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  • 1. Aas, W.
    et al.
    Tsyro, S.
    Bieber, E.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Ceburnis, D.
    Ellermann, T.
    Fagerli, H.
    Froelich, M.
    Gehrig, R.
    Makkonen, U.
    Nemitz, E.
    Otjes, R.
    Perez, N.
    Perrino, C.
    Prevot, A. S. H.
    Putaud, J. -P
    Simpson, D.
    Spindler, G.
    Vana, M.
    Yttri, K. E.
    Lessons learnt from the first EMEP intensive measurement periods2012In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 12, no 17, 8073-8094 p.Article in journal (Refereed)
    Abstract [en]

    The first EMEP intensive measurement periods were held in June 2006 and January 2007. The measurements aimed to characterize the aerosol chemical compositions, including the gas/aerosol partitioning of inorganic compounds. The measurement program during these periods included daily or hourly measurements of the secondary inorganic components, with additional measurements of elemental- and organic carbon (EC and OC) and mineral dust in PM1, PM2.5 and PM10. These measurements have provided extended knowledge regarding the composition of particulate matter and the temporal and spatial variability of PM, as well as an extended database for the assessment of chemical transport models. This paper summarise the first experiences of making use of measurements from the first EMEP intensive measurement periods along with EMEP model results from the updated model version to characterise aerosol composition. We investigated how the PM chemical composition varies between the summer and the winter month and geographically. The observation and model data are in general agreement regarding the main features of PM10 and PM2.5 composition and the relative contribution of different components, though the EMEP model tends to give slightly lower estimates of PM10 and PM2.5 compared to measurements. The intensive measurement data has identified areas where improvements are needed. Hourly concurrent measurements of gaseous and particulate components for the first time facilitated testing of modelled diurnal variability of the gas/aerosol partitioning of nitrogen species. In general, the modelled diurnal cycles of nitrate and ammonium aerosols are in fair agreement with the measurements, but the diurnal variability of ammonia is not well captured. The largest differences between model and observations of aerosol mass are seen in Italy during winter, which to a large extent may be explained by an underestimation of residential wood burning sources. It should be noted that both primary and secondary OC has been included in the calculations for the first time, showing promising results. Mineral dust is important, especially in southern Europe, and the model seems to capture the dust episodes well. The lack of measurements of mineral dust hampers the possibility for model evaluation for this highly uncertain PM component. There are also lessons learnt regarding improved measurements for future intensive periods. There is a need for increased comparability between the measurements at different sites. For the nitrogen compounds it is clear that more measurements using artefact free methods based on continuous measurement methods and/or denuders are needed. For EC/OC, a reference methodology (both in field and laboratory) was lacking during these periods giving problems with comparability, though measurement protocols have recently been established and these should be followed by the Parties to the EMEP Protocol. For measurements with no defined protocols, it might be a good solution to use centralised laboratories to ensure comparability across the network. To cope with the introduction of these new measurements, new reporting guidelines have been developed to ensure that all proper information about the methodologies and data quality is given.

  • 2. Achberger, C
    et al.
    Chen, D L
    Alexandersson, Hans
    SMHI.
    The surface winds of Sweden during 1999-20002006In: International Journal of Climatology, ISSN 0899-8418, E-ISSN 1097-0088, Vol. 26, no 2, 159-178 p.Article in journal (Refereed)
    Abstract [en]

    This study aims at increasing our understanding of the regional wind climate in Sweden. Spatial and temporal patterns of the surface winds are presented for the years 1999-2000. Annual mean wind speeds range between 2 and 5 m/s with high values at exposed mountainous sites and on islands off the coast. Combining wind speed and direction into mean wind velocities shows that flow conditions are stronger and more coherent in space in southern Sweden than in central and northern Sweden. The spatial scale, defined as the distance between stations when the correlation for wind speed drops to similar to 0.37, was determined by pairwise correlations between all possible station pairs. Scales range from 38 to 530 km for wind speed and from 40 to 830 km for wind direction depending on the region. They tend to be smaller in central and northern Sweden, where the more pronounced relief has a larger influence on the local wind conditions. The strength and the timing of the annual and diurnal wind speed cycle have been estimated for each station. Amplitudes of the annual cycle are greater at exposed sites and correlate generally well with annual mean wind speeds. Monthly mean wind speeds peak in winter in southern Sweden, but peak in other seasons in the remaining regions. In winter, weaker pressure gradients over northern Sweden and surface-near temperature inversions contribute to weaker surface winds. Diurnal cycles vary in strength between summer and winter. Compared to the last normal climate period (1961-1990), 1999-2000 is characterized by the increased occurrence of westerly and southerly geostrophic flow. Copyright (C) 2005 Royal Meteorological Society.

