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  • 201.
    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.

  • 202.
    Höglund, Anders
    et al.
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Broman, Barry
    SMHI, Research Department, Climate research - Rossby Centre.
    Kriezi, Ekaterini
    SMHI.
    Validation and correction of regionalised ERA-40 wind fields over the Baltic Sea using the Rossby Centre Atmosphere model RCA3.02009Report (Other academic)
    Abstract [en]

    Surface wind fields from ERA-40 regionalised with the Rossby Centre Atmosphere model RCA3.0 are underestimated. In this report a method for correcting the wind fields is evaluated. The method is based on the empirical linear relationship between gusty winds and mean wind. For the validation observations from 26 automatic stations along the Swedish coasts have been used. We found that the validation of wind over the open sea is difficult due to the impact of land that cannot be resolved properly by the atmospheric model as the horizontal grid resolution amounts to about 25 km. In addition, long homogeneous wind data sets are not available due to a switch from manual to automatic readings during the 1990s. The results show that the correction method improves the frequency distribution of simulated wind speed at most stations. Thus the corrected wind fields may be used to force Baltic Sea models during 1961-2004. However, the suggested correction method should be regarded only as a temporary solution while waiting for improved boundary layer

  • 203.
    Karlson, Bengt
    et al.
    SMHI, Research Department, Oceanography.
    Axe, Philip
    SMHI, Research Department, Oceanography.
    Funquist, Lennart
    SMHI, Research Department, Oceanography.
    Kaitala, Seppo
    FIMR, Finnish Institute for Marine Research/SYKE Marine Centre.
    Sørensen, Kai
    NIVA, Norwegian Institute for Water Research.
    Infrastructure for marine monitoring and operational oceanography2009Report (Other academic)
    Abstract [en]

    Automated systems for observing physical, chemical and biological conditions in the sea are being implemented worldwide as part of the Global Ocean Observing System. This report describes their use in the Baltic and the Skagerrak-Kattegat areas. An evaluation of the use of FerryBox systems in the waters around Sweden shows that the quality of data from near surface waters is high, and that the frequent sampling makes possible observations of short term phenomena such as algal blooms. These events are often overlooked by infrequent sampling using research vessels, which leads to erroneous estimates of phytoplankton biomass, ecosystem carrying capacity etc. Data come from the Helsinki Lübeck route, operated by the Finnish Institute for Marine Research and from routes in the Skagerrak- Kattegat operated by the Norwegian Institute for Water Research. FerryBox data were compared with data from traditional sampling, principally from RV Argos operated by SMHI, but also from the HELCOM databank at ICES.Observations using automated systems such as satellites, stationary platforms (buoys and piles) and FerryBox systems may contribute substantially to improving the quality of results from models describing the physical and biogeochemical conditions in Scandinavian waters. Boundary conditions for models can be obtained using measurements in the eastern North Sea and in the Skagerrak, while data assimilation from a network of buoys, FerryBoxsystems and research vessels improves the quality of model results. Today, between four and six automated oceanographic observation systems are in operation in Swedish waters, which can be compared to more than 700 for meteorological purposes. A dramatic increase in the number of observations is necessary for effective data assimilation. To make the observations useful for biogeochemical models, parameters such as inorganic nutrients, phytoplankton biomass and oxygen must be added to the basic parameters salinity and temperature.A detailed proposal for a new infrastructure for marine monitoring and operational oceanography in Sweden is put forward. FerryBox systems should be operated in collaboration with institutes in Finland, Estonia, Poland, Germany, Denmark and Norway. Coastal buoys contribute to the monitoring needs of the EU Water Framework Directive while offshore buoys are for long term climate and ecological research and for fulfilment of the EU Marine Strategy Directive . Products combining satellite data with in-situ observations should be developed. These automated systems augment monitoring using research vessels but do not replace it. SMHI, the Swedish Institute for the Marine Environment, the Swedish Water Authorities, the Swedish Environmental Protection Agency, Swedish Navy, Coast guard, Maritime Administration and Board of Fisheries are proposed to govern and operate the system, with SMHI as the lead partner. The function -National data host for operational oceanographic data- is proposed, to be established at the National Oceanographic Data Centre at SMHI.A number of indicators for describing the status of the pelagic environment around Sweden are proposed. Some already exist while some are new. New ones include indicators for acidification, changes in plankton community structure and physical climate indicators. Basin wide indicators are based on measurements using a combination of sampling platforms. Other indicators are more specific, e.g. for transport between basins and inflow of water to the deep basins of the Baltic Proper.This report was commissioned by the Swedish National Environment Protection Agency

