were used to explore the relationships between vegetation productivity and Arctic sea ice concentration and extent, and temperatures. Results indicate that an unusually large number of black spruce (Picea mariana) trees entered into a period of growth decline during the late-20th century (62% of sampled trees; n = 724 cross sections of age >70 years). This finding is coherent with evidence encoded in NDVI and simulated NPP data. Analyses of climatic and vegetation productivity relationships indicate that the influence of recent climatic changes in the studied forests has been via the enhanced moisture stress (i.e. greater water demands) and autotrophic respiration amplified by the declining sea ice concentration in Hudson Bay and Hudson Strait. The recent decline strongly contrasts with other growth reduction events that occurred during the 19th century, which were associated with cooling and high sea ice severity. The recent decline of vegetation productivity is the first one to occur under circumstances related to excess heat in a 300-year period, and further culminates with an intensifying wildfire regime in the region. Our results concur with observations from other forest ecosystems about intensifying temperature-driven drought stress and tree mortality with ongoing climatic changes.

  6. The Baltic Sea region and increasing international tension

    Directory of Open Access Journals (Sweden)

    Khudolei Konstantin

    2016-03-01

    Full Text Available For many years, the Baltic Sea region stood out for its remarkable stability. The dramatic changes following the end of the Cold War did not have a profound effect on the territory. However, Russia's cooperation with other states in the Baltic Sea region began to lose momentum. This paper discusses the negative effects of the Ukrainian and Syrian crises and the increasing tension between Russia and other countries in the Baltic Sea region. In the short term, these trends are unlikely to re¬verse. Of the two possible scenarios — suspending relations until a solution to the political and military problems is found or trying to make use of every opportunity in economy, culture, science, education, etc., — the latter is preferable. A breakdown in regional cooperation will weaken Russia’s position. However, gaining positive momentum may prove instrumental in overcoming the confrontation between Russia and the West in the future.

  7. Wind energy resource atlas. Volume 2. The North Central Region

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, D.L.; Hadley, D.L.; Elliott, D.L.; Barchet, W.R.; George, R.L.

    1981-02-01

    The North Central atlas assimilates six collections of wind resource data: one for the region and one for each of the five states that compose the North Central region (Iowa, Minnesota, Nebraska, North Dakota, and South Dakota). At the state level, features of the climate, topography and wind resource are discussed in greater detail than is provided in the regional discussion, and that data locations on which the assessment is based are mapped. Variations, over several time scales, in the wind resource at selected stations in each state are shown on graphs of monthly average and international wind speed and power, and hourly average wind speed for each season. Other graphs present speed direction and duration frequencies of the wind at these locations.

  8. Avian Influenza Ecology in North Atlantic Sea Ducks: Not All Ducks Are Created Equal.

    Science.gov (United States)

    Hall, Jeffrey S; Russell, Robin E; Franson, J Christian; Soos, Catherine; Dusek, Robert J; Allen, R Bradford; Nashold, Sean W; TeSlaa, Joshua L; Jónsson, Jón Eínar; Ballard, Jennifer R; Harms, Naomi Jane; Brown, Justin D

    2015-01-01

    Wild waterfowl are primary reservoirs of avian influenza viruses (AIV). However the role of sea ducks in the ecology of avian influenza, and how that role differs from freshwater ducks, has not been examined. We obtained and analyzed sera from North Atlantic sea ducks and determined the seroprevalence in those populations. We also tested swab samples from North Atlantic sea ducks for the presence of AIV. We found relatively high serological prevalence (61%) in these sea duck populations but low virus prevalence (0.3%). Using these data we estimated that an antibody half-life of 141 weeks (3.2 years) would be required to attain these prevalences. These findings are much different than what is known in freshwater waterfowl and have implications for surveillance efforts, AIV in marine environments, and the roles of sea ducks and other long-lived waterfowl in avian influenza ecology.

  9. Avian influenza ecology in North Atlantic sea ducks: Not all ducks are created equal

    Science.gov (United States)

    Hall, Jeffrey S.; Russell, Robin E.; Franson, J. Christian; Soos, Catherine; Dusek, Robert J.; Allen, R. Bradford; Nashold, Sean W.; Teslaa, Joshua L.; Jónsson, Jón Einar; Ballard, Jennifer R.; Harms, Naomi Jnae; Brown, Justin D.

    2015-01-01

    Wild waterfowl are primary reservoirs of avian influenza viruses (AIV). However the role of sea ducks in the ecology of avian influenza, and how that role differs from freshwater ducks, has not been examined. We obtained and analyzed sera from North Atlantic sea ducks and determined the seroprevalence in those populations. We also tested swab samples from North Atlantic sea ducks for the presence of AIV. We found relatively high serological prevalence (61%) in these sea duck populations but low virus prevalence (0.3%). Using these data we estimated that an antibody half-life of 141 weeks (3.2 years) would be required to attain these prevalences. These findings are much different than what is known in freshwater waterfowl and have implications for surveillance efforts, AIV in marine environments, and the roles of sea ducks and other long-lived waterfowl in avian influenza ecology.

  10. Estimating sea floor dynamics in the Southern North Sea to improve bathymetric survey planning

    NARCIS (Netherlands)

    Dorst, Leendert Louis

    2009-01-01

    Safe nautical charts require a carefully designed bathymetric survey policy, especially in shallow sandy seas that potentially have dynamic sea floor patterns. Bathymetric resurveying at sea is a costly process with limited resources, though. A pattern on the sea floor known as tidal sand waves is c

  11. Year aridity index patterns in northwest China and the relationship to summer North Atlantic sea surface temperature

    Institute of Scientific and Technical Information of China (English)

    YAN Yan; ZHAO Xinyi; ZHOU Liping

    2008-01-01

    Aim to linking the variability of drought in northwest China to the oceanic influence of North Atlantic SSTs at the background of global warming and at the regional climate change shifting stages, year aridity index variations in northwest China and summer North Atlantic sea surface temperature (SST) variations are examined for the 44 a period of 1961--2004 using singular value de-composition (SVD) analysis. Results show that the SST anomalies (SSTA) in the North Atlantic in summer reflected three basic models. The first SVD mode of SST pattern shows a dipole - like variation with the positive center located at southwest and nega-tive center at northeast of extratropical North Atlantic. And it strongly relates to the positive trend in AI variation in northwest China. The second coupled modes display the coherent positive anomalies in extratropical North Atlantic SST and the marked opposite trend of AI variability between north and south of Xinjiang. In addition, the lag correlation analysis of the first mode of SSTA and geopotential heights at 500 hPa variations also shows that the indication of the former influencing the latter configuration, which re-sult in higher air temperature and less precipitation when the SSTA in the North Atlantic Ocean in summer motivated Eurasian cir-culation of EA pattern, further to influence the wet - dry variations in northwest China by the ocean-to - atmosphere forcing.

  12. Why is the North Sea West of Us?

    DEFF Research Database (Denmark)

    Gammeltoft, Peder

    2016-01-01

    This article focuses on the motivations behind sea-naming, by means of examples from Europe but also elsewhere. Why do certain sea names become dominant while others retract into local forms or simply die out? The article takes us back in time to the early days of map-making and, indeed, earlier...

  13. Analysis on a Regional Heavy Rainstorm Process in North Henan

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The research aimed to analyze a regional heavy rainstorm process in North Henan.[Method] Based on routine weather chart,rainfall station in county and town,satellite cloud chart,etc.,by using synoptic diagnostic method,formation reason of the regional heavy rainstorm weather in North Henan during 18-19 August,2010 was analyzed initially from large-scale circulation background,influence system,physical quantity field and terrain influence.[Result] The strong precipitation had obvious meso-scale c...

  14. Buried paleo-sedimentary basins in the north-eastern Black Sea-Azov Sea area and tectonic implications (DOBRE-2)

    Science.gov (United States)

    Starostenko, Vitaly; Stephenson, Randell; Janik, Tomasz; Tolkunov, Anatoly

    2014-05-01

    A number of independent but inter-related projects carried out under the auspices of various national and international programmes in Ukraine including DARIUS were aimed at imaging the upper lithosphere, crustal and sedimentary basin architecture in the north-eastern Black Sea, southern Crimea and Kerch peninsulas and the Azov Sea. This region marks the transition from relatively undisturbed Precambrian European cratonic crust and lithosphere north of the Azov Sea to areas of significant Phanerozoic tectonics and basin development, in both extensional as well as compressional environments, to the south, including the eastern Black Sea rift, which is the main sedimentary basin of the study area. The wide-angle reflection and refraction (WARR) profile DOBRE-2, a Ukrainian national project with international participation (see below), overlapping some 115 km of the southern end of the DOBREfraction'99 profile (that crosses the intracratonic Donbas Foldbelt) in the north and running to the eastern Black Sea basin in the south, utilised on- and offshore recording and energy sources. It maps crustal velocity structure across the craton margin and documents, among other things, that the Moho deepens from 40 km to ~47 km to the southwest below the Azov Sea and Crimean-Caucasus deformed zone. A regional CDP seismic profile coincident with DOBRE-2, crossing the Azov Sea, Kerch Peninsula and the north-eastern Black Sea southwest to the Ukraine-Turkey border, acquired by Ukrgeofisika (the Ukrainian national geophysical company) reveals in its inferred structural relationships the ages of Cretaceous and younger extensional and subsequent basin inversion tectonic events as well as the 2D geometry of basement displacement associated with post mid-Eocene inversion. A direct comparison of the results of the WARR velocity model and the near-vertical reflection structural image has been made by converting the former into the time domain. The results dramatically demonstrate that

  15. 78 FR 41033 - Fisheries of the Northeast Region, Southeast Region, North Pacific Region, Pacific Region...

    Science.gov (United States)

    2013-07-09

    ... a determination of overfishing or an overfished condition. SUMMARY: This action serves as a notice... are subject to overfishing or are in an overfished state: Georges Bank (GB) yellowtail flounder is subject to overfishing and continues to be in an overfished condition; Bering Sea and Aleutian...

  16. Monitoring the Dead Sea Region by Multi-Parameter Stations

    Science.gov (United States)

    Mohsen, A.; Weber, M. H.; Kottmeier, C.; Asch, G.

    2015-12-01

    The Dead Sea Region is an exceptional ecosystem whose seismic activity has influenced all facets of the development, from ground water availability to human evolution. Israelis, Palestinians and Jordanians living in the Dead Sea region are exposed to severe earthquake hazard. Repeatedly large earthquakes (e.g. 1927, magnitude 6.0; (Ambraseys, 2009)) shook the whole Dead Sea region proving that earthquake hazard knows no borders and damaging seismic events can strike anytime. Combined with the high vulnerability of cities in the region and with the enormous concentration of historical values this natural hazard results in an extreme earthquake risk. Thus, an integration of earthquake parameters at all scales (size and time) and their combination with data of infrastructure are needed with the specific aim of providing a state-of-the-art seismic hazard assessment for the Dead Sea region as well as a first quantitative estimate of vulnerability and risk. A strong motivation for our research is the lack of reliable multi-parameter ground-based geophysical information on earthquakes in the Dead Sea region. The proposed set up of a number of observatories with on-line data access will enable to derive the present-day seismicity and deformation pattern in the Dead Sea region. The first multi-parameter stations were installed in Jordan, Israel and Palestine for long-time monitoring. All partners will jointly use these locations. All stations will have an open data policy, with the Deutsches GeoForschungsZentrum (GFZ, Potsdam, Germany) providing the hard and software for real-time data transmission via satellite to Germany, where all partners can access the data via standard data protocols.

  17. Mechanisms of Region Construction: the Case of International Projects in the Baltic Sea Region

    Directory of Open Access Journals (Sweden)

    Sologub Anastasiya Petrovna

    2015-12-01

    Full Text Available The article analyzes the processes of regional construction and their specific features in the Baltic Sea region. The article provides insights into main approaches to defining the notion of the Baltic Sea Region, its geography, rationales and preconditions of the Baltic Sea Region construction. The author makes conclusion that currently the construction process is being continued, and it involves a wide range of actors: NGOs, local and regional authorities, scientific organizations, higher education institutions, business structures, international organizations. All these actors use different tools and act in different spheres. Although there is no clear answer to the question “Who and how constructs the Baltic Sea Region?”, it is concluded that the cooperation played a significant role in this process, for example, by determining the geography of the region and creating communication networks. Projects, in turn, become a widespread form of cooperation which are used by large Baltic interregional organizations, such as the Northern Dimension, Interregional programmes, the Council of the Baltic Sea States. International project activity of the described above actors, being the point of pooled resources application and also narratives on the regional issues, became one of the mechanisms of the region construction. The article proves that a wide variety of projects in various fields with the participation of different actors creates a picture of the Baltic Sea region building some of its features and providing common identity and responsibility ideas.

  18. North Indian Ocean warming and sea level rise in an OGCM

    Indian Academy of Sciences (India)

    Bijoy Thompson; C Gnanaseelan; Anant Parekh; P S Salvekar

    2008-04-01

    The variability in the long-term temperature and sea level over the north Indian Ocean during the period 1958–2000 has been investigated using an Ocean General Circulation Model, Modular Ocean Model version 4. The model simulated fields are compared with the sea level observations from tide-gauges, Topex/Poseidon (T/P) satellite, in situ temperature profile observations from WHOI moored buoy and sea surface temperature (SST) observations from DS1, DS3 and DS4 moored buoys. It is seen that the long (6–8 years) warming episodes in the SST over the north Indian Ocean are followed by short episodes (2–3 years) of cooling. The model temperature and sea level anomaly over the north Indian Ocean show an increasing trend in the study period. The model thermocline heat content per unit area shows a linear increasing trend (from 1958–2000) at the rate of 0.0018 × 1011J/m2 per year for north Indian Ocean. North Indian Ocean sea level anomaly (thermosteric component) also shows a linear increasing trend of 0.31mm/year during 1958–2000.

  19. Hyperpigmentation in North Sea dab Limanda limanda. I. Spatial and temporal patterns and host effects.

    Science.gov (United States)

    Grütjen, F; Lang, T; Feist, S; Bruno, D; Noguera, P; Wosniok, W

    2013-03-13

    Hyperpigmentation is a term describing a specific pigment anomaly affecting common dab Limanda limanda in the North Sea and, less frequently, in adjacent areas, e.g. the English Channel, Irish and Celtic Seas, western Baltic Sea and Icelandic waters. Other North Sea flatfish species are also affected, but at a markedly lower prevalence. The condition is characterised by the occurrence of varying degrees of green to black patchy pigment spots in the skin of the upper (ocular) body side and pearly-white pigment spots in the skin of the lower (abocular) body side. In the course of fish disease monitoring programmes carried out by Germany and the UK (England and Scotland), a pronounced spatial pattern of hyperpigmentation has been detected in the North Sea. An increase in prevalence has been recorded in almost all North Sea areas studied in the past 2 decades. The prevalence recorded in hot spot areas of the condition increased from 5 to >40% between 1988 and 2009. Analysis of the German data indicates that the prevalence and intensity (degree of discolouration) of hyperpigmentation increase with size and age, indicating a temporal progression of the condition with size and age. Intense hyperpigmentation is associated with increased growth (length) and decreased condition factor. Potential causes of the condition (UV-B radiation nutrition, water temperature increase, demographic changes) and, in particular, of the spatial/temporal patterns recorded as well as the relationship to host-specific factors (sex, age, length, growth, condition factor) are discussed.

  20. Sankt-Peterburg v Baltijskom regione [Saint Petersburg in the Baltic Sea region

    Directory of Open Access Journals (Sweden)

    Khudoley Konstantin

    2009-01-01

    Full Text Available The article describes the place of St Petersburg in international cooperation in the Baltic Sea region and the role of the Baltic region as one of the priorities of the international relations of the city. The authors show continual attention of Saint-Petersburg to developing international relations in the Baltic Sea region. The article indicates one of the most important areas of international cooperation – the participation of the city in the renewed Northern Dimension policy.

