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  • 1701. Silgram, M.
    et al.
    Anthony, S. G.
    Collins, A. L.
    Stromqvist, J.
    Bouraoui, F.
    Schoumans, O.
    Lo Porto, A.
    Groenendijk, P.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Mimikou, M.
    Johnsson, H.
    Evaluation of diffuse pollution model applications in EUROHARP catchments with limited data2009In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 11, no 3, p. 554-571Article in journal (Refereed)
    Abstract [en]

    The application of diffuse pollution models included in EUROHARP encompassed varying levels of parameterisation and approaches to the preparation of input data depending on the model and modelling team involved. Modellers consistently faced important decisions in relation to data interpretation, especially in those catchments with unfamiliar physical or climatic characteristics, where catchment conditions were beyond the range for which a particular model was originally developed, or where only limited input data were available. In addition to a broad discussion of data issues, this paper compares the performance of the four sub-annual output models tested in EUROHARP (EveNFlow, NL-CAT, SWAT and TRK) in three test catchments without the modelling teams having sight of measured flow and nitrate concentration data. Model performance in this "blind test" indicate that the range of predictions generated by any individual models pre and post calibration exceed the differences between the estimates yielded by all four models. Comparison of Analysis of Variance (ANOVA) statistics for simulated and observed flow, concentration and loads underscores the benefits of calibration for these intermediate and complex model formulations. Interpretation of input data (e. g. rainfall interpolation method and pedotransfer functions selected) appeared equally (or more) important than process representation. In the absence of calibration data, modeller unfamiliarity with a particular catchment and its environmental processes sometimes resulted in questionable assumptions and input errors which highlight the problems facing modellers charged with implementing policies under the Water Framework Directive (2000/60/EC) in poorly monitored catchments. Catchment data owners and modellers must therefore work more closely given that the output from diffuse pollution models is clearly modeller-limited as well as model-limited.

  • 1702. Silgram, M.
    et al.
    Schoumans, O. F.
    Walvoort, D. J. J.
    Anthony, S. G.
    Groenendijk, P.
    Stromqvist, J.
    Bouraoui, F.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Kapetanaki, M.
    Lo Porto, A.
    Martensson, K.
    Subannual models for catchment management: evaluating model performance on three European catchments2009In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 11, no 3, p. 526-539Article in journal (Refereed)
    Abstract [en]

    Models' abilities to predict nutrient losses at subannual timesteps is highly significant for evaluating policy measures, as it enables trends and the frequency of exceedance of water quality thresholds to be predicted. Subannual predictions also permit assessments of seasonality in nutrient concentrations, which are necessary to determine susceptibility to eutrophic conditions and the impact of management practices on water quality. Predictions of subannual concentrations are pertinent to EC Directives, whereas load estimates are relevant to the 50% target reduction in nutrient loading to the maritime area under OSPAR. This article considers the ability of four models ( ranging from conceptual to fully mechanistic), to predict river flows, concentrations and loads of nitrogen and phosphorus on a subannual basis in catchments in Norway, England, and Italy. Results demonstrate that model performance deemed satisfactory on an annual basis may conceal considerable divergence in performance when scrutinised on a weekly or monthly basis. In most cases the four models performed satisfactorily, and mismatches between measurements and model predictions were primarily ascribed to the limitations in input data ( soils in the Norwegian catchment; weather in the Italian catchment). However, results identified limitations in model conceptualisation associated with the damping and lagging effect of a large lake leading to contrasts in model performance upstream and downstream of this feature in the Norwegian catchment. For SWAT applied to the Norwegian catchment, although flow predictions were reasonable, the large number of parameters requiring identification, and the lack of familiarity with this environment, led to poor predictions of river nutrient concentrations.

  • 1703. Silva, F. C.
    et al.
    Borrego, C.
    Keizer, J. J.
    Amorim, Jorge Humberto
    SMHI, Research Department, Air quality.
    Verheijen, F. G. A.
    Effects of moisture content on wind erosion thresholds of biochar2015In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 123, p. 121-128Article in journal (Refereed)
    Abstract [en]

    Biochar, i.e. pyrolysed biomass, as a soil conditioner is gaining increasing attention in research and industry, with guidelines and certifications being developed for biochar production, storage and handling, as well as for application to soils. Adding water to biochar aims to reduce its susceptibility to become airborne during and after the application to soils, thereby preventing, amongst others, human health issues from inhalation. The Bagnold model has previously been modified to explain the threshold friction velocity of coal particles at different moisture contents, by adding an adhesive effect. However, it is unknown if this model also works for biochar particles. We measured the threshold friction velocities of a range of biochar particles (woody feedstock) under a range of moisture contents by using a wind tunnel, and tested the performance of the modified Bagnold model. Results showed that the threshold friction velocity can be significantly increased by keeping the gravimetric moisture content at or above 15% to promote adhesive effects between the small particles. For the specific biochar of this study, the modified Bagnold model accurately estimated threshold friction velocities of biochar particles up to moisture contents of 10%. (C) 2015 Elsevier Ltd. All rights reserved.

  • 1704. Silver, Jeremy D.
    et al.
    Christensen, Jesper H.
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Rayner, Peter J.
    Brandt, Jorgen
    Multi-species chemical data assimilation with the Danish Eulerian hemispheric model: system description and verification2016In: Journal of Atmospheric Chemistry, ISSN 0167-7764, E-ISSN 1573-0662, Vol. 73, no 3, p. 261-302Article in journal (Refereed)
  • 1705. Simpson, D.
    et al.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Christensen, J. H.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Geels, C.
    Nyiri, A.
    Posch, M.
    Soares, J.
    Sofiev, M.
    Wind, P.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Impacts of climate and emission changes on nitrogen deposition in Europe: a multi-model study2014In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 14, no 13, p. 6995-7017Article in journal (Refereed)
    Abstract [en]

    The impact of climate and emissions changes on the deposition of reactive nitrogen (Nr) over Europe was studied using four offline regional chemistry transport models (CTMs) driven by the same global projection of future climate over the period 2000-2050. Anthropogenic emissions for the years 2005 and 2050 were used for simulations of both present and future periods in order to isolate the impact of climate change, hemispheric boundary conditions and emissions, and to assess the robustness of the results across the different models. The results from these four CTMs clearly show that the main driver of future N-deposition changes is the specified emission change. Under the specified emission scenario for 2050, emissions of oxidised nitrogen were reduced substantially, whereas emissions of NH3 increase to some extent, and these changes are largely reflected in the modelled concentrations and depositions. The lack of sulfur and oxidised nitrogen in the future atmosphere results in a much larger fraction of NHx being present in the form of gaseous ammonia. Predictions for wet and total deposition were broadly consistent, although the three fine-scale models resolve European emission areas and changes better than the hemisphericscale model. The biggest difference in the models is for predictions of individual N compounds. One model (EMEP) was used to explore changes in critical loads, also in conjunction with speculative climate-induced increases in NH3 emissions. These calculations suggest that the area of ecosystems that exceeds critical loads is reduced from 64% for year 2005 emissions levels to 50% for currently estimated 2050 levels. A possible climate-induced increase in NH3 emissions could worsen the situation, with areas exceeded increasing again to 57% (for a 30% NH3 emission increase).

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  • 1706. Simpson, D.
    et al.
    Benedictow, A.
    Berge, H.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Emberson, L. D.
    Fagerli, H.
    Flechard, C. R.
    Hayman, G. D.
    Gauss, M.
    Jonson, J. E.
    Jenkin, M. E.
    Nyiri, A.
    Richter, C.
    Semeena, V. S.
    Tsyro, S.
    Tuovinen, J-P
    Valdebenito, A.
    Wind, P.
    The EMEP MSC-W chemical transport model - technical description2012In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 12, no 16, p. 7825-7865Article in journal (Refereed)
    Abstract [en]

    The Meteorological Synthesizing Centre-West (MSC-W) of the European Monitoring and Evaluation Programme (EMEP) has been performing model calculations in support of the Convention on Long Range Transboundary Air Pollution (CLRTAP) for more than 30 years. The EMEP MSC-W chemical transport model is still one of the key tools within European air pollution policy assessments. Traditionally, the model has covered all of Europe with a resolution of about 50 km x 50 km, and extending vertically from ground level to the tropopause (100 hPa). The model has changed extensively over the last ten years, however, with flexible processing of chemical schemes, meteorological inputs, and with nesting capability: the code is now applied on scales ranging from local (ca. 5 km grid size) to global (with 1 degree resolution). The model is used to simulate photo-oxidants and both inorganic and organic aerosols. In 2008 the EMEP model was released for the first time as public domain code, along with all required input data for model runs for one year. The second release of the EMEP MSC-W model became available in mid 2011, and a new release is targeted for summer 2012. This publication is in-tended to document this third release of the EMEP MSC-W model. The model formulations are given, along with details of input data-sets which are used, and a brief background on some of the choices made in the formulation is presented. The model code itself is available at www.emep.int, along with the data required to run for a full year over Europe.

