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  • 51.
    Carlund, Thomas
    et al.
    SMHI, Core Services.
    Håkansson, Bertil
    SMHI, Research Department, Oceanography.
    Land, P
    Aerosol optical depth over the Baltic Sea derived from AERONET and SeaWiFS measurements2005In: International Journal of Remote Sensing, ISSN 0143-1161, E-ISSN 1366-5901, Vol. 26, no 2, p. 233-245Article in journal (Refereed)
    Abstract [en]

    Three years of data on aerosol optical depth (tau(a)) from the Aerosol Robotic Network (AERONET) station on the island of Gotland in the Baltic Sea have been analysed and compared with Sea-viewing Wide Field of view Sensor (SeaWiFS) data. Normally, the atmosphere over Gotland could be considered as clear, with a daily median value Of tau(a) at 500 nm of about 0.08. The median value of Angstrom's wavelength exponent (alpha) for wavelengths between 440 nm and 870 nm was 1.37, indicating that the dominant aerosol is more of a continental than of a pure maritime type. SeaWiFS GAC level 2 data on tau(a) and alpha were compared to data from the ground-based AERONET station. For the 37 cases of simultaneous satellite and ground-based measurements under cloud-free skies it was found that, on average, the value of tau(a)(865 nm) from SeaWiFS was about 0.02 higher than tau(a)(870 nm) from the AERONET station. At the same time approximate tau(a)(440 nm) from SeaWiFS was about 0.03 lower than tau(a)(440 nm) of AERONET. alpha(510, 865) from SeaWiFS was, on average, 1.2 lower than alpha(500, 870) from the AERONET measurements. These results cannot explain the very frequent occurences of negative values of normalized water-leaving radiance at 412 nm and 443 nm in the SeaWiFS reprocessing #3 data.

  • 52.
    Cato, Ingemar
    et al.
    Geological Survey of Sweden (SGU),.
    Håkansson, Bertil
    SMHI, Research Department, Oceanography.
    Hallberg, Ola
    Geological Survey of Sweden (SGU),.
    Kjellin, Bernt
    Geological Survey of Sweden (SGU),.
    Andersson, Pia
    SMHI, Core Services.
    Erlandsson, Cecilia
    Geological Survey of Sweden (SGU),.
    Axe, Philip
    SMHI, Research Department, Oceanography.
    A new approach to state the areas of oxygen deficits in the Baltic Sea2008Report (Other academic)
    Abstract [en]

    Sediment and near bottom water oxygen data was evaluated to look for correspondence in anoxic conditions. The SGU and SMHI monitoring data showed high correlation, although the actual data tested proved to be few, coincidence in space was promising. The conclusion drawn from the evaluation is that anoxic postglacial sediments were generally overlaid by near bottom anoxic waters. Hence, it is suggested that the spatial distribution of postglacial clays in the sea-bottom surface can be used, together with near bottom waters oxygen data, to improve spatial distribution in mapping oxygen deficits.Time series of oxygen deficit volume and area was calculated from near bottom data from several sub basins in the southern and central Baltic Proper. In general, hypoxic and anoxic water conditions increased over time but perturbations of improved oxygen conditions linked to major inflow events occurs especially in the Bornholm, Eastern and Western Gotland Basins.The high spatial variability of the postglacial sediments in the Western Gotland Basin compared to other basins indicates that it is indeed sensitive to the area coverage of anoxic waters. In addition, the relatively weak stratification and high variability over time of oxygen deficit make this basin favourable for oxygen improvement engineering methods.In coastal waters several bays along the Östergötland and Småland archipelagos should be further evaluated before selected for ecological engineering methods to improve oxygen conditions.

  • 53. Conley, Daniel J.
    et al.
    Bjorck, Svante
    Bonsdorff, Erik
    Carstensen, Jacob
    Destouni, Georgia
    Gustafsson, Bo G.
    Hietanen, Susanna
    Kortekaas, Marloes
    Kuosa, Harri
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Mueller-Karulis, Baerbel
    Nordberg, Kjell
    Norkko, Alf
    Nuernberg, Gertrud
    Pitkanen, Heikki
    Rabalais, Nancy N.
    Rosenberg, Rutger
    Savchuk, Oleg P.
    Slomp, Caroline P.
    Voss, Maren
    Wulff, Fredrik
    Zillen, Lovisa
    Hypoxia-Related Processes in the Baltic Sea2009In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 43, no 10, p. 3412-3420Article, review/survey (Refereed)
    Abstract [en]

    Hypoxia, a growing worldwide problem, has been intermittently present in the modern Baltic Sea since its formation ca. 8000 cal. yr BP. However, both the spatial extent and intensity of hypoxia have increased with anthropogenic eutrophication due to nutrient inputs. Physical processes, which control stratification and the renewal of oxygen in bottom waters, are important constraints on the formation and maintenance of hypoxia. Climate controlled inflows of saline water from the North Sea through the Danish Straits is a critical controlling factor governing the spatial extent and duration of hypoxia. Hypoxia regulates the biogeochemical cycles of both phosphorus (P) and nitrogen (N) in the water column and sediments. Significant amounts of P are currently released from sediments, an order of magnitude larger than anthropogenic inputs. The Baltic Sea is unique for coastal marine ecosystems experiencing N losses in hypoxic waters below the halocline. Although benthic communities in the Baltic Sea are naturally constrained by salinity gradients, hypoxia has resulted in habitat loss over vast areas and the elimination of benthic fauna, and has severely disrupted benthic food webs. Nutrient load reductions are needed to reduce the extent, severity, and effects of hypoxia.

  • 54. Conley, Daniel J.
    et al.
    Carstensen, Jacob
    Aigars, Juris
    Axe, Philip
    SMHI, Research Department, Oceanography.
    Bonsdorff, Erik
    Eremina, Tatjana
    Haahti, Britt-Marie
    Humborg, Christoph
    Jonsson, Per
    Kotta, Jonne
    Lannegren, Christer
    Larsson, Ulf
    Maximov, Alexey
    Medina, Miguel Rodriguez
    Lysiak-Pastuszak, Elzbieta
    Remeikaite-Nikiene, Nijole
    Walve, Jakob
    Wilhelms, Sunhild
    Zillen, Lovisa
    Hypoxia Is Increasing in the Coastal Zone of the Baltic Sea2011In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 45, no 16, p. 6777-6783Article in journal (Refereed)
    Abstract [en]

    Hypoxia is a well-described phenomenon in the offshore waters of the Baltic Sea with both the spatial extent and intensity of hypoxia known to have increased due to anthropogenic eutrophication, however, an unknown amount of hypoxia is present in the coastal zone. Here we report on the widespread unprecedented occurrence of hypoxia across the coastal zone of the Baltic Sea. We have identified 115 sites that have experienced hypoxia during the period 1955-2009 increasing the global total to ca. 500 sites, with the Baltic Sea coastal zone containing over 20% of all known sites worldwide. Most sites experienced episodic hypoxia, which is a precursor to development of seasonal hypoxia. The Baltic Sea coastal zone displays an alarming trend with hypoxia steadily increasing with time since the 1950s effecting nutrient biogeochemical processes, ecosystem services, and coastal habitat.

  • 55. Danielssen, D S
    et al.
    Edler, Lars
    SMHI, Research Department, Oceanography.
    Fonselius, Stig
    SMHI, Research Department, Oceanography.
    Hernroth, L
    Ostrowski, M
    Svendsen, E
    Talpsepp, L
    Oceanographic variability in the Skagerrak and Northern Kattegat, May-June, 19901997In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 54, no 5, p. 753-773Article in journal (Refereed)
    Abstract [en]

    The Skagerrak Experiment (SKAGEX), was a large, international, ICES-supported joint venture, carried out in the Skagerrak-Kattegat area on four different surveys in the period 1990-1991. It involved some 20 institutes and, at times, up to 17 research vessels. The main aim of the Experiment was to identify and quantify the different water masses entering and leaving the Skagerrak area and their variation over lime. It also aimed to investigate the mechanisms that drive the circulation and to study their effects on biological processes. The aim was to be attained mostly through extensive synoptic observations. This paper focuses on the variability in physical, chemical and biological parameters during the first part of SKAGEX, 24 May-20 June 1990. During the first half of the period of investigation, the main outflow from the Skagerrak, represented by the Norwegian Coastal Current, was barotropic with daily mean velocities varying from 10-40 cm s(-1). During the second half a clear baroclinic current component developed, giving rise to near surface velocities of up to 100 cm s(-1). A pronounced feature in the Skagerrak during the study was the counter-clockwise circulation of the Norwegian Coastal Current at times of strong northwesterly winds. During such conditions this surface water reached as far as the Danish coast south of 57 degrees N and upwelling along the Norwegian coast was also found. During northerly winds upwelling also occurred along the Swedish coast. The nutrient-rich Jutland Coastal Water, originating from the German Eight, was never found to reach the inner part of the Skagerrak during this first part of SKAGEX. It was partly blocked or diluted by other water-masses. A large ''ridge'' of nutrient-rich Atlantic water was found in the central Skagerrak throughout the investigation. It is shown that this elongated ''ridge'' was associated with the deepest (>500 m) area of the Skagerrak. Within this area, high subsurface chlorophyll concentrations were always found and, due to the persistence of the supply of nutrients, it is concluded that this phenomenon could be one of the main reasons for the high productivity of the Skagerrak. (C) 1997 International Council for the Exploration of the Sea.