  1. Zircon age and heavy mineral constraints on provenance of North Sea Carboniferous sandstones

    Energy Technology Data Exchange (ETDEWEB)

    Morton, A.C. [HM Research Associates, Woodhouse Eaves (United Kingdom); University of Aberdeen (United Kingdom). Dept. of Geology and Petroleum Geology; Hallsworth, C.R. [HM Research Associates, Woodhouse Eaves (United Kingdom); Claoue-Long, J.C. [Australian Geological Survey Organisation, Canberra (Australia)

    2001-03-01

    The understanding of sediment provenance and sediment transport routes is a key element in establishing reservoir presence in clastic petroleum systems. Determination of sediment provenance is particularly difficult in structurally complex areas and in sequences that have undergone extensive burial diagenesis. This paper describes a method that overcomes these problems, by combining quantitative heavy mineral analysis with detrital zircon age dating. Quantitative heavy mineral analysis identifies differences in sediment provenance within the sample set, and zircon age data provide diagnostic criteria for the identification of the various source terrains. The high degree of resolution shown by this approach is demonstrated using the North Sea Carboniferous as an example. The Carboniferous of the North Sea has suffered extensive diagenetic modification during its complex burial history, is difficult to image with seismic data, and in some areas, notably the central and northern North Sea, preservation is patchy. The understanding of Carboniferous sand provenance is therefore rudimentary. The Tayport and Firth Coal formations (latest Devonian to Early Carboniferous) of the Outer Moray Firth (central North Sea) were derived from a source area to the north of the British Isles, with sediment transported along the proto-Viking Graben. Some local input is recognised in the Firth Coal Formation. The Westoe Coal Formation (Westphalian B) in the southern North Sea was derived from the southeast, probably from the Saxo-Thuringian Zone of the central European Variscides. The Lower Ketch Member (Westphalian C) in the southern North Sea has a northern provenance, with abundant chrome spinel suggesting derivation from ophiolitic material on the Rinkoebing-Fyn High. (author)

  2. Checklist of sea turtles endohelminth in Neotropical region

    Directory of Open Access Journals (Sweden)

    Werneck M. R.

    2016-09-01

    Full Text Available This paper presents a list of parasites described in sea turtles from the Neotropical region. Through the review of literature the occurrence of 79 taxa of helminthes parasites were observed, mostly consisting of the Phylum Platyhelminthes with 76 species distributed in 14 families and 2 families of the Phylum Nematoda within 3 species. Regarding the parasite records, the most studied host was the green turtle (Chelonia mydas followed by the hawksbill turtle (Eretmochelys imbricata, olive ridley turtle (Lepidochelys olivacea, loggerhead turtle (Caretta caretta and leatherback turtle (Dermochelys coriacea. Overall helminths were reported in 12 countries and in the Caribbean Sea region. This checklist is the largest compilation of data on helminths found in sea turtles in the Neotropical region.

  3. BALTEX - A science broker for the Baltic Sea Region

    Science.gov (United States)

    Reckermann, M.; von Storch, H.; Langner, J.; Omstedt, A. T.

    2010-12-01

    BALTEX (the Baltic Sea Experiment) is an interdisciplinary research network of scientists involved in environmental research dedicated to the Baltic Sea drainage basin (including disciplines such as meteorology, hydrology, oceanography, biogeochemistry and climate research). Originally founded in 1992 as a Continental Scale Experiment in GEWEX (the Global Energy and Water Cycle Experiment within the World Climate Research Programme (WCRP) of the World Meteorological Organization, WMO), it was intended to form a common science, communication and data platform with the overall goal to integrate efforts to gain a better understanding of the water and energy cycle in the Baltic Sea basin. BALTEX Phase II (since 2003) has extended the scope to research on regional climate change and variability, climate change impacts on biogeochemistry and water management, but also made first steps towards overarching social and political issues as cross-cutting activities in the context of the scientific objectives. An important aspect of BALTEX Phase II is a more holistic approach towards observing, understanding and modelling major environmental relevant for the entire Baltic Sea region. Parts of the BALTEX Phase II research activities thus contribute to the establishment of a high resolution integrated modelling system for Northern Europe, embedded in an Earth System Model. An outstanding product of BALTEX as a “knowledge broker” for regional political institutions is the BACC report. Following to a large extent the method of IPCC, a regional assessment report on climate change in the Baltic Sea basin was compiled, which summarizes the published scientifically legitimate knowledge on regional climate change in the Baltic Sea basin and its impacts. The assessment, known as the BACC report (BALTEX Assessment of Climate Change for the Baltic Sea Basin; BACC author team 2008, Reckermann et al., 2008) was published in 2008 as a book. A survey among climate researchers in the area

  4. Diagnostic sea ice predictability in the pan-Arctic and U.S. Arctic regional seas

    Science.gov (United States)

    Cheng, Wei; Blanchard-Wrigglesworth, Edward; Bitz, Cecilia M.; Ladd, Carol; Stabeno, Phyllis J.

    2016-11-01

    This study assesses sea ice predictability in the pan-Arctic and U.S. Arctic regional (Bering, Chukchi, and Beaufort) seas with a purpose of understanding regional differences from the pan-Arctic perspective and how predictability might change under changing climate. Lagged correlation is derived using existing output from the Community Earth System Model Large Ensemble (CESM-LE), Pan-Arctic Ice-Ocean Modeling and Assimilation System, and NOAA Coupled Forecast System Reanalysis models. While qualitatively similar, quantitative differences exist in Arctic ice area lagged correlation in models with or without data assimilation. On regional scales, modeled ice area lagged correlations are strongly location and season dependent. A robust feature in the CESM-LE is that the pan-Arctic melt-to-freeze season ice area memory intensifies, whereas the freeze-to-melt season memory weakens as climate warms, but there are across-region variations in the sea ice predictability changes with changing climate.

  5. Controls on the genesis and prospectivity of Paleogene palaeogeomorphic traps, East Shetland Platform, UK North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Underhill, J.R. [University of Edinburgh (United Kingdom). Dept. of Geology and Geophysics

    2001-07-01

    A seismic stratigraphic interpretation of the Bressay area of the East Shetland Platform demonstrates the key role that fluctuations in relative sea-level had in the development and evolution of Paleogene deposition in proximal parts of the Viking Graben. Relative sea-level fall, probably driven by events associated with the early development and evolution of the Iceland plume, enabled a Late Paleocene-Early Eocene coarsening-up deltaic system to initially prograde and offlap as part of a forced regressive wedge. Coeval and subsequent erosion led to deep (>250m) incision of the delta and formation of significant drainage system consisting initially of a dendritic incised valley network and a major, deep, low sinuosity channel, all of which fed sediment into distal parts of the basin. The highly localised nature of major incision, the area's situation above the known occurrence of a buried Late Caledonian granitic intrusion (the Bressay Granite) and coincident fault reactivation combine to suggest that the regional transient plume-related uplift was locally enhanced by Late Palaeocene-Early Eocene tectonic uplift of a previously suppressed crustal root. Subsequently, Early-Mid Eocene sea-level rise, coeval with North Atlantic opening, caused transgressive backfill of the erosional (palaeogeomorphic) relief and drape of the clastic wedge by tuffaceous marine mudstones of the Balder Formation. Two, distinctive and mutually exclusive palaeogeomorphic clay types have resulted. Structural relief on the delta top incision surface combines with either the onlapping, fine-grained tuffaceous valley fill or compactional drape above the coarse axial fill of the main low-sinuosity channel system to form good reservoir-seal pairs. A third closure exists in association with activity on a prominent reverse fault that also appears to have initiated in response to the rejuvenation of the Bressay Granite. Present-day hydrocarbon charge from the basin and the occurrence of heavy

  6. Eutrophication status of the North Sea, Skagerrak, Kattegat and the Baltic Sea in present and future climates: A model study

    Science.gov (United States)

    Skogen, Morten D.; Eilola, Kari; Hansen, Jørgen L. S.; Meier, H. E. Markus; Molchanov, Mikhail S.; Ryabchenko, Vladimir A.

    2014-04-01

    A method to combine observations and an ensemble of ecological models has been used to assess eutrophication. Using downscaled forcing from two GCMs under the A1B emission scenario, an assessment of the eutrophication status was made for a control (1970-2000) and a future climate (2070-2100) period. By using validation results from a hindcast to compute individual weights between the models, an assessment of eutrophication is done using a set of threshold values. The final classification distinguishes between three categories: problem area, potential problem area, and non-problem area, in accordance with current management practice as suggested by the Oslo and Paris Commissions (OSPAR) and the Helsinki Commission (HELCOM). For the control run the assessment indicates that the Kattegat, the Danish Straits, the Gulf of Finland, the Gotland Basin as well as main parts of the Arkona Basin, the Bornholm Basin, and the Baltic proper may be classified as problem areas. The main part of the North Sea and also the Skagerrak are non-problem areas while the main parts of the Gulf of Bothnia, Gulf of Riga and the entire southeastern continental coast of the North Sea may be classified as potential problem areas. In the future climate scenarios most of the previous potential problem areas in the Baltic Sea have become problem areas, except for the Bothnian Bay where the situation remain fairly unchanged. In the North Sea there seems to be no obvious changes in eutrophication status in the projected future climate.

  7. North American regional climate reconstruction from ground surface temperature histories

    Science.gov (United States)

    Jaume-Santero, Fernando; Pickler, Carolyne; Beltrami, Hugo; Mareschal, Jean-Claude

    2016-12-01

    Within the framework of the PAGES NAm2k project, 510 North American borehole temperature-depth profiles were analyzed to infer recent climate changes. To facilitate comparisons and to study the same time period, the profiles were truncated at 300 m. Ground surface temperature histories for the last 500 years were obtained for a model describing temperature changes at the surface for several climate-differentiated regions in North America. The evaluation of the model is done by inversion of temperature perturbations using singular value decomposition and its solutions are assessed using a Monte Carlo approach. The results within 95 % confidence interval suggest a warming between 1.0 and 2.5 K during the last two centuries. A regional analysis, composed of mean temperature changes over the last 500 years and geographical maps of ground surface temperatures, show that all regions experienced warming, but this warming is not spatially uniform and is more marked in northern regions.

  8. Influence of Sea Ice on the Thermohaline Circulation in the Arctic-North Atlantic Ocean

    Science.gov (United States)

    Mauritzen, Cecilie; Haekkinen, Sirpa

    1997-01-01

    A fully prognostic coupled ocean-ice model is used to study the sensitivity of the overturning cell of the Arctic-North-Atlantic system to sea ice forcing. The strength of the thermohaline cell will be shown to depend on the amount of sea ice transported from the Arctic to the Greenland Sea and further to the subpolar gyre. The model produces a 2-3 Sv increase of the meridional circulation cell at 25N (at the simulation year 15) corresponding to a decrease of 800 cu km in the sea ice export from the Arctic. Previous modeling studies suggest that interannual and decadal variability in sea ice export of this magnitude is realistic, implying that sea ice induced variability in the overturning cell can reach 5-6 Sv from peak to peak.

  9. Identification of cephalopod species from the North and Baltic Seas using morphology, COI and 18S rDNA sequences

    Science.gov (United States)

    Gebhardt, Katharina; Knebelsberger, Thomas

    2015-09-01

    We morphologically analyzed 79 cephalopod specimens from the North and Baltic Seas belonging to 13 separate species. Another 29 specimens showed morphological features of either Alloteuthis mediaor Alloteuthis subulata or were found to be in between. Reliable identification features to distinguish between A. media and A. subulata are currently not available. The analysis of the DNA barcoding region of the COI gene revealed intraspecific distances (uncorrected p) ranging from 0 to 2.13 % (average 0.1 %) and interspecific distances between 3.31 and 22 % (average 15.52 %). All species formed monophyletic clusters in a neighbor-joining analysis and were supported by bootstrap values of ≥99 %. All COI haplotypes belonging to the 29 Alloteuthis specimens were grouped in one cluster. Neither COI nor 18S rDNA sequences helped to distinguish between the different Alloteuthis morphotypes. For species identification purposes, we recommend the use of COI, as it showed higher bootstrap support of species clusters and less amplification and sequencing failure compared to 18S. Our data strongly support the assumption that the genus Alloteuthis is only represented by a single species, at least in the North Sea. It remained unclear whether this species is A. subulata or A. media. All COI sequences including important metadata were uploaded to the Barcode of Life Data Systems and can be used as reference library for the molecular identification of more than 50 % of the cephalopod fauna known from the North and Baltic Seas.

  10. Cenozoic uplift and subsidence in the North Atlantic region

    DEFF Research Database (Denmark)

    Anell, Ingrid Anna Margareta; Thybo, Hans; Artemieva, Irina

    2009-01-01

    , time and amplitude (where possible) of topographic changes in the North Atlantic region during the Cenozoic (65-0 Ma). Our compilation is based on published results from reflection seismic studies, AFT (apatite fission track) studies, VR (vitrinite reflectance) trends, maximum burial, sediment supply...

  11. Forestry serving urban societies in the north atlantic region

    DEFF Research Database (Denmark)

    2010-01-01

    In the North Atlantic Region, the social services provided by forests play a major role. With the high level of urbanisation in many of these countries, forests and other green areas are of great importance as recreational settings for urban dwellers. In order to ensure that forests cater for the...

  12. Northern North Atlantic Sea Surface Height and Ocean Heat Content Variability

    Science.gov (United States)

    Hakkinen, Sirpa; Rhines, Peter; Worthen, Denise L.

    2013-01-01

    The evolution of nearly 20 years of altimetric sea surface height (SSH) is investigated to understand its association with decadal to multidecadal variability of the North Atlantic heat content. Altimetric SSH is dominated by an increase of about 14 cm in the Labrador and Irminger seas from 1993 to 2011, while the opposite has occurred over the Gulf Stream region over the same time period. During the altimeter period the observed 0-700 m ocean heat content (OHC) in the subpolar gyre mirrors the increased SSH by its dominantly positive trend. Over a longer period, 1955-2011, fluctuations in the subpolar OHC reflect Atlantic multidecadal variability (AMV) and can be attributed to advection driven by the wind stress ''gyre mode'' bringing more subtropical waters into the subpolar gyre. The extended subpolar warming evident in SSH and OHC during the altimeter period represents transition of the AMV from cold to warm phase. In addition to the dominant trend, the first empirical orthogonal function SSH time series shows an abrupt change 2009-2010 reaching a new minimum in 2010. The change coincides with the change in the meridional overturning circulation at 26.5N as observed by the RAPID (Rapid Climate Change) project, and with extreme behavior of the wind stress gyre mode and of atmospheric blocking. While the general relationship between northern warming and Atlantic meridional overturning circulation (AMOC) volume transport remains undetermined, the meridional heat and salt transport carried by AMOC's arteries are rich with decade-to-century timescale variability.

  13. Fungi found in Mediterranean and North Sea sponges: how specific are they?

    Directory of Open Access Journals (Sweden)

    Mohd Azrul Naim

    2017-09-01

    Full Text Available Fungi and other eukaryotes represent one of the last frontiers of microbial diversity in the sponge holobiont. In this study we employed pyrosequencing of 18S ribosomal RNA gene amplicons containing the V7 and V8 hypervariable regions to explore the fungal diversity of seven sponge species from the North Sea and the Mediterranean Sea. For most sponges, fungi were present at a low relative abundance averaging 0.75% of the 18S rRNA gene reads. In total, 44 fungal OTUs (operational taxonomic units were detected in sponges, and 28 of these OTUs were also found in seawater. Twenty-two of the sponge-associated OTUs were identified as yeasts (mainly Malasseziales, representing 84% of the fungal reads. Several OTUs were related to fungal sequences previously retrieved from other sponges, but all OTUs were also related to fungi from other biological sources, such as seawater, sediments, lakes and anaerobic digesters. Therefore our data, supported by currently available data, point in the direction of mostly accidental presence of fungi in sponges and do not support the existence of a sponge-specific fungal community.

