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  • 1. Aas, W.
    et al.
    Tsyro, S.
    Bieber, E.
    Bergström, Robert
    SMHI, Forskningsavdelningen, Luftmiljö.
    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 periods2012Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 12, nr 17, s. 8073-8094Artikel i tidskrift (Refereegranskat)
    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 1999-20002006Ingår i: International Journal of Climatology, ISSN 0899-8418, E-ISSN 1097-0088, Vol. 26, nr 2, s. 159-178Artikel i tidskrift (Refereegranskat)
    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, Forskningsavdelningen, Hydrologi.
    Schumacher, Courtney
    Funk, Aaron
    Proportions of convective and stratiform precipitation revealed in water isotope ratios2016Ingår i: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 9, nr 8, s. 624-+Artikel i tidskrift (Refereegranskat)
  • 4.
    Ahlkrona, Malva
    SMHI.
    Phospherous in a Biogeochemical Lake Model2002Rapport (Övrigt vetenskapligt)
    Abstract [en]

    BIOLA isa biogeochemical lake model within the V ASTRA research programme. The model's

    main purpose is to predict the ecological responses to changed nutrient loads. The phosphorus simulations were not satisfactory and the sediment was thought to be the critical part. The aim of this work was to improve the phosphorus simulations. Therefore a new sediment approach has been developed. Three main changes of the sediment processes were carried through:

    • Resuspension of sediments from erosion and transportation bottoms was added

    • The sediments were divided into an upper, aerobic, and a lower, anaerobic, layer

    • The relation between sorbed and dissolved phosphorus in the sediments was described by

    Langmuir isotherms, with a sorption 2.5 times higher at aerobic compared to anaerobic

    conditions

    The modelling of total phosphorus and blue-green algae was improved. Especially the timing of high concentration peaks was much better. One problem still lingering is the modelled oxygen levels, which were much higher than the observed levels. Therefore the model has not been tested for anaerobic conditions. A verage release rates from the sediments were 2.5 mg Pa-1 <luring the summer, which is reasonable. A 20-year simulation of step-response was run with increased and decreased nutrient loads. Roughly four years after the change, the model had reached a new equilibrium.

  • 5. Ahmadalipour, Ali
    et al.
    Moradkhani, Hamid
    Rana, Arun
    SMHI.
    Accounting for downscaling and model uncertainty in fine-resolution seasonal climate projections over the Columbia River Basin2018Ingår i: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 50, nr 1-2, s. 717-733Artikel i tidskrift (Refereegranskat)
  • 6. Aich, Valentin
    et al.
    Liersch, Stefan
    Vetter, Tobias
    Andersson, Jafet
    SMHI, Forskningsavdelningen, Hydrologi.
    Mueller, Eva N.
    Hattermann, Fred F.
    Climate or Land Use?-Attribution of Changes in River Flooding in the Sahel Zone2015Ingår i: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 7, nr 6, s. 2796-2820Artikel i tidskrift (Refereegranskat)
    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, Forskningsavdelningen, Hydrologi.
    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 change2016Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 562, s. 666-677Artikel i tidskrift (Refereegranskat)
    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 warehouses2003Ingår i: Information Systems, ISSN 0306-4379, E-ISSN 1873-6076, Vol. 28, nr 1-2, s. 111-135Artikel i tidskrift (Refereegranskat)
    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. Akinsanola, A. A.
    et al.
    Ajayi, V. O.
    Adejare, A. T.
    Adeyeri, O. E.
    Gbode, I. E.
    Ogunjobi, K. O.
    Nikulin, Grigory
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Abolude, A. T.
    Evaluation of rainfall simulations over West Africa in dynamically downscaled CMIP5 global circulation models2018Ingår i: Journal of Theoretical and Applied Climatology, ISSN 0177-798X, E-ISSN 1434-4483, Vol. 132, nr 1-2, s. 437-450Artikel i tidskrift (Refereegranskat)
  • 10. Akperov, Mirseid
    et al.
    Rinke, Annette
    Mokhov, Igor I.
    Matthes, Heidrun
    Semenov, Vladimir A.
    Adakudlu, Muralidhar
    Cassano, John
    Christensen, Jens H.
    Dembitskaya, Mariya A.
    Dethloff, Klaus
    Fettweis, Xavier
    Glisan, Justin
    Gutjahr, Oliver
    Heinemann, Guenther
    Koenigk, Torben
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Koldunov, Nikolay V.
    Laprise, Rene
    Mottram, Ruth
    Nikiema, Oumarou
    Scinocca, John F.
    Sein, Dmitry
    Sobolowski, Stefan
    Winger, Katja
    Zhang, Wenxin
    Cyclone Activity in the Arctic From an Ensemble of Regional Climate Models (Arctic CORDEX)2018Ingår i: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 123, nr 5, s. 2537-2554Artikel i tidskrift (Refereegranskat)
  • 11. Akselsson, Cecilia
    et al.
    Olsson, Jonas
    SMHI, Forskningsavdelningen, Hydrologi.
    Belyazid, Salim
    Capell, Réne
    SMHI, Forskningsavdelningen, Hydrologi.
    Can increased weathering rates due to future warming compensate for base cation losses following whole-tree harvesting in spruce forests?2016Ingår i: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 128, nr 1-2, s. 89-105Artikel i tidskrift (Refereegranskat)
  • 12. Alberoni, P P
    et al.
    Andersson, T
    SMHI.
    Mezzasalma, P
    Michelson, Daniel
    SMHI, Samhälle och säkerhet.
    Nanni, S
    Use of the vertical reflectivity profile for identification of anomalous propagation2001Ingår i: Meteorological Applications, ISSN 1350-4827, E-ISSN 1469-8080, Vol. 8, nr 3, s. 257-266Artikel i tidskrift (Refereegranskat)
    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.