  • 56. Danielsson, A.
    et al.
    Jönsson, Anette
    SMHI, Core Services.
    Rahm, Lars
    SMHI, Research Department, Oceanography.
    Resuspension patterns in the Baltic proper2007In: Journal of Sea Research, ISSN 1385-1101, E-ISSN 1873-1414, Vol. 57, no 4, p. 257-269Article in journal (Refereed)
    Abstract [en]

    Waves induce resuspension of surface sediments and contribute to the long-term mobilisation of particulate matter from erosion to accumulation bottoms. This has a major impact on the nutrient cycle in shallow seas by enhancing degradation, microbial production and recycling. The Baltic Sea represents such an area. The aim of this work is to analyse the spatial and temporal resuspension patterns in the Baltic Sea. To estimate the bottom friction velocity, modelled wave data are used in combination with data on grain size. This new data set is compared to a resuspension threshold of friction velocity to estimate the events of resuspension. The variation in bottom friction velocity, resuspension frequency and duration are related to wind climate, fetch, water depth and sediment type. Substantial resuspension can be found down to 40-60 m, with durations from one day to as much as two weeks. The highest winds in the area are highly anisotropic with a dominance of S-SW-W winds and the highest resuspension frequencies are found along the shallow eastern coasts. A seasonal pattern is observed with relatively high friction velocities and high resuspension frequencies during winter. There is also a variation depending on grain size, where sediments with fine and medium sand have a considerably higher percentage of resuspension events than bottoms with other dominant grain sizes. Five sub-areas are identified, characterised by different sediment types, resuspension and wind characteristics. If, in the future, wind speed increases as predicted, resuspension of sediments will also increase with effects on the nutrient cycle. (c) 2006 Elsevier B.V. All rights reserved.

  • 57. Deng, Junjie
    et al.
    Harff, Jan
    Schimanke, Semjon
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    A method for assessing the coastline recession due to the sea level rise by assuming stationary wind-wave climate2015In: OCEANOLOGICAL AND HYDROBIOLOGICAL STUDIES, ISSN 1730-413X, Vol. 44, no 3, p. 362-380Article in journal (Refereed)
    Abstract [en]

    The method introduced in this study for future projection of coastline changes hits the vital need of communicating the potential climate change impact on the coast in the 21th century. A quantitative method called the Dynamic Equilibrium Shore Model (DESM) has been developed to hindcast historical sediment mass budgets and to reconstruct a paleo Digital Elevation Model (DEM). The forward mode of the DESM model relies on paleo-scenarios reconstructed by the DESM model assuming stationary wind-wave climate. A linear relationship between the sea level, coastline changes and sediment budget is formulated and proven by the least square regression method. In addition to its forward prediction of coastline changes, this linear relationship can also estimate the sediment budget by using the information on the coastline and relative sea level changes. Wind climate change is examined based on regional climate model data. Our projections for the end of the 21st century suggest that the wind and wave climates in the southern Baltic Sea may not change compared to present conditions and that the investigated coastline along the Pomeranian Bay may retreat from 10 to 100 m depending on the location and on the sea level rise which was assumed to be in the range of 0.12 to 0.24 m.

  • 58.
    Dieterich, Christian
    et al.
    SMHI, Research Department, Oceanography.
    Schimanke, Semjon
    SMHI, Research Department, Oceanography.
    Wang, Shiyu
    SMHI, Research Department, Climate research - Rossby Centre.
    Väli, Germo
    SMHI, Research Department, Oceanography.
    Liu, Ye
    SMHI, Research Department, Oceanography.
    Hordoir, Robinson
    SMHI, Research Department, Oceanography.
    Höglund, Anders
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Evaluation of the SMHI coupled atmosphere-ice-ocean model RCA4-NEMO2013Report (Other academic)
    Abstract [en]

    AbstractThe regional, coupled atmosphere-ice-ocean model RCA4-NEMO developed at the SMHI is evaluated on the basis of an ERA40 hindcast. While the development of the regional climate model is continuing a first assessment is presented here to allow for an orientation about the status guo. RCA4-NEMO in its present form consists of two model components. The regional atmosphere model RCA4 covers the whole of Europe and is interactvely coupled to a North Sea and Baltic Sea ice-ocean model based on NEMO. RCA4-NEMO is currently being used to downscale CMIP5 scenarios for the North Sea and Baltic Sea region for this century. As a part of the validation of RCA4-NEMO we present an analysis and discussion of the hindcast period 1970-1999. The model realization is compared to observational records. Near surface temperatures and heat fluxes compare reasonably well with records of in-situ measurments and satellite derived estimates. For salinities and freshwater fluxes the agreement with observations in not satisfactory yet. The momentum fluxes transferred from the atmosphere to the ice-ocean model are identified as on of the sensitive processes in the coupling of both model components. Except for the freshwater exchange between atmosphere and ocean the climatological near surface properties and corresponding fluxes compare well with climatological estimates for the period 1970-1999.

  • 59.
    Dieterich, Christian
    et al.
    SMHI, Research Department, Oceanography.
    Wang, Shiyu
    SMHI, Research Department, Climate research - Rossby Centre.
    Schimanke, Semjon
    SMHI, Research Department, Oceanography.
    Groger, Matthias
    SMHI, Research Department, Oceanography.
    Klein, Birgit
    Hordoir, Robinson
    SMHI, Research Department, Oceanography.
    Samuelsson, Patrick
    SMHI, Research Department, Climate research - Rossby Centre.
    Liu, Ye
    SMHI, Research Department, Oceanography.
    Axell, Lars
    SMHI, Research Department, Oceanography.
    Höglund, Anders
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Surface Heat Budget over the North Sea in Climate Change Simulations2019In: Atmosphere, ISSN 2073-4433, E-ISSN 2073-4433, Vol. 10, no 5, article id 272Article in journal (Refereed)
  • 60. Dietze, H.
    et al.
    Löptien, Ulrike
    SMHI, Research Department, Oceanography.
    Revisiting "nutrient trapping" in global coupled biogeochemical ocean circulation models2013In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 27, no 2, p. 265-284Article in journal (Refereed)
    Abstract [en]

    We analyze an extensive set of global coupled biogeochemical ocean circulation models. The focus is on the equatorial Pacific. In all simulations, which are consistent with observed standing stocks of relevant biogeochemical species at the surface, we find spuriously enhanced (reduced) macronutrient (oxygen) concentrations in the deep eastern equatorial Pacific. This modeling problem, apparently endemic to global coupled biogeochemical ocean circulation models, was coined " nutrient trapping" by Najjar et al. (1992). In contrast to Aumont et al. (1999), we argue that " nutrient trapping" is still a persistent problem, even in eddy-permitting models and, further, that the scale of the problem retards model projections of nitrogen cycling. In line with previous work, our results indicate that a deficient circulation is at the core of the problem rather than an admittedly poor quantitative understanding of biogeochemical cycles. More specifically, we present indications that " nutrient trapping" in models is a result of a spuriously damped Equatorial Intermediate (zonal) Current System and Equatorial Deep Jets-phenomenon which await a comprehensive understanding and have, to date, not been successfully simulated.