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  • 1707. Simpson, David
    et al.
    Bartnicki, Jerzy
    Jalkanen, Jukka-Pekka
    Hansson, Hans-Christen
    Hertel, Ole
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Pryor, Sara C.
    Environmental Impacts-Atmospheric Chemistry2015Chapter in book (Other academic)
    Abstract [en]

    This chapter addresses sources and trends of atmospheric pollutants and deposition in relation to the Baltic Sea region. Air pollution is shown to have important effects, including significant contributions to nitrogen loading of the Baltic Sea area, ecosystem impacts due to acidifying and eutrophying pollutants and ozone, and human health impacts. Compounds such as sulphate and ozone also have climate impacts. Emission changes have been very significant over the past 100 years, although very different for land-and sea-based sources. Land-based emissions generally peaked around 1980-1990 and have since reduced due to emissions control measures. Emissions from shipping have been steadily increasing for decades, but recent measures have reduced sulphur and particulate emissions. Future developments depend strongly on policy developments. Changes in concentration and deposition of the acidifying components generally follow emission changes within the European area. Mean ozone levels roughly doubled during the twentieth century across the northern hemisphere, but peak levels have reduced in many regions in the past 20 years. The main changes in air pollution in the Baltic Sea region are due to changes in emissions rather than to climate change.

  • 1708. Siniarovina, U
    et al.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    High-resolution model simulations of anthropogenic sulphate and sulphur dioxide in Southeast Asia2005In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 39, no 11, p. 2021-2034Article in journal (Refereed)
    Abstract [en]

    The Multiple-scale Atmospheric Transport and CHemical modelling system (MATCH)-driven by meteorological data from the ECMWF has been applied to a model domain covering Southeast Asia to complete a simulation extending over the full year of 2000. The current paper presents an evaluation of the model performance using archived chemical and meteorological data collected in the region during the year 2000. The calculated sulphate concentrations (on atmospheric aerosols and in precipitation) compare reasonably with observations while the atmospheric SO(2) mixing ratios show worse correspondence. This latter mismatch is attributed to local variations in the measured SO(2) concentrations that are not resolved in the regional model and possible miss-location of the emissions in our model. It can also be pointed out that different laboratories measuring SO(2) at the same site occasionally report SO(2) concentrations that differs by an order of magnitude or more. The seasonal variations of the modelled species are less than initially expected but generally in accordance with the measurements available. Most of the Malaysian cities have comparatively low concentrations of sulphate in precipitation. This is supported both by the model results and by independent measurements. From the model simulations and the measurements, it is concluded that the sulphur deposition is still relatively low (i.e. < 0.5 g sulphur m(-2) year(-1)) in most of rural Malaysia. This is also the case in Myanmar, Laos, central Vietnam, Kampuchea and southern Thailand. The situation in the vicinity of the large cities in the region is, however, much worse and the deposition is similar, or larger, than estimated critical loads. (c) 2005 Elsevier Ltd. All rights reserved.

  • 1709. Sitz, L. E.
    et al.
    Di Sante, F.
    Farneti, R.
    Fuentes Franco, Ramon
    SMHI, Research Department, Climate research - Rossby Centre.
    Coppola, E.
    Mariotti, L.
    Reale, M.
    Sannino, G.
    Barreiro, M.
    Nogherotto, R.
    Giuliani, G.
    Graffino, G.
    Solidoro, C.
    Cossarini, G.
    Giorgi, F.
    Description and evaluation of the Earth System Regional Climate Model (Reg CM-ES)2017In: Journal of Advances in Modeling Earth Systems, ISSN 1942-2466, Vol. 9, no 4, p. 1863-1886Article in journal (Refereed)
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  • 1710. SJODIN, A
    et al.
    LOMAN, G
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    LONG-TERM CONTINUOUS MEASUREMENTS OF AIR POLLUTANT CONCENTRATIONS, METEOROLOGY AND TRAFFIC ON A RURAL MOTORWAY AND A MODEL VALIDATION1994In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 147, p. 365-375Article in journal (Refereed)
    Abstract [en]

    Air concentrations of carbon monoxide (CO), nitrogen oxide (NO) and nitrogen dioxide (NO2) were continuously monitored at a rural motorway site in Sweden for the period February-December 1990. In addition, local meteorology and traffic parameters were measured in order to validate a dispersion model. Even close to the motorway, the concentrations of CO and NO2 were well below Swedish air quality guidelines. For long-term averages the regional background contributed significantly to the downwind levels. The atmospheric reaction between primary emitted NO and background ozone (O3) tends to be a major source of downwind NO2, also fairly close to the road (10 m from the road shoulder), where the average NO2/NO(x) ratio was approximately 0.4. The validated model employs a percentile analysis on the basis of the HIWAY-2 and CALINE4 models and a separate emission model. The agreement between measured and modelled data, as refered to the 98th percentile, was good for NO2 but moderate for CO. This is probably partly caused by uncertainties in emission factors for CO for heavy vehicles. Since a good agreement was observed between measured and calculated NO(x) concentrations, problems in adequately modelling NO2 are probably associated with uncertainties as to NO2/NO(x) ratios in the exhaust, or the modelling of the O3 reaction.

  • 1711. Sjodin, A
    et al.
    Sjoberg, K
    Svanberg, P A
    Backström, Hans
    SMHI, Professional Services.
    Verification of expected trends in urban traffic NOx emissions from long-term measurements of ambient NO2 concentrations in urban air1996In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 189, p. 213-220Article in journal (Refereed)
    Abstract [en]

    Data from long-term measurements of ambient NO2 concentrations at roof level in 15 Swedish cities have been used to verify expected trends in urban traffic NOx emissions, resulting mainly from the growth in the number of threeway catalyst (TWC) cars in Sweden since the mid 1980s. The results show that, with few exceptions, all cities exhibit a highly significant downward trend in ambient NO2 concentration since the winter season 1986/1987, as regards both winter season averages and 98th percentiles of daily averages, with an average decrease in both cases of approximately 30% through the winter season 1993/1994. The same trend is also observed when meteorological variations between years are taken into account. Corrections for NO2 in background air yield an even stronger downward trend, or an average 40% decrease for the study period. Simultaneously, rough calculations indicate a 30% decrease in urban traffic NOx emissions during the study period. The conclusions are that, since emission calculations always involve a high degree of uncertainty, use of data from long-term measurements of NO2 concentrations in urban air can be very helpful in establishing real-world trends for urban traffic NOx emissions, as soon as NOx-levels are low enough for the NO + ozone reaction to become 'NOx-limited'.

  • 1712.
    Sjöberg, Björn
    et al.
    SMHI, Core Services.
    STIGEBRANDT, A
    COMPUTATIONS OF THE GEOGRAPHICAL-DISTRIBUTION OF THE ENERGY FLUX TO MIXING PROCESSES VIA INTERNAL TIDES AND THE ASSOCIATED VERTICAL CIRCULATION IN THE OCEAN1992In: DEEP-SEA RESEARCH PART A-OCEANOGRAPHIC RESEARCH PAPERS, ISSN 0198-0149, Vol. 39, no 2A, p. 269-&Article in journal (Refereed)
    Abstract [en]

    The global flux of tidal energy to mixing processes via topographically generated internal waves is estimated utilizing gridded databases for bathymetry, vertical density stratification and barotropic tides together with a simple, local model for the generation of progressive internal tides at vertical steps in the ocean floor. Both the horizontal distribution of the energy flux to internal tides and its ocean mean are discussed. The computed oceanic mean value is 44 x 10(-4) W m-2, a factor of about 2-3 greater than previous estimates (MUNK, 1966, Deep-Sea Research, 13, 707-730; BELL. 1975, Journal of Geophysical Research, 80, 320-327). The global distribution of vertical diffusivity in the abyss is computed by assuming that topographically generated baroclinic motions dissipate locally and that the dissipation is distributed vertically according to an empirical law. Our results are linearly dependent on the flux Richardson number R(f). From the computed vertical diffusivities and the known vertical stratification we finally compute the global distribution of vertical velocities. Choosing a value of R(f) almost-equal-to 0.05 we obtain an upward vertical transport in the interior of the ocean, at the 1000 m level, of about 15 x 10(6) m3 s-1, which agrees with WARREN's (1981, in: Evolution of physical oceanography, B. A. WARREN and C. WUNSCH, editors. 6-41) estimated rate of sinking from surface waters at high latitudes. Below the 1000 m level the upward vertical transport increases and a maximum value of about 25 x 10(6) m3 s-1 is found at the 2000 m level, after which the transport decreases to about 8 x 10(6) m3 s-1 at the 4000 m level. This may be explained by the action of bottom currents. These currents entrain ambient water whereby the upward interior vertical transports tend to increase with depth. However, because of the entrainment of lighter ambient fluid the dense currents become less dense and only the most dense flows penetrate to the greatest depths.