  • 13.
    Alexandersson, Hans
    SMHI.
    Temperatur och nederbörd i Sverige 1860 -20012002Rapport (Övrigt vetenskapligt)
    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
    et al.
    SMHI.
    Moberg, A
    Homogenization of Swedish temperature data .1. Homogeneity test for linear trends1997Ingår i: International Journal of Climatology, ISSN 0899-8418, E-ISSN 1097-0088, Vol. 17, nr 1, s. 25-34Artikel i tidskrift (Refereegranskat)
    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.

  • 15.
    Alexandersson, Hans
    et al.
    SMHI.
    Tuomenvirta, H
    Schmith, T
    Iden, K
    Trends of storms in NW Europe derived from an updated pressure data set2000Ingår i: Climate Research (CR), ISSN 0936-577X, E-ISSN 1616-1572, Vol. 14, nr 1, s. 71-73Artikel i tidskrift (Refereegranskat)
    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.

  • 16. Alfieri, Lorenzo
    et al.
    Bisselink, Berny
    Dottori, Francesco
    Naumann, Gustavo
    de Roo, Ad
    Salamon, Peter
    Wyser, Klaus
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Feyen, Luc
    Global projections of river flood risk in a warmer world2017Ingår i: Earth's Future, ISSN 1384-5160, E-ISSN 2328-4277, Vol. 5, nr 2, s. 171-182Artikel i tidskrift (Refereegranskat)
  • 17.
    Algotsson, Josefina
    et al.
    SMHI, Samhälle och säkerhet.
    Van Der Stelt, Frank
    SMHI, Affärsverksamhet.
    Abdoush, Diala
    SMHI, Samhälle och säkerhet.
    Swedish coastal water bodies on Wikidata Combining WFD data with Wikidata2019Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    I enlighet med Vattendirektivet rapporterar Vattenmyndigheterna miljöinformation om Sveriges ytvattenförekomster till EU.Under Naturvårdsverkets regeringsuppdrag Smartare miljöinformation togs initiativet upp att visualisera den till EU rapporterade miljöinformationen om Sveriges kustvattenförekomster på Wikidata och Wikipedia. SMHI har lett initiativet med stöd från Wikimedia Sverige, Vattenmyndigheten för Södra Östersjöns vattendistrikt, Jönköpings länsstyrelse och volontärer från Wikimedias gemenskap.Syftet med arbetet var att göra miljöinformation om Sveriges kustvattenförekomster mer tillgänglig för allmänheten, sprida kunskap om statusklassning samt skapa förutsättningar att öka miljömedvetenheten hos allmänheten. Projektet har resulterat i att:• 653 nya kustvattenförekomster beskrivs på Wikidata.• Artiklar om vattenförvaltning i Sverige, kustvattenförekomster och databasen SVAR har skapats på Wikipedia.• En mall för informationsrutor på Wikipedia har tagits fram och kan automatiskt hämta och visa information om kustvattenförekomsters statusklassning från Wikidata.• Mallen för informationsrutor om kustvattenförekomster används i artiklar om kustvatten på Wikipedia.• Information på smhi.se om SMHIs datapolicy är uppdaterad.• Licensen för databasen SVAR är fastställd till CC0 vilket förenklar användningen av informationen och öppnar möjligheten att använda den på fler sätt än tidigare.

  • 18.
    Almroth-Rosell, Elin
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Edman, Moa
    SMHI, Forskningsavdelningen, Oceanografi.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Sahlberg, Jörgen
    SMHI, Affärsverksamhet.
    Modelling nutrient retention in the coastal zone of an eutrophic sea2016Ingår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 13, nr 20, s. 5753-5769Artikel i tidskrift (Refereegranskat)
  • 19.
    Almroth-Rosell, Elin
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Hordoir, Robinson
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Hall, Per O. J.
    Transport of fresh and resuspended particulate organic material in the Baltic Sea - a model study2011Ingår i: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 87, nr 1, s. 1-12Artikel i tidskrift (Refereegranskat)
    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.

  • 20.
    Almroth-Rosell, Elin
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Kuznetsov, Ivan
    Hall, Per O. J.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    A new approach to model oxygen dependent benthic phosphate fluxes in the Baltic Sea2015Ingår i: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 144, s. 127-141Artikel i tidskrift (Refereegranskat)
    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/).

  • 21.
    Almroth-Rosell, Elin
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Skogen, Morten D.
    A North Sea and Baltic Sea Model Ensemble Eutrophication Assessment2010Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 39, nr 1, s. 59-69Artikel i tidskrift (Refereegranskat)
    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.