  14. Emergence of a new predator in the North Sea: evaluation of potential trophic impacts focused on hake, saithe, and Norway pout

    DEFF Research Database (Denmark)

    Cormon, Xochitl; Kempf, Alexander; Vermard, Youen

    2016-01-01

    During the last 15 years, northern European hake (Merluccius merluccius) has increased in abundance, and its spatial distribution has expanded in the North Sea region in correlation with temperature. In a context of global warming, this spatial shift could impact local trophic interactions: direc...

  15. Russia’s energy geostrategy in the Baltic Sea region

    Directory of Open Access Journals (Sweden)

    Zeleneva Irina

    2013-06-01

    Full Text Available This article explores Russian energy policy in the Baltic Sea region in the context of the world energy market globalization. The study focuses on the three Baltic States — Latvia, Lithuania, and Estonia — which have a similar geographical location and history. The dynamic development of the region as a whole is strongly influenced by the stability of energy supply in each state. The article analyses the role Russia plays in the energy policy of the region from both geopolitical and geostrategic viewpoints. The author identifies the main characteristics of the Russian energy policy in these countries, and provides with a forecast for energy policy development in the region. A geostrategic approach dictates any successful energy policy in the Baltic Sea region to bring in line Russian interests with those of the European states.

  16. Water scaling in the North Sea oil and gas fields and scale prediction: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, M.

    1996-12-31

    Water-scaling is a common and major production chemistry problem in the North Sea oil and gas fields and scale prediction has been an important means to assess the potential and extent of scale deposition. This paper presents an overview of sulphate and carbonate scaling problems in the North Sea and a review of several widely used and commercially available scale prediction software. In the paper, the water chemistries and scale types and severities are discussed relative of the geographical distribution of the fields in the North Sea. The theories behind scale prediction are then briefly described. Five scale or geochemical models are presented and various definitions of saturation index are compared and correlated. Views are the expressed on how to predict scale precipitation under some extreme conditions such as that encountered in HPHT reservoirs. 15 refs., 7 figs., 9 tabs.

  17. Vertical distributions of autumn spawned larval herring (Clupea harengus L.) in the North Sea

    DEFF Research Database (Denmark)

    Heath, M.; Brander, Keith; Munk, Peter;

    1991-01-01

    , and appeared to be related to the tidal cycle rather than crepuscular periods. Diel cycles in vertical distribution could not be detected at sites in the southeastern North Sea, characterized by water depths less than 45 m, high vertical shear and high light attenuation coefficients. It is suggested......Vertical distributions of autumn spawned herring larvae were sampled at 10 sites in the North Sea between October 1987 and March 1988 during the Autumn Circulation Experiment (ACE). Several different patterns of vertical migrations occurred. Diel variations in the vertical distributions were found...... that strong turbulence inhibits diel vertical migrations by herring larvae. This feature has important consequences for the advection of larvae in the North Sea....

  18. Changes in distributional patterns of plaice Pleuronectes platessa in the central and eastern North Sea; do declining nutrient loadings play a role?

    DEFF Research Database (Denmark)

    Støttrup, Josianne Gatt; Munk, Peter; Kodama, Masashi

    2017-01-01

    . For the same time period available time series data on nutrient conditions in the coastalNorth Sea area showthat the freshwater nitrogen loading has decreased by about 50%. While nutrient concentrations in the ambient environment have been shown to influence growth in juvenile plaice through influence...... sandbank in a shallowoffshore area of the North Sea. The Dogger Bank, was used as a reference location assuming this area has been less influenced from coastal eutrophication but similar regional climate conditions, and here we found no changes in the abundances of juvenile plaice. The increase in the use...... of offshore habitats as nursery areas by juvenile plaice in the North Sea appears not related to water depth per se but driven by specific processes dominating in near-shore areas and may be related to changes in nutrient loadings. This point to the importance of separating more general depth-related factors...

  19. Economic and Geographical Structure of the Baltic Sea region

    Directory of Open Access Journals (Sweden)

    Mezhevich Nikolai M.

    2016-09-01

    Full Text Available The Baltic Sea region is one of the most developed transnational regions. It comprises the coastal areas of Russia, Germany, and Poland and the entire territories of Sweden, Denmark, Finland, Lithuania, Latvia, and Estonia. New spatial forms of international economic cooperation develop in the region. The region is not homogeneous in terms of socioeconomic development, thus there are certain differences in the areas and the intensity of international cooperation. The article sets out to identify structural characteristics of the Baltic Sea region. This requires studying practices of transnational and transboundary cooperation and possibilities for their adoption in other regions of the world. An important characteristic of the Baltic Sea region is a considerable difference between its coastal territories, the fact that affects the development of multilateral relations. This article examines the most pronounced socioeconomic differences that should be taken into account when forecasting cooperation trends in t he region, including those between the Baltic territories of Russia and their international partners.

  20. Atlantic meridional overturning circulation and the prediction of North Atlantic sea surface temperature

    Science.gov (United States)

    Klöwer, M.; Latif, M.; Ding, H.; Greatbatch, R. J.; Park, W.

    2014-11-01

    The Atlantic Meridional Overturning Circulation (AMOC), a major current system in the Atlantic Ocean, is thought to be an important driver of climate variability, both regionally and globally and on a large range of time scales from decadal to centennial and even longer. Measurements to monitor the AMOC strength have only started in 2004, which is too short to investigate its link to long-term climate variability. Here the surface heat flux-driven part of the AMOC during 1900-2010 is reconstructed from the history of the North Atlantic Oscillation, the most energetic mode of internal atmospheric variability in the Atlantic sector. The decadal variations of the AMOC obtained in that way are shown to precede the observed decadal variations in basin-wide North Atlantic sea surface temperature (SST), known as the Atlantic Multidecadal Oscillation (AMO) which strongly impacts societally important quantities such as Atlantic hurricane activity and Sahel rainfall. The future evolution of the AMO is forecast using the AMOC reconstructed up to 2010. The present warm phase of the AMO is predicted to continue until the end of the next decade, but with a negative tendency.

  1. Albatross species demonstrate regional differences in North Pacific marine contamination.

    Science.gov (United States)

    Finkelstein, Myra; Keitt, Bradford S; Croll, Donald A; Tershy, Bernie; Jarman, Walter M; Rodriguez-Pastor, Sue; Anderson, David J; Sievert, Paul R; Smith, Donald R

    2006-04-01

    Recent concern about negative effects on human health from elevated organochlorine and mercury concentrations in marine foods has highlighted the need to understand temporal and spatial patterns of marine pollution. Seabirds, long-lived pelagic predators with wide foraging ranges, can be used as indicators of regional contaminant patterns across large temporal and spatial scales. Here we evaluate contaminant levels, carbon and nitrogen stable isotope ratios, and satellite telemetry data from two sympatrically breeding North Pacific albatross species to demonstrate that (1) organochlorine and mercury contaminant levels are significantly higher in the California Current compared to levels in the high-latitude North Pacific and (2) levels of organochlorine contaminants in the North Pacific are increasing over time. Black-footed Albatrosses (Phoebastria nigripes) had 370-460% higher organochlorine (polychlorinated biphenyls [PCBs], dichlorodiphenyltrichloroethanes [DDTs]) and mercury body burdens than a closely related species, the Laysan Albatross (P. immutabilis), primarily due to regional segregation of their North Pacific foraging areas. PCBs (the sum of the individual PCB congeners analyzed) and DDE concentrations in both albatross species were 130-360% higher than concentrations measured a decade ago. Our results demonstrate dramatically high and increasing contaminant concentrations in the eastern North Pacific Ocean, a finding relevant to other marine predators, including humans.

  2. Model calculations of the effects of present and future emissions of air pollutants from shipping in the Baltic Sea and the North Sea

    Directory of Open Access Journals (Sweden)

    J. E. Jonson

    2014-08-01

    Full Text Available Land-based emissions of air pollutants in Europe have steadily decreased over the past two decades, and this decrease is expected to continue. Within the same time span emissions from shipping have increased, although recently sulphur emissions, and subsequently particle emissions, have decreased in EU ports and in the Baltic Sea and the North Sea, defined as SECAs (Sulphur Emission Control Areas. The maximum allowed sulphur content in marine fuels in EU ports is now 0.1%, as required by the European Union sulphur directive. In the SECAs the maximum fuel content of sulphur is currently 1% (the global average is about 2.4%. This will be reduced to 0.1% from 2015, following the new IMO rules (International Maritime Organisation. In order to assess the effects of ship emissions in and around the Baltic Sea and the North Sea, regional model calculations with the EMEP air pollution model have been made on a 1/4° longitude × 1/8° latitude resolution, using ship emissions in the Baltic Sea and the North Sea that are based on accurate ship positioning data. The effects on depositions and air pollution and the resulting number of years of life lost (YOLL have been calculated by comparing model calculations with and without ship emissions in the two sea areas. The calculations have been made with emissions representative of 2009 and 2011, i.e. before and after the implementation of stricter controls on sulphur emissions from mid 2010. The calculations with present emissions show that per person, an additional 0.1–0.2 years of life lost is estimated in areas close to the major ship tracks with present emission levels. Comparisons of model calculations with emissions before and after the implementation of stricter emission control on sulphur show a general decrease in calculated particle concentration. At the same time, however, an increase in ship activity has resulted in higher emissions and subsequently air concentrations, in particular of NOx

  3. Phylogenetics, phylogeography and population genetics of North American sea ducks (tribe: Mergini)

    Science.gov (United States)

    Talbot, Sandra; Sonsthagen, Sarah A.; Pearce, John M.; Scribner, Kim T.

    2015-01-01

    Many environments occupied by North American sea ducks are remote and difficult to access, and as a result, detailed information about life history characteristics that drive population dynamics within and across species is limited. Nevertheless, progress on this front during the past several decades has benefited by the application of genetic technologies, and for several species, these technologies have allowed for concomitant tracking of population trends and genetic diversity, delineation of populations, assessment of gene flow among metapopulations, and understanding of migratory connectivity between breeding and wintering grounds. This chapter provides an overview of phylogenetic, phylogeographic, and population genetics studies of North American sea duck species, many of which have sought to understand the major and minor genetic divisions within and among sea duck species, and most of which have been conducted with the understanding that the maintenance of genetic variation in wild sea duck populations is fundamental to the group’s long-term persistence.

  4. Long-term stability and effective population size in North Sea and Baltic Sea cod ( Gadus morhua )

    DEFF Research Database (Denmark)

    Poulsen, Nina Aagaard; Eg Nielsen, Einar; Schierup, M.H.;

    2006-01-01

    DNA from archived otoliths was used to explore the temporal stability of the genetic composition of two cod populations, the Moray Firth (North Sea) sampled in 1965 and 2002, and the Bornholm Basin (Baltic Sea) sampled in 1928 and 1997. We found no significant changes in the allele frequencies...... for the Moray Firth population, while subtle but significant genetic changes over time were detected for the Bornholm Basin population. Estimates of the effective population size (N-e) generally exceeded 500 for both populations when employing a number of varieties of the temporal genetic method. However...

  5. Certified reference material for radionuclides in fish flesh sample IAEA-414 (mixed fish from the Irish Sea and North Sea)

    DEFF Research Database (Denmark)

    Pham, M.K.; Sanchez-Cabeza, J.A.; Povinec, P.P.

    2006-01-01

    ratios are also included. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in fish sample, for the development and validation of analytical methods and for training purposes. The material is available from IAEA, Vienna, in 100 g units. (c) 2006 Elsevier Ltd. All......A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) is described and the results of the certification process are presented. Nine radionuclides (K-40, Cs-137, Th-232, U-234, U-235, U-238, Pu-238, Pu239+240 and Am-241) were...

  6. Temporal and spatial characteristics of sea surface height variability in the North Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    D. Cromwell

    2006-01-01

    Full Text Available We investigate the spatial and temporal variability of sea surface height (SSH in the North Atlantic basin using satellite altimeter data from October 1992–January 2004. Our primary aim is to provide a detailed description of such variability, including that associated with propagating signals. We also investigate possible correlations between SSH variability and atmospheric pressure changes as represented by climate indices. We first investigate interannual SSH variations by deriving the complex empirical orthogonal functions (CEOFs of altimeter data lowpass-filtered at 18 months. We determine the spatial structure of the leading four modes (both in amplitude and phase and also the associated principal component (PC time series. Using wavelet analysis we derive the time-varying spectral density of the PCs, revealing when particular modes were strongest between 1992–2004. The spatial pattern of the leading CEOF, comprising 30% of the total variability, displays a 5-year periodicity in phase; signal propagation is particularly marked in the Labrador Sea. The second mode, with a dominant 3-year signal, has strong variability in the eastern basin. Secondly, we focus on the Azores subtropical frontal zone. The leading mode (35% is strong in the south and east of this region with strong variations at 3- and 5-year periods. The second mode (21% has a near-zonal band of low variance between  22°–27° N, sandwiched between two regions of high variance. Thirdly, we lowpass filter the altimeter data at a cutoff of 30 days, instead of 18 months, in order to retain signals associated with propagating baroclinic Rossby waves and/or eddies. The leading mode is the annual steric signal, around 46% of the SSH variability. The third and fourth CEOFs,  11% of the remaining variability, are associated with westward propagation which is particularly dominant in a "waveband" between 32°–36° N. For all three cases considered above, no significant cross

  7. Multi-phase structural and tectonic evolution of the Andaman Sea Region

    Science.gov (United States)

    Masterton, Sheona; Hill, Catherine; Sagi, David Adam; Webb, Peter; Sevastjanova, Inga

    2017-04-01

    We present a new regional tectonic interpretation for Myanmar and the Andaman Sea, built within the framework of global plate motions. In our model the Present Day Andaman Sea region has been subjected to multiple phases of extension, culminating in its mid-Miocene to Present Day opening as a rhomboidal pull-apart basin. The Andaman Sea region is historically thought to have developed as a consequence of back-arc opening associated with plate convergence at the Andaman-Nicobar subduction system. We have undertaken detailed structural interpretation of potential field, Landsat and SRTM data, supported by 2-D crustal models of the Andaman Sea. From this analysis we identified several major north-south striking faults and a series of northeast-southwest striking structures across the region. We have also mapped the extent of the Andaman-Nicobar Accretionary Prism, a fore arc trough and volcanic arc, which we associate with a phase of traditional trench-parallel back-arc extension from the Paleocene to the middle Miocene. A regional tectonic event occurred during the middle Miocene that caused the cessation of back-arc extension in the Present Day Andaman Sea and an eastward shift in the locus of arc-related volcanism. At that time, N-S striking faults onshore and offshore Myanmar were reactivated with widespread right-lateral motion. This motion, accompanied by extension along new NE-SW striking faults, facilitated the opening of the Central Andaman Basin as a pull-apart basin (rhombochasm) in which a strike-slip tectonic regime has a greater impact on the mode of opening than the subduction process. The integration of our plate model solution within a global framework allows identification of major plate reorganisation events and their impact on a regional scale. We therefore attribute the onset of pull-apart opening in the Andaman Sea to ongoing clockwise rotation of the western Sundaland margin throughout the late Paleogene and early Miocene, possibly driven by the

  8. Microbial diversity in the deep-sea sediments of Iheya North and Iheya Ridge, Okinawa Trough.

    Science.gov (United States)

    Zhang, Jian; Sun, Qing-lei; Zeng, Zhi-gang; Chen, Shuai; Sun, Li

    2015-08-01

    In this study, we analyzed the bacterial and archaeal diversities of the deep-sea sediments in Iheya North and Iheya Ridge, Okinawa Trough, using the high-throughput sequencing technology of Illumina MiSeq 2500 platform. Four samples (IN1, IN2, IR1 and IR2) were used in this study, of which IN1 and IN2 were located at regions close to and distant, respectively, from the active hydrothermal vents in Iheya North, while IR1 and IR2 were located at regions close to and distant, respectively, from the active hydrothermal vents in Iheya Ridge. The four samples were rich in different metal elements. Sequence analysis based on the V3-V4 regions of 16S rDNA gene obtained 170,363 taxon tags, including 122,920 bacterial tags and 47,433 archaeal tags, which cover 31 phyla, 50 classes, 59 orders, 87 families, and 138 genera. Overall, the microbial communities in all samples were dominated by bacteria, in which Proteobacteria was the largest phylum, followed by Chloroflexi, Firmicutes, Acidobacteria, Actinobacteria, Gemmatimonadetes, and Nitrospirae, which together accounted for 64.6% of the total taxon tags. In contrast to the high bacterial diversities, the archaeal diversity was low and dominated by Thaumarchaeota, which accounted for 22.9% of the total taxon tags. Comparative analysis showed that (i) IN2 and IR2 exhibited more microbial richness than IN1 and IR1, (ii) IR1 and IR2 exhibited higher microbial diversities than IN1 and IN2, (iii) samples from Iheya Ridge and Iheya North fell into two groups based on principle component analysis. Furthermore, microbes potentially involved in sulfur, nitrogen, and metal metabolism and cycling were detected in all samples. These results provide for the first time a comparative picture of the microbial diversities in the sediments of Iheya North and Iheya Ridge and indicate that geological features and distance from active hydrothermal vents likely play important roles in the shaping of microbial community structure. Copyright

  9. Changes in the North Sea fish community: evidence of indirect effects of fishing?

    DEFF Research Database (Denmark)

    Daan, N.; Gislason, Henrik; Pope, J.;

    2005-01-01

    We investigate changes in the North Sea fish community with particular reference to possible indirect effects of fishing, mediated through the ecosystem. In the past, long-term changes in the slope of size spectra of research vessel catches have been related to changes in fishing effort, but such...... were obtained only if time lags greater than or equal to 6 years were introduced. (C) 2004 International Council for the Exploration of the Sea. Published by Elsevier Ltd. All rights reserved....