  • 3. Aggarwal, Pradeep K.
    et al.
    Romatschke, Ulrike
    Araguas-Araguas, Luis
    Belachew, Dagnachew
    Longstaffe, Frederick J.
    Berg, Peter
    SMHI, Research Department, Hydrology.
    Schumacher, Courtney
    Funk, Aaron
    Proportions of convective and stratiform precipitation revealed in water isotope ratios2016In: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 9, no 8, 624-+ p.Article in journal (Refereed)
  • 4.
    Ahlkrona, Malva
    SMHI.
    Phospherous in a Biogeochemical Lake Model2002Report (Other academic)
  • 5.
    Ahlström, B.
    et al.
    SMHI.
    Salomonsson, Gösta
    SMHI.
    Resultat av 5-dygnsprognos till ledning för isbrytarverksamhet vintern 1984–851985Report (Other academic)
  • 6. Aich, Valentin
    et al.
    Liersch, Stefan
    Vetter, Tobias
    Andersson, Jafet
    SMHI, Research Department, Hydrology.
    Mueller, Eva N.
    Hattermann, Fred F.
    Climate or Land Use?-Attribution of Changes in River Flooding in the Sahel Zone2015In: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 7, no 6, 2796-2820 p.Article in journal (Refereed)
    Abstract [en]

    This study intends to contribute to the ongoing discussion on whether land use and land cover changes (LULC) or climate trends have the major influence on the observed increase of flood magnitudes in the Sahel. A simulation-based approach is used for attributing the observed trends to the postulated drivers. For this purpose, the ecohydrological model SWIM (Soil and Water Integrated Model) with a new, dynamic LULC module was set up for the Sahelian part of the Niger River until Niamey, including the main tributaries Sirba and Goroul. The model was driven with observed, reanalyzed climate and LULC data for the years 1950-2009. In order to quantify the shares of influence, one simulation was carried out with constant land cover as of 1950, and one including LULC. As quantitative measure, the gradients of the simulated trends were compared to the observed trend. The modeling studies showed that for the Sirba River only the simulation which included LULC was able to reproduce the observed trend. The simulation without LULC showed a positive trend for flood magnitudes, but underestimated the trend significantly. For the Goroul River and the local flood of the Niger River at Niamey, the simulations were only partly able to reproduce the observed trend. In conclusion, the new LULC module enabled some first quantitative insights into the relative influence of LULC and climatic changes. For the Sirba catchment, the results imply that LULC and climatic changes contribute in roughly equal shares to the observed increase in flooding. For the other parts of the subcatchment, the results are less clear but show, that climatic changes and LULC are drivers for the flood increase; however their shares cannot be quantified. Based on these modeling results, we argue for a two-pillar adaptation strategy to reduce current and future flood risk: Flood mitigation for reducing LULC-induced flood increase, and flood adaptation for a general reduction of flood vulnerability.

  • 7. Aich, Valentin
    et al.
    Liersch, Stefan
    Vetter, Tobias
    Fournet, Samuel
    Andersson, Jafet
    SMHI, Research Department, Hydrology.
    Calmanti, Sandro
    van Weert, Frank H. A.
    Hattermann, Fred F.
    Paton, Eva N.
    Flood projections within the Niger River Basin under future land use and climate change2016In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 562, 666-677 p.Article in journal (Refereed)
    Abstract [en]

    This study assesses future flood risk in the Niger River Basin (NRB), for the first time considering the simultaneous effects of both projected climate change and land use changes. For this purpose, an ecohydrological process-based model (SWIM) was set up and validated for past climate and land use dynamics of the entire NRB. Model runs for future flood risks were conducted with an ensemble of 18 climate models, 13 of them dynamically downscaled from the CORDEX Africa project and five statistically downscaled Earth System Models. Two climate and two land use change scenarios were used to cover a broad range of potential developments in the region. Two flood indicators (annual 90th percentile and the 20-year return flood) were used to assess the future flood risk for the Upper, Middle and Lower Niger as well as the Benue. The modeling results generally show increases of flood magnitudes when comparing a scenario period in the near future (2021-2050) with a base period (1976-2005). Land use effects are more uncertain, but trends and relative changes for the different catchments of the NRB seem robust. The dry areas of the Sahelian and Sudanian regions of the basin show a particularly high sensitivity to climatic and land use changes, with an alarming increase of flood magnitudes in parts. A scenario with continuing transformation of natural vegetation into agricultural land and urbanization intensifies the flood risk in all parts of the NRB, while a "regreening" scenario can reduce flood magnitudes to some extent. Yet, land use change effects were smaller when compared to the effects of climate change. In the face of an already existing adaptation deficit to catastrophic flooding in the region, the authors argue for a mix of adaptation and mitigation efforts in order to reduce the flood risk in the NRB. (C) 2016 Elsevier B.V. All rights reserved.