  • 22.
    Almroth-Rosell, Elin
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    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 Sea2007Ingår i: BANSAI- The Baltic and North Sea marine environmental modelling Asessment Initaiative / [ed] the Nordic Council of Ministers’ Sea and Air Group, 2007Konferensbidrag (Övrigt vetenskapligt)
  • 23. Amador, Jorge A.
    et al.
    Ambrizzi, Tercio
    Arritt, Raymond W.
    Castro, Christopher L.
    Cavazos, Tereza
    Cerezo-Mota, Ruth
    Fuentes Franco, Ramon
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Giorgi, Filippo
    Guiliani, Graziano
    Lee, Huikyo
    Mendez-Perez, Matias
    Rivera, Erick R.
    Putting into action the REGCM4.6 regional climate model for the study of climate change, variability and modeling over Central America and Mexico2018Ingår i: Atmósfera, ISSN 0187-6236, Vol. 31, nr 2, s. 185-188Artikel i tidskrift (Refereegranskat)
  • 24. Amaguchi, H.
    et al.
    Kawamura, A.
    Olsson, Jonas
    SMHI, Forskningsavdelningen, Hydrologi.
    Takasaki, T.
    Development and testing of a distributed urban storm runoff event model with a vector-based catchment delineation2012Ingår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 420, s. 205-215Artikel i tidskrift (Refereegranskat)
    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.

  • 25.
    Ambjörn, Cecilia
    SMHI, Affärsverksamhet.
    Strömningsteknisk utredning avseende utbyggnad av gipsdeponi i Landskrona1990Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    HYDRO SUPRA AB planerar att utvidga sin gipsdeponering utanför Landskrona söderut. SMHI har därför fått i uppdrag att beräkna eventuella förändringar av vattenutbyte och strömmar i norra Lundåkrabukten. Strömförhållandena idag och efter en utbyggnad simuleras med en numerisk tredimensionell hydrodynamisk modell. Beräkningarna stöder sig på strömmätningar i två punkter i det studerade området samt strömförhållandena i centrala Öresund.

    Strömmen mättes under maj månad 1990. Resultaten visar att cirkulationen i Lundåkrabukten drivs av strömningen i centrala Öresund, speciellt gäller det för den långperiodiska strömningen. Tidvattnet har en viss betydelse i bukten och bidrar till relativt täta strömväxlingar. På det grunda området, mindre än I meter, har den lokala vinden stor betydelse för strömmarna. Innanför vågbrottszonen bildas intermittent en restström av de brytande ytvågorna.

    Strömmen mättes under maj månad 1990. Resultaten visar att cirkulationen i Lundåkrabukten drivs av strömningen i centrala Öresund, speciellt gäller det för den långperiodiska strömningen. Tidvattnet har en viss betydelse i bukten och bidrar till relativt täta strömväxlingar. På det grunda området, mindre än I meter, har den lokala vinden stor betydelse för strömmarna. Innanför vågbrottszonen bildas intermittent en restström av de brytande ytvågorna.

    Vattenutbyte

    Vid nordgående ström och nordlig eller sydlig vind påverkas vattenutbytet 1 nordligaste delen relativt litet, det minskar med storleksordningen någon procent. Vid nordgående ström och ostlig vind är förändringen av vattenutbytet något större. Strax öster om utbyggnaden sker en minskning på 50 procent över en bredd av cirka 600 meter. Öster härom sker ingen förändring. När utbytet betraktas i en linje från Gipsön och in mot land rakt österut, kan minskningen uppskattas till maximalt 10 procent. Denna strömsituation förekommer under I O - 20 procent av tiden, vilket innebär att sett över en längre tidsperiod är förändringen I - 2 procent.

    Vid sydgående ström och västlig vind är minskningen i det nordligaste delen av området cirka 10 - 15 procent. Totalt sett är volymerna här små. Vid svaga västvindar blir förändringen mindre. Förändringen är lokal strax öster och sydost om utfyllnaden. Västlig vind förekommer till cirka 40 procent under 1 år. Det ger totalt sett över en längre tidsperiod en minskning i nordligaste delen på 4-6 procent.

    Strömförhållanden

    Strömmen har studerats i närområdet före och efter utbyggnad. En förstoring av området gör att en visuell bedömning kan göras. För alla de fyra olika strömningssimuleringarna gäller att förändringen av strömmarna är obetydlig.

  • 26. Aminot, A
    et al.
    Kirkwood, D
    Carlberg, Stig
    SMHI, Forskningsavdelningen, Oceanografi.
    The QUASIMEME laboratory performance studies (1993-1995): Overview of the nutrients section1997Ingår i: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 35, nr 1-6, s. 28-41Artikel i tidskrift (Refereegranskat)
    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.