  • 1713.
    Sjökvist, Elin
    et al.
    SMHI, Professional Services.
    Abdoush, Diala
    SMHI, Core Services.
    Sommaren 2018 - en glimt av framtiden?2019Report (Other academic)
    Abstract [en]

    The weather in the summer of 2018 was extreme compared to what Sweden experienced during the 20th century. In some places, heat records were broken, and the combination of exceptional warm conditions with a deficit in precipitation caused a severe drought followed by forest fires and crop failure. Knowledge about impacts from climate change leads to the question: Will conditions like those in the summer of 2018 be average at the end of this century? This report compares different statistical measures from the summer of 2018 with by SMHI previously published climate scenarios.

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  • 1714. Skalak, Petr
    et al.
    Deque, Michel
    Belda, Michal
    Farda, Ales
    Halenka, Tomas
    Csima, Gabriella
    Bartholy, Judit
    Caian, Mihaela
    SMHI, Research Department, Climate research - Rossby Centre.
    Spiridonov, Valery
    CECILIA regional climate simulations for the present climate: validation and inter-comparison2014In: Climate Research (CR), ISSN 0936-577X, E-ISSN 1616-1572, Vol. 60, no 1, p. 1-12Article in journal (Refereed)
    Abstract [en]

    We investigated high-resolution simulations of regional climate models (RCMs) driven by ERA-40 reanalyses over areas of selected European countries (Austria, Czech Republic, Hungary, Slovakia and Romania) for the period 1961-1990. RCMs were run at a spatial resolution of 10 km in the framework of the CECILIA project, and their outputs were compared with the EOBS dataset of gridded observations and RCM simulations at coarser 25 km resolution from the ENSEMBLES project to identify a possible gain from the CECILIA experiments over ENSEMBLES. Cold biases of air temperature and wet biases of precipitation dominate in the CECILIA simulations. Spatial variability and distribution of the air temperature field are well captured. The precipitation field, relative to observations, often shows inadequately small spatial variability and lowered correlations but is nevertheless comparable to the ENSEMBLES model. Inter-annual variability (IAV) of air temperature is captured differently among seasons but mostly improved in CECILIA compared with ENSEMBLES. Precipitation IAV shows a similar or worse score. The detected weaknesses found within the validation of the CECILIA RCMs are attributed to the resolution dependence of the set of physical parameterizations in the models and the choice of integration domain. The gain obtained by using a high resolution over a small domain (as in CECILIA) relative to a lower resolution (25 km) over a larger domain (as in ENSEMBLES) is clear for air temperature but limited for precipitation.

  • 1715. Skogen, Morten D.
    et al.
    Eilola, Kari
    SMHI, Research Department, Oceanography.
    Hansen, Jorgen L. S.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Molchanov, Mikhail S.
    Ryabchenko, Vladimir A.
    Eutrophication status of the North Sea, Skagerrak, Kattegat and the Baltic Sea in present and future climates: A model study2014In: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 132, p. 174-184Article in journal (Refereed)
    Abstract [en]

    A method to combine observations and an ensemble of ecological models has been used to assess eutrophication. Using downscaled forcing from two GCMs under the A1B emission scenario, an assessment of the eutrophication status was made for a control (19702000) and a future climate (20702100) period. By using validation results from a hindcast to compute individual weights between the models, an assessment of eutrophication is done using a set of threshold values. The final classification distinguishes between three categories: problem area, potential problem area, and non-problem area, in accordance with current management practice as suggested by the Oslo and Paris Commissions (OSPAR) and the Helsinki Commission (HELCOM). For the control run the assessment indicates that the Kattegat, the Danish Straits, the Gulf of Finland, the Gotland Basin as well as main parts of the Arkona Basin, the Bornholm Basin, and the Baltic proper may be classified as problem areas. The main part of the North Sea and also the Skagerrak are non-problem areas while the main parts of the Gulf of Bothnia, Gulf of Riga and the entire southeastern continental coast of the North Sea may be classified as potential problem areas. In the future climate scenarios most of the previous potential problem areas in the Baltic Sea have become problem areas, except for the Bothnian Bay where the situation remain fairly unchanged. In the North Sea there seems to be no obvious changes in eutrophication status in the projected future climate.

  • 1716. Skyllas, Nomikos
    et al.
    Bintanja, Richard
    Buma, Anita G. J.
    Brussaard, Corina P. D.
    Groger, Matthias
    SMHI, Research Department, Oceanography.
    Hieronymus, Jenny
    SMHI, Research Department, Oceanography.
    van de Poll, Willem H.
    Validation of Stratification-Driven Phytoplankton Biomass and Nutrient Concentrations in the Northeast Atlantic Ocean as Simulated by EC-Earth2019In: GEOSCIENCES, ISSN 2076-3263, Vol. 9, no 10, article id 450Article in journal (Refereed)
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  • 1717. SMHI/SNV,
    Fasta förbindelser över Öresund - utredning av effekter på vattenmiljön i Östersjön1987Report (Other academic)
    Abstract [sv]

    Denna rapport sammanfattar resultaten av beräkningar av vilken inverkan en fast bro och tunnelförbindelse Malmö-Köpenhamn kan få för vattenutbytet mellan Östersjön och Västerhavet. Beräkningarna gäller eventuella förändringar av de relativt sällsynta men ändå ytterst viktiga inflödena av salt djupvatten till Östersjön. Den vanliga, mindre salthaltiga vattenutväxlingen har inte behandlats här utan tas med i helhetsbedömningen på annat sätt.

    Arbetet har omfattat:

    a lntensivmätningar av ström och salthalt i Öresund med registrerande instrument. (SMHI)

    b Simulering i dator av ett typiskt saltvatteninbrott genom Öresund med och utan fast förbindelse enligt grundförslaget till en fast förbindelse. (SMHI)

    c Simulering i dator av oceanografisk/biologiska förhållanden i Östersjön. Beräkningarna omfattar 100 år. Resultat för två sådana perioder med och utan fast förbindelse enligt grundförslaget har tagits fram. (SNV)

    d Biologisk utvärdering av beräknad påverkan av fast förbindelse (grundförslaget) över Öresund. (SNV)

    e Simulering i dator av flera alternativa utformningar av bro/tunnel som inte påverkar Östersjöns salthalt eller syreförhållanden.(SMHI)

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  • 1718. Smith, D. M.
    et al.
    Scaife, A. A.
    Hawkins, E.
    Bilbao, R.
    Boer, G. J.
    Caian, Mihaela
    SMHI, Research Department, Climate research - Rossby Centre.
    Caron, L. -P
    Danabasoglu, G.
    Delworth, T.
    Doblas-Reyes, F. J.
    Doescher, Ralf
    SMHI, Research Department, Climate research - Rossby Centre.
    Dunstone, N. J.
    Eade, R.
    Hermanson, L.
    Ishii, M.
    Kharin, V.
    Kimoto, M.
    Koenigk, Torben
    SMHI, Research Department, Climate research - Rossby Centre.
    Kushnir, Y.
    Matei, D.
    Meehl, G. A.
    Menegoz, M.
    Merryfield, W. J.
    Mochizuki, T.
    Mueller, W. A.
    Pohlmann, H.
    Power, S.
    Rixen, M.
    Sospedra-Alfonso, R.
    Tuma, M.
    Wyser, Klaus
    SMHI, Research Department, Climate research - Rossby Centre.
    Yang, X.
    Yeager, S.
    Predicted Chance That Global Warming Will Temporarily Exceed 1.5 degrees C2018In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 45, no 21, p. 11895-11903Article in journal (Refereed)
  • 1719. Smith, Doug M.
    et al.
    Scaife, Adam A.
    Boer, George J.
    Caian, Mihaela
    SMHI, Research Department, Climate research - Rossby Centre.
    Doblas-Reyes, Francisco J.
    Guemas, Virginie
    Hawkins, Ed
    Hazeleger, Wilco
    Hermanson, Leon
    Ho, Chun Kit
    Ishii, Masayoshi
    Kharin, Viatcheslav
    Kimoto, Masahide
    Kirtman, Ben
    Lean, Judith
    Matei, Daniela
    Merryfield, William J.
    Mueller, Wolfgang A.
    Pohlmann, Holger
    Rosati, Anthony
    Wouters, Bert
    Wyser, Klaus
    SMHI, Research Department, Climate research - Rossby Centre.
    Real-time multi-model decadal climate predictions2013In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 41, no 11-12, p. 2875-2888Article in journal (Refereed)
    Abstract [en]