  • 61.
    Doescher, Ralf
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Hansson, Ulf
    SMHI, Research Department, Climate research - Rossby Centre.
    Jones, Colin
    SMHI, Research Department, Climate research - Rossby Centre.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Rutgersson, Anna
    Willén, Ulrika
    SMHI, Research Department, Climate research - Rossby Centre.
    The development of the coupled ocean-atmosphere model RCAO2001In: Third study conference on BALTEX / [ed] J. Meywerk, 2001, p. 45-46Conference paper (Other academic)
  • 62.
    Doescher, Ralf
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Simulated sea surface temperature and heat fluxes in different climates of the Baltic Sea2004In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 33, no 4-5, p. 242-248Article in journal (Refereed)
    Abstract [en]

    The physical state of the Baltic Sea in possible future climates is approached by numerical model experiments with a regional coupled ocean-atmosphere model driven by different global simulations. Scenarios and recent climate simulations are compared to estimate changes. The sea surface is clearly warmer by 2.9degreesC in the ensemble mean. The horizontal pattern of average annual mean warming can largely be explained in terms of ice-cover reduction. The transfer of heat from the atmosphere to the Baltic Sea shows a changed seasonal cycle: a reduced heat loss in fall, increased heat uptake in spring, and reduced heat uptake in summer. The interannual variability of surface temperature is generally increased. This is associated with a smoothed frequency distribution in northern basins. The overall heat budget shows increased solar radiation to the sea surface, which is balanced by changes of the other heat flux components.

  • 63.
    Doescher, Ralf
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Simulated Sea Surface Temperature and Sea Ice in Different Climates of the Baltic2004In: Fourth Study Conference on BALTEX: Conference Proceedings / [ed] Hans-Jörg Isemer, Risø National Laboratory Technical University of Denmark GKSS Forschungszentrum Geesthacht GmbH , 2004, Vol. 4, p. 162-163Conference paper (Other academic)
  • 64.
    Doescher, Ralf
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Willen, Ulrika
    SMHI, Research Department, Climate research - Rossby Centre.
    Jones, Colin
    SMHI, Research Department, Climate research - Rossby Centre.
    Rutgersson, Anna
    SMHI, Research Department, Climate research - Rossby Centre.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Hansson, Ulf
    SMHI, Research Department, Climate research - Rossby Centre.
    Graham, Phil
    SMHI, Research Department, Climate research - Rossby Centre.
    The development of the regional coupled ocean-atmosphere model RCAO2002In: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 7, no 3, p. 183-192Article in journal (Refereed)
    Abstract [en]

    A regional coupled ocean-atmosphere-ice general circulation model for northern Europe is introduced for climate study purposes. The Baltic Sea is interactively coupled. The coupled model is validated in a 5-year hind-cast experiment with a focus on surface quantities and atmosphere-ocean heat fluxes. The coupled sea surface temperature matches observations well. The system is free of drift, does not need flux corrections and is suitable for multi-year climate runs. With flux forcing from the atmospheric model the regional ocean model gives sea surface temperatures statistically equivalent to the uncoupled ocean model forced by observations. Other oceanic surface quantities do not reach this quality in combination with the current atmosphere model. A strong dependence of sea ice extent on details of the atmospheric radiation scheme is found. Our standard scheme leads to an overestimation of ice, most likely due to a negative bias of long-wave radiation. There is indication that a latent heat flux bias in fall contributes to the ice problem. Other atmosphere-ocean heat fluxes are generally realistic in the long term mean.

  • 65.
    Doescher, Ralf
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Wyser, Klaus
    SMHI, Research Department, Climate research - Rossby Centre.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Qian, Minwei
    Redler, Ren
    Quantifying Arctic contributions to climate predictability in a regional coupled ocean-ice-atmosphere model2010In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 34, no 7-8, p. 1157-1176Article in journal (Refereed)
    Abstract [en]

    The relative importance of regional processes inside the Arctic climate system and the large scale atmospheric circulation for Arctic interannual climate variability has been estimated with the help of a regional Arctic coupled ocean-ice-atmosphere model. The study focuses on sea ice and surface climate during the 1980s and 1990s. Simulations agree reasonably well with observations. Correlations between the winter North Atlantic Oscillation index and the summer Arctic sea ice thickness and summer sea ice extent are found. Spread of sea ice extent within an ensemble of model runs can be associated with a surface pressure gradient between the Nordic Seas and the Kara Sea. Trends in the sea ice thickness field are widely significant and can formally be attributed to large scale forcing outside the Arctic model domain. Concerning predictability, results indicate that the variability generated by the external forcing is more important in most regions than the internally generated variability. However, both are in the same order of magnitude. Local areas such as the Northern Greenland coast together with Fram Straits and parts of the Greenland Sea show a strong importance of internally generated variability, which is associated with wind direction variability due to interaction with atmospheric dynamics on the Greenland ice sheet. High predictability of sea ice extent is supported by north-easterly winds from the Arctic Ocean to Scandinavia.

  • 66. Doos, K
    et al.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Doescher, Ralf
    SMHI, Research Department, Climate research - Rossby Centre.
    The Baltic haline conveyor belt or the overturning circulation and mixing in the Baltic2004In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 33, no 4-5, p. 261-266Article in journal (Refereed)
    Abstract [en]

    A study of the water-mass circulation of the Baltic has been undertaken by making use of a three dimensional Baltic Sea model simulation. The saline water from the North Atlantic is traced through the Danish Sounds into the Baltic where it upwells and mixes with the fresh water inflow from the rivers forming a Baltic haline conveyor belt. The mixing of the saline water from the Great Belt and Oresund with the fresh water is investigated making use of overturning stream functions and Lagrangian trajectories. The overturning stream function was calculated as a function of four different vertical coordinates (depth, salinity, temperature and density) in order to understand the path of the water and where it upwells and mixes. Evidence of a fictive depth overturning cell similar to the Deacon Cell in the Southern Ocean was found in the Baltic proper corresponding to the gyre circulation around Gotland, which vanishes when the overturning stream function is projected on density layers. A Lagrangian trajectory study was performed to obtain a better view of the circulation and mixing of the saline and fresh waters. The residence time of the water masses in the Baltic is calculated to be 26-29 years and the Lagrangian dispersion reaches basin saturation after 5 years.

  • 67.
    Edman, Moa
    et al.
    SMHI, Research Department, Oceanography.
    Eilola, Kari
    SMHI, Research Department, Oceanography.
    Almroth-Rosell, Elin
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Wåhlstrom, Irene
    SMHI, Research Department, Oceanography.
    Arneborg, Lars
    SMHI, Research Department, Oceanography.
    Nutrient Retention in the Swedish Coastal Zone2018In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 5, article id UNSP 415Article in journal (Refereed)
  • 68. Eero, Margit
    et al.
    Andersson, Helén
    SMHI, Research Department, Oceanography.
    Almroth-Rosell, Elin
    SMHI, Research Department, Oceanography.
    MacKenzie, Brian R.
    Has eutrophication promoted forage fish production in the Baltic Sea?2016In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 45, no 6, p. 649-660Article in journal (Refereed)
  • 69.
    Eigenheer, Andrea
    et al.
    SMHI, Research Department, Oceanography.
    Quadfasel, D
    Seasonal variability of the Bay of Bengal circulation inferred from TOPEX/Poseidon altimetry2000In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 105, no C2, p. 3243-3252Article in journal (Refereed)
    Abstract [en]

    The circulation in the interior of the Bay of Bengal and of its western boundary current, the East Indian Coastal Current, is inferred from historical ship drift data and from TOPEX/Poseidon altimeter data. The boundary current shows a strong seasonal variability with reversals twice per year that lead the reversal of the local monsoon wind field by several months. On the basis of model simulations it has been suggested that this unusual behavior can be explained by the influence of remotely forced planetary waves. Our data analysis confirms and refines this view by showing the role of topography in the northern bay. We also give an estimate of the relative importance of the different contributions.