  • 27. Amir-Heidari, Payam
    et al.
    Arneborg, Lars
    SMHI, Forskningsavdelningen, Oceanografi.
    Lindgren, J. Fredrik
    Lindhe, Andreas
    Rosen, Lars
    Raie, Mohammad
    Axell, Lars
    SMHI, Forskningsavdelningen, Oceanografi.
    Hassellov, Ida-Maja
    A state-of-the-art model for spatial and stochastic oil spill risk assessment: A case study of oil spill from a shipwreck2019Ingår i: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 126, s. 309-320Artikel i tidskrift (Refereegranskat)
  • 28.
    Amorim, Jorge Humberto
    et al.
    SMHI, Forskningsavdelningen, Luftmiljö.
    Asker, Christian
    SMHI, Forskningsavdelningen, Luftmiljö.
    Belusic, Danijel
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Carvalho, Ana
    SMHI, Forskningsavdelningen, Luftmiljö.
    Engardt, Magnuz
    SMHI, Forskningsavdelningen, Luftmiljö.
    Gidhagen, Lars
    SMHI, Forskningsavdelningen, Luftmiljö.
    Hundecha, Yeshewatesfa
    SMHI, Forskningsavdelningen, Hydrologi.
    Körnich, Heiner
    SMHI, Forskningsavdelningen, Meteorologi.
    Lind, Petter
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Olsson, Esbjörn
    SMHI, Forskningsavdelningen, Meteorologi.
    Olsson, Jonas
    SMHI, Forskningsavdelningen, Hydrologi.
    Segersson, David
    SMHI, Forskningsavdelningen, Luftmiljö.
    Strombäck, Lena
    SMHI, Forskningsavdelningen, Hydrologi.
    Joe, Paul
    Baklanov, Alexander
    Integrated Urban Services for European cities: the Stockholm case2018Ingår i: WMO Bulletin, ISSN 0042-9767, Vol. 67, nr 2, s. 33-40Artikel i tidskrift (Refereegranskat)
  • 29.
    Amorim, Jorge Humberto
    et al.
    SMHI, Forskningsavdelningen, Luftmiljö.
    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 shrubland2016Ingår i: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 145, s. 19-28Artikel i tidskrift (Refereegranskat)
  • 30. Anastasiadis, Stavros
    et al.
    Boglis, Argiris
    Pechlivanidis, Ilias
    SMHI, Forskningsavdelningen, Hydrologi.
    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, GREECE2013Ingår i: Fresenius Environmental Bulletin, ISSN 1018-4619, E-ISSN 1610-2304, Vol. 22, nr 7B, s. 2152-2158Artikel i tidskrift (Refereegranskat)
    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.

  • 31. Andersen, Jesper H.
    et al.
    Axe, Philip
    SMHI, Forskningsavdelningen, Oceanografi.
    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 methods2011Ingår i: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 106, nr 2, s. 137-156Artikel i tidskrift (Refereegranskat)
    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.

  • 32. Andersen, Jesper H.
    et al.
    Murray, Ciaran
    Kaartokallio, Hermanni
    Axe, Philip
    SMHI, Forskningsavdelningen, Oceanografi.
    Molvaer, Jarle
    A simple method for confidence rating of eutrophication status classifications2010Ingår i: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 60, nr 6, s. 919-924Artikel i tidskrift (Refereegranskat)
    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.

  • 33. 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, Forskningsavdelningen, Klimatforskning - 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 19932003Ingår i: Journal of Hydrometeorology, ISSN 1525-755X, E-ISSN 1525-7541, Vol. 4, nr 3, s. 584-598Artikel i tidskrift (Refereegranskat)
    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.

  • 34. Anderson., D. M
    et al.
    Karlson, Bengt
    SMHI, Forskningsavdelningen, Oceanografi.
    Preservatives and methods for algal cell enumeration2017Ingår i: Harmful Algal Blooms (HABs) and Desalination: A Guide to Impacts, Monitoring and Management / [ed] Anderson D. M., S. F. E. Boerlage, M. B. Dixon, Paris: Intergovernmental Oceanographic Commission of UNESCO , 2017, s. 509-517Kapitel i bok, del av antologi (Refereegranskat)
  • 35. Andersson, Agneta
    et al.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Ripszam, Matyas
    Rowe, Owen
    Wikner, Johan
    Haglund, Peter
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Legrand, Catherine
    Figueroa, Daniela
    Paczkowska, Joanna
    Lindehoff, Elin
    Tysklind, Mats
    Elmgren, Ragnar
    Projected future climate change and Baltic Sea ecosystem management2015Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, s. S345-S356Artikel i tidskrift (Refereegranskat)
    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.

  • 36.
    Andersson, Camilla
    et al.
    SMHI, Forskningsavdelningen, Luftmiljö.
    Alpfjord, Helene
    SMHI, Affärsverksamhet.
    Robertson, Lennart
    SMHI, Forskningsavdelningen, Luftmiljö.
    Karlsson, Per Erik
    Miljöforskningsinstitutet.
    Engardt, Magnuz
    SMHI, Forskningsavdelningen, Luftmiljö.
    Reanalysis of and attribution to near-surface ozone concentrations in Sweden during 1990-20132017Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 17, nr 22Artikel i tidskrift (Refereegranskat)
  • 37.
    Andersson, Camilla
    et al.
    SMHI, Forskningsavdelningen, Luftmiljö.
    Alpfjord Wylde, Helene
    SMHI, Affärsverksamhet.
    Engardt, Magnuz
    SMHI, Forskningsavdelningen, Luftmiljö.
    Long-term sulfur and nitrogen deposition in Sweden: 1983-2013 reanalysis2018Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Ett unikt långt dataset (1983-2013) för svavel- och kvävedeposition har skapats för Sverige samt Östersjön och omgivande länder. Det baseras på kvalitetsgranskade mätningar och modellfält, kombinerade genom avancerade metoder för att fånga spatiala och temporala variationer. Datasetet kan användas för att beskriva trender i deposition till olika relevanta marktyper.Återanalysen stämmer väl överens med mätningar, men vi har identifierat skillnader i torrdeposition till barrskog. Detta visar på behov av djupare studier och metodikförbättringar för bestämning av torrdeposition.Vi rekommenderar mer avancerade metoder för att beskriva spatial variation än genom medelvärdesbildning eller spatial interpolering av uppmätt deposition.Vi finner en markant minskning från 1980-talet fram till idag för både svavel- och kvävedeposition (med cirka 80 % respektive 30 %).Kritiska belastningar till både barr- och lövskog, fjällmarker och våtmarker har överskridits framförallt i sydvästra Sverige, men också i sydöstra Sverige och södra fjällen. Situationen förbättras men överskridanden sker fortfarande även över större områden.