    We present the first climate prediction of the coming decade made with multiple models, initialized with prior observations. This prediction accrues from an international activity to exchange decadal predictions in near real-time, in order to assess differences and similarities, provide a consensus view to prevent over-confidence in forecasts from any single model, and establish current collective capability. We stress that the forecast is experimental, since the skill of the multi-model system is as yet unknown. Nevertheless, the forecast systems used here are based on models that have undergone rigorous evaluation and individually have been evaluated for forecast skill. Moreover, it is important to publish forecasts to enable open evaluation, and to provide a focus on climate change in the coming decade. Initialized forecasts of the year 2011 agree well with observations, with a pattern correlation of 0.62 compared to 0.31 for uninitialized projections. In particular, the forecast correctly predicted La Nia in the Pacific, and warm conditions in the north Atlantic and USA. A similar pattern is predicted for 2012 but with a weaker La Nia. Indices of Atlantic multi-decadal variability and Pacific decadal variability show no signal beyond climatology after 2015, while temperature in the Nio3 region is predicted to warm slightly by about 0.5 A degrees C over the coming decade. However, uncertainties are large for individual years and initialization has little impact beyond the first 4 years in most regions. Relative to uninitialized forecasts, initialized forecasts are significantly warmer in the north Atlantic sub-polar gyre and cooler in the north Pacific throughout the decade. They are also significantly cooler in the global average and over most land and ocean regions out to several years ahead. However, in the absence of volcanic eruptions, global temperature is predicted to continue to rise, with each year from 2013 onwards having a 50 % chance of exceeding the current observed record. Verification of these forecasts will provide an important opportunity to test the performance of models and our understanding and knowledge of the drivers of climate change.

  • 1720. Soares, Ana R. A.
    et al.
    Lapierre, Jean-Francois
    Selvam, Balathandayuthabani P.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Berggren, Martin
    Controls on Dissolved Organic Carbon Bioreactivity in River Systems2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 14897Article in journal (Refereed)
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  • 1721. Soares, Joana
    et al.
    Sofiev, Mikhail
    Geels, Camilla
    Christensen, Jens H.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Tsyro, Svetlana
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Impact of climate change on the production and transport of sea salt aerosol on European seas2016In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, no 20, p. 13081-13104Article in journal (Refereed)
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  • 1722. Sobotkova, Martina
    et al.
    Dusek, Jaromir
    Alavi, Ghasem
    SMHI, Professional Services.
    Sharma, Laxman
    Ray, Chittaranjan
    Assessing the Feasibility of Soil Infiltration Trenches for Highway Runoff Control on the Island of Oahu, Hawaii2018In: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 10, no 12, article id 1832Article in journal (Refereed)
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  • 1723. Sobotkova, Martina
    et al.
    Dusek, Jaromir
    Alavi, Ghasem
    SMHI, Professional Services.
    Sharma, Laxman
    Ray, Chittaranjan
    Assessing the Feasibility of Soil Infiltration Trenches for Highway Runoff Control on the Island of Oahu, Hawaii (vol 10, 1832, 2018)2019In: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 11, no 3, article id 474Article in journal (Refereed)
  • 1724. Soci, Cornel
    et al.
    Bazile, Eric
    Besson, Francois
    Landelius, Tomas
    SMHI, Research Department, Atmospheric remote sensing.
    High-resolution precipitation re-analysis system for climatological purposes2016In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 68, article id 29879Article in journal (Refereed)
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  • 1725. Soerensson, Anna A.
    et al.
    Menendez, Claudio G.
    Ruscica, Romina
    Alexander, Peter
    Samuelsson, Patrick
    SMHI, Research Department, Climate research - Rossby Centre.
    Willén, Ulrika
    SMHI, Research Department, Climate research - Rossby Centre.
    Projected precipitation changes in South America: a dynamical downscaling within CLARIS2010In: Meteorologische Zeitschrift, ISSN 0941-2948, E-ISSN 1610-1227, Vol. 19, no 4, p. 347-355Article in journal (Refereed)
    Abstract [en]

    Responses of precipitation seasonal means and extremes over South America in a downscaling of a Climate change scenario are assessed with the Rossby Centre Regional Atmospheric Model (RCA). The anthropogenic warming under A1B scenario influences more on the likelihood of occurrence of severe extreme events like heavy precipitation and dry spells than on the mean seasonal precipitation. The risk of extreme precipitation increases in the La Plata Basin with a factor of 1.5-2.5 during all seasons and in the northwestern part of the continent with a factor 1.5-3 in summer, while it decreases in central and northeastern Brazil during winter and spring. The maximum amount of 5-days precipitation increases by up to 50% in La Plata Basin, indicating risks of flooding. Over central Brazil and the Bolivian lowland, where present 5-days precipitation is higher, the increases are similar in magnitude and could cause less impacts. In southern Amazonia, northeastern Brazil and the Amazon basin, the maximum number of consecutive dry days increases and mean winter and spring precipitation decreases, indicating a longer dry season. In the La Plata Basin, there is no clear pattern of change for the dry spell duration.

  • 1726. Soerensson, Anna A.
    et al.
    Menendez, Claudio G.
    Samuelsson, Patrick
    SMHI, Research Department, Climate research - Rossby Centre.
    Willén, Ulrika
    SMHI, Research Department, Climate research - Rossby Centre.
    Hansson, Ulf
    SMHI, Research Department, Climate research - Rossby Centre.
    Soil-precipitation feedbacks during the South American Monsoon as simulated by a regional climate model2010In: Climatic Change, ISSN 0165-0009, E-ISSN 1573-1480, Vol. 98, no 3-4, p. 429-447Article in journal (Refereed)
    Abstract [en]

    We summarize the recent progress in regional climate modeling in South America with the Rossby Centre regional atmospheric climate model (RCA3-E), with emphasis on soil moisture processes. A series of climatological integrations using a continental scale domain nested in reanalysis data were carried out for the initial and mature stages of the South American Monsoon System (SAMS) of 1993-92 and were analyzed on seasonal and monthly timescales. The role of including a spatially varying soil depth, which extends to 8 m in tropical forest, was evaluated against the standard constant soil depth of the model of about 2 m, through two five member ensemble simulations. The influence of the soil depth was relatively weak, with both beneficial and detrimental effects on the simulation of the seasonal mean rainfall. Secondly, two ensembles that differ in their initial state of soil moisture were prepared to study the influence of anomalously in subtropical South America as well. Finally, we calculated the soil moisture-precipitation coupling strength through comparing a ten member ensemble forced by the same space-time series of soil moisture fields with an ensemble with interactive soil moisture. Coupling strength is defined as the degree to which the prescribed boundary conditions affect some atmospheric quantity in a climate model, in this context a quantification of the fraction of atmospheric variability that can be ascribed to soil moisture anomalies. La Plata Basin appears as a region where the precipitation is partly controlled by soil moisture, especially in November and January. The continental convective monsoon regions and subtropical South America appears as a region with relatively high coupling strength during the mature phase of monsoon development dry and wet soil moisture initial conditions on the intraseasonal development of the SAMS. In these simulations the austral winter soil moisture initial condition has a strong influence on wet season rainfall over feed back upon the monsoon, not only over the Amazon region but in subtropical South America as well. Finally, we calculated the soil moisture-precipitation coupling strength through comparing a ten member ensemble forced by the same space-time series of soil moisture fields with an ensemble with interactive soil moisture. Coupling strength is defined as the degree to which the prescribed boundary conditions affect some atmospheric quantity in a climate model, in this context a quantification of the fraction of atmospheric variability that can be ascribed to soil moisture anomalies. La Plata Basin appears as a region where the precipitation is partly controlled by soil moisture, especially in November and January. The continental convective monsoon regions and subtropical South America appears as a region with relatively high coupling strength during the mature phase of monsoon development.

