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  • 1.
    Eilola, Kari
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Gustafson, B.G
    Kuznetsov, Ivan
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Neumann, T.
    Savchuk, O. P.
    Evaluation of biogeochemical cycles in an ensemble of three state-of-the-art numerical models of the Baltic Sea2011Ingår i: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 88, nr 2, s. 267-284Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three state-of-the-art coupled physical–biogeochemical models, the BAltic sea Long-Term large-Scale Eutrophication Model (BALTSEM), the Ecological Regional Ocean Model (ERGOM), and the Swedish Coastal and Ocean Biogeochemical model coupled to the Rossby Centre Ocean circulation model (RCO–SCOBI), are used to calculate changing nutrient and oxygen dynamics in the Baltic Sea. The models are different in that ERGOM and RCO–SCOBI are three-dimensional (3D) circulation models while BALTSEM resolves the Baltic Sea into 13 dynamically interconnected and horizontally integrated sub-basins. The aim is to assess the simulated long-term dynamics and to discuss the response of the coupled physical–biogeochemical models to changing physical conditions and nutrient loadings during the period 1970–2005. We compared the long-term seasonal and annual statistics of inorganic nitrogen, phosphorus, and oxygen from hindcast simulations with those estimated from observations. We also studied the extension of hypoxic bottom areas covered by waters with O2 b2 ml O2 l −1 and cod reproductive volumes comprising waters with salinity N11 and O2 N2 ml O2 l −1 . The models reproduce much of the nutrient biogeochemical cycling in the Baltic proper. However, biases are larger in the Bothnian Sea and Bothnian Bay. No model shows outstanding performance in all aspects but instead the ensemble mean results are better than or as good as the results of any of the individual models. Uncertainties are primarily related to differences in the bioavailable fractions of nutrient loadings from land and parameterizations of key processes like sediment fluxes that are presently not well known. Also the uncertainty related to the initialization of the models in the early 1960s influence the modeled biogeochemical cycles during the investigated period. ©

  • 2.
    Hordoir, Robinson
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Axell, Lars
    SMHI, Forskningsavdelningen, Oceanografi.
    Löptien, Ulrike
    SMHI, Forskningsavdelningen, Oceanografi.
    Dietze, Heiner
    Kuznetsov, Ivan
    SMHI, Forskningsavdelningen, Oceanografi.
    Influence of sea level rise on the dynamics of salt inflows in the Baltic Sea2015Ingår i: Journal of Geophysical Research - Oceans, ISSN 2169-9275, E-ISSN 2169-9291, Vol. 120, nr 10, s. 6653-6668Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Baltic Sea is a marginal sea, located in a highly industrialized region in Central Northern Europe. Saltwater inflows from the North Sea and associated ventilation of the deep exert crucial control on the entire Baltic Sea ecosystem. This study explores the impact of anticipated sea level changes on the dynamics of those inflows. We use a numerical oceanic general circulation model covering both the Baltic and the North Sea. The model successfully retraces the essential ventilation dynamics throughout the period 1961-2007. A suite of idealized experiments suggests that rising sea level is associated with intensified ventilation as saltwater inflows become stronger, longer, and more frequent. Expressed quantitatively as a salinity increase in the deep central Baltic Sea, we find that a sea level rise of 1 m triggers a saltening of more than 1 PSU. This substantial increase in ventilation is the consequence of the increasing cross section in the Danish Straits amplified by a reduction of vertical mixing.

  • 3.
    Kuznetsov, Ivan
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Dieterich, Christian
    SMHI, Forskningsavdelningen, Oceanografi.
    Hordoir, Robinson
    SMHI, Forskningsavdelningen, Oceanografi.
    Axell, Lars
    SMHI, Forskningsavdelningen, Oceanografi.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Model study on the variability of ecosystem parameters in the Skagerrak-Kattegat area, effect of load reduction in the North Sea and possible effect of BSAP on Skagerrak-Kattegat area2016Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Den nyligen utvecklade ekosystemmodellen NEMO-Nordic-SCOBI användes för att studera variabiliteten av några indikatorer för ekosystemet i Skagerrak- kattegatt området. Även två känslighetsstudier gjordes för att undersöka möjliga effekter av Baltic Sea Action Plan (BSAP) och en reduktion scenario av närsaltstillförsel på Skagerrak-Kattegatt området. Den utförda studien kan användas som underlag och stöd vid tolkningen av observationsdata inför utvärderingen ”Intermediate Assessments Eutrophication status assessment”. Jämförelsen mellan modelldata och observationer indikerar att modellens resultat är acceptabla. Modellerade ytvärden av salthalt, temperatur och löst fosfat (DIP) visar god överenskommelse med observerade värden. Samtidigt har modellresultaten avvikelser i vissa delområden vad gäller löst oorganiskt kväve (DIN) och löst kisel under vitertid. Dock visar modellen i sitt nuvarande tillstånd tillräckligt goda resultat för den aktuella studien. Resultaten från de två känslighetsstudierna visar en minskning av näringskoncentrationer i ytan under vintern i båda havsområdena. I Skagerrak är minskningen orsakad av reducerad närsaltstillförsel i Nordsjön. I Kattegatt minskar lösta fosfatet på grund av genomförandet av BSAP. Ingen av scenarierna visade någon signifikant påverkan på syre vid havsbotten eller på ytkoncentratiner av Chl-a.