  • 204.
    Skogen, Morten
    et al.
    Havforskningsinstituttet, Norway.
    Søiland, H.
    Havforskningsinstituttet, Norway.
    Almroth, Elin
    SMHI, Research Department, Oceanography.
    Eilola, Kari
    SMHI, Research Department, Oceanography.
    Sehested Hansen, Ian
    DHI Water & Environment, Denmark.
    The year 2005: An environmental status report of the Skagerrak, Kattegat and the North Sea2009Report (Other academic)
    Abstract [en]

    This is the second year joint status report for the North Sea, Skagerrak and Kattegat area (Fig.1) carried out by SMHI, IMR and DHI as a part of the project BANSAI, supported by the Nordic Council of Ministers’ Sea and Air Group. The aim of the project is to integrate marine observations and ecological model simulations in an annual assessment of the Baltic and the North seas. The present report is mainly based on model estimates of some of the indicators suggested by the OSPAR Common Procedure (c.f. Appendix) for the identification of the eutrophication status of the maritime area (OSPAR, 2002 and 2003). This first joint report serve as a basis for the on-going discussions about the ecological quality indicators included in the assessment, and the way to merge results from different models and observations for the assessment.Estimations of river discharges and model results are used to describe the degree of nutrient enrichment (Category I) defined by the riverine loadings of nitrogen and phosphorus, and winter surface concentrations and ratios of DIN and DIP. The direct effects of nutrient enrichment during the growing season (Category II) are described in terms of the mean and maximum chlorophyll concentrations and model estimations of primary production. The ratio between diatoms and flagellates is used as an indicator of region specific phytoplankton indicator species (Category II). The indirect effects of nutrient enrichment (Category III) are discussed in terms of oxygen depletion in bottom waters. Estimations of region specific background concentrations and threshold values are gathered from the literature and used for the model assessment.The three model systems used for the joint assessment (Fig. 2) cover different parts of the North Sea, Skagerrak and the Kattegat area. Detailed descriptions of the models may be found on the websites presented below the figure.In section 2 the key messages from this assessment will be presented. In section 3, each country gives a brief observations overview for 2005 and some references to other sources and reports that might be useful for the readers. The methods of the assessment are described in section 4. Statistical characteristics of model results and in-situ data are presented in section 5 and the model assessment of eutrophication status is done in section 6. Conclusions and comments to the assessment are presented in section 7.

  • 205. Prendergast, Gabrielle S.
    et al.
    Zurn, Constanze M.
    Bers, A. Valeria
    Head, Ritchie M.
    Hansson, Lars J.
    SMHI, Research Department, Oceanography.
    Thomason, Jeremy C.
    The relative magnitude of the effects of biological and physical settlement cues for cypris larvae of the acorn barnacle, Semibalanus balanoides L.2009In: Biofouling (Print), ISSN 0892-7014, E-ISSN 1029-2454, Vol. 25, no 1, p. 35-44Article in journal (Refereed)
    Abstract [en]

    Barnacle cypris larvae respond to many cues when selecting a settlement site. The settlement of over a million larvae on tiles of different textures, orientations and densities of incumbent settlers was measured on the rocky intertidal at Great Cumbrae, Scotland. Half of the tiles were replaced every tide whereas the others simultaneously accumulated settlers. Factor effects varied on each tide, and converged in the accumulating deployment. Increasing incumbent density led to net loss of settlement, which was less probable on the textures on which fastest settlment occurred ('very fine'), and more probable on those on which settlement was slowest ('smooth'). More settlement occurred on down-facing orientations during daylight and vice versa. Cue ranks were non-linear, so a path analysis model quantified the relative influence of each factor. Gregariousness was the most influential cue measured, although unmeasured factors had greater effects, highlighting the complexity of settlement influences in this species.