  • 8.
    Akinde, Michael
    et al.
    SMHI.
    Bohlen, M H
    Johnson, T
    Lakshmanan, L V S
    Srivastava, D
    Efficient OLAP query processing in distributed data warehouses2003In: Information Systems, ISSN 0306-4379, Vol. 28, no 1-2, 111-135 p.Article in journal (Refereed)
    Abstract [en]

    The success of Internet applications has led to an explosive growth in the demand for bandwidth from. Internet Service Providers. Managing an Internet protocol network requires collecting and analyzing network data, such as flow-level traffic statistics. Such analyses can typically be expressed as OLAP queries, e.g., correlated aggregate queries and data cubes. Current day OLAP tools for this task assume the availability of the data in a centralized data warehouse. However, the inherently distributed nature of data collection and the huge amount of data extracted at each collection point make it impractical to gather all data at a centralized site. One solution is to maintain a distributed data warehouse, consisting of local data warehouses at-each collection point and a coordinator site, with most of the processing being performed at the local sites. In this paper, we consider the problem of efficient evaluation of OLAP queries over a distributed data warehouse. We have developed the Skalla system for this task. Skalla translates OLAP queries, specified as certain algebraic expressions, into distributed evaluation plans which are shipped to individual sites. A salient property of our approach is that only partial results are shipped - never parts of the detail data. We propose a variety of optimizations to minimize both the synchronization traffic and the local processing done at each site. We finally present an experimental study based on TPC-R data. Our results demonstrate the scalability of our techniques and quantify the performance benefits of the optimization techniques that have gone into the Skalla system. (C) 2002 Elsevier Science Ltd. All rights reserved.

  • 9. Akselsson, Cecilia
    et al.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Belyazid, Salim
    Capell, Réne
    SMHI, Research Department, Hydrology.
    Can increased weathering rates due to future warming compensate for base cation losses following whole-tree harvesting in spruce forests?2016In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 128, no 1-2, 89-105 p.Article in journal (Refereed)
  • 10. Alberoni, P P
    et al.
    Andersson, T
    SMHI.
    Mezzasalma, P
    Michelson, Daniel
    SMHI, Core Services.
    Nanni, S
    Use of the vertical reflectivity profile for identification of anomalous propagation2001In: Meteorological Applications, ISSN 1350-4827, E-ISSN 1469-8080, Vol. 8, no 3, 257-266 p.Article in journal (Refereed)
    Abstract [en]

    Anomalous propagation (anaprop), analogous to the upper mirage in the visual wavelengths, is still a major problem in radar meteorology. This phenomenon assumes particular importance in automatic recognition and estimation of rainfall. Anaprop echoes from terrain features such as hills and coasts Often give echoes up to 50-60 dBZ equivalent to heavy rain or hail in severe thunderstorms. Anaprop echoes from sea waves may be comparable in strength to those from moderate precipitation and also form similar patterns. Based on the evidence that the vertical reflectivity profile of precipitation is quite different from the anaprop profile, two methods for anaprop identification are presented. The method proposed by the Servizio Meteorologico Regionale (SMR, Italy) simply uses the operational scan procedure to discriminate between precipitation and anaprop. At the Swedish Meteorological and Hydrological Institute an 'ad hoc' scan strategy has been developed in order to obtain much more detail of the lowest reflectivity profile. A number of statistical parameters have been used to achieve a better discrimination between precipitation, land and sea clutter. A number of case studies, representing different echo intensities and patterns, and including a case of anaprop with embedded precipitation, are presented to assess the impact of these methods.

  • 11.
    Alexandersson, Hans
    SMHI.
    Korrektion av nederbörd enligt enkel klimatologisk metodik2003Report (Other academic)
  • 12.
    Alexandersson, Hans
    SMHI.
    Temperatur och nederbörd i Sverige 1860 -20012002Report (Other academic)
  • 13.
    Alexandersson, Hans
    SMHI.
    Temperatur och nederbörd i Sverige 1860 -20012002Report (Other academic)
    Abstract [en]

    Swedish temperature and precipitation series from 1860-2001 are analysed  in this report. Sweden  is divided into four regions. These are defined according to the drainage basins: Gulf of Bothnia (Bv), Bothnian Sea (Bh), Proper Baltic Sea (EÖ) and Kattegatt and Skagerrak (Vh). Annual series of  temperature and precipitation as well as series for the traditional  seasons  winter (December  previous year, January, February), spring (March, April, May), summer (June, July, August) and autumn (Sep­ tember, October, November) are presented. All series have been homgenised and all missing values for incomplete series have been filled out by    interpolation.

     

    Generally the analyses show that Sweden has become warmer  and wetter  in this centennial  perspective.  As a rule changes and trends are larger in the two northerly regions (Bv and Bh). The increase of annual temperature amounts to 0.9° (Bv), 0.8° (Bh), 0.5° (EÖ) and 0.5° (Vh) when data from the colder period 1860-1925 is compared with the warmer period 1926-2001. Annual precipitation <luring the drier period 1860-1920  is compared  with the wetter  period  1921-2001. The  relative changes  are 23% (Bv), 15% (Bh), 7% (EÖ) and 7% (Vh). Spring temperature  and winter precipitation  show especially !arge    mcreases.

     

    Comparisons with runoff data indicate that evapotranspiration has become much larger. It is argued that the substantial increase of forest biomass could be one explanation and higher temperatures could be another. The increase of forest biomass leads to larger interception and then larger evaporation and as a rule also larger transpiration. The warming in spring and autumn leads to a longer active season for the vegetation.