  • 70.
    Eilola, Kari
    SMHI, Research Department, Oceanography.
    On the dynamics of organic nutrients, nitrogen and phosphorus, in the Baltic Sea2009Report (Other academic)
    Abstract [en]

    In this report we study the dynamics of organic nutrients, nitrogen and phosphorus, in the Baltic Sea. The results indicate that much of the characteristics of the surface layer dynamics of organic nutrients can be described by the Redfield ratio especially in the Baltic proper. There is however deviations from the Redfield ratio that are discussed and needs to be further investigated. The seasonal variations at all investigated stations indicate that the increase and decrease of the organic phosphorus and nitrogen concentrations in spring and autumn takes place with stoichiometric values different from the Redfield ratio. It is also found that organic phosphorus concentrations start to decrease earlier in summer than organic nitrogen that may continue to increase during summer and early autumn. There is a clear trend with decreasing DIN:DIP ratios in late winter at the Gotland Deep during the period 1995-2008 while there is an improved correlation of the Redfield model during the later part of the period when we have extremely low DIN:DIP ratios. Also the results from the Bothnian bay show that the variability of organic matter is fairly well described by the Redfield model despite the extremely high late winter N:P ratios observed in this region. Hence, the seasonal variability of organic matter seems to be rather independent of the ratio of inorganic nutrients. The variability of the inorganic N to P ratios in late winter and early spring across the Baltic Sea is much larger than seen from the variability of the organic matter. This suggests that other sources than DIN and DIP as sources for new nutrients in spring are used. This is true both in the Baltic proper, where an additional nitrogen source for organic matter production in spring is needed besides inorganic nitrogen, and in the Bothnian Bay, where an additional phosphorus source is needed. Nitrogen fixation by cyanobacteria that grow later in the summer in the southern Baltic Sea can not explain the additional nitrogen source needed in early spring. Future model experiments may reveal more information about the dynamics of organic matter in the Baltic Sea.

  • 71.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Almroth-Rosell, Elin
    SMHI, Research Department, Oceanography.
    Andersen, Per
    Nautsvoll, Lars Johan
    Karlson, Bengt
    SMHI, Research Department, Oceanography.
    Modelling the dynamics of harmful blooms of Chattonella sp. in the Skagerrak and the Kattegat2011In: ICES CM 2006/E:12, 2011Conference paper (Other academic)
    Abstract [en]

    The presentation shows observations, satellite images and model results describing the growth and spreading of Chattonella sp. flagellates in the Skagerrak and the Kattegat. Chattonella sp. is a harmful alga that may cause fish kills due to damage of the gills. Calm weather, stable water column stratification, and low turbulence may facilitate the onset of a Chattonella bloom. Results from the three-dimensional hydrodynamical model HIROMB (High Resolution Operational Model for the Baltic Sea) are used as forcing of a transport model that computes vertical and horizontal transports of chemical and biological compounds. A modified version of the Swedish Coastal and Ocean Biogeochemical model (SCOBI) is used to describe the temporal evolution of the phytoplankton spring blooms in the year 2001 when Chattonella was abundant and 2002 when only small amounts of Chattonella were observed. A comparison with satellite images and cell counts indicates that the model captures the main transport patterns of phytoplankton in the surface layers of the offshore areas. The Chattonella bloom of the model starts in the quite shallow parts of the western Kattegat and in the stratified coastal areas of the northern Skagerrak. The coastal waters near the river Göta Älv of Sweden also indicate a tendency of an increased occurrence of Chattonella. Chattonella is observed in the model during both years but the occurrence of Chattonella is more significant in the year 2001 than in 2002.

  • 72.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Almroth-Rosell, Elin
    SMHI, Research Department, Oceanography.
    Dieterich, Christian
    SMHI, Research Department, Oceanography.
    Fransner, Filippa
    Höglund, Anders
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Modeling Nutrient Transports and Exchanges of Nutrients Between Shallow Regions and the Open Baltic Sea in Present and Future Climate2012In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, no 6, p. 586-599Article in journal (Refereed)
    Abstract [en]

    We quantified horizontal transport patterns and the net exchange of nutrients between shallow regions and the open sea in the Baltic proper. A coupled biogeochemical-physical circulation model was used for transient simulations 1961-2100. The model was driven by regional downscaling of the IPCC climate change scenario A1B from two global General Circulation Models in combination with two nutrient load scenarios. Modeled nutrient transports followed mainly the large-scale internal water circulation and showed only small circulation changes in the future projections. The internal nutrient cycling and exchanges between shallow and deeper waters became intensified, and the internal removal of phosphorus became weaker in the warmer future climate. These effects counteracted the impact from nutrient load reductions according to the Baltic Sea Action Plan. The net effect of climate change and nutrient reductions was an increased net import of dissolved inorganic phosphorus to shallow areas in the Baltic proper.

  • 73.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Almroth-Rosell, Elin
    SMHI, Research Department, Oceanography.
    Edman, Moa
    SMHI, Research Department, Oceanography.
    Eremina, Tatjana 
    Russian State Hydrometeorological University, Sankt-Petersburg, Russia.
    Larsen, Janus
    Aarhus University, Roskilde, Denmark.
    Janas, Urszula 
    Institute of Oceanography, Gdansk University, Poland.
    Timmermann, Karen 
    Aarhus University, Roskilde, Denmark.
    Tedesco, Letizia 
    Finnish Environment Institute, Helsinki, Finland.
    Voloshchuk, Ekaterina 
    Russian State Hydrometeorological University, Sankt-Petersburg, Russia.
    Model set-up at COCOA study sites2015Report (Other academic)
    Abstract [en]

    COCOA will investigate physical, biogeochemical and biological processes in a combined and coordinated fashion to improve the understanding of the interaction of these processes on the removal of nutrients along the land-sea interface. The results from the project will be used to estimate nutrient retention capacity in the coastal zone of the entire Baltic Sea coast. An ensemble of biogeochemical models will be used in combination with field studies at seven different coastal study sites around the Baltic Sea. The present report is a deliverable of COCOA work package 5 (WP5). Within the objective of WP5 process understanding and process descriptions will be improved in state-of-the-art biogeochemical models of the Baltic Sea coastal zone. This report presents brief information about the models available for the COCOA project and defines the needed input to the models that will be set-up at several learning sites. The aim is to perform ensemble modelling at several sites, using at least two different models at each site. A pilot study to estimate nutrient retention capacity in the Stockholm Archipelago with the existing Swedish model system is ongoing and first results are presented and the concept of nutrient retention is briefly discussed. The existing models for different learning sites presented in the report are; 1) The Swedish model system SCM (Öre river estuary and the Stockholm archipelago) - A multi-box-model approach 2) The Danish model system FLEXSEM (Roskilde fjord) - A combined box-model and 3-D model approach 3) The Finnish model system ESIM-BFMSI (Tvärminne Archipelago) - A 1D box-model approach 4) The Polish model system M3D UG/ProDeMo (Puck Bay) - A 3-D model approach. Operational model. 5) The Lithuanian model system SYFEM/AQUABC (Curonian Lagoon) - A combined box-model and 3-D model approach 6) The Swedish open Baltic model system RCO-SCOBI (for the open Baltic Sea and the Gulf of Gdansk/Vistula). - A 3-D model approach In addition a biogeochemical model (Boudreau, 1996) for the Gulf of Finland (Russian State Hydrometeorological University model) is used to study the quantitative effect of Marenzelleria on the Gulf of Finland ecosystem. Process studies at selected sites will be performed with a reactive transport model developed at Utrecht University. Focus will be on the role of iron and phosphorus cycling. Process studies with the Danish model system will support the development of new parameterizations of nutrient fluxes taking benthic habitat into account. The new parameterizations of the nutrient fluxes will in addition also be implemented into SCM and the models will be used to estimate nutrient fluxes, retention times and the filter capacity of the coastal zones. The In Kind contributions from previously (in the literature) well described open Baltic Sea models RCO-SCOBI, BALTSEM, ERGOM and SPBEM that will be used for the description of open sea conditions are also briefly mentioned in the report with references to the relevant literature. 6) The Swedish open Baltic model system RCO-SCOBI (for the open Baltic Sea and the Gulf of Gdansk/Vistula). - A 3-D model approach In addition a biogeochemical model (Boudreau, 1996) for the Gulf of Finland (Russian State Hydrometeorological University model) is used to study the quantitative effect of Marenzelleria on the Gulf of Finland ecosystem. Process studies at selected sites will be performed with a reactive transport model developed at Utrecht University. Focus will be on the role of iron and phosphorus cycling. Process studies with the Danish model system will support the development of new parameterizations of nutrient fluxes taking benthic habitat into account. The new parameterizations of the nutrient fluxes will in addition also be implemented into SCM and the models will be used to estimate nutrient fluxes, retention times and the filter capacity of the coastal zones. The In Kind contributions from previously (in the literature) well described open Baltic Sea models RCO-SCOBI, BALTSEM, ERGOM and SPBEM that will be used for the description of open sea conditions are also briefly mentioned in the report with references to the relevant literature.