  • 38.
    Andersson, Camilla
    et al.
    SMHI, Forskningsavdelningen, Luftmiljö.
    Bergström, Robert
    SMHI, Forskningsavdelningen, Luftmiljö.
    Bennet, Cecilia
    SMHI, Forskningsavdelningen, Luftmiljö.
    Robertson, Lennart
    SMHI, Forskningsavdelningen, Luftmiljö.
    Thomas, Manu
    SMHI, Forskningsavdelningen, Luftmiljö.
    Korhonen, H.
    Lehtinen, K. E. J.
    Kokkola, H.
    MATCH-SALSA - Multi-scale Atmospheric Transport and CHemistry model coupled to the SALSA aerosol microphysics model - Part 1: Model description and evaluation2015Ingår i: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 8, nr 2, s. 171-189Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have implemented the sectional aerosol dynamics model SALSA (Sectional Aerosol module for Large Scale Applications) in the European-scale chemistry-transport model MATCH (Multi-scale Atmospheric Transport and Chemistry). The new model is called MATCH-SALSA. It includes aerosol microphysics, with several formulations for nucleation, wet scavenging and condensation. The model reproduces observed higher particle number concentration (PNC) in central Europe and lower concentrations in remote regions. The modeled PNC size distribution peak occurs at the same or smaller particle size as the observed peak at four measurement sites spread across Europe. Total PNC is underestimated at northern and central European sites and accumulation-mode PNC is underestimated at all investigated sites. The low nucleation rate coefficient used in this study is an important reason for the underestimation. On the other hand, the model performs well for particle mass (including secondary inorganic aerosol components), while elemental and organic carbon concentrations are underestimated at many of the sites. Further development is needed, primarily for treatment of secondary organic aerosol, in terms of biogenic emissions and chemical transformation. Updating the biogenic secondary organic aerosol (SOA) scheme will likely have a large impact on modeled PM2.5 and also affect the model performance for PNC through impacts on nucleation and condensation.

  • 39.
    Andersson, Camilla
    et al.
    SMHI, Forskningsavdelningen, Luftmiljö.
    Bergström, Robert
    SMHI, Forskningsavdelningen, Luftmiljö.
    Johansson, Christer
    Population exposure and mortality due to regional background PM in Europe - Long-term simulations of source region and shipping contributions2009Ingår i: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, nr 22-23, s. 3614-3620Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents the contribution to population exposure (PE) of regional background fine primary (PPM(2.5)) and secondary inorganic (SIA) particulate matter and its impact on mortality in Europe during 1997-2003 calculated with a chemistry transport model. Contributions to concentrations and PE due to emissions from shipping, Western (WEU), Eastern (EEU), and Northern Europe are compared. WEU contributes about 40% to both PPM(2.5) and SIA concentrations, whereas the EEU contribution to PPM(2.5) is much higher (43% of total PPM(2.5)) than to SIA (29% of total SIA). The population weighted average concentration (PWC) of PPM(2.5) is a factor of 2.3 higher than average (non-weighted) concentrations, whereas for SIA the PWC is only a factor 1.6 higher. This is due to PPM(2.5) concentrations having larger gradients and being relatively high over densely populated areas, whereas SIA is formed outside populated areas. WEU emissions contribute relatively more than EEU to PWC and mortality due to both PPM(2.5) and SIA in Europe. The number of premature deaths in Europe is estimated to 301000 per year due to PPM(2.5) exposure and 245 000 due to SIA, despite 3.3 times higher average SIA concentrations. This is due to population weighting and assumed (and uncertain) higher relative risk of mortality for PPM(2.5) components (2.8 times higher RR for PPM(2.5)). This study indicates that it might be more efficient, for the health of the European population, to decrease primary PM emissions (especially in WEU) than to decrease precursors of SIA, but more knowledge on the toxicity of different PM constituents is needed before firm conclusions can be drawn. (C) 2009 Elsevier Ltd. All rights reserved.