  • 14.
    Alexandersson, Hans
    SMHI.
    Vindstatistik för Sverige 1961-20042010Report (Other academic)
    Abstract [sv]

    Rapportens främsta syfte är att ta fram medelvärden som kan användas för att bedöma om en aktuell månad har varit blåsigare eller lugnare än normalt och med hur mycket, till exempel i procent. Vindobservationer från perioden 1961- 2004 har ingått i bearbetningen vilket gör att det finns vissa möjligheter att se på förändringar under denna ganska långa period. Då den aktuella normalperioden är 1961-1990 har tonvikten lagts på denna period. Många av stationerna startade dock i mitten av 1990-talet varför det för de flesta stationerna finns fler direkt uppmätta värden under perioden 1991-2004. Medelvärden för denna period ges därför också i tabellform. Senaste publikationen med omfattande vindstatistik är Klimatdata för Sverige (Taesler, 1972)

  • 15.
    Alexandersson, Hans
    et al.
    SMHI.
    Dahlström, Bengt
    SMHI, Core Services.
    Future climate in the Nordic region – survey and synthesis for the next century1992Report (Other academic)
  • 16.
    Alexandersson, Hans
    et al.
    SMHI.
    Eggertsson Karlström, Carla
    SMHI.
    Temperaturen och nederbörden i Sverige 1961-1990: Referensnormaler - utgåva 22001Report (Other academic)
  • 17.
    Alexandersson, Hans
    et al.
    SMHI.
    Eggertsson Karlström, Carla
    SMHI.
    Larsson-McCann, Sonja
    SMHI, Professional Services.
    Temperaturen och nederbörden i Sverige 1961-90: Referensnormaler1991Report (Other academic)
  • 18.
    Alexandersson, Hans
    et al.
    SMHI.
    Eggertsson Karlström, Carla
    SMHI.
    Laurin, Sten
    SMHI.
    Några huvuddrag i det svenska nederbördsklimatet 1961-19901997Report (Other academic)
  • 19.
    Alexandersson, Hans
    et al.
    SMHI.
    Eriksson, Bertil
    SMHI.
    Climate fluctuations in Sweden 1860–19871989Report (Other academic)
  • 20.
    Alexandersson, Hans
    et al.
    SMHI.
    Gollvik, Stefan
    Meterologi.
    Meuller, Lars
    SMHI.
    An energy balance model for prediction of surface temperatures1991Report (Other academic)
  • 21.
    Alexandersson, Hans
    et al.
    SMHI.
    Moberg, A
    Homogenization of Swedish temperature data .1. Homogeneity test for linear trends1997In: International Journal of Climatology, ISSN 0899-8418, E-ISSN 1097-0088, Vol. 17, no 1, 25-34 p.Article in journal (Refereed)
    Abstract [en]

    A new test for the detection of linear trends of arbitrary length in normally distributed time series is developed. With this test it is possible to detect and estimate gradual changes of the mean value in a candidate series compared with a homogeneous reference series. The test is intended for studies of artificial relative trends in climatological time series, e.g. an increasing urban heat island effect. The basic structure of the new test is similar to that of a widely used test for abrupt changes, the standard normal homogeneity test. The test for abrupt changes is found to remain unaltered after an important generalization.

  • 22.
    Alexandersson, Hans
    et al.
    SMHI.
    Tuomenvirta, H
    Schmith, T
    Iden, K
    Trends of storms in NW Europe derived from an updated pressure data set2000In: Climate Research (CR), ISSN 0936-577X, E-ISSN 1616-1572, Vol. 14, no 1, 71-73 p.Article in journal (Refereed)
    Abstract [en]

    Within the WASA project (von Storch et al. 1998; Bull Am Meterol Soc 79(5):741-760) an extensive data set containing station pressure values was used to calculate geostrophic winds (Alexandersson et al. 1998; Global Atmos Ocean Syst 6:97-120). Geostrophic winds were analysed in terms of percentiles to give a measure of long-term variations in synoptic-scale storminess. In this paper an update to 1998 is presented. In the Scandinavia, Finland and Baltic Sea area the most recent years, especially the cold and calm year 1996, seem to have brought an end to the stormy period centred on 1990. In the more westerly British Isles, North Sea and Norwegian Sea area, storminess is still at high levels compared with the less intense period between 1930 and 1980. The long-term increasing trend in NW Europe storminess that started in the 1960s seems to have been broken.

  • 23.
    Alexandersson, Hans
    et al.
    SMHI.
    Vedin, Haldo
    SMHI.
    Dimensionerande regn för mycket små avrinningsområden2003Report (Other academic)
  • 24. Alfieri, Lorenzo
    et al.
    Bisselink, Berny
    Dottori, Francesco
    Naumann, Gustavo
    de Roo, Ad
    Salamon, Peter
    Wyser, Klaus
    SMHI, Research Department, Climate research - Rossby Centre.
    Feyen, Luc
    Global projections of river flood risk in a warmer world2017In: Earth's Future, ISSN 1384-5160, E-ISSN 2328-4277, Vol. 5, no 2, 171-182 p.Article in journal (Refereed)
  • 25.
    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.