  • 74.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Almroth-Rosell, Elin
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Impact of saltwater inflows on phosphorus cycling and eutrophication in the Baltic Sea: a 3D model study2014In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 66, article id 23985Article in journal (Refereed)
    Abstract [en]

    The impact of dense saltwater inflows on the phosphorus dynamics in the Baltic Sea is studied from tracer experiments with a three-dimensional physical model. Model simulations showed that the coasts of the North West Gotland Basin and the Gulf of Finland, the Estonian coast in the East Gotland Basin are regions where tracers from below the halocline are primarily lifted up above the halocline. After 1 yr tracers are accumulated at the surface along the Swedish east coast and at the western and southern sides of Gotland. Elevated concentrations are also found east and southeast of Gotland, in the northern Bornholm Basin and in the central parts of the East Gotland Basin. The annual supplies of phosphorus from the deeper waters to the productive surface layers are estimated to be of the same order of magnitude as the waterborne inputs of phosphorus to the entire Baltic Sea. The model results suggest that regionally the impact of these nutrients may be quite large, and the largest regional increases in surface concentrations are found after large inflows. However, the overall direct impact of major Baltic inflows on the annual uplift of nutrients from below the halocline to the surface waters is small because vertical transports are comparably large also during periods without major inflows. Our model results suggest that phosphorus released from the sediments between 60 and 100 m depth in the East Gotland Basin contributes to the eutrophication, especially in the coastal regions of the eastern Baltic Proper.

  • 75.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Gustafson, B.G.
    Baltic Nest Institute, Resilience Centre, Stockholm University, Sweden.
    Hordoir, Robinson
    SMHI, Research Department, Oceanography.
    Höglund, Anders
    SMHI, Research Department, Oceanography.
    Kuznetsov, I.
    Baltic Sea Research Institute Warnemünde, Germany.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Savchuk, O.P.
    Baltic Nest Institute, Resilience Centre, Stockholm University, Sweden.
    Quality assessment of state-of-the-art coupled physical-biogeochemical models in hind cast simulations 1970-20052010Report (Other academic)
    Abstract [en]

    The objectives of the project ECOSUPPORT (Advanced modeling tool for scenarios of the Baltic Sea ECOsystem to SUPPORT decision making) are to calculate the combined effects of changing climate and changing human activity (e.g. changing nutrient loads) on the Baltic Sea ecosystem. Three state-of-the-art coupled physical-biogeochemical models (BALTSEM, ERGOM, and RCO-SCOBI) are used to calculate changing concentrations of nitrate, ammonium, phosphate, diatoms, flagellates, cyanobacteria, zooplankton, detritus, and oxygen in the Baltic Sea. The models are structurally different in that ERGOM and RCO-SCOBI are 3D circulation models with uniform high horizontal resolution while BALTSEM resolves the Baltic Sea spatially in 13 sub-basins. This report summarises first results of the quality assessment and model intercomparison within ECOSUPPORT. Results from hindcast simulations are compared with observations for the period 1970-2005. We found that all three investigated models are able to reproduce the observed variability of biogeochemical cycles well. 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. Avsikten med projektet ECOSUPPORT (Advanced modeling tool for scenarios of the Baltic Sea ECOsystem to SUPPORT decision making) är att undersöka hur klimatförändringar tillsammans med mänsklig aktivitet (förändrad närsaltstillförsel) påverkar Östersjöns ekosystem. Tre kopplade fysiska-biogeokemiska modeller (BALTSEM, ERGOM, and RCO-SCOBI) används för att beräkna hur koncentrationer av nitrat, ammonium, fosfat, diatoméer, flagellater, cyanobakterier, djurplankton, detritus och löst syrgas i Östersjön förändras. Modellerna skiljer sig strukturellt åt genom att ERGOM och RCO-SCOBI är tredimensionella modeller med hög horisontell upplösning medan BALTSEM delar upp östersjön rumsligt i 13 delbassänger. Denna rapport sammanfattar resultaten från en första modelljämförelse och kvalitetsbedömning där modellresultat för tidsperioden 1970-2005 jämförs med observationer från samma period. Alla tre modellerna visar att de kan återskapa den observerade biogeokemiska variabiliteten väl. Osäkerheter är huvudsakligen relaterade till skillnader i andelen av näringstillförseln från land som antas vara biologiskt tillgänglig och till beskrivningarna av viktiga processer, som t.ex. flöden från sedimenten, där kunskapen för närvarande är bristfällig.

  • 76.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Gustafson, B.G
    Kuznetsov, Ivan
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Neumann, T.
    Savchuk, O. P.
    Evaluation of biogeochemical cycles in an ensemble of three state-of-the-art numerical models of the Baltic Sea2011In: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 88, no 2, p. 267-284Article in journal (Refereed)
    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. ©

  • 77.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Hansen, J.
    National Environmental Research Institute, Aarhus University, Denmark.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Myrberg, K.
    Finnish Environment Institute, Finland Nordic.
    Ryabchenko, V.A.
    St. Petersburg Branch, P.P.Shirshov Institute of Oceanology, Russia.
    Skogen, Morten
    Institute of Marine Research, Norway.
    Eutrophication Status Report of the North Sea, Skagerrak, Kattegat and the Baltic Sea: A model study Years 2001-20052011Report (Other academic)
    Abstract [en]

    This joint status report for the North Sea, Skagerrak, Kattegat and the Baltic Sea area is carried out by SMHI Sweden, IMR Norway, NERI Denmark, SPBIO Russia, and SYKE Finland as a part of the project “A Baltic and NORth sea Model eutrophication Assessment in a future cLimate” (ABNORMAL), supported by the Nordic Council of Ministers’ Sea and Air Group (NMR-HLG). The previous NMR-HLG projects NO COMMENTS and BANSAI focused on the establishment and main-tenance of operational models and the use of these to develop methods for assessing the eutrophication status. Within ABNORMAL the issues are brought forward with a focus also on the use of ecological models for an assessment of marine eutrophication in a future climate. The main finding of this study is the proposed way of combining observations and results from an ensemble of ecological models to make an assessment of the eutrophication status in present climate for five different years (2001-2005). Threshold values and methodology from the Oslo and Paris Commissions (OSPAR) and the Helsinki Commission (HELCOM) are used and possible improvements of the methods are briefly discussed. The assessment of eutrophication status according to the integration of the categorized assessment parameters 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.

  • 78.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Hansen, J.L.S:
    Department of Bioscience, Aarhus University, Denmark.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Molchanov, M.S.
    St. Petersburg Branch, P.P. Shirshov Institute of Oceanology, Russia.
    Ryabchenko, V.A.
    St. Petersburg Branch, P.P. Shirshov Institute of Oceanology, Russia.
    Skogen, Morten
    Institute of Marine Research, Norway.
    Eutrophication Status Report of the North Sea, Skagerrak, Kattegat and the Baltic Sea: A model study. Present and future climate2013Report (Other academic)
    Abstract [en]

    An ensemble of models has been used to assess eutrophication in the North Sea and Baltic Sea in the present and the future climate, using a method suggested in Almroth and Skogen (2010). In the control run, the assessment of eutrophication status according to the integration of the categorized assessment parameters 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 (Fig. 16).The temperature increase by itself will worsen the oxygen condition throughout the area and on top of this; elevated nutrient levels in the whole Baltic will amplify this effect due to elevated primary production. Therefore declining oxygen condition and increasing phytoplankton biomasses will be the main problem causing the areas to be classified as problem areas. In the Western Gotland Basin low oxygen seems to be the sole reason for this classification. In the North Sea, the classification as potential problem areas are due to high nitrate and N:P ratio. 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. Also in the North Sea there seems to be no obvious changes in the projected future climate. Comparing the ECHAM5 driven changes to simulations using the HadCM3 forcing show that; all changes except the surface layer winterDIN in the future climate have the same sign and that; the overall eutrophication status assessment is robust and insensitive to the choice of future scenario.