  • 40.
    Andersson, Camilla
    et al.
    SMHI, Forskningsavdelningen, Luftmiljö.
    Engardt, Magnuz
    SMHI, Forskningsavdelningen, Luftmiljö.
    European ozone in a future climate: Importance of changes in dry deposition and isoprene emissions2010Ingår i: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 115, artikel-id D02303Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Projections of future surface ozone over Europe conducted utilizing chemistry transport models (CTMs) coupled to climate models differ greatly, even in sign. CTM sensitivity studies were conducted in order to investigate the importance of changes in natural isoprene emissions and dry deposition to vegetation, both coupled to meteorology. This knowledge can be used to improve surface ozone projections. Our simulations suggest climate change over Europe would cause changes in surface ozone between -4.0 to +13 ppb(v) on average (April-September) and -3.5 to +25 ppb(v) on average (April-September) daily maximum from 1961 - 1990 to 2071 - 2100. The change is positive in the southwest and negative in the north. The isoprene emissions increased by a factor of about 1.8 from 1961 - 1990 to 2071 - 2100. A rescaling of isoprene emissions shows that the large increase in isoprene emission is of importance (0 - 30% of the change in surface ozone) in central, southern, and western Europe. The use of a formulation for ozone dry deposition to vegetation, dependent on meteorology, and changes in snow cover, affecting the dry deposition, are more important processes. The changes in dry deposition to vegetation (not including changes in aerodynamic resistance) explain up to 80% of the surface ozone change in Spain. Therefore it is vital to include meteorological dependence for dry deposition of ozone to vegetation in surface ozone projections. Isoprene emissions are of less importance, but they are nonnegligible and should definitely be emitted online in climate ozone projection studies.

  • 41.
    Andersson, Camilla
    et al.
    SMHI, Forskningsavdelningen, Luftmiljö.
    Langner, Joakim
    SMHI, Forskningsavdelningen, Luftmiljö.
    Bergström, Robert
    SMHI, Forskningsavdelningen, Luftmiljö.
    Interannual variation and trends in air pollution over Europe due to climate variability during 1958-2001 simulated with a regional CTM coupled to the ERA40 reanalysis2007Ingår i: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 59, nr 1, s. 77-98Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A three-dimensional Chemistry Transport Model was used to study the meteorologically induced interannual variability and trends in deposition of sulphur and nitrogen as well as concentrations of surface ozone (O(3)), nitrogen dioxide (NO(2)) and particulate matter (PM) and its constituents over Europe during 1958-2001. The model was coupled to the meteorological reanalysis ERA40, produced at the European Centre for Medium-range Weather Forecasts. Emissions and boundary conditions of chemical compounds and PM were kept constant at present levels. The average European interannual variation, due to meteorological variability, ranges from 3% for O(3), 5% for NO(2), 9% for PM, 6-9% for dry deposition, to about 20% for wet deposition of sulphur and nitrogen. For the period 1979-2001 the trend in ozone, due to climate variability is increasing in central and southwestern Europe and decreasing in northeastern Europe, the trend in NO(2) is approximately opposite. The trend in PM is positive in eastern Europe. There are negative trends in wet deposition in southwestern and central Europe and positive trends in dry deposition overall. A bias in ERA40 precipitation could be partly responsible for the trends. The variation and trends need to be considered when interpreting measurements and designing measurement campaigns.

  • 42. Andersson, E.
    et al.
    Kahnert, Michael
    SMHI, Forskningsavdelningen, Luftmiljö.
    Devasthale, Abhay
    SMHI, Forskningsavdelningen, Atmosfärisk fjärranalys.
    Methodology for evaluating lateral boundary conditions in the regional chemical transport model MATCH (v5.5.0) using combined satellite and ground-based observations2015Ingår i: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 8, nr 11, s. 3747-3763Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hemispheric transport of air pollutants can have a significant impact on regional air quality, as well as on the effect of air pollutants on regional climate. An accurate representation of hemispheric transport in regional chemical transport models (CTMs) depends on the specification of the lateral boundary conditions (LBCs). This study focuses on the methodology for evaluating LBCs of two moderately long-lived trace gases, carbon monoxide (CO) and ozone (O-3), for the European model domain and over a 7-year period, 2006-2012. The method is based on combining the use of satellite observations at the lateral boundary with the use of both satellite and in situ ground observations within the model domain. The LBCs are generated by the global European Monitoring and Evaluation Programme Meteorological Synthesizing Centre - West (EMEP MSC-W) model; they are evaluated at the lateral boundaries by comparison with satellite observations of the Terra-MOPITT (Measurements Of Pollution In The Troposphere) sensor (CO) and the Aura-OMI (Ozone Monitoring Instrument) sensor (O-3). The LBCs from the global model lie well within the satellite uncertainties for both CO and O-3. The biases increase below 700 hPa for both species. However, the satellite retrievals below this height are strongly influenced by the a priori data; hence, they are less reliable than at, e.g. 500 hPa. CO is, on average, underestimated by the global model, while O-3 tends to be overestimated during winter, and underestimated during summer. A regional CTM is run with (a) the validated monthly climatological LBCs from the global model; (b) dynamical LBCs from the global model; and (c) constant LBCs based on in situ ground observations near the domain boundary. The results are validated against independent satellite retrievals from the Aqua-AIRS (Atmospheric InfraRed Sounder) sensor at 500 hPa, and against in situ ground observations from the Global Atmospheric Watch (GAW) network. It is found that (i) the use of LBCs from the global model gives reliable in-domain results for O-3 and CO at 500 hPa. Taking AIRS retrievals as a reference, the use of these LBCs substantially improves spatial pattern correlations in the free troposphere as compared to results obtained with fixed LBCs based on ground observations. Also, the magnitude of the bias is reduced by the new LBCs for both trace gases. This demonstrates that the validation methodology based on using satellite observations at the domain boundary is sufficiently robust in the free troposphere. (ii) The impact of the LBCs on ground concentrations is significant only at locations in close proximity to the domain boundary. As the satellite data near the ground mainly reflect the a priori estimate used in the retrieval procedure, they are of little use for evaluating the effect of LBCs on ground concentrations. Rather, the evaluation of ground-level concentrations needs to rely on in situ ground observations. (iii) The improvements of dynamic over climatological LBCs become most apparent when using accumulated ozone over threshold 40 ppb (AOT40) as a metric. Also, when focusing on ground observations taken near the inflow boundary of the model domain, one finds that the use of dynamical LBCs yields a more accurate representation of the seasonal variation, as well as of the variability of the trace gas concentrations on shorter timescales.