  • 26.
    Almroth-Rosell, Elin
    et al.
    SMHI, Research Department, Oceanography.
    Edman, Moa
    SMHI, Research Department, Oceanography.
    Eilola, Kari
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Sahlberg, Jörgen
    SMHI, Professional Services.
    Modelling nutrient retention in the coastal zone of an eutrophic sea2016In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 13, no 20, 5753-5769 p.Article in journal (Refereed)
  • 27.
    Almroth-Rosell, Elin
    et al.
    SMHI, Research Department, Oceanography.
    Eilola, Kari
    SMHI, Research Department, Oceanography.
    Hordoir, Robinson
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Hall, Per O. J.
    Transport of fresh and resuspended particulate organic material in the Baltic Sea - a model study2011In: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 87, no 1, 1-12 p.Article in journal (Refereed)
    Abstract [en]

    A fully coupled high-resolution 3-dimensional biogeochemical-physical ocean model including an empirical wave model was used to investigate the long-term average (1970-2007) distributions and transports of resuspended matter and other types of suspended organic matter in the Baltic Sea. Modelled bottom types were compared to observations and the results showed that the model successfully managed to capture the horizontal, as well as the vertical, distribution of the different bottom types: accumulation, transport and erosion bottoms. The model also captured well the nutrient element contents in the sediments. On average the largest contribution of resuspended organic carbon to the transport of total organic carbon is found at erosion and transport bottoms. Although the relative transport of resuspended organic carbon at deeper accumulation bottoms in general is low (< 10% of total), the central parts of the sub-basins act on average as sinks that import organic matter while the more shallow areas and the coastal regions acts as sources of organic carbon in the water column. This indicates that the particulate organic matter produced in erosion and transport areas might be kept in suspension long enough to be transported and settle in less energetic areas, i.e. on accumulation bottoms. (C) 2011 Elsevier B.V. All rights reserved.

  • 28.
    Almroth-Rosell, Elin
    et al.
    SMHI, Research Department, Oceanography.
    Eilola, Kari
    SMHI, Research Department, Oceanography.
    Kuznetsov, Ivan
    Hall, Per O. J.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    A new approach to model oxygen dependent benthic phosphate fluxes in the Baltic Sea2015In: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 144, 127-141 p.Article in journal (Refereed)
    Abstract [en]

    The new approach to model the oxygen dependent phosphate release by implementing formulations of the oxygen penetration depths (OPD) and mineral bound inorganic phosphorus pools to the Swedish Coastal and Ocean Biogeochemical model (SCOBI) is described. The phosphorus dynamics and the oxygen concentrations in the Baltic proper sediment are studied during the period 1980-2008 using SCOBI coupled to the 3D-Rossby Centre Ocean model. Model data are compared to observations from monitoring stations and experiments. The impact from oxygen consumption on the determination of the OPD is found to be largest in the coastal zones where also the largest OPD are found. In the deep water the low oxygen concentrations mainly determine the OPD. Highest modelled release rate of phosphate from the sediment is about 59 x 10(3) t P year(-1) and is found on anoxic sediment at depths between 60-150 m, corresponding to 17% of the Baltic proper total area. The deposition of organic and inorganic phosphorus on sediments with oxic bottom water is larger than the release of phosphorus, about 43 x 10(3) t P year(-1). For anoxic bottoms the release of total phosphorus during the investigated period is larger than the deposition, about 19 x 10(3) t P year(-1). In total the net Baltic proper sediment sink is about 23.7 x 10(3) t P year(-1). The estimated phosphorus sink efficiency of the entire Baltic Sea is on average about 83% during the period. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

  • 29.
    Almroth-Rosell, Elin
    et al.
    SMHI, Research Department, Oceanography.
    Skogen, Morten D.
    A North Sea and Baltic Sea Model Ensemble Eutrophication Assessment2010In: Ambio, ISSN 0044-7447, Vol. 39, no 1, 59-69 p.Article in journal (Refereed)
    Abstract [en]

    A method to combine observations and an ensemble of ecological models is suggested to produce a eutrophication assessment. Using threshold values and methodology from the Oslo and Paris Commissions (OSPAR) and the Helsinki Commission (HELCOM), four models are combined to assess eutrophication for the Baltic and North Seas for the year 2006. The assessment indicates that the entire southeastern part of the North Sea, the Kattegat, the Danish Straits, the Gulf of Finland, and the Gulf of Riga as well as parts of the Arkona Basin, the Bornholm Basin, and the Baltic proper may be classified as problem areas. The Bothnian Bay and parts of the Baltic proper, the Bornholm Basin, and the Arkona Basin are classified as potential problem areas. This method is a useful tool for the classification of eutrophication; however, the results depend on the threshold values, and further work is needed within both OSPAR and HELCOM to harmonize these values.