  • 79.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Lindqvist, Stina
    Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.
    Almroth-Rosell, Elin
    SMHI, Research Department, Oceanography.
    Edman, Moa
    SMHI, Research Department, Oceanography.
    Wåhlstrom, Irene
    SMHI, Research Department, Oceanography.
    Bartoli, Marco
    Klaipeda University, Lithuania.
    Burska, Dorota
    Institute of Oceanography, University of Gdansk, Poland.
    Carstensen, Jacob
    Aarhus University, Denmark.
    Hellemann, Dana
    Department of Environmental Sciences, University of Helsinki, Helsinki, Finland.
    Hietanen, Susanna
    Department of Environmental Sciences, University of Helsinki, Helsinki, Finland.
    Hulth, Stefan
    Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.
    Janas, Urszula
    Institute of Oceanography, University of Gdansk, Poland.
    Kendzierska, Halina
    Institute of Oceanography, University of Gdansk, Poland.
    Pryputniewicz-Flis, Dorota
    Institute of Oceanography, University of Gdansk, Poland.
    Voss, Maren
    Leibniz Institute for Baltic Sea Research Warnemünde, Germany.
    Zilius, Mindaugas
    Klaipeda University, Lithuania.
    Linking process rates with modellingdata and ecosystem characteristics2017Report (Refereed)
    Abstract [en]

    This report is related to the BONUS project “Nutrient Cocktails in COAstal zones of the Baltic Sea” alias COCOA. The aim of BONUS COCOA is to investigate physical, biogeochemical and biological processes in a combined and coordinated fashion to improve the understanding of the interaction of these processes on the removal of nutrients along the land-sea interface. The report is especially related to BONUS COCOA WP 6 in which the main objective is extrapolation of results from the BONUS COCOA learning sites to coastal sites around the Baltic Sea in general. Specific objectives of this deliverable (D6.4) were to connect observed process rates with modelling data and ecosystem characteristics.

    In the report we made statistical analyses of observations from BONUS COCOA study sites together with results from the Swedish Coastal zone Model (SCM). Eight structural variables (water depth, temperature, salinity, bottom water concentrations of oxygen, ammonium, nitrate and phosphate, as well as nitrogen content in sediment) were found common to both the experimentally determined and the model data sets. The observed process rate evaluated in this report was denitrification. In addition regressions were tested between observed denitrification rates and several structural variables (latitude, longitude, depth, light, temperature, salinity, grain class, porosity, loss of ignition, sediment organic carbon, total nitrogen content in the sediment,  sediment carbon/nitrogen-ratio, sediment chlorphyll-a as well as bottom water concentrations of oxygen, ammonium, nitrate, and dissolved inorganic  phosphorus and silicate) for pooled data from all learning sites.

    The statistical results showed that experimentally determined multivariate data set from the shallow, illuminated stations was mainly found to be similar to the multivariate data set produced by the SCM model. Generally, no strong correlations of simple relations between observed denitrification and available structural variables were found for data collected from all the learning sites. We found some non-significant correlation between denitrification rates and bottom water dissolved inorganic phosphorous and dissolved silica but the reason behind the correlations is not clear.

    We also developed and evaluated a theory to relate process rates to monitoring data and nutrient retention. The theoretical analysis included nutrient retention due to denitrification as well as burial of phosphorus and nitrogen. The theory of nutrient retention showed good correlations with model results. It was found that area-specific nitrogen and phosphorus retention capacity in a sub-basin depend much on mean water depth, water residence time, basin area and the mean nutrient concentrations in the active sediment layer and in the water column.

  • 80.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Martensson, S.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Modeling the impact of reduced sea ice cover in future climate on the Baltic Sea biogeochemistry2013In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 40, no 1, p. 149-154Article in journal (Refereed)
    Abstract [en]

    In a warming future climate, the sea ice cover is expected to decrease, with very likely large consequences for the marine ecosystem. We investigated the impact of future sea ice retreat on the Baltic Sea biogeochemistry at the end of the century, using an ensemble of regionalized global climate simulations. We found that the spring bloom will start by up to one month earlier and winds and wave-induced resuspension will increase, causing an increased transport of nutrients from the productive coastal zone into the deeper areas. The internal nutrient fluxes do not necessarily increase because they also depend on oxygen and temperature conditions of the bottom water. Winter mixing increases in areas having reduced ice cover and in areas having reduced stratification due to increased freshwater supply. The reduced sea ice cover therefore partly counteracts eutrophication because increased vertical mixing improves oxygen conditions in lower layers. Citation: Eilola, K., S. Martensson, and H. E. M. Meier (2013), Modeling the impact of reduced sea ice cover in future climate on the Baltic Sea biogeochemistry, Geophys. Res. Lett., 40, 149-154, doi:10.1029/2012GL054375.

  • 81.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Almroth, Elin
    SMHI, Research Department, Oceanography.
    Höglund, Anders
    SMHI, Research Department, Oceanography.
    Transports and budgets of oxygen and phosphorus in the Baltic sea2008Report (Other academic)
    Abstract [en]

    In this report we present budgets of oxygen and phosphorus for the deeper layers of the Baltic proper. The budgets give calculations of sedimentation, erosion and horizontal and vertical transports based on model simulations. The fluxes of oxygen and phosphorus as well as trends in contents have been computed.

  • 82.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Almroth-Rosell, Elin
    SMHI, Research Department, Oceanography.
    On the dynamics of oxygen, phosphorus and cyanobacteria in the Baltic Sea; A model study2009In: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 75, no 1-2, p. 163-184Article in journal (Refereed)
    Abstract [en]

    Oxygen and phosphorus dynamics and cyanobacterial blooms in the Baltic Sea are discussed using results from the Swedish Coastal and Ocean Biogeochemical model (SCOBI) coupled to the Rossby Centre Ocean model (RCO). The high-resolution circulation model is used to simulate the time period from 1902 to 1998 using reconstructed physical forcing and climatological nutrient loads of the late 20th century. The analysis of the results covers the last 30 years of the simulation period. The results emphasize the importance of internal phosphorus and oxygen dynamics, the variability of physical conditions and the natural long-term variability of phosphorus supplies from land on the phosphorus content in the Baltic Sea. These mechanisms play an important role on the variability of available surface layer phosphorus in late winter in the Baltic Sea. The content of cyanobacteria increases with the availability of phosphorus in the surface layers of the Baltic proper and the probability for large cyanobacteria blooms in the model is rapidly increased at higher concentrations of excess dissolved inorganic phosphorus in late winter. The natural increase of phosphorus supplies from land due to increased river runoff since the early 1970s may to a large degree explain the increased phosphorus content in the Baltic proper. Another significant fraction of the increase is explained by the release of phosphorus from increased anoxic areas during the period. These results refer to the long-term variability of the phosphorus cycle. In accordance to earlier publications is the short-term (i.e. interannual) variability of the phosphorus content in the Baltic proper mainly explained by oxygen dependent sediment fluxes. (c) 2008 Elsevier B.V. All rights reserved.

  • 83.
    Eilola, Kari
    et al.
    SMHI, Research Department, Oceanography.
    Sahlberg, Jörgen
    SMHI, Professional Services.
    Model assessment of the predicted environmental consequences for OSPAR problem areas following nutrient reductions2009Report (Other academic)
    Abstract [en]

    The Swedish Coastal and Ocean Biogeochemical model (SCOBI) is used for the assessment of eutrophication status in the Skagerrak and the Kattegat, and of the following long-term effects on the ecosystem for the 50% nutrient reduction target (PARCOM Recommendation 88/2). Model validation and the final reporting of the results in accordance with the OSPAR comprehensive procedure are presented.The model is validated by a comparison of a long time series (1985-2002) of the model results to data from a number of stations representing different parts of the model domain. A quantitative examination of the model performance is done by a comparison between the seasonal and annual averages of the model results and in-situ data. The model response to nutrient reductions shows that reducing nutrient inputs from land have the largest effects on the nitrate concentrations in the Kattegat and along the Swedish coast in the Skagerrak. The effects on phosphate concentrations are relatively small. The largest effect obtained from a 50% reduction of anthropogenic nitrogen and phosphorus from the runoff in one country alone is obtained for Sweden. This model experiment reduces the nitrate and chlorophyll concentrations in the Swedish coastal waters by 5%-10% and 3%-6%, respectively. The annual net production is reduced by 2%-4% and changes in sedimentation are less than 1%. The largest reduction is found in the Kattegat.The combined effect from a 50% reduction of anthropogenic nutrient supplies from land and an anticipated realistic reduction of nutrient concentrations in the Baltic Sea and the North Sea reduces the nitrate and phosphate concentrations in the Kattegat and the Swedish parts of the Skagerrak coastal area by 20%-30%. The average chlorophyll concentrations are reduced by 8%-11%. The annual net production and the sedimentation are reduced by 12%-20% and 5%-12%, respectively.