  • 206. Kotovirta, Ville
    et al.
    Jalonen, Risto
    Axell, Lars
    SMHI, Research Department, Oceanography.
    Riska, Kaj
    Berglund, Robin
    A system for route optimization in ice-covered waters2009In: Cold Regions Science and Technology, ISSN 0165-232X, E-ISSN 1872-7441, Vol. 55, no 1, p. 52-62Article in journal (Refereed)
    Abstract [en]

    Information about ice is indispensable to navigation in ice-covered sea areas. For vessels traveling long distances in ice, it is worth planning routes that will reduce fuel consumption and travel time, as well as the risk of ending up in hazardous areas or getting stuck in the ice. In addition to observations on board. there is a multitude of data sources available for seafarers like satellite images, ice model data, weather observations and forecasts. However, it is difficult for a human to take into consideration all the time-varying data parameters when planning a route. In this paper, a prototype system for optimizing routes through the ice field is presented. The system integrates state-of-the-art ice modeling, ship transit modeling, and an enduser system as a route optimization tool for vessels navigating in ice-covered waters. The system has recently been validated on board merchant vessels in the Baltic Sea, and the system's performance has been analyzed statistically using AIS data. Based on the AIS data analysis the mean relative error of the estimated transit time was 0.144 [s/s] with a standard deviation of 0.147 [s/s] for long routes (90-650 km), and 0.018 [s/s] with standard deviation of 0.193 [s/s] for 50 km route segments. (C) 2008 Elsevier B.V. All rights reserved.

  • 207. 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.

  • 208. Moellmann, Christian
    et al.
    Diekmann, Rabea
    Muller-Karulis, Barbel
    Kornilovs, Georgs
    Plikshs, Maris
    Axe, Philip
    SMHI, Research Department, Oceanography.
    Reorganization of a large marine ecosystem due to atmospheric and anthropogenic pressure: a discontinuous regime shift in the Central Baltic Sea2009In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 15, no 6, p. 1377-1393Article in journal (Refereed)
    Abstract [en]

    Marine ecosystems such as the Baltic Sea are currently under strong atmospheric and anthropogenic pressure. Besides natural and human-induced changes in climate, major anthropogenic drivers such as overfishing and anthropogenic eutrophication are significantly affecting ecosystem structure and function. Recently, studies demonstrated the existence of alternative stable states in various terrestrial and aquatic ecosystems. These so-called ecosystem regime shifts have been explained mainly as a result of multiple causes, e.g. climatic regime shifts, overexploitation or a combination of both. The occurrence of ecosystem regime shifts has important management implications, as they can cause significant losses of ecological and economic resources. Because of hysteresis in ecosystem responses, restoring regimes considered as favourable may require drastic and expensive management actions. Also the Baltic Sea, the largest brackish water body in the world ocean, and its ecosystems are strongly affected by atmospheric and anthropogenic drivers. Here, we present results of an analysis of the state and development of the Central Baltic Sea ecosystem integrating hydroclimatic, nutrient, phyto- and zooplankton as well as fisheries data. Our analyses of 52 biotic and abiotic variables using multivariate statistics demonstrated a major reorganization of the ecosystem and identified two stable states between 1974 and 2005, separated by a transition period in 1988-1993. We show the change in Baltic ecosystem structure to have the characteristics of a discontinuous regime shift, initiated by climate-induced changes in the abiotic environment and stabilized by fisheries-induced feedback loops in the food web. Our results indicate the importance of maintaining the resilience of an ecosystem to atmospherically induced environmental change by reducing the anthropogenic impact.

  • 209.
    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.

  • 210.
    Graham, Phil
    et al.
    SMHI, Professional Services.
    Chen, Deliang
    Bøssing Christensen, Ole
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Krysanova, Valentina
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Radziejewski, Maciej
    Räisänen, Jouni
    Rockel, Burkhardt
    Ruosteenoja, Kimmo
    Projections of Future Anthropogenic Climate Change2008In: Assessment of Climate Change for the Baltic Sea Basin / [ed] The BACC Author Team, Springer, Berlin , 2008, p. 133-219Chapter in book (Other academic)
  • 211.
    Axe, Philip
    SMHI, Research Department, Oceanography.
    Temporal and spatial monitoring of eutrophication variables in CEMP2008Report (Other academic)
    Abstract [en]