  10. Hydrocarbon Potential of Pre-cenozoic Strata in the North Yellow Sea Basin

    Institute of Scientific and Technical Information of China (English)

    CAI Feng; DAI Chunshan; CHEN Jianwen; LI Gang; SUN Ping

    2005-01-01

    The North Yellow Sea Basin ( NYSB ), which was developed on the basement of North China (Huabei) continental block, is a typical continental Mesozoic-Cenozoic sedimentary basin in the sea area. Its Mesozoic basin is a residual basin,below which there is probably a larger Paleozoic sedimentary basin. The North Yellow Sea Basin comprises four sags and three uplifts. Of them, the eastern sag is a Mesozoic-Cenozoic sedimentary sag in NYSB and has the biggest sediment thickness; the current Korean drilling wells are concentrated in the eastern sag. This sag is comparatively rich in oil and gas resources and thus has a relatively good petroleum prospect in the sea.The central sag has also accommodated thick Mesozoic-Cenozoic sediments. The latest research results show that there are three series of hydrocarbon source rocks in the North Yellow Sea Basin, namely, black shales of the Paleogene, Jurassic and Cretaceous. The principal hydrocarbon source rocks in NYSB are the Mesozoic black shale. According to the drilling data of Korea, the black shales of the Paleogene,Jurassic and Cretaceous have all come up to the standards of good and mature source rocks. The NYSB owns an intact system of oil generation, reservoir and capping rocks that can help hydrocarbon to form in the basin and thus it has the great potential of oil and gas. The vertical distribution of the hydrocarbon resources is mainly considered to be in the Cretaceous and then in the Jurassic.

  11. Temperature affects the timing of spawning and migration of North Sea mackerel

    Science.gov (United States)

    Jansen, Teunis; Gislason, Henrik

    2011-01-01

    Climate change accentuates the need for knowing how temperature impacts the life history and productivity of economically and ecologically important species of fish. We examine the influence of temperature on the timing of the spawning and migrations of North Sea Mackerel using data from larvae CPR surveys, egg surveys and commercial landings from Danish coastal fisheries in the North Sea, Skagerrak, Kattegat and inner Danish waters. The three independent sources of data all show that there is a significant relationship between the timing of spawning and sea surface temperature. Large mackerel are shown to arrive at the feeding areas before and leave later than small mackerel and the sequential appearance of mackerel in each of the feeding areas studied supports the anecdotal evidence for an eastward post-spawning migration. Occasional commercial catches taken in winter in the Sound N, Kattegat and Skagerrak together with catches in the first quarter IBTS survey furthermore indicate some overwintering here. Significant relationships between temperature and North Sea mackerel spawning and migration have not been documented before. The results have implications for mackerel resource management and monitoring. An increase in temperature is likely to affect the timing and magnitude of the growth, recruitment and migration of North Sea mackerel with subsequent impacts on its sustainable exploitation.

  12. Mapping the spawning grounds of North Sea cod ( Gadus morhua ) by direct and indirect means

    DEFF Research Database (Denmark)

    Fox, C.J.; Taylor, M.; Dickey-Collas, M.

    2008-01-01

    Despite recent evidence for sub-stock structuring, North Sea cod are assessed as a single unit. As a consequence, knowledge of sub-stock trends is poor. In particular, there are no recent evaluations of which spawning grounds are active. Here we report results from the first ichthyoplankton survey...... with known spawning locations from the period 1940 to 1970. We were, however, unable to directly detect significant numbers of cod eggs at the historic spawning ground off Flamborough (northeast coast of England). The results demonstrate that most of the major spawning grounds of cod in the North Sea...

  13. Long-term retrospective analysis of mackerel spawning in the North Sea

    DEFF Research Database (Denmark)

    Jansen, Teunis; Kristensen, Kasper; Payne, Mark

    2012-01-01

    We present a unique view of mackerel (Scomber scombrus) in the North Sea based on a new time series of larvae caught by the Continuous Plankton Recorder (CPR) survey from 1948-2005, covering the period both before and after the collapse of the North Sea stock. Hydrographic backtrack modelling...... suggested that the effect of advection is very limited between spawning and larvae capture in the CPR survey. Using a statistical technique not previously applied to CPR data, we then generated a larval index that accounts for both catchability as well as spatial and temporal autocorrelation. The resulting...

  14. What can we learn from the stock collapse and recovery of North Sea herring? A review

    DEFF Research Database (Denmark)

    Dickey-Collas, M.; Nash, R.D.M.; Brunel, T.

    The collapse and recovery of North Sea herring in the latter half of the twentieth century hasbeen well documented. With hindsight and the benefit of almost 40 years of extra data andstudies, we can now obtain a clear view of the impact of the collapse and the recovery onthe stock, the fishery......, and the North Sea system. The study will review the changes in productivity in terms of growth, maturity, natural mortality and recruitment and the changesin distribution and demography of the stock associated with the collapse and recovery. Itwill also comment on the impact on the genetic makeup of the stock...

  15. Growth, temperature and density relationships of North Sea cod ( Gadus morhua )

    DEFF Research Database (Denmark)

    Rindorf, Anna; Jensen, Henrik; Schrum, Corinna

    2008-01-01

    This study presents an analysis of the relationship between ambient temperature, cod density, fishing mortality, prey fish biomass, and growth of North Sea cod (Gadus morhua) as estimated from survey catches during the period from 1983 to 2006. Growth of young cod was positively related to temper......This study presents an analysis of the relationship between ambient temperature, cod density, fishing mortality, prey fish biomass, and growth of North Sea cod (Gadus morhua) as estimated from survey catches during the period from 1983 to 2006. Growth of young cod was positively related...

  16. Delayed ENSO impact on spring precipitation over North/Atlantic European region

    Energy Technology Data Exchange (ETDEWEB)

    Herceg Bulic, Ivana [Faculty of Science, University of Zagreb, Andrija Mohorovicic Geophysical Institute, Department of Geophysics, Zagreb (Croatia); Kucharski, Fred [Abdus Salam International Centre for Theoretical Physics, Earth System Physics Section, Trieste (Italy)

    2012-06-15

    The delayed impact of winter sea-surface temperature (SST) anomalies in tropical Pacific on spring precipitation over the North Atlantic/European (NAE) region is examined using both measured and modeled data for the period 1901-2002. In an AMIP-type Atmospheric General Circulation Model (AGCM) ensemble, the observed delayed spring precipitation response in Europe to winter ENSO-related SST anomalies is well reproduced. A series of targeted AGCM/coupled GCM experiments are performed to further investigate the mechanisms for this delayed influence. It is found that late winter ENSO SST anomalies lead to the well-documented Rossby wave train arching from the Pacific into the Atlantic region. A positive (negative) ENSO event leads to a quasi-barotropic trough (ridge) in the North Atlantic region. The resulting wind and cloud changes cause anomalies in the surface heat fluxes that result in negative (positive) SST anomalies in the central North Atlantic and anomalies of the opposite sign further to the south. The SST anomalies persist into spring and the atmospheric response to these anomalies is an extension of the ENSO-induced trough (ridge) into the European region, leading to enhanced (reduced) moisture flux and low-level convergence (divergence) and thus positive (negative) precipitation anomalies. Although the signal is overall relatively weak (correlation coefficients of European spring rainfall with winter ENSO SSTs of about 0.3), a proper representation of the outlined mechanism in seasonal forecasting systems may lead to improved seasonal predictions. (orig.)

  17. Holocene trends in the foraminifer record from the Norwegian Sea and the North Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    C. Andersson

    2010-03-01

    Full Text Available The early to mid-Holocene thermal optimum is a well-known feature in a wide variety of paleoclimate archives from the Northern Hemisphere. Reconstructed summer temperature anomalies from across northern Europe show a clear maximum around 6000 years before present (6 ka. For the marine realm, Holocene trends in sea-surface temperature reconstructions for the North Atlantic and Norwegian Sea do not exhibit a consistent pattern of early to mid-Holocene warmth. Sea-surface temperature records based on alkenones and diatoms generally show the existence of a warm early to mid-Holocene optimum. In contrast, several foraminifer and radiolarian based temperature records from the North Atlantic and Norwegian Sea show a cool mid-Holocene anomaly and a trend towards warmer temperatures in the late Holocene. In this paper, we revisit the foraminifer record from the Vøring Plateau in the Norwegian Sea. We also compare this record with published foraminifer based temperature reconstructions from the North Atlantic and with modelled (CCSM3 upper ocean temperatures. Model results indicate that while the seasonal summer warming of the sea-surface was stronger during the mid-Holocene, sub-surface depths experienced a cooling. This hydrographic setting can explain the discrepancies between the Holocene trends exhibited by phytoplankton and zooplankton based temperature proxy records.

  18. Innovative economy in the Baltic Sea region

    Directory of Open Access Journals (Sweden)

    Mezhevich N. M.

    2012-01-01

    Full Text Available Innovative activity is carried out at three levels — those of the state, region and a company or a university. This article considers the level of development of knowledge-based economy in Germany, Denmark, Sweden, Finland, Estonia, Latvia, Lithuania, and Poland at each of the three levels, as well as descripes the spatial differentiation of innovative activity within the Baltic region. The analysis is done on the basis of national and international research, as well as statistical data on the intensity of research and development, structure of research expenditure, human capital in the field of advanced technologies, and the methods of institutional support for innovative activity. The authors characterise the role of business, university, and authorities — which constitute the «triple helix» — in national innovative systems. The article also analyses such important factors as the intensity of research and development, the share of employees in the field of advanced technologies, and the methods of public support. Examples of private-public infrastructure for the implementation of innovative projects are offered.

  19. Innovative economy in the Baltic Sea region

    Directory of Open Access Journals (Sweden)

    Mezhevich Nikolay

    2012-03-01

    Full Text Available Innovative activity is carried out at three levels — those of the state, region and a company or a university. This article considers the level of development of knowledge-based economy in Germany, Denmark, Sweden, Finland, Estonia, Latvia, Lithuania, and Poland at each of the three levels, as well as descripes the spatial differentiation of innovative activity within the Baltic region. The analysis is done on the basis of national and international research, as well as statistical data on the intensity of research and development, structure of research expenditure, human capital in the field of advanced technologies, and the methods of institutional support for innovative activity. The authors characterise the role of business, university, and authorities — which constitute the «triple helix» — in national innovative systems. The article also analyses such important factors as the intensity of research and development, the share of employees in the field of advanced technologies, and the methods of public support. Examples of private-public infrastructure for the implementation of innovative projects are offered.

  20. North Pacific Acoustic Laboratory: Deep Water Acoustic Propagation in the Philippine Sea

    Science.gov (United States)

    2013-09-30

    relatively benign northeast and north central Pacific Ocean. During 2009–2011 the methods developed to study long-range, deep water broadband...These papers include results from the 2004–2005 NPAL experiment in the central North Pacific, in addition to results from the NPAL Philippine Sea...PERFORMANCE BY MAN” Award Universidad Autonoma de Baja California, Facultad de Ciencias Marinas (Ensenada, Mexico) XXI Student Congress (May 14–16, 2013) W. H

  1. Seamount physiography and biology in North-East Atlantic and Mediterranean Sea

    OpenAIRE

    Morato, T.; K. Ø. Kvile; Taranto, G. H.; F. Tempera; Narayanaswamy, B.E.; Hebbeln, D.; Menezes, G.; Wienberg, C.; SANTOS, R. S.; T. J. Pitcher

    2012-01-01

    This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (North-East Atlantic Ocean) and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in-situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (North-East Atlantic) and in Mediterran...

  2. Seamount physiography and biology in the north-east Atlantic and Mediterranean Sea

    OpenAIRE

    Morato, T.; K. Ø. Kvile; Taranto, G. H.; F. Tempera; Narayanaswamy, B.E.; Hebbeln, D.; Menezes, G. M.; Wienberg, C.; SANTOS, R. S.; T. J. Pitcher

    2013-01-01

    This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (north-east Atlantic Ocean) and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (north-east Atlantic)...

  3. Kimmeridgian Shales Total Petroleum System of the North Sea Graben Province

    Science.gov (United States)

    Gautier, Donald L.

    2005-01-01

    place continuously since Mesozoic time. As a result, oil and gas are present in a wide variety of settings within Province 4025. Assessment units for the World Energy Project were defined geographically in order to capture regional differ-ences in exploration history, geography, and geological evolution. Three geographic areas were assessed. The Viking Graben, in the northern part of the province, includes both United Kingdom and Norwegian territorial areas. The Moray Firth/Witch Ground in the west-central part of the province is entirely in United Kingdom. waters. The Central Graben in the southern part of the province includes territorial areas of Denmark, Germany, the Netherlands, Norway, and the United Kingdom. The North Sea Graben is estimated to contain between 4.3 and 25.6 billion barrels (BBO) of undiscovered, conventionally recoverable oil. Of that total, the Viking Graben is believed to contain 2.2 to 14.8 BBO of undiscov-ered oil, the Moray Firth/Witch Ground may contain between 0.3 and 1.9 BBO, and the Central Graben was estimated to contain undiscovered oil resources of 1.7 to 8.8 BBO. Prov-ince 4025 was also estimated to hold between 11.8 and 75 trillion cubic feet (TCF) of undiscovered natural gas. Of this total, 6.8 to 44.5 TCF is thought to exist in the Viking Graben, 0.6 to 3.4 TCF is estimated to be in the Moray Firth/Witch Ground, and 4.5 to 27.1 TCF of undiscovered gas is estimated to be in the Central Graben.