  • 84. Eissler, Y
    et al.
    Sahlsten, Elisabeth
    SMHI, Research Department, Oceanography.
    Quinones, R A
    Effects of virus infection on respiration rates of marine phytoplankton and microplankton communities2003In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 262, p. 71-80Article in journal (Refereed)
    Abstract [en]

    The possible influence of viral infection on respiration rates in marine microbial pelagic communities was assessed by means of 3 experiments on respiration rate with viral concentrate addition on single-species cultures of Mantoniella sp. and Micromonas pusilla and another 3 on natural microplankton communities (organisms < 200 mum) from the Kattegat Sea ((A) over circle stol) and the Baltic Sea. Coastal surface seawater samples were taken during cruises of the RVs 'Ancylus' and 'Argos' during winter and spring 2000. Approximately 50 to 70 l of seawater were concentrated by ultrafiltration. The experiments were started by adding a viral particle concentrate to a container with algae or a natural microplankton community; a control container was kept free of the viral concentrate addition. Oxygen concentration determinations were carried out on each treatment and control to measure respiration rates throughout the incubation period. The in vivo chlorophyll a fluorescence was also monitored as an indication of algal infection. The rates of respiration indicated that the addition of the viral particle concentrate affected the respective metabolisms of the Mantoniella sp. and Micromonas pusilla cultures as well as natural microplankton communities. Viral infection decreased the Mantoniella sp. respiration rate (by 96%) and increased the Micromonas pusilla respiration rate (by 235%). Hence, if our results can be extrapolated to nature, then, at least in a bloom situation, the fate of primary production and carbon fluxes could be strongly modulated by viral infection. The addition of a viral particle concentrate to the microplankton community generated complex responses in terms of respiration rates, which increased (by 84%) or remained similar to the controls. Our results suggest that viral infection of microplanktonic organisms could be one of the factors significantly modifying pelagic carbon fluxes.

  • 85. ENGQVIST, A
    et al.
    Omstedt, Anders
    SMHI, Research Department, Oceanography.
    WATER EXCHANGE AND DENSITY STRUCTURE IN A MULTIBASIN ESTUARY1992In: Continental Shelf Research, ISSN 0278-4343, E-ISSN 1873-6955, Vol. 12, no 9, p. 1003-1026Article in journal (Refereed)
    Abstract [en]

    A mathematical model of the Himmerfjard estuary. divided into four basins. has been formulated and validated against measured data for 1986. The structure of each sub-basin is assumed to be horizontally homogeneous with vertical mean velocities based upon in- and outflows from adjacent basins and freshwater supply to each basin. The horizontal water exchange is formulated as a quasi-stationary Bernioulli flow, driven by horizontal pressure gradients over the sounds and instantaneously interleaved at a neutral buoyancy level. Thc salinity and temperature profiles measured outside the mouth of the estuary serve as forcing, as do the water level changes, the freshwater run-off and the local wind. Inherent in the model assumptions of the horizontal exchange over the sounds is that only a fraction, alpha, of the pressure gradient is used to accelerate each stratum. Variation of the alpha-value shows that the best statistical fit is found for alpha = 0.15 when compared with water exchange estimates based on measurements in one of the internal sounds tor almost an entire month. Using this alpha-value, in combination with standard mixing parameters and hypsographical data, the model satisfactorily captures the major features of the salinity and temperature-profiles development for the year 1986. This is substantiated by statistical analysis of the salinity profiles in the sub-basins for which different measures of similarity between simulated and measured data give the best fit for the same alpha-value as above.

  • 86. Enmar, Linda
    et al.
    Lake, Irene
    SMHI, Research Department, Oceanography.
    Lundberg, Peter
    Sigray, Peter
    A note on ADCP-based indirect observations of turbulence2016In: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 21, no 1-2, p. 44-52Article in journal (Refereed)
    Abstract [en]

    A 70-day data set from bottom-mounted ADCPs on the two sides of the Faroe-Bank Channel was analysed using the recorded flow variance and echo intensity in the deeper reaches of the passage as proxies for turbulence. A consistent picture emerged, not least since the data losses (which were ascribed to turbulence-induced activation of the fish-elimination option in the ADCP software) could be shown to co-vary with the internal M-2 tide affecting the vertical shear, which in turn proved to be correlated with the flow variance.

  • 87. Enoksson, V
    et al.
    Fogelqvist, E
    Fonselius, Stig
    SMHI, Research Department, Oceanography.
    Nitrogen speciation and nitrification potential in the Skagerrak area during the SKAGEX IV experiment1996In: Deep Sea Research Part I: Oceanographic Research Papers, ISSN 0967-0637, E-ISSN 1879-0119, Vol. 43, no 7, p. 1029-1044Article in journal (Refereed)
    Abstract [en]

    Nitrification was studied in relation to the inorganic nitrogen species in the Skagerrak in May 1991 during the SKAGEX IV expedition. The distribution of density, ammonium, nitrite and nitrate are shown for the four north-south sections and, for two of these, the distribution of nitrification potential (NP, i.e. nitrification with excess ammonium during incubation) and oxygen saturation values are also presented. Highly saline and ammonium rich Atlantic/North Sea water was sinking into the Skagerrak along the Danish slope, where it gradually mixed with the ''old'' and relatively stagnant Skagerrak water with high nitrate concentrations but very low ammonium concentrations. The zone of mixing was characterised by high concentrations of nitrite, an intermediate product during the,bacterial oxidation of ammonium to nitrate. The NP rates were in the range 0-60 nmoll(-1) day(-1). Water masses with undetectable or low NP included the upper water layers and water flowing in at depth. Maximum NP rates were found in or near the zone with high nitrite concentrations just below the upper layers and at the border between inflowing water and ''old'' Skagerrak water at depth. It is postulated that nitrification was stimulated in the mixture of inflowing, ammonium rich water and ''old'' Skagerrak water. Copyright (C) 1996 Elsevier Science Ltd.

  • 88. Eriksson, Leif E. B.
    et al.
    Borenäs, Karin
    SMHI, Core Services.
    Dierking, Wolfgang
    Berg, Anders
    Santoro, Maurizio
    Pemberton, Per
    SMHI, Research Department, Oceanography.
    Lindh, Henrik
    SMHI, Core Services.
    Karlson, Bengt
    SMHI, Research Department, Oceanography.
    Evaluation of new spaceborne SAR sensors for sea-ice monitoring in the Baltic Sea2010In: CANADIAN JOURNAL OF REMOTE SENSING, ISSN 1712-7971, Vol. 36, p. S56-S73Article in journal (Refereed)
    Abstract [en]

    In this study, synthetic aperture radar (SAR) data from the Advanced Land Observing Satellite (ALOS) and the Envisat, RADARSAT-2, and TerraSAR-X satellites were compared to evaluate their usefulness for sea-ice monitoring in the Baltic Sea. Radar signature characteristics at different frequencies, polarizations, and spatial resolutions are presented for three examples from 2009. C-band like-polarization data, which have been used for operational sea-ice mapping since the early 1990s, serve as a reference. Advantages and disadvantages were identified for the different SAR systems and imaging modes. One conclusion is that cross-polarized data improve the discrimination between sea ice and open water. Another observation is that it is easier to identify ice ridges in L-band data than in images from shorter wavelengths. The information content of X-and C-band images is largely equivalent, whereas L-band data provide complementary information. L-band SAR also seems to be less sensitive to wet snow cover on the ice.

  • 89.
    Fogelqvist, Elisabet
    SMHI, Research Department, Oceanography.
    DIMETHYLSULFIDE (DMS) IN THE WEDDELL SEA-SURFACE AND BOTTOM WATER1991In: Marine Chemistry, ISSN 0304-4203, E-ISSN 1872-7581, Vol. 35, no 1-4, p. 169-177Article in journal (Refereed)
    Abstract [en]

    Dimethylsulphide (DMS) has been measured in the water of the Weddell Sea during the austral summer 1988-1989. In the Summer Surface Water, which generally contained a maximum at 20-50 m depth, the concentrations were extremely high, up to 12 000 ng l-1 DMS, but showed a significant spatial variability. Data from the central part of the Weddell Sea show a steep gradient downwards, and below about 200 m depth, in the Weddell Sea Deep Water, concentrations were below the detection limit of 1 ng l-1. The high-density Ice Shelf Water, when flowing down the continental slope, brings DMS down to the Weddell Sea Bottom Water in significant amounts before its eventual decay.