  • 1727. Sofiev, M.
    et al.
    Berger, U.
    Prank, M.
    Vira, J.
    Arteta, J.
    Belmonte, J.
    Bergmann, K. -C
    Cheroux, F.
    Elbern, H.
    Friese, E.
    Galan, C.
    Gehrig, R.
    Khvorostyanov, D.
    Kranenburg, R.
    Kumar, U.
    Marecal, V.
    Meleux, F.
    Menut, L.
    Pessi, A. -M
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Ritenberga, O.
    Rodinkova, V.
    Saarto, A.
    Segers, A.
    Severova, E.
    Sauliene, I.
    Siljamo, P.
    Steensen, B. M.
    Teinemaa, E.
    Thibaudon, M.
    Peuch, V. -H
    MACC regional multi-model ensemble simulations of birch pollen dispersion in Europe2015In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, no 14, p. 8115-8130Article in journal (Refereed)
    Abstract [en]

    This paper presents the first ensemble modelling experiment in relation to birch pollen in Europe. The seven-model European ensemble of MACC-ENS, tested in trial simulations over the flowering season of 2010, was run through the flowering season of 2013. The simulations have been compared with observations in 11 countries, all members of the European Aeroallergen Network, for both individual models and the ensemble mean and median. It is shown that the models successfully reproduced the timing of the very late season of 2013, generally within a couple of days from the observed start of the season. The end of the season was generally predicted later than observed, by 5 days or more, which is a known feature of the source term used in the study. Absolute pollen concentrations during the season were somewhat underestimated in the southern part of the birch habitat. In the northern part of Europe, a record-low pollen season was strongly overestimated by all models. The median of the multi-model ensemble demonstrated robust performance, successfully eliminating the impact of outliers, which was particularly useful since for most models this was the first experience of pollen forecasting.

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  • 1728. Sofiev, Mikhail
    et al.
    Ritenberga, Olga
    Albertini, Roberto
    Arteta, Joaquim
    Belmonte, Jordina
    Bernstein, Carmi Geller
    Bonini, Maira
    Celenk, Sevcan
    Damialis, Athanasios
    Douros, John
    Elbern, Hendrik
    Friese, Elmar
    Galan, Carmen
    Oliver, Gilles
    Hrga, Ivana
    Kouznetsov, Rostislav
    Krajsek, Kai
    Magyar, Donat
    Parmentier, Jonathan
    Plu, Matthieu
    Prank, Marje
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Steensen, Birthe Marie
    Thibaudon, Michel
    Segers, Arjo
    Stepanovich, Barbara
    Valdebenito, Alvaro M.
    Vira, Julius
    Vokou, Despoina
    Multi-model ensemble simulations of olive pollen distribution in Europe in 2014: current status and outlook2017In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 17, no 20, p. 12341-12360Article in journal (Refereed)
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  • 1729. Solberg, S
    et al.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Laurila, T
    Lindskog, A
    Changes in Nordic surface ozone episodes due to European emission reductions in the 1990s2005In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 39, no 1, p. 179-192Article in journal (Refereed)
    Abstract [en]

    Based on analyses of model calculations with a regional scale CTM for two different years and measurement data from background locations in northern Europe, we have found several indications that peak ozone value, in the Nordic countries have been reduced during the 1990s as a result of reduced emissions of precursors in Europe. Official European emission data for 1999 gave a better model performance than the emission data for 1990 when modelling 1999 and 2000. A bootstrap resampling technique indicated that the improvement in performance was significant. The model predicted a reduction in peak ozone values of the order of 30 mug m(-3) due to European emission reductions during the 1990s in the Nordic countries. It is thus likely that the number of exceedances of hourly threshold values has been reduced, although the small number of episodes does not allow strict statements. The number and magnitude of the ozone episodes as well as the model performance was clearly higher for southern Sweden and Norway compared to Finland, presumably reflecting differences in meteorological transport and emission source regions. (C) 2004 Elsevier Ltd. All rights reserved.

  • 1730. Solberg, S
    et al.
    Derwent, R G
    Hov, O
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Lindskog, A
    European abatement of surface ozone in a global perspective2005In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 34, no 1, p. 47-53Article in journal (Refereed)
    Abstract [en]

    EU's programme Clean Air for Europe (CAFE) is presently revising the policy on air quality which will lead to the adoption of a thematic strategy on air pollution under the Sixth Environmental Action Programme by mid-2005. For the abatement of surface ozone it is becoming evident that processes outside European control will be crucial for meeting long-term aims and air quality guidelines in Europe in the future. Measurements and modelling results indicate that there is a strong link between climate change and surface ozone. A warmer and dryer European climate is very likely to lead to increased ozone concentrations. Furthermore, increased anthropogenic emissions in developing economies in Asia are likely to raise the hemispheric background level of ozone. A significant increase in the background concentration of ozone has been observed at several sites in Northern Europe although the underlying causes are not settled. The photochemical formation of tropospheric ozone from increased concentrations of methane and CO may also lead to a higher ozone level on a global scale. Gradually, these effects may outweigh the effect of the reduced European ozone precursor emissions. This calls for a global or hemispheric perspective in the revision of the European air quality policy for ozone.

  • 1731. Solman, Silvina A.
    et al.
    Sanchez, E.
    Samuelsson, Patrick
    SMHI, Research Department, Climate research - Rossby Centre.
    da Rocha, R. P.
    Li, L.
    Marengo, J.
    Pessacg, N. L.
    Remedio, A. R. C.
    Chou, S. C.
    Berbery, H.
    Le Treut, H.
    de Castro, M.
    Jacob, D.
    Evaluation of an ensemble of regional climate model simulations over South America driven by the ERA-Interim reanalysis: model performance and uncertainties2013In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 41, no 5-6, p. 1139-1157Article in journal (Refereed)
    Abstract [en]

    The capability of a set of 7 coordinated regional climate model simulations performed in the framework of the CLARIS-LPB Project in reproducing the mean climate conditions over the South American continent has been evaluated. The model simulations were forced by the ERA-Interim reanalysis dataset for the period 1990-2008 on a grid resolution of 50 km, following the CORDEX protocol. The analysis was focused on evaluating the reliability of simulating mean precipitation and surface air temperature, which are the variables most commonly used for impact studies. Both the common features and the differences among individual models have been evaluated and compared against several observational datasets. In this study the ensemble bias and the degree of agreement among individual models have been quantified. The evaluation was focused on the seasonal means, the area-averaged annual cycles and the frequency distributions of monthly means over target sub-regions. Results show that the Regional Climate Model ensemble reproduces adequately well these features, with biases mostly within +/- 2 A degrees C and +/- 20 % for temperature and precipitation, respectively. However, the multi-model ensemble depicts larger biases and larger uncertainty (as defined by the standard deviation of the models) over tropical regions compared with subtropical regions. Though some systematic biases were detected particularly over the La Plata Basin region, such as underestimation of rainfall during winter months and overestimation of temperature during summer months, every model shares a similar behavior and, consequently, the uncertainty in simulating current climate conditions is low. Every model is able to capture the variety in the shape of the frequency distribution for both temperature and precipitation along the South American continent. Differences among individual models and observations revealed the nature of individual model biases, showing either a shift in the distribution or an overestimation or underestimation of the range of variability.

  • 1732. Sommer, Stefan
    et al.
    Clemens, David
    Yücel, Mustafa
    Pfannkuche, Olaf
    Hall, Per O. J.
    Almroth-Rosell, Elin
    SMHI, Research Department, Oceanography.
    Schulz-Vogt, Heide N.
    Dale, Andrew W .
    Major Bottom Water Ventilation Events Do Not Significantly Reduce Basin-Wide Benthic N and P Release in the Eastern Gotland Basin (Baltic Sea)2017In: Frontiers in Marine Science, ISSN 2296-7745, Vol. 4, no 18, p. 77-92Article in journal (Refereed)
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  • 1733. Soomere, Tarmo
    et al.
    Delpeche, Nicole
    Viikmaee, Bert
    Quak, Ewald
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Doeoes, Kristofer
    Patterns of current-induced transport in the surface layer of the Gulf of Finland2011In: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 16, p. 49-63Article in journal (Refereed)
    Abstract [en]

    The Lagrangian trajectory model TRACMASS based on an Eulerian field of velocities (calculated using the Rossby Centre Ocean Model), combined with relevant statistical analysis, is used for the identification of transport patterns in the surface layer of the Gulf of Finland from 1987-1991. The analysis of velocity fields and properties of net and bulk transport (the distance between the start and end positions of a trajectory, and the total length of the trajectory, respectively) shows the presence of semi-persistent (with a typical lifetime from a week to a few months) features of the surface-layer dynamics, a part of which evidently cannot be extracted directly from the velocity fields. The modelled surface dynamics mostly hosts an Ekman-type drift and, in yearly average, contains an anticyclonic gyre occupying the western part of the gulf. The prevailing transport directions to the east and slightly to the south match the direction of the Ekman surface drift created by predominant south-western winds. The spatial patterns of the net transport substantially vary over different seasons. The most intense net transport along the coasts occurs in the western and central parts of the gulf but contains relatively intense largely meridional transport pathways in some seasons.