  • 30.
    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)
  • 31. Amaguchi, H.
    et al.
    Kawamura, A.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Takasaki, T.
    Development and testing of a distributed urban storm runoff event model with a vector-based catchment delineation2012In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 420, 205-215 p.Article in journal (Refereed)
    Abstract [en]

    The recent advances in GIS technology as well as data availability open up new possibilities concerning urban storm runoff modeling. In this paper, a vector-based distributed storm event runoff model - the Tokyo Storm Runoff (TSR) model - is developed and tested for urban runoff analysis using two historical storm events. The set-up of this model is based on urban landscape GIS delineation that faithfully describes the complicated urban land use features in detail. The flow between single spatial elements is based on established hydraulic and hydrological models with equations that describe all aspects of storm runoff generation in an urban environment. The model was set up and evaluated for the small urban lower Ekota catchment in Tokyo Metropolis, Japan. No calibration or tuning was performed, but the general model formulation was used with standard parameter values obtained from the literature. The runoff response to two storm events were simulated; one minor event resulting only in a small-scale flood wave and one major event which inundated parts of the catchment. For both events, the simulated water levels closely reproduced the observed ones. For the major event, also the reported inundation area was well described by the model. It was also demonstrated how the model can be used to evaluate the flow conditions in specific components of the urban hydrological system, which facilitates e.g. evaluation of flood-preventive measures. (C) 2011 Elsevier B.V. All rights reserved.

  • 32.
    Ambjörn, Cecilia
    SMHI, Professional Services.
    Förstudie av ett nordiskt modellsystem för kemikaliespridning i vatten1988Report (Other academic)
  • 33.
    Ambjörn, Cecilia
    SMHI, Professional Services.
    Isproppsförebyggande muddring och dess inverkan på strömmarna i Torneälven1992Report (Other academic)
  • 34.
    Ambjörn, Cecilia
    SMHI, Professional Services.
    Oceanografiska förhållanden i Brofjorden i samband med kylvattenutsläpp i Trommekilen1989Report (Other academic)
  • 35.
    Ambjörn, Cecilia
    SMHI, Professional Services.
    Oceanografiska förhållanden utanför Vendelsöfjorden i samband med kylvattenutsläpp1990Report (Other academic)
  • 36.
    Ambjörn, Cecilia
    SMHI, Professional Services.
    Spridning av kylvatten från Öresundsverket1987Report (Other academic)
  • 37.
    Ambjörn, Cecilia
    SMHI, Professional Services.
    Spridning och sedimentation av tippat lermaterial utanför Helsingborgs hamnområde1989Report (Other academic)
  • 38.
    Ambjörn, Cecilia
    SMHI, Professional Services.
    Strömningsteknisk utredning avseende utbyggnad av gipsdeponi i Landskrona1990Report (Other academic)
  • 39.
    Ambjörn, Cecilia
    SMHI, Professional Services.
    Utbyggnad vid Malmö hamn; effekter för Lommabuktens vattenutbyte1986Report (Other academic)
  • 40.
    Ambjörn, Cecilia
    et al.
    SMHI, Professional Services.
    Aranibar, Enrique
    ENDE Empresa Nacional de Electricidad.
    Llobet, Robert
    ENDE Empresa Nacional de Electricidad.
    Monthly streamflow simulation in Bolivian basins with a stochastic model1987Report (Other academic)
  • 41.
    Ambjörn, Cecilia
    et al.
    SMHI, Professional Services.
    Grafström, Torbjörn
    SMHI.
    Andersson, Jan
    SMHI, Core Services.
    Spridningsberäkningar - Klints Bank1990Report (Other academic)
  • 42.
    Ambjörn, Cecilia
    et al.
    SMHI, Professional Services.
    Wickström, Kjell
    SMHI.
    Spridningsundersökningar i norra Kalmarsund för Mönsterås bruk1990Report (Other academic)
  • 43.
    Ambjörn, Cecilia
    et al.
    SMHI, Professional Services.
    Wickström, Kjell
    SMHI.
    Undersökning av vattenmiljön vid utfyllnaden av Kockums varvsbassäng: Slutrapport för perioden 18 juni - 21 augusti 19871987Report (Other academic)
  • 44. Aminot, A
    et al.
    Kirkwood, D
    Carlberg, Stig
    SMHI, Research Department, Oceanography.
    The QUASIMEME laboratory performance studies (1993-1995): Overview of the nutrients section1997In: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 35, no 1-6, 28-41 p.Article in journal (Refereed)
    Abstract [en]

    The QUASIMEME Project (1993-1996) was established to assist European laboratories to improve the data they produce in marine monitoring programmes. Through laboratory performance Studies (with six-monthly reports), workshops and expert visits the programme was fully interactive. There were five rounds of laboratory performance studies. For the nutrient section, in which about 50 laboratories took part, the reference materials distributed to the participants consisted of standard solutions of nutrients and seawater samples stabilized by autoclaving. The material included low and high concentrations typical of those encountered in coastal seawater; at least two samples with different concentrations were distributed in each round. Robust statistics were used to determine the means and standard deviations for each set of results. For inorganic nutrients, the assessment of the data for bias and precision was based mainly on a Z- and P-scoring system in which targets of +/- 6% were allocated to the high concentrations, likewise +/- 12.5% to the low concentrations. This overview discusses overall performance separately for nitrate plus nitrite, nitrite, ammonia, phosphate, total nitrogen and total phosphorus, and classifies the performance of individual laboratories in each round, while maintaining their anonymity. Performance for nitrate plus nitrite and nitrite improved steadily and these determinands are now fully under control; at the end of the programme, standard deviations (SD) for nitrate plus nitrite were 0.2 mu mol l(-1) at low concentration and 0.6 mu mol l(-1) (4%) at high concentration, and for nitrite they were 0.03 mu mol l(-1) and 0.06 mu mol l(-1) (5%) respectively. Phosphate showed a somewhat stable level of performance with SD of 0.06 mu mol l(-1) and 0.10 mu mol l(-1) (10%) at low and high concentrations respectively, but this could be improved. Ammonia proved the most difficult to determine, and in spite of a substantial improvement at the beginning of the exercise, this determinand is not under control in many laboratories. At low concentrations, ammonia shows a positive bias of 0.2 mu mol l(-1) and a SD of 0.3 mu mol l(-1), while at high concentrations SD reaches 0.5 mu mol l(-1) (20%). For total nitrogen (TN) and total phosphorus (TP), the exercises show that only two thirds of the participants produced consistent data for TN, and less than half of them produced consistent data for TP. (C) 1997 Elsevier Science Ltd. All rights reserved.