  4. Late Pliocene-Pleistocene environments and glacial history of the northern North Sea

    Science.gov (United States)

    Reinardy, Benedict T. I.; Hjelstuen, Berit O.; Sejrup, Hans Petter; Augedal, Hans; Jørstad, Arild

    2017-02-01

    Based on new geochronological (amino acids and Sr-isotopes) and lithological data combined with analyses of 3D seismic data, the Pliocene-Pleistocene development of the central northern North Sea has been investigated. At the start of the Plio-Pleistocene Transition the study area was dominated by a deltaic, shallow marine or tidal depositional environment with sediments mainly sourced from the west. These sand-rich sediments include green glauconitic grains that belong to the Utsira Sand with a local provenance. Directly above the base Quaternary (R2) a 60 m thick layer of mud-rich sediments of glacimarine origin were deposited at a rate of ∼12 cm/ka between ∼2-1.5 Ma and up to 80 cm/ka between 1.5 and 1.2 Ma possibly reflecting glacial ice advancing to the Norwegian coastline. The high rate of deposition in the Early Pleistocene occurred immediately before the initiation of the Norwegian Channel Ice Stream at ∼1.1 Ma. Following this, a large part of the sediment input from Fennoscandia seems to have been directed away from the study area to the shelf break. At the start of the Mid Pleistocene Transition (MPT), subaerial conditions allowed the formation of a >50 km long fluvial channel across the study area draining water from the east to the south west. The earliest evidence of grounded ice in the investigated area comes from mega scale glacial lineations formed during the MPT, at or just after ∼1.2 Ma. Following this, a regional unconformity (R4) was formed by one or more grounded ice advances across the study area possibly during or directly after the MPT and likely marks the boundary between the Early and Mid Pleistocene glacimarine sediments. The Mid to Late Pleistocene stratigraphy is dominated by glacimarine sediments and tills and is associated with multiple generations of tunnel valleys observed within the seismic data. A high shear strength till containing chalk clasts transported from the west and/or south of the study area was likely deposited

  5. Teleconnected influence of North Atlantic sea surface temperature on the El Nino onset

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xin [Chinese Academy of Sciences, Key Laboratory of Tropical Marine Environmental Dynamics, South China Sea Institute of Oceanology, Guangzhou (China); City University of Hong Kong, Guy Carpenter Asia-Pacific Climate Impact Centre, School of Energy and Environment, Hong Kong (China); Wang, Chunzai [NOAA/Atlantic Oceanographic and Meteorological Laboratory, Miami, FL (United States); Zhou, Wen [City University of Hong Kong, Guy Carpenter Asia-Pacific Climate Impact Centre, School of Energy and Environment, Hong Kong (China); Wang, Dongxiao [Chinese Academy of Sciences, Key Laboratory of Tropical Marine Environmental Dynamics, South China Sea Institute of Oceanology, Guangzhou (China); Song, Jie [Chinese Academy of Sciences, LASG, Institute of Atmospheric Physics, Beijing (China)

    2011-08-15

    Influence of North Atlantic sea surface temperature (SST) anomalies on tropical Pacific SST anomalies is examined. Both summer and winter North Atlantic SST anomalies are negatively related to central-eastern tropical Pacific SST anomalies in the subsequent months varying from 5 to 13 months. In particular, when the North Atlantic is colder than normal in the summer, an El Nino event is likely to be initiated in the subsequent spring in the tropical Pacific. Associated with summer cold North Atlantic SST anomalies is an anomalous cyclonic circulation at low-level over the North Atlantic from subsequent October to April. Corresponded to this local response, an SST-induced heating over the North Atlantic produces a teleconnected pattern, similar to the East Atlantic/West Russia teleconnection. The pattern features two anticyclonic circulations near England and Lake Baikal, and two cyclonic circulations over the North Atlantic and near the Caspian Sea. The anticyclonic circulation near Lake Baikal enhances the continent northerlies, and strengthens the East-Asian winter monsoon. These are also associated with an off-equatorial cyclonic circulation in the western Pacific during the subsequent winter and spring, which produces equatorial westerly wind anomalies in the western Pacific. The equatorial westerly wind anomalies in the winter and spring can help initiate a Pacific El Nino event following a cold North Atlantic in the summer. (orig.)

  6. Combining sea state and land subsidence rates in an assessment of flooding hazards at the Danish North Sea coast

    DEFF Research Database (Denmark)

    Sørensen, Carlo Sass; Broge, Niels; Knudsen, Per

    Sand nourishments (2-3 M3/y) counteract erosion on the central North Sea coast of Denmark and dikes and artificial dunes protect the low-lying hinterland from flooding. The fisheries towns of Thyboron, Thorsminde and Hvide Sande are all liable to flooding during storm surges. Tide gauge series fr...... the coast are presented and the town of Thyboron is used as a case where, in addition to SLR and extremes, analyses of land movement and ocean-groundwater interactions are included in an integrated method for assessing future coastal flooding hazards.......Sand nourishments (2-3 M3/y) counteract erosion on the central North Sea coast of Denmark and dikes and artificial dunes protect the low-lying hinterland from flooding. The fisheries towns of Thyboron, Thorsminde and Hvide Sande are all liable to flooding during storm surges. Tide gauge series from...

  7. Atmospheric forcing of sea ice anomalies in the Ross Sea polynya region

    Science.gov (United States)

    Dale, Ethan R.; McDonald, Adrian J.; Coggins, Jack H. J.; Rack, Wolfgang

    2017-01-01

    We investigate the impacts of strong wind events on the sea ice concentration within the Ross Sea polynya (RSP), which may have consequences on sea ice formation. Bootstrap sea ice concentration (SIC) measurements derived from satellite SSM/I brightness temperatures are correlated with surface winds and temperatures from Ross Ice Shelf automatic weather stations (AWSs) and weather models (ERA-Interim). Daily data in the austral winter period were used to classify characteristic weather regimes based on the percentiles of wind speed. For each regime a composite of a SIC anomaly was formed for the entire Ross Sea region and we found that persistent weak winds near the edge of the Ross Ice Shelf are generally associated with positive SIC anomalies in the Ross Sea polynya and vice versa. By analyzing sea ice motion vectors derived from the SSM/I brightness temperatures we find significant sea ice motion anomalies throughout the Ross Sea during strong wind events, which persist for several days after a strong wind event has ended. Strong, negative correlations are found between SIC and AWS wind speed within the RSP indicating that strong winds cause significant advection of sea ice in the region. We were able to partially recreate these correlations using colocated, modeled ERA-Interim wind speeds. However, large AWS and model differences are observed in the vicinity of Ross Island, where ERA-Interim underestimates wind speeds by a factor of 1.7 resulting in a significant misrepresentation of RSP processes in this area based on model data. Thus, the cross-correlation functions produced by compositing based on ERA-Interim wind speeds differed significantly from those produced with AWS wind speeds. In general the rapid decrease in SIC during a strong wind event is followed by a more gradual recovery in SIC. The SIC recovery continues over a time period greater than the average persistence of strong wind events and sea ice motion anomalies. This suggests that sea ice

  8. AoA Region: Red Sea And Gulf of Aden

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.

    , Sudan and Yemen, but it does not include the regional states of Eritrea and Israel. The legal foundation for PERSGA is the Regional Convention for the Conservation of the Red Sea and Gulf of Aden Environment (Jeddah Convention) of 1982... on the Scientifi c Aspects of Marine Environmental Protection (GESAMP) global analysis of land-based activities (UNEP 2001), is utilized also in an updated form in the SOMER 2006 (PERSGA 2006), described in some detail below. 4.2 Integrated assessments SOMER...

  9. Spatially-Resolved Influence of Temperature and Salinity on Stock and Recruitment Variability of Commercially Important Fishes in the North Sea.

    Science.gov (United States)

    Akimova, Anna; Núñez-Riboni, Ismael; Kempf, Alexander; Taylor, Marc H

    2016-01-01

    Understanding of the processes affecting recruitment of commercially important fish species is one of the major challenges in fisheries science. Towards this aim, we investigated the relation between North Sea hydrography (temperature and salinity) and fish stock variables (recruitment, spawning stock biomass and pre-recruitment survival index) for 9 commercially important fishes using spatially-resolved cross-correlation analysis. We used high-resolution (0.2° × 0.2°) hydrographic data fields matching the maximal temporal extent of the fish population assessments (1948-2013). Our approach allowed for the identification of regions in the North Sea where environmental variables seem to be more influential on the fish stocks, as well as the regions of a lesser or nil influence. Our results confirmed previously demonstrated negative correlations between temperature and recruitment of cod and plaice and identified regions of the strongest correlations (German Bight for plaice and north-western North Sea for cod). We also revealed a positive correlation between herring spawning stock biomass and temperature in the Orkney-Shetland area, as well as a negative correlation between sole pre-recruitment survival index and temperature in the German Bight. A strong positive correlation between sprat stock variables and salinity in the central North Sea was also found. To our knowledge the results concerning correlations between North Sea hydrography and stocks' dynamics of herring, sole and sprat are novel. The new information about spatial distribution of the correlation provides an additional help to identify mechanisms underlying these correlations. As an illustration of the utility of these results for fishery management, an example is provided that incorporates the identified environmental covariates in stock-recruitment models.

  10. Lipid biomarkers : Linking the utilization of frontal plankton biomass to enhanced condition of juvenile North Sea cod

    DEFF Research Database (Denmark)

    St. John, Michael; Lund, T.

    1996-01-01

    - specific fatty acid content to trace the phytoplankton group and mixing regime contributing to the condition of individual juvenile North Sea cod. In order to establish a relationship between lipid tracer content and algal utilization, post yolk- sac larval North Sea cod were reared in the laboratory...

  11. Effort allocation of the Dutch beam trawl fleet in response to a temporarily closed area in the North Sea

    NARCIS (Netherlands)

    Rijnsdorp, A.D.; Piet, G.J.; Poos, J.J.

    2001-01-01

    The spawning stock of North Sea cod is at a historic low level and immediate management measures are needed to improve this situation. As a first step, the European Commission in 2001 closed a large area in the North Sea between February 15 and April 30 to all cod related fishing fleets in order to

  12. Historic and Contemporary Status of Sea Otters in the North Pacific

    Science.gov (United States)

    Bodkin, James L.; Larson, Shawn E.; Bodkin, James L; Vanblaricom, Glenn R.

    2015-01-01

    Similar to other species that in recent centuries experienced unregulated human exploitation, sea otters were extirpated throughout large portions of their historic range in the North Pacific. For most of the twentieth century, with cessation of the fur trade and because of concerted efforts at conservation, sea otters recovered much of their historic range and abundance. Late in the twentieth century, increased predation by killer whales in southwest Alaska drove sea otter populations to a few percentage points of their prior abundance, and one of the nation’s largest oil spills in south-central Alaska caused the death of several thousand animals and required more than two decades for recovery. In California, entanglement in fishing gear and environmental degradation, among other factors, have contributed to slow growth in sea otter abundance. We discuss the role of density dependence and spatial structuring of populations in reduced rates of sea otter recovery recently detected in the Northeast Pacific, and consider the potential effects of multiple low-level and cumulative threats on sea otter populations. The resilience demonstrated by sea otters over the past century will be tested in upcoming decades as human activities continue to degrade nearshore coastal areas of the North Pacific.

  13. Variability and connectivity of plaice populations from the Eastern North Sea to the Baltic Sea, part II. Biological evidence of population mixing

    DEFF Research Database (Denmark)

    Ulrich, Clara; Hansen, Jakob Hemmer; Boje, Jesper

    2016-01-01

    A multi-disciplinary study was conducted to clarify stock identity and connectivity patterns in the populations of European plaice (Pleuronectes platessa) in the Skagerrak-Kattegat transition area between the Eastern North Sea and the Baltic Sea. Five independent biological studies were carried out...... in parallel. Genetic markers suggested the existence of different genetic populations in the transition area. Growth backcalculation with otoliths resulted in significant although limited differences in growth rates between North Sea and Skagerrak, indicating weak differentiation or important mixing....... Hydrogeographical drift modelling suggested that some North Sea juveniles could settle along the coast line of the Skagerrak and the Kattegat. Tagging data suggested that both juveniles and adult fish from the North Sea perform feeding migrations into Skagerrak in summer/autumn. Finally, survey data suggested...

  14. REGIONAL BLACK SEA ARCHITECTURE AND CONSEQUENCES FOR THE REGIONAL COOPERATION FRAMEWORK

    Directory of Open Access Journals (Sweden)

    Alina Homorozean

    2010-12-01

    Full Text Available Sometimes considered an asset, other times a liability, the Black Sea started recently to be regarded as a region. However, the Black Sea Region lacks a common vision, often due to the complicated and often inefficient nexus of regional cooperation initiatives. Following the logic of finding regional solutions for regional problems, this paper aims to assess existing institutional and regional initiatives, reflecting on the implications for the success of Black Sea regionalism in creating patterns of sustained and sustainable development and a high degree of actors' involvement.This paper concentrates on two complementary research questions: What is the regional order in the BSR and what does it imply for its future? What is the current contribution of the most significant cooperation initiatives and what are the consequences for regional institutionalism? For the purpose of this paper, I draw on best-practices from other two regions: the Northern Dimension and South- East Asia. Through a comparative perspective, I suggest an analysis of the most important initiatives: BSEC, CDC, Black Sea Synergy, Eastern Partnership, Baku Initiative and the BSF. This paper argues that a possible strategic solution for successful policy development lies in the creation of an integrated regional cooperation package, functioning on the principles of multi-speed and multi-dimensional cooperation in several policy fields, in a context in which the BSR seems to be caught between two paradigms: a European and a Russian-oriented one.

  15. A regional model for sustainable biogas production. Case study: North Savo, Finland

    Energy Technology Data Exchange (ETDEWEB)

    Huopana, T.; Niska, H.; Jaeskelaeinen, A.; Loonik, J.; Den Boer, E.; Song, H.; Thorin, E.

    2012-11-15

    This report is one of the outputs from the REMOWE (Regional Mobilizing of Sustainable Waste-to-Energy Production) project. REMOWE is one of the projects within the Baltic Sea Region Programme. The overall objective of the REMOWE project is, on regional levels, to contribute to a decreased negative effect on the environment by reduction of carbon dioxide emission by creating a balance between energy consumption and sustainable use of renewable energy sources. Reduction of carbon dioxide emissions and use of renewable energy sources are broad areas and this project will focus on energy resources from waste and actions to facilitate implementation of energy efficient technology in the Baltic Sea region within the waste-to-energy area. The focus is to utilize waste from cities, farming and industry for energy purposes in an efficient way. The problem addressed by the project concerns how to facilitate the implementation of sustainable systems for waste-to-energy in the Baltic Sea region and specifically, in a first step, in the project partner regions. The project partnership consists of the Maelardalen University, with the School of Sustainable Development of Society and Technology coordinating the project, and The County Administrative Board of Vaestmanland in Sweden, Savonia University of Applied Sciences, Centre for Economic Development, Transport and the Environment for North Savo, and University of Eastern Finland (UEF) in Finland, Marshal Office of Lower Silesia in Poland, Ostfalia University of Applied Sciences, Ostfalia University of Applied Sciences in Wolfenbuettel in Germany, Klaipeda University in Lithuania, and Estonian Regional and Local Development Agency (ERKAS) in Estonia. This report is based on the modelling work performed in the work package 5 ('Model of sustainable regional waste-to-energy production') of the REMOWE project. The key objective has been on developing a regional model based on available geographic information for

  16. Storm impacts and shoreline recovery: Mechanisms and controls in the southern North Sea

    Science.gov (United States)

    Brooks, S. M.; Spencer, T.; Christie, E. K.