  • 43. Andersson, Emma
    et al.
    Kahnert, Michael
    SMHI, Forskningsavdelningen, Luftmiljö.
    Coupling aerosol optics to the MATCH (v5.5.0) chemical transport model and the SALSA (v1) aerosol microphysics module2016Ingår i: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 9, nr 5, s. 1803-1826Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new aerosol-optics model is implemented in which realistic morphologies and mixing states are assumed, especially for black carbon particles. The model includes both external and internal mixing of all chemical species, it treats externally mixed black carbon as fractal aggregates, and it accounts for inhomogeneous internal mixing of black carbon by use of a novel "core-grey-shell" model. Simulated results of aerosol optical properties, such as aerosol optical depth, backscattering coefficients and the Angstrom exponent, as well as radiative fluxes are computed with the new optics model and compared with results from an older optics-model version that treats all particles as externally mixed homogeneous spheres. The results show that using a more detailed description of particle morphology and mixing state impacts the aerosol optical properties to a degree of the same order of magnitude as the effects of aerosol-microphysical processes. For instance, the aerosol optical depth computed for two cases in 2007 shows a relative difference between the two optics models that varies over the European region between 28 and 18 %, while the differences caused by the inclusion or omission of the aerosol-microphysical processes range from 50 to 37 %. This is an important finding, suggesting that a simple optics model coupled to a chemical transport model can introduce considerable errors affecting radiative fluxes in chemistry-climate models, compromising comparisons of model results with remote sensing observations of aerosols, and impeding the assimilation of satellite products for aerosols into chemical-transport models.

  • 44.
    Andersson, Helén
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Eriksson Bram, Lena
    SMHI, Samhälle och säkerhet.
    Hjerdt, Niclas
    SMHI, Samhälle och säkerhet.
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Löptien, Ulrike
    SMHI, Forskningsavdelningen, Oceanografi.
    Strömqvist, Johan
    SMHI, Forskningsavdelningen, Hydrologi.
    Översikt av beräkningsmodeller för bedömning av fiskodlingars näringsämnesbelastning på sjöar, vattendrag, magasin och kustvatten2016Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Den här rapporten är en kunskapssammanställning som utförts av SMHI på uppdrag av Havs- och Vattenmyndigheten. Den utgör inte något ställningstagande från Havs- och vattenmyndighetens sida. Rapporten försöker att sammanfatta den problematik som associeras med näringsämnesbelastningar från fiskodlingar i öppna kassar, vilka typer av beräkningar som kan behöva göras för att få en uppfattning om hur dessa kan påverka miljön samt några olika typer av modeller för detta ändamål.

    Fisk-, alg- och skaldjursodling är en växande industri runt om i världen som kan ge såväl näringsrik och hälsosam mat som arbetstillfällen. En nackdel med framförallt fiskodling i öppna kassar är att den kan innebära en påfrestning för vattenmiljön. De näringsämnen som ofta släpps ut från odlingen kan bidra till den övergödningsproblematik som redan finns i många sjöar och havsområden. Det är därför av största vikt att få en god uppskattning av den förväntade storleken på utsläppen förknippade med en öppen odling samt hur de kan tänkas förändra vattenkvaliteten på odlingsplatsen och dess närhet. Beräkningsmodeller kan vara till god hjälp vid bedömningen.

    Fiskar utsöndrar lösta näringsämnen och från odlingskassarna faller det också ut partikulärt organiskt material i form av fekalier och oätet foder. Storleken på näringsämneskällorna behöver beräknas och det finns modeller av olika komplexitet för att uppskatta detta. Storleken på det partikulära avfallet är viktigt dels för att det bidrarmed näringsämnen till vattnet och dels för att det kan ge upphov till ansamlingar av organiskt material på bottnen. När det organiska materialet bryts ner förbrukas syre och om ansamlingarna blir omfattande finns en risk för att det uppstår syrebrist vid bottnen. Om svavelväte bildas kan det orsaka skador på såväl den odlade fisken som det lokala ekosystemet. Odlingen kan också bidra till en försämrad vattenkvalitet i sin omgivning genom att tillgången av lösta näringsämnen blir större och därmed ge en ökad algproduktion. Den ökade algproduktionen skall i sin tur brytas ner och kan i förlängningen bidra till syrebristproblematiken.