  • 45.
    Amorim, Jorge Humberto
    et al.
    SMHI, Research Department, Air quality.
    Valente, J.
    Cascao, P.
    Ribeiro, L. M.
    Viegas, D. X.
    Ottmar, R.
    Miranda, A. I.
    Near-source grid-based measurement of CO and PM2.5 concentration during a full-scale fire experiment in southern European shrubland2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 145, 19-28 p.Article in journal (Refereed)
  • 46. Anastasiadis, Stavros
    et al.
    Boglis, Argiris
    Pechlivanidis, Ilias
    SMHI, Research Department, Hydrology.
    Lekkas, Demetris F.
    Baltas, Evaggelos
    APPLICATION OF GIS BASED CLARK'S UNIT HYDROGRAPH AND TRANSFER FUNCTION MODEL TO DESCRIBE RUNOFF RESPONSE IN A SMALL CATCHMENT, CASE STUDY: LYKOREMMA RIVER, GREECE2013In: Fresenius Environmental Bulletin, ISSN 1018-4619, Vol. 22, no 7B, 2152-2158 p.Article in journal (Refereed)
    Abstract [en]

    The hydrologic community has recently focused substantial attention on ungauged or poorly gauged catchments, since hydrological prediction under these conditions is highly uncertain, but represents the majority of practical applications. Catchments in Greece are usually ungauged, due to resource constrains, whilst in gauged areas the period of record is often short for safe estimation of highly parameterised hydrological models. This paper is driven by the Prediction in Ungauged Basins initiative aiming to estimate catchment responses using readily available data, i.e. topographical, soil and land use information. The parsimonious rainfall-runoff model developed in a Geographical Information System (GIS) environment is based on the Clark's synthetic unit hydrograph technique to estimate the hydrological response. The method requires estimation of the time of concentration (based on the curve number), the storage attenuation coefficient and the time area histogram of the catchment. The models further compared with a data-based modelling approach using a Transfer Function and the simulated streamflow is analysed to investigate similarities as well as to better understand possible extensions of the resulting unit hydrograph. A case study using 10-minute observed data from the 15 km(2) Lykorema catchment, Attica, Greece, highlights the potential of the GIS-based model to predict, at least, the dynamic characteristics of the runoff response in ungauged or poorly gauged catchments.

  • 47. Andersen, Jesper H.
    et al.
    Axe, Philip
    SMHI, Research Department, Oceanography.
    Backer, Hermanni
    Carstensen, Jacob
    Claussen, Ulrich
    Fleming-Lehtinen, Vivi
    Jarvinen, Marko
    Kaartokallio, Hermanni
    Knuuttila, Seppo
    Korpinen, Samuli
    Kubiliute, Aiste
    Laamanen, Maria
    Lysiak-Pastuszak, Elzbieta
    Martin, Georg
    Murray, Ciaran
    Mohlenberg, Flemming
    Nausch, Guenther
    Norkko, Alf
    Villnas, Anna
    Getting the measure of eutrophication in the Baltic Sea: towards improved assessment principles and methods2011In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 106, no 2, 137-156 p.Article in journal (Refereed)
    Abstract [en]

    The eutrophication status of the entire Baltic Sea is classified using a multi-metric indicator-based assessment tool. A total of 189 areas are assessed using indicators where information on reference conditions (RefCon), and acceptable deviation (AcDev) from reference condition could be combined with national monitoring data from the period 2001-2006. Most areas (176) are classified as 'affected by eutrophication' and only two open water areas and 11 coastal areas are classified as 'unaffected by eutrophication'. The classification is made by application of the recently developed HELCOM Eutrophication Assessment Tool (HEAT), which is described in this paper. The use of harmonized assessment principles and the HEAT tool allows for direct comparisons between different parts of the Baltic Sea despite variations in monitoring activities. The impaired status of 176 areas is directly related to nutrient enrichment and elevated loads from upstream catchments. Baltic Sea States have implemented nutrient management strategies since years which have reduced nutrient inputs. However, eutrophication is still a major problem for large parts of the Baltic Sea. The 2007 Baltic Sea Action Plan is projected to further reduce nutrient inputs aiming for a Baltic Sea unaffected by eutrophication by 2021.