  • 1734. Soomere, Tarmo
    et al.
    Doos, Kristofer
    Lehmann, Andreas
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Murawski, Jens
    Myrberg, Kai
    Stanev, Emil
    The Potential of Current- and Wind-Driven Transport for Environmental Management of the Baltic Sea2014In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 43, no 1, p. 94-104Article in journal (Refereed)
    Abstract [en]

    The ever increasing impact of the marine industry and transport on vulnerable sea areas puts the marine environment under exceptional pressure and calls for inspired methods for mitigating the impact of the related risks. We describe a method for preventive reduction of remote environmental risks caused by the shipping and maritime industry that are transported by surface currents and wind impact to the coasts. This method is based on characterizing systematically the damaging potential of the offshore areas in terms of potential transport to vulnerable regions of an oil spill or other pollution that has occurred in a particular area. The resulting maps of probabilities of pollution to be transported to the nearshore and the time it takes for the pollution to reach the nearshore are used to design environmentally optimized fairways for the Gulf of Finland, Baltic Proper, and south-western Baltic Sea.

  • 1735. Sorland, Silje Lund
    et al.
    Schar, Christoph
    Luthi, Daniel
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Bias patterns and climate change signals in GCM-RCM model chains2018In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 13, no 7, article id 074017Article in journal (Refereed)
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  • 1736. Sponseller, Ryan A.
    et al.
    Temnerud, Johan
    SMHI, Research Department, Hydrology.
    Bishop, Kevin
    Laudon, Hjalmar
    Patterns and drivers of riverine nitrogen (N) across alpine, subarctic, and boreal Sweden2014In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 120, no 1-3, p. 105-120Article in journal (Refereed)
    Abstract [en]

    Concentrations of nitrogen (N) in surface waters reflect the export of different organic and inorganic forms from terrestrial environments and the modification of these resources within aquatic habitats. We evaluated the relative influence of terrestrial ecosystem state factors, anthropogenic gradients, and aquatic habitat variables on patterns of N concentration in streams and rivers across Sweden. We analyzed data from 115 national monitoring stations distributed along a 1,300 km latitudinal gradient, draining catchments that differed by more than 10 A degrees C in mean annual temperature (MAT), and more than five orders of magnitude in area. Regional trends in total organic nitrogen (TON) and carbon:nitrogen (C:N) were closely linked to broad-scale gradients in state factors (e.g., MAT), reflecting the importance of long-term ecosystem development on terrestrial organic matter accrual and export. In contrast, trends in nitrate (NO3 (-)), the dominant form of inorganic N, were largely unrelated to state factors, but instead were closely connected to gradients related to anthropogenic inputs (e.g., agricultural cover). Despite large differences in drainage size and cover by lakes and wetlands among sites, these descriptors of the aquatic environment had little influence on spatial patterns of N chemistry. The temporal variability in N concentrations also differed between forms: inorganic N was strongly seasonal, with peaks during dormant periods that underscore biotic control over terrestrial losses of limiting resources. Organic N showed comparatively weaker seasonality, but summertime increases suggest temperature-driven patterns of soil TON production and export-temporal signals which were modified by variables that govern water residence time within catchments. Unique combinations of regional predictors reflect basic differences in the cycling of organic versus inorganic N and highlight variation in the sensitivity of these different N forms to environmental changes that directly alter inputs of resources, or indirectly modify terrestrial ecosystems through shifts in species composition, rates of forest productivity, soil development, and hydrologic routing.

  • 1737. Sporre, Moa K.
    et al.
    O'Connor, Ewan J.
    Håkansson, Nina
    SMHI, Research Department, Atmospheric remote sensing.
    Thoss, Anke
    SMHI, Research Department, Atmospheric remote sensing.
    Swietlicki, Erik
    Petaja, Tuukka
    Comparison of MODIS and VIIRS cloud properties with ARM ground-based observations over Finland2016In: Atmospheric Measurement Techniques, ISSN 1867-1381, E-ISSN 1867-8548, Vol. 9, no 7, p. 3193-3203Article in journal (Refereed)
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  • 1738. Steffens, K.
    et al.
    Larsbo, M.
    Moeys, J.
    Kjellstrom, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Jarvis, N.
    Lewan, E.
    Modelling pesticide leaching under climate change: parameter vs. climate input uncertainty2014In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 18, no 2, p. 479-491Article in journal (Refereed)
    Abstract [en]

    Assessing climate change impacts on pesticide leaching requires careful consideration of different sources of uncertainty. We investigated the uncertainty related to climate scenario input and its importance relative to parameter uncertainty of the pesticide leaching model. The pesticide fate model MACRO was calibrated against a comprehensive one-year field data set for a well-structured clay soil in southwestern Sweden. We obtained an ensemble of 56 acceptable parameter sets that represented the parameter uncertainty. Nine different climate model projections of the regional climate model RCA3 were available as driven by different combinations of global climate models (GCM), greenhouse gas emission scenarios and initial states of the GCM. The future time series of weather data used to drive the MACRO model were generated by scaling a reference climate data set (1970-1999) for an important agricultural production area in south-western Sweden based on monthly change factors for 2070-2099. 30 yr simulations were performed for different combinations of pesticide properties and application seasons. Our analysis showed that both the magnitude and the direction of predicted change in pesticide leaching from present to future depended strongly on the particular climate scenario. The effect of parameter uncertainty was of major importance for simulating absolute pesticide losses, whereas the climate uncertainty was relatively more important for predictions of changes of pesticide losses from present to future. The climate uncertainty should be accounted for by applying an ensemble of different climate scenarios. The aggregated ensemble prediction based on both acceptable parameterizations and different climate scenarios has the potential to provide robust probabilistic estimates of future pesticide losses.

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  • 1739. Steffens, Karin
    et al.
    Jarvis, Nicholas
    Lewan, Elisabet
    Lindstrom, Bodil
    Kreuger, Jenny
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Moeys, Julien
    Direct and indirect effects of climate change on herbicide leaching - A regional scale assessment in Sweden2015In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 514, p. 239-249Article in journal (Refereed)
    Abstract [en]

    Climate change is not only likely to improve conditions for crop production in Sweden, but also to increase weed pressure and the need for herbicides. This study aimed at assessing and contrasting the direct and indirect effects of climate change on herbicide leaching to groundwater in a major crop production region in south-west Sweden with the help of the regional pesticide fate and transport model MACRO-SE. We simulated 37 out of the 41 herbicides that are currently approved for use in Sweden on-eight major crop types for the 24 most common soil types in the region. The results were aggregated accounting for the fractional coverage of the crop and the area sprayed with a particular herbicide. For simulations of the future, we used projections of five different climate models as model driving data and assessed three different future scenarios: (A) only changes in climate, (B) changes in climate and land-use (altered crop distribution), and (C) changes in climate, land-use, and an increase in herbicide use. The model successfully distinguished between leachable and non-leachable compounds (88% correctly classified) in a qualitative comparison against regional-scale monitoring data. Leaching was dominated by only a few herbicides and crops under current climate and agronomic conditions. The model simulations suggest that the direct effects of an increase in temperature, which enhances degradation, and precipitation which promotes leaching, cancel each other at a regional scale, resulting ifs a slight decrease in leachate concentrations in a future climate. However, the area at risk of groundwater contamination doubled when indirect effects of changes in land-use and herbicide use, were considered. We therefore concluded that it is important to consider the indirect effects of climate change alongside the direct effects and that effective mitigation strategies and strict regulation are required to secure future (drinking) water resources. (C) 2014 Elsevier B.V. All rights reserved.