    Det finns ett antal modeller som är specifikt utvecklade för fiskodlingar i öppna kassar och de tar i olika hög grad upp den beskrivna problematiken. Rapporten innehåller detaljerade genomgångar av några av modeller för att visa på styrkor och svagheter kring olika angreppsätt. Den innehåller också sammanfattningar av några vanligt förekommande modeller som använts internationellt vid bedömning av fiskodlingars miljöpåverkan. För att minska den negativa påverkan på vattenmiljön från har det också utvecklats recirkulerande system för odling. Rapporten tar inte upp belastning från den typen av fiskodlingar. Om utsläppen från ett sådant system är känt kan dock vattenkvalitetsmodeller användas för att se effekten av utsläpp från en punktkälla.

    Rapporten sammanfattar ett antal vattenkvalitetsmodeller för sjöar, vattendrag, kust och hav. En vattenkvalitetsmodell behöver inte nödvändigtvis vara utvecklad för att beskriva konsekvenser av fiskodlingar men bör kunna hantera frågeställningar som uppkommer vid bedömningar av övergödningsrisk vid utsläpp från en punktkälla. Den behöver därför kunna simulera parametrar såsom förändringen av näringsämneskoncentrationer, primärproduktion, siktdjup och syrgashalter på olika nivåer i vattenmassan. Modeller för den här typen av uppskattningar finns också i olika komplexitetsgrad och för olika skalor i tid och rum.

    Vid modellering är en god tillgång till observationer en förutsättning för pålitliga modellresultat och behövs såväl för att driva och kalibrera modellen som för validering av modellresultaten. Det är viktigt att tillgängliga data håller god kvalitet. En noggrann analys och beskrivning av den tillgängliga databasen hjälper därmed till att bedöma tillförlitligheten av modellsimuleringarna.

  • 45.
    Andersson, Jafet
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Ali, Abdou
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Gustafsson, David
    SMHI, Forskningsavdelningen, Hydrologi.
    Minoungou, Bernard
    Providing peak river flow statistics and forecasting in the Niger River basin2017Ingår i: Physics and Chemistry of the Earth, ISSN 1474-7065, E-ISSN 1873-5193, Vol. 100, s. 3-12Artikel i tidskrift (Refereegranskat)
  • 46.
    Andersson, Jafet
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Hjerdt, Niclas
    SMHI, Samhälle och säkerhet.
    Combine and Share Essential Knowledge for Sustainable2016Ingår i: The Solutions Journal, ISSN 2154-0926, Vol. 7, nr 3, s. 30-32Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 47.
    Andersson, Jafet
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Hjerdt, Niclas
    SMHI, Samhälle och säkerhet.
    Combine and Share Essential Knowledge for Sustainable Water Management2016Ingår i: Solutions Journal, ISSN 2154-0896, E-ISSN 2154-0926, Vol. 7, nr 3Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 48.
    Andersson, Jafet
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Traore, Farid
    Gustafsson, David
    SMHI, Forskningsavdelningen, Hydrologi.
    Ali, Abdou
    Process refinements improve a hydrological model concept applied to the Niger River basin2017Ingår i: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 31, nr 25, s. 4540-4554Artikel i tidskrift (Refereegranskat)
  • 49.
    Andersson, Jafet
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Pechlivanidis, Ilias
    SMHI, Forskningsavdelningen, Hydrologi.
    Gustafsson, David
    SMHI, Forskningsavdelningen, Hydrologi.
    Donnelly, Chantal
    SMHI, Forskningsavdelningen, Hydrologi.
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Key factors for improving large-scale hydrological model performance2015Ingår i: European Water, ISSN 1792-085X, Vol. 49, s. 77-88Artikel i tidskrift (Refereegranskat)
  • 50.
    Andersson, Jafet
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Zehnder, Alexander J. B.
    Wehrli, Bernhard
    Jewitt, Graham P. W.
    Abbaspour, Karim C.
    Yang, Hong
    Improving Crop Yield and Water Productivity by Ecological Sanitation and Water Harvesting in South Africa2013Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 47, nr 9, s. 4341-4348Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study quantifies the potential effects of a set of technologies to address wafer and fertility constraints in rain. fed smallholder agriculture in South Africa, namely in situ water harvesting (WH), external WH, and ecological sanitation (Ecosan, fertilization with human urine); We Used the Soil and Water Assessment Tool to model spatiotemporally differentiated effects on maize yield, river flow, evaporation, and transpiration. Ecosan Met some of the plant nitrogen demands, which significantly increased maize yields by 12% and transpiration by 2% on average across South Africa. In situ and external WH did not significantly affect the yield, transpiration or river flow on the South Africa scale. However, external WH. more than doubled the yields for specific seasons and locations. WH particularly increased the lowest yields. Significant, water and nutrient demands remained even with WH and Ecosan management. Additional fertility enhancements raised the yield levels but also the yield variability, whereas soil moisture enhancements improved the yield stability. Hence, coupled policies' addressing both constraints will likely be Most effective for improving food security.

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