    2017-04-01

    Storm impacts play a significant role in shoreline dynamics on barrier coastlines. Furthermore, inter-storm recovery is a key parameter determining long-term coastal resilience to climate change, storminess variability and sea level rise. Over the last decade, four extreme storms, with strong energetic waves and high still water levels resulting from high spring tides and large skew surge residuals, have impacted the shoreline of the southern North Sea. The 5th December 2013 storm, with the highest run-up levels recorded in the last 60 years, resulted in large sections of the frontline of the North Norfolk coast being translated inland by over 10 m. Storms in March and November 2007 also generated barrier scarping and shoreline retreat, although not on the scale of 2013. Between 2008 and 2013, a calm period, recovery dominated barrier position and elevation but was spatially differentiated alongshore. For one study area, Scolt Head Island, no recovery was seen; this section of the coast is being reset episodically landwards during storms. By contrast, the study area at Holkham Bay showed considerable recovery between 2008 and 2013, with barrier sections developing seaward through foredune recovery. The third study area, Brancaster Bay, showed partial recovery in barrier location and elevation. Results suggest that recovery is promoted by high sediment supply and onshore intertidal bar migration, at rates of 40 m a- 1. These processes bring sand to elevations where substrate drying enables aeolian processes to entrain and transport sand from upper foreshores to foredunes. We identify three potential sediment transport pathways that create a region of positive diffusivity at Holkham Bay. During calm periods, a general westward movement of sediment from the drift divide at Sheringham sources the intertidal bar and foredune development at Holkham Bay. However, during and following storms the drift switches to eastward, not only on the beach itself but also below the

  17. Sensitivity of Greenland Ice Sheet surface mass balance to perturbations in sea surface temperature and sea ice cover: a study with the regional climate model MAR

    Science.gov (United States)

    Noël, B.; Fettweis, X.; van de Berg, W. J.; van den Broeke, M. R.; Erpicum, M.

    2014-10-01

    During recent summers (2007-2012), several surface melt records were broken over the Greenland Ice Sheet (GrIS). The extreme summer melt resulted in part from a persistent negative phase of the North Atlantic Oscillation (NAO), favoring warmer atmospheric conditions than normal over the GrIS. Simultaneously, large anomalies in sea ice cover (SIC) and sea surface temperature (SST) were observed in the North Atlantic, suggesting a possible connection. To assess the direct impact of 2007-2012 SIC and SST anomalies on GrIS surface mass balance (SMB), a set of sensitivity experiments was carried out with the regional climate model MAR forced by ERA-Interim. These simulations suggest that perturbations in SST and SIC in the seas surrounding Greenland do not considerably impact GrIS SMB, as a result of the katabatic wind blocking effect. These offshore-directed winds prevent oceanic near-surface air, influenced by SIC and SST anomalies, from penetrating far inland. Therefore, the ice sheet SMB response is restricted to coastal regions, where katabatic winds cease. A topic for further investigation is how anomalies in SIC and SST might have indirectly affected the surface melt by changing the general circulation in the North Atlantic region, hence favoring more frequent warm air advection towards the GrIS.

  18. Regional variability in sea ice melt in a changing Arctic

    OpenAIRE

    Perovich, Donald K.; Richter-Menge, Jacqueline A.

    2015-01-01

    In recent years, the Arctic sea ice cover has undergone a precipitous decline in summer extent. The sea ice mass balance integrates heat and provides insight on atmospheric and oceanic forcing. The amount of surface melt and bottom melt that occurs during the summer melt season was measured at 41 sites over the time period 1957 to 2014. There are large regional and temporal variations in both surface and bottom melting. Combined surface and bottom melt ranged from 16 to 294 cm, with a mean of...

  19. Spatial variability in structural and functional aspects of macrofauna communities and their environmental parameters in the Jade Bay (Wadden Sea Lower Saxony, southern North Sea)

    Science.gov (United States)

    Schückel, Ulrike; Beck, Melanie; Kröncke, Ingrid

    2013-03-01

    Spatial distribution and functional structure of intertidal benthic macrofauna in relation to environmental variables in the Jade Bay (southern North Sea) were studied and compared with other intertidal areas of the Wadden Sea. A total of 128 stations covering the whole Jade Bay were sampled in summer 2009. A total of 114 taxa were found. Highest species numbers occurred in the subtidal areas, whereas highest mean abundances were found in the upper intertidal areas. Based on species abundance data, six significantly distinct macrofauna communities in the Jade Bay were identified and evaluated with multivariate statistics, univariate correlations and canonical correspondence analysis. Differences in these community patterns were caused by the response of the dominant species ( Hydrobia ulvae, Tubificoides benedii, Pygospio elegans, Caulleriella killariensis, Scoloplos armiger, Urothoe poseidonis, Microprotopus maculatus) to prevailing environmental conditions along the gradient from the lower and exposed sandy intertidal areas via intermediate mixed sediments to the upper mudflat areas. Distribution patterns in relation to tidal zonation were best explained by variability in submergence time, Chlorophyll a (chl a) content and sediment composition (mud content), which are proxies for hydrodynamic conditions and food availability. Species inventory and species richness were comparable with other intertidal areas of the Wadden Sea, but the Jade Bay differs from these areas regarding dominant species. Differences in sediment composition and morphological characteristics (macrotidal versus mesotidal Wadden Sea areas) are discussed for comparison of regional differences.

  20. Regional turbulence patterns driven by meso- and submesoscale processes in the Caribbean Sea

    Science.gov (United States)

    Pérez, Juan G. C.; Calil, Paulo H. R.

    2017-09-01

    The surface ocean circulation in the Caribbean Sea is characterized by the interaction between anticyclonic eddies and the Caribbean Upwelling System (CUS). These interactions lead to instabilities that modulate the transfer of kinetic energy up- or down-cascade. The interaction of North Brazil Current rings with the islands leads to the formation of submesoscale vorticity filaments leeward of the Lesser Antilles, thus transferring kinetic energy from large to small scales. Within the Caribbean, the upper ocean dynamic ranges from large-scale currents to coastal upwelling filaments and allow the vertical exchange of physical properties and supply KE to larger scales. In this study, we use a regional model with different spatial resolutions (6, 3, and 1 km), focusing on the Guajira Peninsula and the Lesser Antilles in the Caribbean Sea, in order to evaluate the impact of submesoscale processes on the regional KE energy cascade. Ageostrophic velocities emerge as the Rossby number becomes O(1). As model resolution is increased submesoscale motions are more energetic, as seen by the flatter KE spectra when compared to the lower resolution run. KE injection at the large scales is greater in the Guajira region than in the others regions, being more effectively transferred to smaller scales, thus showing that submesoscale dynamics is key in modulating eddy kinetic energy and the energy cascade within the Caribbean Sea.

  1. CRUDE OIL TRANSPORT FROM THE CASPIAN SEA REGION TO EUROPE

    Directory of Open Access Journals (Sweden)

    Adam Przybyłowski

    2014-07-01

    Full Text Available In the contemporary world, despite the growing importance and scale of the use of renewable energy , conventional energy resources still play a huge role. The European Union countries are dependent on the oil imports and the their main supplier of crude oil and natural gas has been the Russian Federation. After the collapse of the Soviet Union , the Caspian Sea region has become an alternative to Russian energy resources. The Unit-ed States , European Union, China and many other countries have shown their interest about this region. Despite a relatively large oil and natural gas reserves, the export of the-se commodities to the West is still problematic. Based on the available data and infor-mation, the publication explores the issue of energy resources transport directions with a particular emphasis on the crude oil from the Caspian Sea region to Europe.

  2. Comparative analysis of time series of marine litter surveyed on beaches and the seafloor in the southeastern North Sea.

    Science.gov (United States)

    Schulz, Marcus; Krone, Roland; Dederer, Gabriele; Wätjen, Kai; Matthies, Michael

    2015-05-01

    The comparative analysis of marine litter in different marine compartments has rarely been attempted. In this study, long-term time series of marine litter abundance on the seafloor and on the coast, both from the southeastern North Sea, were analyzed for temporal trends and correlations. On four beach sections of 100 m length, mean abundances of total beach litter collected four times a year from 2002 to 2008 varied between 105 and 435 items. Mean densities of total inorganic litter on the seafloor amounted to 10.6 ± 9.7 kg km(-2) in the offshore region (2001-2010) and 13.7 ± 12.6 kg km(-2) in the Wadden Sea (1998-2007), respectively. In the offshore region, there was no significant long-term trend, while in the Wadden Sea, densities of marine litter declined significantly. Correlations between time series were weak, indicating different sources and transport processes responsible for compositions of beach litter and litter on the seafloor. Decreases in inputs from fisheries and substantial export due to resuspension are discussed as reasons for the decrease in litter on the seafloor in the Wadden Sea. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Petroleum Migration, Filling and Biological Degradation in Mesozoic Reservoirs in the Northern North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Horstad, I.

    1995-12-31

    This thesis comprises five papers the first of which discusses the distribution of petroleum within the Gullfaks Field and applies conventional geochemical techniques to characterize the petroleum distribution within a single field. The paper also shows how understanding geochemical heterogeneities in the petroleum fluids helped to build a better geological model of the development of the Gullfaks Field. Based on this work an improved filling model was proposed for the Gullfaks Field. The second paper discusses the biological degradation of the hydrocarbons within the Gullfaks Field, and shows how several samples from neighbouring fields were analyzed to confirm the filling model of the field. It also demonstrates how the quantification of biological degradation of hydrocarbons in the reservoir places constraints on acceptable models of the geological development of the Tampen Spur Area. The third paper discusses the source vs. sink problems of petroleum migration in the North Sea. The fourth paper is a regional study of the petroleum migration within the Tampen Spur area and proposes a regional migration model. The fifth paper is a detailed reservoir geochemical study of the giant Troll Field on the Horda Platform and proposes a revised filling model for the field. 224 refs., 86 figs., 5 tabs.

  4. Performance of precautionary reference points in providing management advice on North Sea fish stocks

    NARCIS (Netherlands)

    Piet, G.J.; Rice, J.C.

    2004-01-01

    For 17 stocks in the North Sea. the performance and effectiveness of management advice using precautionary reference points was evaluated. Three criteria were used to identify whether a stock was within safe biological limits: SSB F-pa, or SSB F-pa. Four scenario

  5. Dissolved organic nitrogen dynamics in the North Sea: A time series analysis (1995-2005)

    NARCIS (Netherlands)

    van Engeland, T.; Soetaert, K.; Knuijt, K.; Laane, R.W.P.M.; Middelburg, J.J.

    2010-01-01

    Dissolved organic nitrogen (DON) dynamics in the North Sea was explored by means of long-term time series of nitrogen parameters from the Dutch national monitoring program. Generally, the data quality was good with little missing data points. Different imputation methods were used to verify the robu

  6. Feasibility of Flat Oyster (Ostrea edulis L.) restoration in the Dutch part of the North Sea

    NARCIS (Netherlands)

    Smaal, A.C.; Kamermans, P.; Have, van der T.M.; Engelsma, M.Y.; Sas, H.

    2015-01-01

    For the recovery of flat oyster beds, knowledge is required of the conditions under which the active restoration of this species in the North Sea can be successfully implemented. This is the subject of the current feasibility study. Living flat oysters have occasionally been found in wind farms. Fla

  7. Description of the North Sea wind climate for wind energy applications

    NARCIS (Netherlands)

    Coelingh, J.P.; Wijk, A.J.M. van; Cleijne, J.W.; Pleune, R.

    1992-01-01

    In The Netherlands it is foreseen that wind turbines will be installed on offshore locations in the North Sea before the year 2010. Therefore adequate knowledge of the offshore wind climate should be obtained, both for the estimation of energy yields and for the determination of wind load

  8. Trophic impact of Atlantic bluefin tuna migrations in the North Sea

    DEFF Research Database (Denmark)

    Mariani, Patrizio; Andersen, Ken Haste; Lindegren, Martin

    2017-01-01

    spectrum model to analyse the trophic impact of the returning tuna on the entire fish community, under scenarios with varying levels of tuna consumption and fishing mortality on the prey. We show that with high level of prey fishing mortality in the North Sea, the effect of a tuna re-colonization results...

  9. A reanalysis of North Sea plaice spawning-stock biomass using the annual egg production method

    NARCIS (Netherlands)

    Damme, van C.J.G.; Bolle, L.J.; Fossum, P.; Kraus, G.; Dickey-Collas, M.

    2009-01-01

    Uncertainty about the quality of current virtual population analysis-based stock assessment for North Sea plaice (Pleuronectes platessa) has led to various abundance indices. We compared biomass estimates from the annual egg production (AEP) method with current stock assessments based on catch-at-ag

  10. A collaborative approach to mapping value of fisheries resources in the North Sea (Part 1: Methodology)

    NARCIS (Netherlands)

    Hintzen, N.T.; Coers, A.; Hamon, K.

    2013-01-01

    IMARES and LEI are both contracted on occasion to perform VMS-analyses to produce maps of fishing activity or economic value of fisheries in particular area(s) in the North Sea. Until present, IMARES and LEI use their own methodology which is inspired mostly on their own unique data availabilities w

  11. Tracking seasonal changes in North Sea zooplankton trophic dynamics using stable isotopes

    NARCIS (Netherlands)

    Kürten, B.; Painting, S.J.; Struck, U.; Polunin, N.V.C.; Middelburg, J.J.

    2013-01-01

    Trophodynamics of meso-zooplankton in the North Sea (NS) were assessed at a site in the southern NS, and at a shallow and a deep site in the central NS. Offshore and neritic species from different ecological niches, including Calanus spp., Temora spp. and Sagitta spp., were collected during seven cr

  12. Tracing estuarine organic matter sources into the southern North Sea using C and N isotopic signatures

    DEFF Research Database (Denmark)

    Bristow, Laura A.; Jickells, Timothy D.; Weston, Keith;

    2013-01-01

    Sources and distribution of particulate organic matter in surface waters of the Humber and Thames estuaries and in the East Anglian plume in the southern North Sea were investigated in winter 2006/2007. Carbon (C) and nitrogen (N) stable isotopes provided evidence for the presence of three partic...

  13. Mapping the spawning grounds of North Sea cod (Gadus morhua) by direct and indirect means

    NARCIS (Netherlands)

    Fox, C.J.; Taylor, M.; Dickey-Collas, M.; Fossum, P.; Kraus, G.; Rohlf, N.; Damme, van C.J.G.; Bolle, L.J.

    2008-01-01

    Despite recent evidence for sub-stock structuring, North Sea cod are assessed as a single unit. As a consequence, knowledge of sub-stock trends is poor. In particular, there are no recent evaluations of which spawning grounds are active. Here we report results from the first ichthyoplankton survey t

  14. Linkage between fishes'foraging, market and fish stocks density: Examples from some North Sea fisheries

    NARCIS (Netherlands)

    Marchal, P.; Poos, J.J.; Quirijns, F.J.

    2007-01-01

    This study has investigated some properties of fishermen's foraging, using Levy flights theory. The case studies examined were a selection of North Sea Dutch and French vessels, for which catch and effort data were collected on a haul-by-haul basis. Foraging behavior could reasonably be represented

  15. PHYTOPLANKTON OF THE NORTH-SEA AND ITS DYNAMICS - A REVIEW

    NARCIS (Netherlands)

    REID, PC; LANCELOT, C; GIESKES, WWC; HAGMEIER, E; WEICHART, G

    1990-01-01

    Phytoplankton is the major contributor to algal biomass and primary production of the North Sea, although crops of macroalgae can locally be up to 2000 g C.m-2 along the coast of the U.K. and Norway, and microphytobenthos dominates production in the shallow tidal flat areas bordering the coasts of E

  16. Aerosol properties over the Arabian Sea during the north east monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Suresh, T.; Dulac, F.; Leon, G.F.; Desa, E.

    440, 670, 870, 936, 940 and 1020 nm, in the Arabian Sea between 15.4-17.86 degrees N and 73.28-69.3 degrees E, during the North East monsoon period of 1-10 December, 1988. The aerosol optical properties derived from these data showed variations from...

  17. Description of the North Sea wind climate for wind energy applications

    NARCIS (Netherlands)

    Coelingh, J.P.; Wijk, A.J.M. van; Cleijne, J.W.; Pleune, R.

    1992-01-01

    In The Netherlands it is foreseen that wind turbines will be installed on offshore locations in the North Sea before the year 2010. Therefore adequate knowledge of the offshore wind climate should be obtained, both for the estimation of energy yields and for the determination of wind load parameters

  18. Monitoring plastic ingestion by the northern fulmar Fulmarus glacialis in the North Sea

    NARCIS (Netherlands)

    Franeker, van J.A.; Blaize, C.; Danielsen, J.