  • 90.
    Fogelqvist, Elisabet
    et al.
    SMHI, Research Department, Oceanography.
    Krysell, Mikael
    SMHI, Core Services.
    NATURALLY AND ANTHROPOGENICALLY PRODUCED BROMOFORM IN THE KATTEGATT, A SEMIENCLOSED OCEANIC BASIN1991In: Journal of Atmospheric Chemistry, ISSN 0167-7764, E-ISSN 1573-0662, Vol. 13, no 4, p. 315-324Article in journal (Refereed)
    Abstract [en]

    The origin of bromoform in seawater and atmosphere, as well as possible sinks and breakdown mechanisms, is discussed. A bromoform budget is calculated for the Kattegatt area between Sweden and Denmark, where the input of bromoform from a power plant is significant. Both anthropogenically (250 x 10(6) g yr-1) and biogenically (350 x 10(6) g yr-1, 0.016 g m-2 yr-1) produced bromoform is likely to have a great impact locally on the inventory and the release to the atmosphere. Using measured sur-face concentrations of bromoform, the total annual release from the Kattegatt to the atmosphere is estimated to 550 x 10(6) g (0.025 g m-2 yr-1).

  • 91.
    Fonselius, Stig
    SMHI, Research Department, Oceanography.
    Kattegatt - havet i väster1987Report (Other academic)
  • 92.
    Fonselius, Stig
    SMHI, Research Department, Oceanography.
    Skagerrak - porten mot Nordsjön1990Report (Other academic)
  • 93.
    Fonselius, Stig
    SMHI, Research Department, Oceanography.
    Skagerrak - the gateway to the North Sea1990Report (Other academic)
  • 94.
    Fonselius, Stig
    SMHI, Research Department, Oceanography.
    The upwelling of nutrients in the central Skagerrak1996In: Deep-sea research. Part II, Topical studies in oceanography, ISSN 0967-0645, E-ISSN 1879-0100, Vol. 43, no 1, p. 57-71Article in journal (Refereed)
    Abstract [en]

    Measurements of inorganic nutrients during four expeditions to the Skagerrak, within the SKAGEX programme in 1990 and 1991, form the basis for estimation of the magnitude of potential new primary production caused by upwelling of nutrients in the central part of Skagerrak. Calculations have been made using available transport and upwelling data given in the literature together with the concentrations of nitrogenous nutrients (nitrite, nitrate and ammonia), phosphate and silicate in the lower part of the pycnocline in the upwelling area. The potential new production of organic matter due to upwelling is estimated at 6.15 x 10(6) t C year(-1) based on a vegetative period of 8 months. This corresponds to 190 gC m(-2) year(-1) if distributed over the entire Skagerrak area. A possible contribution to diatom production from the upwelling of silicate is estimated to be 2.09 x 10(6) t C year(-1), which corresponds to 64 gC m(-2) year(-1).

  • 95.
    Fonselius, Stig
    et al.
    SMHI, Research Department, Oceanography.
    Valderrama, Jorge
    SMHI, Research Department, Oceanography.
    One hundred years of hydrographic measurements in the Baltic Sea2003In: Journal of Sea Research, ISSN 1385-1101, E-ISSN 1873-1414, Vol. 49, no 4, p. 229-241Article in journal (Refereed)
    Abstract [en]

    The first measurements of salinity of the deep water in the open Baltic Sea were made in the last decades of the 1800s. At a Scandinavian science meeting in Copenhagen in 1892, Professor Otto Pettersson from Sweden suggested that regular measurements of hydrographic parameters should be carried out at some important deep stations in the Baltic Sea. His suggestion was adopted and since that time we have rather complete hydrographical data from the Bornholm Deep, the Gotland Deep, and the Landsort Deep and from some stations in the Gulf of Bothnia. The measurements were interrupted in the Baltic Proper during the two World Wars. At the beginning only salinity, temperature and dissolved oxygen were measured and one or two expeditions were carried out annually, mostly in summer. In the 1920s also alkalinity and pH were occasionally measured and total carbonate was calculated. A few nutrient measurements were also carried out. After World War 11 we find results from four or more expeditions every year and intercalibration of methods was arranged. Results of temperature, salinity and dissolved oxygen measurements from the Bornholm. Deep, the Gotland Deep, the Landsort Deep and salinity measurements from three stations in the Gulf of Bothnia, covering the whole 20th century are presented and discussed. The salinity distribution and the variations between oxygen and hydrogen sulphide periods in the deep water of the Gotland Deep and the Landsort Deep are demonstrated. Series of phosphate and nitrate distribution in the Gotland Deep are shown from the 1950s to the present and the effects of the stagnant conditions are briefly discussed. Two large inflows of highly saline water, the first during the First World War and the second in 195 1, are demonstrated. The 20th century minimum salinity of the bottom water in the Baltic Proper in 1992 is discussed. (C) 2003 Published by Elsevier Science B.V.

  • 96. Fransner, Filippa
    et al.
    Gustafsson, Erik
    Tedesco, Letizia
    Vichi, Marcello
    Hordoir, Robinson
    SMHI, Research Department, Oceanography.
    Roquet, Fabien
    Spilling, Kristian
    Kuznetsov, Ivan
    Eilola, Kari
    SMHI, Research Department, Oceanography.
    Morth, Carl-Magnus
    Humborg, Christoph
    Nycander, Jonas
    Non-Redfieldian Dynamics Explain Seasonal pCO(2) Drawdown in the Gulf of Bothnia2018In: Journal of Geophysical Research - Oceans, ISSN 2169-9275, E-ISSN 2169-9291, Vol. 123, no 1, p. 166-188Article in journal (Refereed)
  • 97. Fransner, Filippa
    et al.
    Nycander, Jonas
    Morth, Carl-Magnus
    Humborg, Christoph
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Hordoir, Robinson
    SMHI, Research Department, Oceanography.
    Gustafsson, Erik
    Deutsch, Barbara
    Tracing terrestrial DOC in the Baltic SeaA 3-D model study2016In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 30, no 2, p. 134-148Article in journal (Refereed)
    Abstract [en]

    The fate of terrestrial organic matter brought to the coastal seas by rivers and its role in the global carbon cycle are still not very well known. Here the degradation rate of terrestrial dissolved organic carbon (DOCter) is studied in the Baltic Sea, a subarctic semienclosed sea, by releasing it as a tracer in a 3-D circulation model and applying linear decay constants. A good agreement with available observational data is obtained by parameterizing the degradation in two rather different ways: one by applying a decay time on the order of 10years to the whole pool of DOCter and one by dividing the DOCter into onerefractory pool and one pool subject to a decay time on the order of 1year. The choice ofparameterization has asignificant effect on where in the Baltic Sea the removal takes place, which can be of importance whenmodeling the full carbon cycle and the CO2 exchange with the atmosphere. In both cases the biogeochemical decayoperates on time scales less than the water residence time. Therefore, only a minor fraction of the DOCter reaches the North Sea, whereas approximately 80% is removed by internal sinks within the Baltic Sea. This further implies that DOCter mineralization is an important link in land-sea-atmosphere cycling of carbon in coastal and shelf seas that are heavily influenced by riverine DOC.

  • 98.
    Fransson, L.
    et al.
    SMHI.
    Håkansson, Bertil
    SMHI, Research Department, Oceanography.
    Omstedt, Anders
    SMHI, Research Department, Oceanography.
    Stehn, L.
    SMHI.
    Sea ice properties studied from the ice-breaker Tor during BEPERS-881989Report (Other academic)
  • 99. Fredriksson, S. T.
    et al.
    Arneborg, Lars
    SMHI, Research Department, Oceanography.
    Nilsson, H.
    Handler, R. A.
    Surface shear stress dependence of gas transfer velocity parameterizations using DNS2016In: Journal of Geophysical Research - Oceans, ISSN 2169-9275, E-ISSN 2169-9291, Vol. 121, no 10, p. 7369-7389Article in journal (Refereed)
  • 100.
    Funquist, Lennart
    SMHI, Research Department, Oceanography.
    An operational Baltic Sea circulation model: Part 1. Barotropic version1993Report (Other academic)
1234567 51 - 100 of 370
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