  • 4.
    Kuznetsov, Ivan
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Neumann, Thomas
    Simulation of carbon dynamics in the Baltic Sea with a 3D model2013Ingår i: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 111, s. 167-174Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A full resolved three-dimensional physical-biogeochemical model ERGOM (Ecological ReGional Ocean model) was used to simulate the carbon dynamics in the Baltic Sea. Here, a simple carbon cycle has been included in the model. This was accomplished by the addition of dissolved inorganic carbon and total alkalinity to the model. Model results of the hindcast simulation (1961-2007) are in a good agreement with observations. Lateral gradients of the alkalinity are well reproduced by the model. A net inorganic carbon transport from the Baltic Sea to the Kattegat is in the range of the results of previous studies. Further, two climate projections with different nutrient load scenarios reflecting the possible development of the carbon system dynamics in the Baltic Sea were conducted. Climate scenario simulations (1961-2100) showed a continuous "acidification effect" of the Baltic Sea that mainly is controlled by changing of the atmospheric pCO(2). However, changes in pH due to other factors (such as changing temperature, primary production) are different for different regions of the sea. Simulated mean total alkalinity and dissolved inorganic carbon decrease in scenarios of climate change despite the increase of total alkalinity and dissolved inorganic carbon loads. The performed climate simulations show that mean total alkalinity decreases by about 150 mmol m(-3) and dissolved inorganic carbon by about 80-120 mmol m(-3). At the same time total alkalinity to salinity relations change in future climate due to that salinity decreases "faster" than alkalinity. Simultaneously, export of the total alkalinity and the dissolved inorganic carbon from the Baltic Sea to the North Sea has the trend to increase from 11% to 18% depending on the climate scenario. C) 2012 Elsevier B.V. All rights reserved.

  • 5.
    Meier, Markus
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Andersson, H. C.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Gustafsson, B. G.
    Kuznetsov, Ivan
    SMHI, Forskningsavdelningen, Oceanografi.
    Muller-Karulis, B.
    Neumann, T.
    Savchuk, O. P.
    Hypoxia in future climates: A model ensemble study for the Baltic Sea2011Ingår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 38, artikel-id L24608Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Using an ensemble of coupled physical-biogeochemical models driven with regionalized data from global climate simulations we are able to quantify the influence of changing climate upon oxygen conditions in one of the numerous coastal seas (the Baltic Sea) that suffers worldwide from eutrophication and from expanding hypoxic zones. Applying various nutrient load scenarios we show that under the impact of warming climate hypoxic and anoxic areas will very likely increase or at best only slightly decrease (in case of optimistic nutrient load reductions) compared to present conditions, regardless of the used global model and climate scenario. The projected decreased oxygen concentrations are caused by (1) enlarged nutrient loads due to increased runoff, (2) reduced oxygen flux from the atmosphere to the ocean due to increased temperature, and (3) intensified internal nutrient cycling. In future climate a similar expansion of hypoxia as projected for the Baltic Sea can be expected also for other coastal oceans worldwide. Citation: Meier, H. E. M., H. C. Andersson, K. Eilola, B. G. Gustafsson, I. Kuznetsov, B. Muller-Karulis, T. Neumann, and O. P. Savchuk (2011), Hypoxia in future climates: A model ensemble study for the Baltic Sea, Geophys. Res. Lett., 38, L24608, doi:10.1029/2011GL049929.

  • 6.
    Meier, Markus
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Muller-Karulis, Barbel
    Andersson, Helén
    SMHI, Forskningsavdelningen, Oceanografi.
    Dieterich, Christian
    SMHI, Forskningsavdelningen, Oceanografi.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Gustafsson, Bo G.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Hordoir, Robinson
    SMHI, Forskningsavdelningen, Oceanografi.
    Kuznetsov, Ivan
    SMHI, Forskningsavdelningen, Oceanografi.
    Neumann, Thomas
    Ranjbar, Zohreh
    Savchuk, Oleg P.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Impact of Climate Change on Ecological Quality Indicators and Biogeochemical Fluxes in the Baltic Sea: A Multi-Model Ensemble Study2012Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, nr 6, s. 558-573Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multi-model ensemble simulations using three coupled physical-biogeochemical models were performed to calculate the combined impact of projected future climate change and plausible nutrient load changes on biogeochemical cycles in the Baltic Sea. Climate projections for 1961-2099 were combined with four nutrient load scenarios ranging from a pessimistic business-as-usual to a more optimistic case following the Helsinki Commission's (HELCOM) Baltic Sea Action Plan (BSAP). The model results suggest that in a future climate, water quality, characterized by ecological quality indicators like winter nutrient, summer bottom oxygen, and annual mean phytoplankton concentrations as well as annual mean Secchi depth (water transparency), will be deteriorated compared to present conditions. In case of nutrient load reductions required by the BSAP, water quality is only slightly improved. Based on the analysis of biogeochemical fluxes, we find that in warmer and more anoxic waters, internal feedbacks could be reinforced. Increased phosphorus fluxes out of the sediments, reduced denitrification efficiency and increased nitrogen fixation may partly counteract nutrient load abatement strategies.

  • 7. Neumann, Thomas
    et al.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Gustafsson, Bo
    Muller-Karulis, Barbel
    Kuznetsov, Ivan
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Savchuk, Oleg P.
    Extremes of Temperature, Oxygen and Blooms in the Baltic Sea in a Changing Climate2012Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, nr 6, s. 574-585Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the future, the Baltic Sea ecosystem will be impacted both by climate change and by riverine and atmospheric nutrient inputs. Multi-model ensemble simulations comprising one IPCC scenario (A1B), two global climate models, two regional climate models, and three Baltic Sea ecosystem models were performed to elucidate the combined effect of climate change and changes in nutrient inputs. This study focuses on the occurrence of extreme events in the projected future climate. Results suggest that the number of days favoring cyanobacteria blooms could increase, anoxic events may become more frequent and last longer, and salinity may tend to decrease. Nutrient load reductions following the Baltic Sea Action Plan can reduce the deterioration of oxygen conditions.

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