    The OSPAR Revised Eutrophication Monitoring Programme (ETG 05/3/Info.1-E) requests that nutrient "monitoring should include sufficient samples to confirm that the maximum winter nutrient concentration has been determined", while para. 7 of the Terms of Reference for the preparation of guidance on the spatial and temporal resolution of monitoring for nutrients and eutrophication effects (ICG 003) states that "there are at least nine different water types covered by the OSPAR Maritime Area"..."guidance must, therefore, be at least complex enough to cover each type with sufficient clarity to guide contracting parties in their evaluation of the temporal and spatial coverage required to adequately assess the relevant water body".This document summarises the national reports submitted to the OSPAR Intersessional Correspondence Group on Eutrophication Monitoring, and highlights common problems faced in the monitoring of (primarily) inorganic nutrients and chlorophyll. In addition, it presents tests of different approaches to solving the spatial and temporal sampling problems associated with delivering marine eutrophication data.Based on tests of model data, monthly sampling appears adequate to give a good estimate of annual mean concentrations. Buoy data suggests that this would not be sufficient where there is tidal variability. It was not possible to determine maximum concentrations through a practical ship sampling scheme, or by using extreme value statistics.The optimum sampling programme to observe rapid events is likely to be a combination of ferrybox systems, which appear to be reliable and give both good spatial and temporal coverage, combined with buoy observations. To ensure data of sufficient quality, these must be controlled against conventional research vessel observations. Research vessels still have a role in seasonal mapping, and in providing data of sufficient quality for trend analysis from a large area. This is likely to remain so, at leastuntil technologies such as gliders and optical nutrient sensors become widely available and capable of delivering reliable, high quality data.

  • 212.
    Almroth, Elin
    et al.
    SMHI, Research Department, Oceanography.
    Skogen, Morten
    Institute of Marine Research, Bergen, Norway..
    Sehested Hansen, Ian
    Institute of Marine Research, Bergen, Norway..
    Stipa, Tapani
    FMI.
    Niiranen, Susa
    FMI.
    The Year 2006 An Eutrophication Status Report of the North Sea, Skagerrak Kattegat and the Baltic Sea: A demonstration Project2008Report (Other academic)
    Abstract [en]

    This is the third year joint status report for the North Sea, Skagerrak, Kattegat and the Baltic Sea area (Fig. 1) carried out by SMHI, IMR, DHI and FIMR as a part of the project BANSAI, supported by the Nordic Council of Ministers’ Sea and Air Group. The aim of the demonstration project is to integrate marine observations and eutrophication model simulations in an annual eutrophication assessment of the Baltic and the North seas. The present report is mainly based on model estimates of some of the indicators suggested by the OSPAR Common Procedure (c.f. Appendix) for the identification of the eutrophication status of the maritime area (OSPAR, 2005). This report serve as a basis for the on-going discussions about the ecological quality indicators included in the assessment, and the way to merge results from different models and observations for the assessment.Estimations of river discharges and model results are used to describe the degree of nutrient enrichment (Category I) defined by the riverine loadings of nitrogen and phosphorus, and winter surface concentrations and ratios of DIN and DIP. The direct effects of nutrient enrichment during the growing season (Category II) are described in terms of the mean and maximum chlorophyll-a concentrations and model estimations of primary production. The ratio between diatoms and flagellates is used as an indicator of region specific phytoplankton indicator species (Category II). The indirect effects of nutrient enrichment (Category III) are discussed in terms of oxygen depletion in bottom waters. Estimations of region specific background concentrations and threshold values are gathered from the literature (Helcom, 2006; OSPAR, 2005) and used for the model assessment. The four model systems used for the joint assessment (Fig. 2) cover different parts of the North Sea, Skagerrak, Kattegat and the Baltic Sea area. Detailed descriptions of the models may be found on the web-sites presented below the figure.In section 2 the key messages from this assessment will be presented. In section 3, each country gives a brief observations overview for 2006 and some references to other sources and reports that might be useful for the readers. The methods of the assessment are described in section 4. Statistical characteristics of model results and in-situ data are presented in section 5 and the model assessment of eutrophication status is done in section 6. Conclusions and comments to the assessment are presented in section 7.

  • 213.
    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.

  • 214.
    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.