    2011-01-01

    The abundance of plastics in stomachs of northern fulmars from the North Sea is used in the OSPAR Ecological Quality Objective (EcoQO) for marine litter. The preliminary EcoQO defines acceptable ecological quality as the situation where no more than 10% of fulmars exceed a critical level of 0.1 g of

  19. Occurrence and activity of anammox bacteria in surface sediments of the southern North Sea

    NARCIS (Netherlands)

    Bale, N.J.; Villanueva, L.; Fan, H.; Stal, L.J.; Hopmans, E.C.; Schouten, S.; Sinninghe Damsté, J.S.

    2014-01-01

    We investigated the occurrence and activity of anaerobic ammonia oxidation (anammox) bacteria in sandy and muddy sand sediments of the southern North Sea. The presence of anammox bacteria was established through the detection of specific phosphocholine-monoether ladderane lipids, 16S rRNA gene, and

  20. Stable isotope evidence of long-term changes in North Sea food web structure

    DEFF Research Database (Denmark)

    Richardson, Katherine; Christensen, Jens Tang

    2008-01-01

    a relatively short period in the middle of the 20th century. Harbour porpoises are generalist feeders and their diet largely reflects the food available to them. Thus, one plausible explanation for the observed change in d15N could be that harbour porpoises in the North Sea have, since the mid-20th century...

  1. A reanalysis of North Sea plaice spawning-stock biomass using the annual egg production method

    NARCIS (Netherlands)

    Damme, van C.J.G.; Bolle, L.J.; Fossum, P.; Kraus, G.; Dickey-Collas, M.

    2009-01-01

    Uncertainty about the quality of current virtual population analysis-based stock assessment for North Sea plaice (Pleuronectes platessa) has led to various abundance indices. We compared biomass estimates from the annual egg production (AEP) method with current stock assessments based on

  2. Gas deliveries from Haltenbanken/North Sea; Gassleveranser Haltenbanken/Nordsjoeen

    Energy Technology Data Exchange (ETDEWEB)

    Ramm, H.H.

    1995-12-31

    The conference paper relates to the development and delivery of natural gas from the Haltenbanken area and the North Sea on the Norwegian continental shelf. Alternatives of field developments and pipelines together with the allocation of contracts for securing the contractual delivery of natural gas to the European continent in future and an alternative delivery to the Scandinavian countries, are discussed. 2 figs.

  3. PHYTOPLANKTON OF THE NORTH-SEA AND ITS DYNAMICS - A REVIEW

    NARCIS (Netherlands)

    REID, PC; LANCELOT, C; GIESKES, WWC; HAGMEIER, E; WEICHART, G

    1990-01-01

    Phytoplankton is the major contributor to algal biomass and primary production of the North Sea, although crops of macroalgae can locally be up to 2000 g C.m-2 along the coast of the U.K. and Norway, and microphytobenthos dominates production in the shallow tidal flat areas bordering the coasts of

  4. Modelling survival and connectivity of Mnemiopsis leidyi in the southern North Sea and Scheldt estuaries

    Directory of Open Access Journals (Sweden)

    J. van der Molen

    2014-06-01

    Full Text Available Three different models were applied to study the reproduction, survival and dispersal of Mnemiopsis leidyi in the Scheldt estuaries and the southern North Sea: a high-resolution particle tracking model with passive particles, a low resolution particle tracking model with a reproduction model coupled to a biogeochemical model, and a dynamic energy budget (DEB model. The results of the models, each with its strengths and weaknesses, suggest the following conceptual situation: (i the estuaries possess enough retention capability to keep an overwintering population, and enough exchange with coastal waters of the North Sea to seed offshore populations; (ii M. leidyi can survive in the North Sea, and be transported over considerable distances, thus facilitating connectivity between coastal embayments; (iii under current climatic conditions, M. leidyi may not be able to reproduce in large numbers in coastal and offshore waters of the North Sea, but this may change with global warming – however this result is subject to substantial uncertainty. Further quantitative observational work is needed on the effects of temperature, salinity and food availability on reproduction and on mortality at different life stages to improve models such as used here.

  5. A collaborative approach to mapping value of fisheries resources in the North Sea (Part 1: Methodology)

    NARCIS (Netherlands)

    Hintzen, N.T.; Coers, A.; Hamon, K.

    2013-01-01

    IMARES and LEI are both contracted on occasion to perform VMS-analyses to produce maps of fishing activity or economic value of fisheries in particular area(s) in the North Sea. Until present, IMARES and LEI use their own methodology which is inspired mostly on their own unique data availabilities w

  6. Diagenetic alteration process of chlorite in Tyr Member sandstone, Siri Canyon, Danish North Sea

    DEFF Research Database (Denmark)

    Kazerouni, Afsoon Moatari; Friis, Henrik; Hansen, Jens Peter Vind

    To evaluate the possible changes in petrology within the reservoir sand and across the oil water contact in Rau-1A, Siri Canyon Danish North Sea, 18 samples were selected and studied mainly by electron microscope and XRD. The major diagenetic phases in the well are micro quartz, large syntaxial...

  7. Comparing uncertain alternatives for a possible airport island location in the North Sea

    NARCIS (Netherlands)

    Kleij, van der Caroline S.; Hulscher, Suzanne J.M.H.; Louters, Teunis

    2003-01-01

    This paper presents a methodology for making decisions based on previous termuncertainnext term information through the use of an analytical feasibility study of an airport island in the North Sea as an previous termalternativenext term to the present inland airport, Amsterdam Schiphol, in The Nethe

  8. Diazotrophic microbial community of coastal microbial mats of the southern North Sea.

    NARCIS (Netherlands)

    Bauersachs, T.; Compaoré, J.; Severin, I.; Hopmans, E.C.; Schouten, S.; Stal, L.J.; Sinninghe Damsté, J.S.

    2011-01-01

    The diazotrophic community in microbial mats growing along the shore of the North Sea barrier island Schiermonnikoog (The Netherlands) was studied using microscopy, lipid biomarkers, stable carbon (δ13CTOC) and nitrogen (δ15N) isotopes as well as by constructing and analyzing 16S rRNA gene

  9. Diazotrophic microbial community of coastal microbial mats of the southern North Sea

    NARCIS (Netherlands)

    Bauersachs, T.; Compaoré, J.; Severin, I.; Hopmans, E.C.; Schouten, S.; Stal, L.J.; Sinninghe Damsté, J.S.

    2011-01-01

    The diazotrophic community in microbial mats growing along the shore of the North Sea barrier island Schiermonnikoog (The Netherlands) was studied using microscopy, lipid biomarkers, stable carbon (delta(13)C(TOC)) and nitrogen (delta(15)N) isotopes as well as by constructing and analyzing 16S rRNA

  10. Diazotrophic microbial community of coastal microbial mats of the southern North Sea

    NARCIS (Netherlands)

    Bauersachs, T.; Compaore, J.; Severin, I.; Hopmans, E.C.; Schouten, S.; Stal, L.J.; Sinninghe Damsté, J.S.

    2011-01-01

    The diazotrophic community in microbial mats growing along the shore of the North Sea barrier island Schiermonnikoog (The Netherlands) was studied using microscopy, lipid biomarkers, stable carbon (δ13CTOC) and nitrogen (δ15N) isotopes as well as by constructing and analyzing 16S rRNA gene

  11. Source receptor relations for the calculation of atmospheric deposition to the North Sea: Nitrogen and Cadmium

    NARCIS (Netherlands)

    van Jaarsveld JA; de Leeuw FAAM

    1993-01-01

    In this report a simplified atmospheric transport model for estimating the deposition of nitrogen (both NOx and NHx) and cadmium to the North Sea is presented. In this so-called meta-model a linear relationship between the emissions from a source area and the resulting deposition at receptor points

  12. A lasting legacy for the Baltic and North Sea GLOBEC Germany program

    DEFF Research Database (Denmark)

    Peck, M.A.; Dutz, Jörg; Voss, R.

    2012-01-01

    This preface introduces four manuscripts that form a special theme section of the GLOBEC Germany program within Progress in Oceanography. The four manuscripts link changes in physical forcing to the trophodynamic structure and function of the Baltic and North Seas. The target species of GLOBEC...... Germany included various species of calanoid copepods and a small pelagic fish (Sprattus sprattus)...

  13. The south-eastern North Sea : losses of vertebrate fauna during the past 2000 years

    NARCIS (Netherlands)

    Wolff, WJ

    2000-01-01

    At least 31 species of marine mammals, marine and coastal birds, and marine and anadromous fish have disappeared temporarily or permanently from the coasts of The Netherlands and in most cases also from the south-eastern North Sea (south of 54 degrees N) during the past 2000 years-In 18-22 cases, th

  14. Fulmar Litter EcoQO monitoring along Durch and North Sea coasts

    NARCIS (Netherlands)

    Franeker, van J.A.

    2011-01-01

    Wastes from ships are an important source of litter in the marine environment in the Southern North Sea and cause serious economic and ecological damage. Inadequacies in the ship to shore waste delivery procedures are considered a major factor in illegal discharges. The European Union addressed the

  15. The environmental impact and recovery at two dumping sites for dredged material in the North Sea

    NARCIS (Netherlands)

    Stronkhorst, J.; Ariese, F.; Hattum, van B.; Postma, J.F.; Kluijver, de M.; Besten, den P.; Bergman, M.J.N.; Daan, R.; Murk, A.J.; Vethaak, A.D.

    2003-01-01

    The environmental impact and recovery associated with the long and uninterrupted disposal of large volumes of moderately contaminated dredged material from the port of Rotterdam was studied at nearby dumping sites in the North Sea. Observations were made on sediment contamination, ecotoxicity, bioma

  16. Scenarios of temporal and spatial evolution of hexabromocyclododecane in the North Sea.

    Science.gov (United States)

    Ilyina, Tatiana; Hunziker, René W

    2010-06-15

    Spatial and temporal distribution of the flame retardant hexabromocyclododecane (HBCD) in the North Sea was examined for the period from 1995 to 2005 using a pollutant transport model FANTOM. Model calculations allow conclusions on relevant sinks and fluxes in and out of the North Sea and on the time needed to establish a steady state. Calculations were performed for two additional scenarios with different rates of primary degradation ranging from fast degrading to absolute persistency. Concentrations calculated in the scenarios with degradation are in line with the monitoring data available for HBCD. Concentrations calculated in the "persistent" scenario disagree with measured data. According to our model calculations, steady state is established within months for the water and the top layer sediment with no evidence for a temporal trend, except for the "persistent" scenario, in which concentrations increase continuously in the southeastern part of the North Sea, where hydrographic and circulation characteristics produce areas of converging currents. Our model study enables a better understanding of the fate of HBCD in the North Sea, its potential for transport and overall elimination. We discuss these findings in the light of different concerns for PBT substances.

  17. Microzooplankton grazing in Phaeocystis and diatom-dominated waters in the southern North Sea in spring

    NARCIS (Netherlands)

    Stelfox-Widdicombe, CE; Archer, SD; Burkill, PH; Stefels, J

    2004-01-01

    The impact of microzooplankton grazing upon phytoplankton production was quantified in surface waters of the Southern Bight of the North Sea, during April 1998. Two sites were studied in order to examine the impact of microzooplankton grazing on phytoplankton communities dominated by either Phaeocys

  18. Modelling survival and connectivity of Mnemiopsis leidyi in the southern North Sea and Scheldt estuaries

    Science.gov (United States)

    van der Molen, J.; van Beek, J.; Augustine, S.; Vansteenbrugge, L.; van Walraven, L.; Langenberg, V.; van der Veer, H. W.; Hostens, K.; Pitois, S.; Robbens, J.

    2014-06-01

    Three different models were applied to study the reproduction, survival and dispersal of Mnemiopsis leidyi in the Scheldt estuaries and the southern North Sea: a high-resolution particle tracking model with passive particles, a low resolution particle tracking model with a reproduction model coupled to a biogeochemical model, and a dynamic energy budget (DEB) model. The results of the models, each with its strengths and weaknesses, suggest the following conceptual situation: (i) the estuaries possess enough retention capability to keep an overwintering population, and enough exchange with coastal waters of the North Sea to seed offshore populations; (ii) M. leidyi can survive in the North Sea, and be transported over considerable distances, thus facilitating connectivity between coastal embayments; (iii) under current climatic conditions, M. leidyi may not be able to reproduce in large numbers in coastal and offshore waters of the North Sea, but this may change with global warming - however this result is subject to substantial uncertainty. Further quantitative observational work is needed on the effects of temperature, salinity and food availability on reproduction and on mortality at different life stages to improve models such as used here.

  19. EPXMA survey of shelf sediments (Southern Bight, North Sea): A glance beyond the XRD-invisible

    NARCIS (Netherlands)

    De Maeyer-Worobiec, A.; Dekov, V.M.; Laane, R.W.P.M.; van Grieken, R.

    2009-01-01

    Shelf sediments of the southern North Sea, were studied with a microanalytical [electron probe X-ray microanalysis (EPXMA)] and two bulk [X-ray diffraction (XRD) and X-ray fluorescence (XRF)] techniques. The investigation proved that the promptness of the microanalytical method is combined with a re

  20. Radium isotopes as a tracer of sediment-water column exchange in the North Sea

    NARCIS (Netherlands)

    Burt, W.J.; Thomas, H.; Pätsch, J.; Omar, A.; Schrum, C.; Daewel, U.; Brenner, H.; de Baar, H.J.W.

    2014-01-01

    Sediment-water column exchange plays an important role in coastal biogeochemistry. We utilize short-lived radium isotopes (224Ra and 223Ra) to understand and quantify the dominant processes governing sediment-water column exchange throughout the North Sea. Our comprehensive survey, conducted in Sept

  1. Mapping the spawning grounds of North Sea cod (Gadus morhua) by direct and indirect means

    NARCIS (Netherlands)

    Fox, C.J.; Taylor, M.; Dickey-Collas, M.; Fossum, P.; Kraus, G.; Rohlf, N.; Damme, van C.J.G.; Bolle, L.J.

    2008-01-01

    Despite recent evidence for sub-stock structuring, North Sea cod are assessed as a single unit. As a consequence, knowledge of sub-stock trends is poor. In particular, there are no recent evaluations of which spawning grounds are active. Here we report results from the first ichthyoplankton survey

  2. Variability in growth rates of larval haddock in the northern North Sea

    DEFF Research Database (Denmark)

    Gallego, A.; Heath, M.R.; Basford, D.J.

    1999-01-01

    The large-scale distribution of haddock (Melanogrammus aeglefinus) larvae in the northern North Sea was mapped in a grid survey carried out in late April 1996. A drifting buoy was deployed in the centre of one of the areas of concentration of larvae located off the east coast of the Shetland Isles...

  3. Palaeoenvironmental changes across the Danian–Selandian boundary in the North Sea Basin

    DEFF Research Database (Denmark)

    Clemmensen, Anne; Thomsen, Erik

    2005-01-01

    in many areas. Secondly, coinciding with the Danian–Selandian boundary, an uplift of the Scotland–Shetland area resulting in a massive input of siliciclastic deposits to the North Sea Basin. Thirdly, during the early Selandian, inversion of the Sorgenfrei-Tornquist Zone and Mesozoic basins in the southern...

  4. Crenarchaeol tracks winter blooms of ammonia-oxidizing Thaumarchaeota in the coastal North Sea

    NARCIS (Netherlands)

    Pitcher, A.; Wuchter, C.; Siedenberg, K.; Schouten, S.; Sinninghe Damsté, J.S.