  • 48. Andersen, Jesper H.
    et al.
    Murray, Ciaran
    Kaartokallio, Hermanni
    Axe, Philip
    SMHI, Research Department, Oceanography.
    Molvaer, Jarle
    A simple method for confidence rating of eutrophication status classifications2010In: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 60, no 6, 919-924 p.Article in journal (Refereed)
    Abstract [en]

    We report the development of a methodology for assessing confidence in ecological status classifications. The method presented here can be considered as a secondary assessment, supporting the primary assessment of eutrophication or ecological status. The confidence assessment is based on scoring the quality of the indicators on which the primary assessment is made. This represents a first step towards linking status classification with information regarding their accuracy and precision. Applied to an existing data set used for assessment of eutrophication status of the Baltic Sea (including the Kattegat and Danish Straits) we demonstrate that confidence in the assessment is Good or High in 149 out of 189 areas assessed (79%). Contrary to our expectations, assessments of the open parts of the Baltic Sea have a higher confidence than assessments of coastal waters. We also find that in open waters of the Baltic Sea, some biological indicators have a higher confidence than indicators representing physical-chemical conditions. In coastal waters, phytoplankton, submerged aquatic vegetation and indicators of physical-chemical conditions have a higher confidence than indicators of the quality of benthic invertebrate communities. Our analyses also show that the perceived weaknesses of eutrophication assessments are due more to Low confidence in reference conditions and acceptable deviations, rather than in the monitoring data. (C) 2010 Elsevier Ltd. All rights reserved.

  • 49. Anderson, C J
    et al.
    Arritt, R W
    Takle, E S
    Pan, Z T
    Gutowski, W J
    Otieno, F O
    da Silva, R
    Caya, D
    Christensen, J H
    Luthi, D
    Gaertner, M A
    Gallardo, C
    Giorgi, F
    Hong, S Y
    Jones, Colin
    SMHI, Research Department, Climate research - Rossby Centre.
    Juang, H M H
    Katzfey, J J
    Lapenta, W M
    Laprise, R
    Larson, J W
    Liston, G E
    McGregor, J L
    Pielke, R A
    Roads, J O
    Taylor, J A
    Hydrological processes in regional climate model simulations of the central United States flood of June-July 19932003In: Journal of Hydrometeorology, ISSN 1525-755X, Vol. 4, no 3, 584-598 p.Article in journal (Refereed)
    Abstract [en]

    Thirteen regional climate model(RCM) simulations of June - July 1993 were compared with each other and observations. Water vapor conservation and precipitation characteristics in each RCM were examined for a 108 x 10degrees subregion of the upper Mississippi River basin, containing the region of maximum 60-day accumulated precipitation in all RCMs and station reports. All RCMs produced positive precipitation minus evapotranspiration ( P - E > 0), though most RCMs produced P - E below the observed range. RCM recycling ratios were within the range estimated from observations. No evidence of common errors of E was found. In contrast, common dry bias of P was found in the simulations. Daily cycles of terms in the water vapor conservation equation were qualitatively similar in most RCMs. Nocturnal maximums of P and C ( convergence) occurred in 9 of 13 RCMs, consistent with observations. Three of the four driest simulations failed to couple P and C overnight, producing afternoon maximum P. Further, dry simulations tended to produce a larger fraction of their 60-day accumulated precipitation from low 3-h totals. In station reports, accumulation from high ( low) 3-h totals had a nocturnal ( early morning) maximum. This time lag occurred, in part, because many mesoscale convective systems had reached peak intensity overnight and had declined in intensity by early morning. None of the RCMs contained such a time lag. It is recommended that short-period experiments be performed to examine the ability of RCMs to simulate mesoscale convective systems prior to generating long-period simulations for hydroclimatology.

  • 50. Andersson, Agneta
    et al.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Ripszam, Matyas
    Rowe, Owen
    Wikner, Johan
    Haglund, Peter
    Eilola, Kari
    SMHI, Research Department, Oceanography.
    Legrand, Catherine
    Figueroa, Daniela
    Paczkowska, Joanna
    Lindehoff, Elin
    Tysklind, Mats
    Elmgren, Ragnar
    Projected future climate change and Baltic Sea ecosystem management2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, S345-S356 p.Article in journal (Refereed)
    Abstract [en]

    Climate change is likely to have large effects on the Baltic Sea ecosystem. Simulations indicate 2-4 degrees C warming and 50-80 % decrease in ice cover by 2100. Precipitation may increase similar to 30 % in the north, causing increased land runoff of allochthonous organic matter (AOM) and organic pollutants and decreased salinity. Coupled physical-biogeochemical models indicate that, in the south, bottom-water anoxia may spread, reducing cod recruitment and increasing sediment phosphorus release, thus promoting cyanobacterial blooms. In the north, heterotrophic bacteria will be favored by AOM, while phytoplankton production may be reduced. Extra trophic levels in the food web may increase energy losses and consequently reduce fish production. Future management of the Baltic Sea must consider the effects of climate change on the ecosystem dynamics and functions, as well as the effects of anthropogenic nutrient and pollutant load. Monitoring should have a holistic approach, encompassing both autotrophic (phytoplankton) and heterotrophic (e.g., bacterial) processes.

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