  • 215. Prendergast, Gabrielle S.
    et al.
    Zurn, Constanze M.
    Bers, A. Valeria
    Head, Ritchie M.
    Hansson, Lars J.
    SMHI, Research Department, Oceanography.
    Thomason, Jeremy C.
    Field-based video observations of wild barnacle cyprid behaviour in response to textural and chemical settlement cues2008In: Biofouling (Print), ISSN 0892-7014, E-ISSN 1029-2454, Vol. 24, no 6, p. 449-459Article in journal (Refereed)
    Abstract [en]

    Many marine invertebrate larvae respond behaviourally to environmental settlement cues, yet behaviours are often only inferred from settlement patterns or are limited to laboratory studies. The behaviour of wild cypris larvae of Semibalanus balanoides L. was filmed on settlement tiles in the field. Tiles were of five different textures with a nested treatment of crude conspecific adult extract (AE). The effects of texture and AE on eleven defined behaviours were analysed. Texture affected the gross and net exploratory distances, velocity, acceleration and time spent exploring. AE attracted more cyprids during the first minute of immersion and increased the time spent on surfaces. Relatively few arrivals that either travel far and fast, or exit the surface rapidly, may indicate a lower chance of settlement. An increase in time spent on a surface may increase the probability of being in contact with the surface when the sign stimulus to settle occurs.

  • 216. Burchard, Hans
    et al.
    Craig, Peter D.
    Gemmrich, Johannes R.
    van Haren, Hans
    Mathieu, Pierre-Philippe
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Smith, W. Alex M. Nimmo
    Prandke, Hartmut
    Rippeth, Tom P.
    Skyllingstad, Eric D.
    Smyth, William D.
    Welsh, David J. S.
    Wijesekera, Hemantha W.
    Observational and numerical modeling methods for quantifying coastal ocean turbulence and mixing2008In: Progress in Oceanography, ISSN 0079-6611, E-ISSN 1873-4472, Vol. 76, no 4, p. 399-442Article, review/survey (Refereed)
    Abstract [en]

    In this review paper, state-of-the-art observational and numerical modeling methods for small scale turbulence and mixing with applications to coastal oceans are presented in one context. Unresolved dynamics and remaining problems of field observations and numerical simulations are reviewed on the basis of the approach that modern process-oriented studies should be based on both observations and models. First of all, the basic dynamics of surface and bottom boundary layers as well as intermediate stratified regimes including the interaction of turbulence and internal waves are briefly discussed. Then, an overview is given on just established or recently emerging mechanical, acoustic and optical observational techniques. Microstructure shear probes although developed already in the 1970s have only recently become reliable commercial products. Specifically under surface waves turbulence measurements are difficult due to the necessary decomposition of waves and turbulence. The methods to apply Acoustic Doppler Current Profilers (ADCPs) for estimations of Reynolds stresses, turbulence kinetic energy and dissipation rates are under further development. Finally, applications of well-established turbulence resolving particle image velocimetry (PIV) to the dynamics of the bottom boundary layer are presented. As counterpart to the field methods the state-of-the-art in numerical modeling in coastal seas is presented. This includes the application of the Large Eddy Simulation (LES) method to shallow water Langmuir Circulation (LC) and to stratified flow over a topographic obstacle. Furthermore, statistical turbulence closure methods as well as empirical turbulence parameterizations and their applicability to coastal ocean turbulence and mixing are discussed. Specific problems related to the combined wave-current bottom boundary layer are discussed. Finally, two coastal modeling sensitivity studies are presented as applications, a two-dimensional study of upwelling and downwelling and a three-dimensional study for a marginal sea scenario (Baltic Sea). It is concluded that the discussed methods need further refinements specifically to account for the complex dynamics associated with the presence of surface and internal waves. (c) 2008 Elsevier Ltd. All rights reserved.