  • 1740. Stengel, M.
    et al.
    Lindskog, Magnus
    SMHI, Research Department, Meteorology.
    Unden, Per
    SMHI, Research Department, Meteorology.
    Gustafsson, Nils
    SMHI, Research Department, Meteorology.
    The impact of cloud-affected IR radiances on forecast accuracy of a limited-area NWP model2013In: Quarterly Journal of the Royal Meteorological Society, ISSN 0035-9009, E-ISSN 1477-870X, Vol. 139, no 677, p. 2081-2096Article in journal (Refereed)
    Abstract [en]

    The impact of cloud-affected satellite radiances on numerical weather prediction (NWP) accuracy is investigated. The NWP model used is the HIgh Resolution Limited Area Model (HIRLAM). Its four-dimensional variational data assimilation (4D-Var) system was used to assimilate cloud-affected infrared (IR) radiances from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI). Cloud parameters are modelled internally in the observation operator and used in the radiative transfer calculations. The interaction between the cloud parameters and the model control vector variables is incorporated in the adjoint version of the observation operator, which is used to derive cloud-affected Jacobians prior to the inner-loop minimization of the cost function. The developed framework supports an extensive usage of satellite observations with spatial coverage extended into cloudy regions, which therefore provides additional analysis increments and supports a more accurate description of the atmospheric state. In extended assimilation and forecast experiments the total number of assimilated satellite observations could be increased by approximately 10%. This was associated with a clear indication of a positive impact of cloud-affected radiances on the moisture and geopotential height fields of the NWP model analysis and forecast accuracy when used on top of clear-sky radiance observations. This is revealed by reduced analysis errors of the total integrated water vapour and by reduced forecast errors in the mid and upper troposphere.

  • 1741. Stengel, M.
    et al.
    Lindskog, Magnus
    SMHI, Research Department, Meteorology.
    Unden, Per
    SMHI, Research Department, Meteorology.
    Gustafsson, Nils
    SMHI, Research Department, Meteorology.
    Bennartz, R.
    An extended observation operator in HIRLAM 4D-VAR for the assimilation of cloud-affected satellite radiances2010In: Quarterly Journal of the Royal Meteorological Society, ISSN 0035-9009, E-ISSN 1477-870X, Vol. 136, no 649, p. 1064-1074Article in journal (Refereed)
    Abstract [en]

    An extended observation operator for the direct assimilation of cloud-affected infrared satellite radiances in the High Resolution Limited Area Model (HIRLAM) is examined. The operator includes a simplified moist-physics scheme, which enables the diagnosis of cloudiness in itself using background values of temperature, moisture and surface pressure. Subsequently, a radiative transfer model provides simulated cloud-affected radiances to be used as background equivalents to the satellite observations. The observation operator was evaluated by using infrared observations measured by the Spinning Enhanced Visible and Infrared Imager (SEVIRI). An observation-screening procedure, which incorporates SEVIRI cloud-retrieval products, supports an improved selection of usable cloudy scenes, leading to good agreement between the observations and background equivalents. The tangent-linear observation operator was verified against finite differences from its nonlinear formulation. The increments revealed a near-linear behaviour for the selected channels for a large number of cases. The adjoint observation operator was used to derive brightness-temperature sensitivities with respect to temperature and moisture changes in the presence of radiance-affecting clouds. Differences from the clear-sky sensitivities were found in and below clouds. In a four-dimensional variational data assimilation experiment, cloud-affected SEVIRI observations were assimilated, resulting in additional increments in both moisture and wind fields. The corresponding analysis fields revealed a reduced deviation from the observations for the majority of all cloudy scenes and a reduced bias for wind and temperature in the upper troposphere against independent radiosonde observations. Overall, our results highlight the capability of this observation operator in the HIRLAM assimilation system and encourage its application for the extended usage of cloudy satellite observations in numerical weather prediction. Copyright (C) 2010 Royal Meteorological Society

  • 1742. Stengel, M.
    et al.
    Mieruch, S.
    Jerg, M.
    Karlsson, Karl-Göran
    SMHI, Research Department, Atmospheric remote sensing.
    Scheirer, Ronald
    SMHI, Research Department, Atmospheric remote sensing.
    Maddux, B.
    Meirink, J. F.
    Poulsen, C.
    Siddans, R.
    Walther, A.
    Hollmann, R.
    The Clouds Climate Change Initiative: Assessment of state-of-the-art cloud property retrieval schemes applied to AVHRR heritage measurements2015In: Remote Sensing of Environment, ISSN 0034-4257, E-ISSN 1879-0704, Vol. 162, p. 363-379Article in journal (Refereed)
    Abstract [en]

    Cloud property retrievals from 3 decades of the Advanced Very High Resolution Radiometer (AVHRR) measurements provide a unique opportunity for a long-term analysis of clouds. In this study, the accuracy of AVHRR-derived cloud properties cloud mask, cloud-top height, cloud phase and cloud liquid water path is assessed using three state-of-the-art retrieval schemes. In addition, the same retrieval schemes are applied to the AVHRR heritage channels of the Moderate Resolution Imaging Spectroradiometer (MODIS) to create AVHRR-like retrievals with higher spatial resolution and based on presumably more accurate spectral calibration. The cloud property retrievals were collocated and inter-compared with observations from CloudSat, CALIPSO and AMSR-E The resulting comparison exhibited good agreement in general. The schemes provide correct cloud detection in 82 to 90% of all cloudy cases. With correct identification of clear-sky in 61 to 85% of all clear areas, the schemes are slightly biased towards cloudy conditions. The evaluation of the cloud phase classification shows correct identification of liquid clouds in 61 to 97% and a correct identification of ice clouds in 68 to 95%, demonstrating a large variability among the schemes. Cloud-top height (CTH) retrievals were of relatively similar quality with standard deviations ranging from 2.1 km to 2.7 km. Significant negative biases in these retrievals are found in particular for cirrus clouds. The biases decrease if optical depth thresholds are applied to determine the reference CTH measure. Cloud liquid water path (LWP) is also retrieved well with relative low standard deviations (20 to 28 g/m(2)), negative bias and high correlations. Cloud ice water path (IWP) retrievals of AVHRR and MODIS exhibit a relative high uncertainty with standard deviations between 800 and 1400 g/m2, which in relative terms exceed 100% when normalized with the mean IWP. However, the global histogram distributions of IWP were similar to the reference dataset MODIS retrievals are for most comparisons of slightly better quality than AVHRR-based retrievals. Additionally, the choice of different near-infrared channels, 3.7 mu M as opposed to 1.6 mu m, can have a significant impact on the retrieval quality, most pronounced for IWP, with better accuracy for the 1.6 mu m channel setup. This study presents a novel assessment of the quality of cloud properties derived from AVHRR channels, which quantifies the accuracy of the considered retrievals based on common approaches and validation data. Furthermore, it assesses the capabilities of AVHRR-like spectral information for retrieving cloud properties in the light of generating climate data records of cloud properties from three decades of AVHRR measurements. (C) 2013 Elsevier Inc. All rights reserved.

  • 1743. Stengel, M.
    et al.
    Undén, Per
    SMHI, Research Department, Meteorology.
    Lindskog, Magnus
    SMHI, Research Department, Meteorology.
    Dahlgren, Per
    SMHI, Research Department, Meteorology.
    Gustafsson, Nils
    SMHI, Research Department, Meteorology.
    Bennartz, R.
    Assimilation of SEVIRI infrared radiances with HIRLAM 4D-Var2009In: Quarterly Journal of the Royal Meteorological Society, ISSN 0035-9009, E-ISSN 1477-870X, Vol. 135, no 645, p. 2100-2109Article in journal (Refereed)
    Abstract [en]

    Four-dimensional variational data assimilation (4D-Var) systems are ideally suited to obtain the best possible initial model state by utilizing information about the dynamical evolution of the. atmospheric state from observations, such as satellite measurements, distributed over a certain period of time. In recent years, 4D-Var systems have been developed for several global and limited-area models. At the same time, spatially and temporally highly resolved satellite observations, as for example performed by the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) on board the Meteosat Second Generation satellites, have become available. Here we demonstrate the benefit of a regional NWP model's analyses and forecasts gained by the assimilation of those radiances. The 4D-Var system of the High Resolution Limited Area Model (HIRLAM) has been adjusted to utilize three of SEVIRI's infrared channels (located around 6.2 mu m, 7.3 mu m, and 13.4 mu m, respectively) under clear-sky and low-level cloud conditions. Extended assimilation and forecast experiments show that the main direct impact of assimilated SEVIRI radiances on the atmospheric analysis were additional tropospheric humidity and wind increments. Forecast verification reveals a positive impact for almost all upper-air variables throughout the troposphere. Largest improvements are found for humidity and geopotential height in the middle troposphere. The observations in regions of low-level clouds provide especially beneficial information to the NWP system, which highlights the importance of satellite observations in cloudy areas for further improvements in the accuracy of weather forecasts. Copyright (C) 2009 Royal Meteorological Society

  • 1744. Stengel, Martin
    et al.
    Schlundt, Cornelia
    Stapelberg, Stefan
    Sus, Oliver
    Eliasson, Salomon
    SMHI, Research Department, Atmospheric remote sensing.
    Willén, Ulrika
    SMHI, Research Department, Climate research - Rossby Centre.
    Meirink, Jan Fokke
    Comparing ERA-Interim clouds with satellite observations using a simplified satellite simulator2018In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 18, no 23, p. 17601-17614Article in journal (Refereed)
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  • 1745.
    Stensen, Katarina
    et al.
    SMHI, Core Services.
    Krunegård, Aino
    SMHI, Core Services.
    Rasmusson, Kristina
    SMHI, Research Department, Oceanography.
    Matti, Bettina
    SMHI, Core Services.
    Hjerdt, Niclas
    SMHI, Core Services.
    Sveriges vattentillgång utifrån perspektivet vattenbrist och torka: – Delrapport 1 i regeringsuppdrag om åtgärder för att motverka vattenbrist i ytvattentäkter.2019Report (Other academic)
    Abstract [en]

    In this report, the concept of drought in Sweden as well as the causes is discussed. Thereport also discusses the spatial variability of water resources in Sweden.