    2011-01-01

    We followed the abundance and distribution of ammonia-oxidizing Archaea (AOA) in the North Sea from April 2003 to February 2005 and from October 2007 to March 2008 by quantification of archaeal genes and core glycerol dibiphytanyl glycerol tetraether (GDGT) membrane lipids in suspended particulate m

  5. Non-predation natural mortality of Norway pout ( Trisopterus esmarkii ) in the North Sea

    DEFF Research Database (Denmark)

    Sparholt, H.; Larsen, L.I.; Nielsen, J. Rasmus

    2002-01-01

    Based on age disaggregated data on catch rates in bottom trawl surveys, commercial catches, and the number consumed by the North Sea piscivorous predators, new estimates of non-predation natural mortality, M1, are obtained for Norway pout [Trisopterus esmarkii (Nilsson)]. Simple log catch ratio...

  6. Review of the spatial and temporal distribution by life stage for 19 North Sea fish species

    NARCIS (Netherlands)

    Teal, L.R.; Hal, van R.; Damme, van C.J.G.; Bolle, L.J.; Hofstede, ter R.

    2009-01-01

    Considering the increase in human activity in the North Sea, particularly cargo shipping and the rapidly expanding construction and operation of oil platforms and wind farms, as well as the continued use of the area for military purposes, fisheries and sand extraction, there is a growing concern

  7. Density and viscosity behavior of a North Sea crude oil, natural gas liquid, and their mixtures

    DEFF Research Database (Denmark)

    Schmidt, KAG; Cisneros, Sergio; Kvamme, B

    2005-01-01

    to accurately model the saturation pressures, densities, and viscosities of petroleum systems ranging from natural gases to heavy crude oils. The applicability of this overall modeling technique to reproduce measured bubble points, densities, and viscosities of a North Sea crude oil, a natural gas liquid...

  8. Detection of low numbers of microplastics in North Sea fish using strict quality assurance criteria

    NARCIS (Netherlands)

    Hermsen, E.; Pompe, R.; Besseling, E.; Koelmans, A.A.

    2017-01-01

    We investigated 400 individual fish of four North Sea species: Atlantic Herring, Sprat, Common Dab, and Whiting on ingestion of > 20 μm microplastic. Strict quality assurance criteria were followed in order to control contamination during the study. Two plastic particles were found in only 1 (a S

  9. A decision support system for assessing offshore wind energy potential in the North Sea

    NARCIS (Netherlands)

    Schillings, Ch.; Wanderer, T.; Cameron, L.; Wal, van der J.T.; Jacquemin, J.; Veum, K.

    2012-01-01

    Offshore wind energy (OWE) in the North Sea has the potential to meet large share of Europe’s future electricity demand. To deploy offshore wind parks in a rational way, the overall OWE potential has to be realistically determined. This has to be done on an international, cross-border level and by t

  10. The continental shelf pump for CO2 in the North Sea-evidence from summer observation

    NARCIS (Netherlands)

    Bozec, Yann; Thomas, Helmuth; Elkalay, Khalid; Baar, Hein J.W. de

    2005-01-01

    Data on the distribution of dissolved inorganic carbon (DIC) and partial pressure of CO2 (pCO2) were obtained during a cruise in the North Sea during late summer 2001. A 1° by 1° grid of 97 stations was sampled for DIC while the pCO2 was measured continuously between the stations. The surface

  11. Long-Term Trends in Calcifying Plankton and pH in the North Sea

    NARCIS (Netherlands)

    Beare, D.J.; McQuatters-Gollop, A.; Hammen, van der T.; Machiels, M.A.M.; Teoh, S.J.

    2013-01-01

    Relationships between six calcifying plankton groups and pH are explored in a highly biologically productive and data-rich area of the central North Sea using time-series datasets. The long-term trends show that abundances of foraminiferans, coccolithophores, and echinoderm larvae have risen over th

  12. Realized habitats of early-stage North Sea herring: looking for signals of environmental change

    NARCIS (Netherlands)

    Rockmann, C.; Dickey-Collas, M.; Payne, M.R.; Hal, van R.

    2011-01-01

    Realized habitats of North Sea herring for two larval and two juvenile stages were estimated over the past 30 years, using abundances from surveys tied to modelled estimates of temperature and salinity. Newly hatched larvae (NHL) were found mainly in water masses of 9–11°C, pre-metamorphosis larvae

  13. Stock and recruitment in North Sea herring (Clupea harengus); compensation and depensation in the population dynamics

    NARCIS (Netherlands)

    Nash, R.D.M.; Dickey-Collas, M.; Kell, L.T.

    2009-01-01

    The recovery of a stock after severe exploitation is of major interest to fish ecologists and managers alike. Understanding the dynamics of recruitment at low stock sizes is crucial to the simulation of stocks as they recover. Compensation in recruitment has occurred in North Sea herring, and it was

  14. Radium isotopes as a tracer of sediment-water column exchange in the North Sea

    NARCIS (Netherlands)

    Burt, W. J.; Thomas, H.; Paetsch, J.; Omar, A. M.; Schrum, C.; Daewel, U.; Brenner, H.; de Baar, H. J. W.

    2014-01-01

    Sediment-water column exchange plays an important role in coastal biogeochemistry. We utilize short-lived radium isotopes (Ra-224 and Ra-223) to understand and quantify the dominant processes governing sediment-water column exchange throughout the North Sea. Our comprehensive survey, conducted in Se

  15. Ethiopian Red Sea petroleum geology and regional geophysical evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Assefa, A. Tadesse, K.; Worku, T.; Tsadik, E.G. (Ethiopian Inst. of Geological Surveys, Addis Ababa (Ethiopia))

    1991-08-01

    The World Bank-executed Red Sea/Gulf of Aden Regional Hydrocarbon Study Project was organized to synthesize data on the Red Sea and Gulf of Aden basins. The primary objectives were to encourage increased hydrocarbon exploration activity within the project area by applying recent exploration techniques basin wide, and to train national geoscientists in exploration techniques. The study of the Ethiopian Red Sea and Gulf of Aden was based on public-domain exploration data, published information, and data released by operating companies. These included reports, sections and wire lines logs from eight wells, samples from seven wells for biostratigraphic analysis, and samples from five wells for geochemical analysis. Interpretation was carried out on 6,600 line-km of seismic data selected from a grid of 29,710 line-km. Four horizons were identified on a regional basis, including the sea floor, top and near base of Middle to Upper Miocene evaporites, and approximate acoustic basement. A bathymetric map, three structure-contour maps, and three interval isopach maps were prepared using digitized picks from the interpreted seismic. The results show that the Ethiopian Red Sea is similar to the better known productive Gulf of Suez in some respects, including the overall tectonic evolution and the Miocene to Holocene stratigraphic sequence. Nevertheless, significant differences result from the location of the Ethiopian Red Sea in the transition zone to the Afar area. An important difference is the development of two major en echelon trends of rifting separated by a block with limited extension in the Danakil Alps. The resulting variations in sedimentary sequence, structural style, and geothermal gradient suggest that a favorable petroleum potential may be present locally in both pre-evaporite and post-evaporite objectives.

  16. Ice stream behaviour in the western sector of the North Sea during the end of the last glacial cycle

    Science.gov (United States)

    Roberts, David; Evans, David; Clark, Chris; Bateman, Mark; Livingstone, Stephen; Medialdea, Alicia; Cofaigh, Colm O.; Grimoldi, Elena; Callard, Louise; Dove, Dayton; Stewart, Heather; Davies, Bethan; Chiverell, Richard

    2016-04-01

    During the last glacial cycle the East coast of the UK was overrun by the British-Irish Ice Sheet (BIIS) flowing eastwards and southwards. In recent years it has become evident that several ice streams including the Tweed, Tyne, and Stainmore Gap ice streams, as well as the late stage North Sea Lobe (NSL), all played a role in shaping the glacial landscape during this period, but understanding the flow phasing of these ice streams during advance and collapse has proved challenging. Here we present new data from the seafloor collected during recent work undertaken by the Britice Chrono and Glanam project teams during cruise JC123 in the North Sea. Sub-bottom seafloor data together with new swath data clearly show that the final phases of the collapse of the NSL were controlled by ice sourced from the Firth of Forth ice stream which deglaciated in a NNW trajectory. Other ice streams being fed from the west (e.g. Stainmore, Tyne, Tweed) were not influential in final phase ice retreat from the southern North Sea. The Forth ice imprint is characterised by several grounding zone/till wedges marking dynamic, oscillatory retreat of the ice as it retreated along an offshore corridor between North Yorkshire and Northumberland. Repeated packages of tills, ice marginal and glaciomarine sediments, which drape glacially scoured bedrock terrain and drumlins along this corridor, point to marine inundation accompanying ice retreat. New TCN ages suggest decoupling of the Tyne Gap ice stream and NSL between 17.8 and 16.5 ka and this coincides with rapid, regional collapse of the NSL between 17.2 and 16.0 ka along the Yorkshire and Durham coasts (new OSL ages; Britice Chrono). Hence, both the central and northern sectors of the BIIS were being strongly influenced by marine margin instability during the latter phases of the last glacial cycle.

  17. Characterisation of hard-substrate habitats in the German Bight (SE North Sea) from video observation

    Science.gov (United States)

    Michaelis, Rune; Mielck, Finn; Papenmeier, Svenja; Sander, Lasse; Hass, H. Christian

    2017-04-01

    Accumulations of cobble- to boulder-sized material provide important habitat functions for many plant and animal species in the marine environment. These include nursery for fish, anchor point for sessile marine species and feeding ground for many different organisms. Detailed knowledge of such reef habitats and their properties is thus crucial for the determination of marine protected areas and consequently also for the management of the North Sea. As stones and boulders usually cannot be recovered from the seafloor to be investigated in the lab most analyses have to rely on non-invasive methods like e.g. underwater video- and diver-observation data. Due to these limitations these habitats are not well understood with regard to their spatial distribution, temporal development and ecology. Furthermore, there is no standardized way to assess the structure and cover of biological communities on such hard-substrates, which discourages comparison of data between different regions. We here present a standardized workflow to analyse underwater videos of hard-substrate habitats recorded in different areas of the North Sea. The idea is to combine these detailed information with an area-wide habitat classification based on sidescan sonar data. For image-based evaluation, the videos are transformed into single frames, extracted every five seconds of video running time and imported into a self-developed image analysis script. This script allows the user to select and count different descriptors in numerical categories. These include amongst others the different size classes of stones, the areal coverage of sessile marine organisms, the surrounding sediment properties or the presence of grazers. These semi-quantitative data are subsequently statistically analysed to produce a set of standardized characteristics of the hard-substrate habitats and the controlling factors of their current state and development. Preliminary results show that boulders in sandy environments are

  18. High-resolution area-wide sea-floor mapping: The paleo Elbe valley (S North Sea) revisited

    Science.gov (United States)

    Papenmeier, Svenja; Hass, H. Christian

    2014-05-01

    The North Sea Basin is shaped by multiple glacial advances and retreats that left complex sequences of glacio-fluvial and sub-glacial deposits, cut by sub-glacial tunnel valleys. Today, the submerged valley of the Elbe forms one of the most prominent structures of the southern North Sea. Flanked by huge moraine deposits of older glacials, the valley developed to its present form during the Weichselian sea-level lowstand (-130 m below present). Melt waters that discharged in north-westerly directions along the Scandinavian Ice Sheet fed the paleo Elbe at that time. During the Holocene the valley drowned in the rising sea. Here we present an area-wide high-resolution map of the seafloor and high-resolution shallow seismic data covering 1,600 km2 of the paleo Elbe valley (PEV) including its eastern levee. The data allow to shed new light on the PEV development including the historical process of sedimentary infill with the successive Holocene sea level rise in detail. Shallow seismic data with transect distances of 400 m and several cross sections allow 3-D visualization. The eastern flank of the valley is characterized by a relatively steep slope with one or more terraces. At its levee a significant sediment change is present on the modern sea floor, representing moraine and marine deposits. High resolution sidescan sonar data of this area show a much higher heterogeneity and complexity in sediment and habitat distribution as assumed before. Holocene marine sediments form a patchy and thin drape east of the valley floor. The western slip-off slope of the valley slope is much smoother than the eastern undercut slope. As yet, significant sedimentological changes at the present seafloor are not known for the western side of the PEV. Shallow seismic data show the base of the PEV. There are conspicuous internal seismic reflectors above the base, inclined in northeastern direction. They indicate a sedimentary infill of the valley from the southwest when the southern part

  19. Holocene Sea-Level Database For The Caribbean Region

    Science.gov (United States)

    Khan, N. S.; Horton, B.; Engelhart, S. E.; Peltier, W. R.; Scatena, F. N.; Vane, C. H.; Liu, S.

    2013-12-01

    Holocene relative sea-level (RSL) records from far-field locations are important for understanding the driving mechanisms controlling the nature and timing of the mid-late Holocene reduction in global meltwaters and providing background rates of late Holocene RSL change with which to compare the magnitude of 20th century RSL rise. The Caribbean region has traditionally been considered far-field (i.e., with negligible glacio-isostatic adjustment (GIA) influence), although recent investigations indicate otherwise. Here, we consider the spatial variability in glacio-isostatic, tectonic and local contributions on RSL records from the circum-Caribbean region to infer a Holocene eustatic sea-level signal. We have constructed a database of quality-controlled, spatially comprehensive, Holocene RSL observations for the circum-Caribbean region. The database contains over 500 index points, which locate the position of RSL in time and space. The database incorporates sea-level observations from a latitudinal range of 5°N to 25°N and longitudinal range of 55°W to 90°W. We include sea-level observations from 11 ka BP to present, although the majority of the index points in the database are younger than 8 ka BP. The database is sub-divided into 13 regions based on the distance from the former Laurentide Ice Sheet and regional tectonic setting. The index points were primarily derived from mangrove peat deposits, which in the Caribbean form in the upper half of the tidal range, and corals (predominantly Acropora palmata), the growth of which is constrained to the upper 5 m of water depth. The index points are classified on the basis of their susceptibility to compaction (e.g., intercalated, basal). The influence of temporal changes in tidal range on index points is also considered. The sea-level reconstructions demonstrate that RSL did not exceed the present height (0 m) during the Holocene in the majority of locations, except at sites in Suriname/Guayana and possibly Trinidad

  20. Marine environment protection of the North Sea and Baltic Sea. Special report - February 2004; Meeresumweltschutz fuer Nord- und Ostsee. Sondergutachten - Februar 2004

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The marine environment of the North Sea and Baltic Sea is still heavily polluted. The marine ecosystems are under severe stress from overfishing, water pollution, raw materials production and tourism. Environmental protection in this region necessitates decisive political initiatives and strict corrections especially in fishery policy, agricultural policy and chemical substances control. This is the balance of the special expert opinion of the Council of Environmental Experts. The publication specifies the main problem areas, the current pollution situation, the fields where action is most urgently required - especially in fishery, chemical substances, agricultural and sea travel policies - and presents suggestions for an integrated European and national marine protection policy including a regional development concept for the marine environment. (orig.) [German] Die Meeresumwelt von Nord- und Ostsee ist nach wie vor stark belastet. Ueberfischung, Schadstoffeintraege und Ueberduengung sowie die intensive Nutzung durch Schifffahrt, Rohstoffabbau und Tourismus beeintraechtigen vielfach massiv die marinen Oekosysteme. Ein wirksamer Meeresumweltschutz erfordert daher einschneidende politische Initiativen und grundlegende Korrekturen insbesondere in der Fischereipolitik, der Agrarpolitik und bei der Chemikalienregulierung. Diese Bilanz zieht der Rat von Sachverstaendigen fuer Umweltfragen in seinem aktuellen Sondergutachten 'Meeresumweltschutz fuer Nord- und Ostsee'. Das Sondergutachen - gibt einen Ueberblick ueber die wichtigsten Problemfelder und die aktuelle Belastungslage, - zeigt den wesentlichen Handlungsbedarf auf, insbesondere fuer die Fischerei-, Chemikalien-, Agrar- und Schifffahrtspolitik und - entwickelt Vorschlaege fuer eine integrierte europaeische und nationale Meeresschutzpolitik einschliesslich einer Merresraumordnung. (orig.)