  • 217. Gastgifvars, Maria
    et al.
    Mueller-Navarra, Sylvin
    Funkquist, Lennart
    SMHI, Research Department, Oceanography.
    Huess, Vibeke
    Performance of operational systems with respect to water level forecasts in the Gulf of Finland2008In: Ocean Dynamics, ISSN 1616-7341, E-ISSN 1616-7228, Vol. 58, no 2, p. 139-153Article in journal (Refereed)
    Abstract [en]

    This paper is devoted to the validation of water level forecasts in the Gulf of Finland. Daily forecasts produced by four setups of operational, three-dimensional Baltic Sea oceanographic models are analyzed using statistical means and are compared with water level observations at three Finnish stations located on the northern coast of the Gulf of Finland. The overall conclusion is that the operational systems were skillful in forecasting water level variations during the study period from November 1, 2003, to January 31, 2005. The factors causing differences between the water level forecasts of different models are discussed as well. An important task of operational sea level forecasting services is to provide accurate and early information about extreme water levels, both positive and negative surges. During the study period, two major winter storms occurred which caused coastal flooding in the region. According to our analysis, the operational models forecast the rise of water levels during these events rather successfully. Nowadays, operational forecasts can provide early warnings of extreme water levels at least 1 day in advance, which may be regarded as a minimum requirement for an operational forecasting system. The paper concludes that the models generally performed very well, with over 93% of the hourly water level forecasts found to be within the range of +/- 15 cm of the observed water levels, and with the timing of the water level peaks accurately predicted. Further discussion and studies dealing with the assessment of the skills of both operational meteorological and oceanographic forecasts, especially in connection with rare surge events, will be necessary. Skill assessment of operational oceanographic models would be relatively easy if acceptable error limits or a quality system was developed for the Baltic Sea operational models.

  • 218.
    Almroth-Rosell, Elin
    et al.
    SMHI, Research Department, Oceanography.
    Skogen, Morten
    Sehested Hansen, Ian
    DHI Water and Environments.
    Stipa, Tapani
    University of Helsinki.
    Niiranen, Susa
    Stockholm University.
    The Year 2006 An Environmental Status report of the North Sea, Skagerrak, Kattegat and the Baltic Sea2007In: BANSAI- The Baltic and North Sea marine environmental modelling Asessment Initaiative / [ed] the Nordic Council of Ministers’ Sea and Air Group, 2007Conference paper (Other academic)
  • 219.
    Funquist, Lennart
    et al.
    SMHI, Research Department, Oceanography.
    Eckhard, Kleine
    SMHI.
    An introduction to HIROMB, an operational baroclinic model for the Baltic Sea2007Report (Other academic)
    Abstract [en]

    A3-dimensional baroclinic model of the North Sea and the Baltic Sea, designed for a daily operational use is described in detail. The model is based on a similar model running in operational mode at the German Federal Maritime and Hydrographic Agency (BSH) in Hamburg, Germany. The operational forecasts started in 1995 with a daily 24-hour forecast and was later extended to 48 hours. The model is mainly forced by SMHI's operational atmospheric model (HIRLAM), but also by river runoff from an operational hydrological model and wave radition stress from a wind wave model. The present version of the model is set up on a nested grid where a 12 nautical mile (nm) grid covers the whole area while Skagerrak, Kattegat, the Belt Sea and the Baltic Sea are covered with a 1 nm grid. A parallelized version of the model has been developed and runs on a distributed memory parallel computer.

  • 220.
    Håkansson, Bertil
    et al.
    SMHI, Core Services.
    Lindahl, Odd
    Kristineberg Marine Research Station.
    Rosenberg, Rutger
    SMHI.
    Axe, Philip
    SMHI, Research Department, Oceanography.
    Eilola, Kari
    SMHI, Research Department, Oceanography.
    Karlson, Bengt
    SMHI, Research Department, Oceanography.
    Swedish National Report on Eutrophication Status in the Kattegat and the Skagerrak: OSPAR ASSESSMENT 20072007Report (Other academic)
    Abstract [en]

    The surface area of the Kattegat and the Skagerrak, located in the eastern North Sea, is about 22 000 km2 and 32 000 km2, and the mean depth is about 23 m and 210 m, respectively. The Skagerrak and the Kattegat forms the inner end of the Norwegian trench, which has the characteristics of a deep (700 m) fjord connecting the Baltic Sea with theNorwegian Sea (e.g. Rodhe, 1987). The sill depth of the fjord is about 270 m. The Kattegat offshore and inshore waters were identified as problem areas, whereas the Inshore Skagerrak waters the OSPAR categories I - IV indicate a slight incoherence in the assessment, although with an overalljudgement to be identifi ed as a problem area. The offshore Skagerrak was identified as a non problem area, according to the OSPAR Comprehensive Procedure. (OSPAR Commission, 2005).

891011121314 201 - 220 of 378
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