    Water shortage is when the demand for water surpasses the water available. It is thereforevery much dependent on the water usage.

    Climate change causes higher temperature and a warmer Sweden thus affecting wateravailability. In general both temperature and precipitation are expected to increase inwintertime leading to more water available during winters. However, higher temperaturesduring summers cause a higher evaporation which might lead to less water available insummertime, especially in the southern parts of Sweden. The climate change will increasethe number of extreme rainfall events. The amount of rain during such short-term extremerainfall events is usually much more than the soil´s infiltration capacity thus makingfloodings more common in future. Milder winters change the snow pattern, which inparticular affect rivers in the northern part of the country.

    During the summers 2016–2018, water shortages occurred in some parts of Sweden. Thecauses of water shortages were different for different parts and different years. Howeverit made Sweden to experience some of the impacts of climate change and a warmerclimate. It was an eye opener and showed us the importance of the adaptation to thesenew circumstances.

    Many factors are involved in the water availability. They can however be summarized in3 categories:

    • Climate – temperature and precipitation for example.
    • Storage capacity – how much water an area can store
    • Water usage

    As a country, Sweden has abundant water resources and available fresh water. But watershortage might still occur. Water availability and water usage can vary a lot locally whichmight lead to water shortage in some regions. To cope with water shortages priorities areneeded between different sectors and interests. Many stakeholders need to agree andcompromise on the usage of water.

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  • 1746.
    Stensen, Katarina
    et al.
    SMHI, Core Services.
    Matti, Bettina
    SMHI, Core Services.
    Rasmusson, Kristina
    SMHI, Research Department, Oceanography.
    Hjerdt, Niclas
    SMHI, Core Services.
    Modellstudie för att undersöka åtgärdersom påverkar lågflöden: – Delrapport 2 i regeringsuppdrag om åtgärder för att motverkavattenbrist i ytvattentäkter.2019Report (Other academic)
    Abstract [en]

    In 2018 the Swedish Meteorological and Hydrological Institute, SMHI was assigned toperform a study of measures to prevent water scarcity in surface water resources. Thework is ongoing and has been performed stepwise. This is the second report produced sofar. The report presents the results from a pre-study that was performed to evaluate theeffect of different measures on low flows and their potential to prevent water scarcity insurface water resources. The aim of the model study was to build a knowledge basis fordeveloping a tool that can be used to prevent water scarcity in surface water resources.Through the tool, municipalities and other actors in the water sector will be able tosimulate water availability in a catchment area independently.

    The weather has the largest impact on water availability, but there are different measuresthat can prevent water scarcity in surface water resources. The measures are mostlypreventative but some can be used in scarcity situations as well.

    The most effective measure is to use the water storage capacity in lakes and to regulatethem wisely. Obviously, this requires that there are lakes to regulate. In the southern partsof Sweden water availability is often good in wintertime while water scarcity occursduring summertime and at the beginning of fall. Through lake regulation, water can bestored in periods with significant water availability and used in periods when water isneeded. It is common to regulate lakes for hydropower production, but some lakes areregulated for water supply as well. SMHI regards this as an important aspect to considerin areas that are in risk for water scarcity since many permissions for water regulation aregoing to be reconsidered now.

    Measures on ditch, drainage and other watercourses can have a local effect, but it is notlarge enough to affect the low flows on a larger scale. Restoration of wetlands has as wellmostly a local effect since very large areas are required to impact on surface waterresources on a larger scale.

    In areas with significant water extractions, the low flow is affected if these are changed.Often, knowledge on water extraction still is inadequate and it is difficult to exactlycalculate the effect if water extractions are changed. It is also complicated to restrictwater extractions. Measures such as establishing water ponds for irrigation might havepotential provided they are filled during periods of good water availability. The effect ofextractions will then decrease during low flow periods.

    The ongoing work to prevent water scarcity in surface water resources will focus ondeveloping methods for sustainable water management. It is evident that the work withwater resources planning needs to be performed mutually between sectors in a catchmentarea. The tool that will be developed within this project will contribute to that this workcan be performed in a sustainable way.

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  • 1747.
    Stensen, Katarina
    et al.
    SMHI, Core Services.
    Tengdelius Brunell, Johanna
    SMHI, Professional Services.
    Sjökvist, Elin
    SMHI, Professional Services.
    Andersson, Elinor
    SMHI, Core Services.
    Eklund, Anna
    SMHI, Core Services.
    Vattentemperaturer och is i Mälaren Beräkningar för dagens och framtidens klimatförhållanden2017Report (Other academic)
    Abstract [sv]

    Denna rapport presenterar hur vattentemperatur och is beräknas förändras i Mälaren tillmitten av seklet och fram till 2100 på grund av den globala uppvärmningen.Beräkningarna är gjorda med en sjömodell där Mälaren är uppdelad i två bassänger. Dekallas västra Mälaren och östra Mälaren.De tydligaste förändringarna i Mälaren i ett framtida klimat beräknas bli högrevattentemperaturer både på ytan och på botten samt kortare period med is. Iberäkningarna har två framtidsscenarier använts, vilka baseras på mängden växthusgaser iatmosfären. I det högre scenariot, vilket motsvarar fortsatta utsläpp med dagensutsläppsnivåer, ökar vattentemperaturen mer jämfört med scenariot där utsläppen avväxthusgaser är begränsade.Sammanfattning av resultaten för klimatscenarierna: Den årliga perioden som Mälaren är täckt med is beräknas minska med enmånad till två månader mot slutet av seklet. Ytvattnets medeltemperatur beräknas öka 1,5 till 2,5 grader för bådabassängerna. Förändringen är ungefär lika stor under hela året. Bottenvattnets medeltemperatur väntas öka mellan 1 till 2 grader i den grundarevästra bassängen och 0,5 till 1,5 grader i den djupare östra bassängen.Förändringen är ungefär lika stor under hela året. Maxtemperaturen ökar något mer än medeltemperaturen för både ytvatten ochbottenvatten. Den period som ytvattnets dygnsmedeltemperatur är över 20 grader, ökar medcirka en månad upp till en och en halv månad.Medeltemperaturen och maxtemperaturen för dagens klimat är beräknad utifråntidsperioden 1997-2015 och utifrån 2032-2050 och 2080-2098 för ett framtida klimat.Maxtemperaturen är det högsta värdet som beräknas uppnås under perioden.

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  • 1748.
    Stensen, Katarina
    et al.
    SMHI, Core Services.
    Tengdelius Brunell, Johanna
    SMHI, Professional Services.
    Sjökvist, Elin
    SMHI, Professional Services.
    Andersson, Elinor
    SMHI, Core Services.
    Eklund, Anna
    SMHI, Core Services.
    Vattentemperaturer och is i Mälaren Beräkningar för dagens och framtidens klimatförhållanden2018Report (Other academic)
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  • 1749. Stensgaard, A. -S
    et al.
    Booth, M.
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Mccreesh, N.
    Combining a process-based and correlative approach to predict the impacts of climate change on schistosomiasis in eastern Africa2015In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, p. 436-436Article in journal (Refereed)
  • 1750. Stensgaard, Anna-Sofie
    et al.
    Booth, Mark
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    McCreesh, Nicky
    Combining process-based and correlative models improves predictions of climate change effects on Schistosoma mansoni transmission in eastern Africa2016In: GEOSPATIAL HEALTH, ISSN 1827-1987, Vol. 11, p. 94-101Article in journal (Refereed)
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32333435363738 1701 - 1750 of 1994
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