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  • 251.
    Persson, Christer
    SMHI, Research Department, Air quality.
    Local scale plume model for nitrogen oxides. Verification1986Report (Other academic)
  • 252.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Atmospheric Transport Model Studies for Sweden – Comparison to EMEP Model Results and Evaluation of Precipitation Chemistry Station Networks2001In: Air Pollution Modeling and Its Application XIV / [ed] Sven-Erik Gryning, Francis A. Schiermeier, Springer, 2001, p. 165-172Chapter in book (Other academic)
  • 253.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Funquist, Lennart
    SMHI, Research Department, Oceanography.
    Local scale plume model for nitrogen oxides: Model description1984Report (Other academic)
  • 254.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Regional spridningsmodell för Göteborgs och Bohus, Hallands och Älvsborgs län: A mesoscale air pollution dispersion model for the Swedish west-coast region. In Swedish with captions also in English1994Report (Other academic)
  • 255.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Magnusson, Mikael
    SMHI, Core Services.
    Kvaliteten i uppmätta nederbördsmängder inom svenska nederbördskemiska stationsnät2003Report (Other academic)
    Abstract [en]

    High quality measurements of precipitation amounts in precipitation chemistry networks are of large importance in order to obtain correct information concerning concentrations in precipitation as well as wet deposition of air pollutants. In this study the quality of measured precipitation amounts at each of three different Swedish precipitation chemistry networks has been investigated. For shorter periods during 1998-2001 quality deficiencies were found at two Swedish EMEP stations. The reason to that seems to be technical problems with the lid samplers used at that network. For the Swedish air and precipitation chemistry network (PMK) and the regional network (REG) deficiencies in precipitation measurements were found for the winter seasons. Very large scatter in precipitation amounts was obtained when comparisons were made with objective interpolated precipitation fields based on all SMHI observations. The reason to this disagreement is assumed to be the use of “snowsacks” on the samplers during the winter half-year regardless of weather condition. These “snow-sacks” are assumed to influence the aerodynamic conditions around the samplers and thus also influence the efficiency in sampling raindrops and snowflakes.

  • 256.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    En modell för beräkning av luftföroreningars spridning och deposition på mesoskala1980Report (Other academic)
    Abstract [sv]

    Mängden föroreningar, som förs till atmosfären, har under de senaste trettio åren kraftigt ökats. Deposition av dessa till marken leder till en rad biologiska effekter. Risker för skador på olika ekosystem genom deposition av tex tungmetaller och syra har därför alltmer börjat diskuteras som viktiga lokaliseringskriterier för fossileldade kraftverk och vissa större industrier. Depositionen av bly i omedelbar närhet av livligt trafikerade motorleder är ett annat exempel där negativa miljöeffekter befaras.

    Uppställandet av effektrelaterade utsläppskriterier medför ett behov av redskap för att kunna göra kvantitativa uppskattningar av förväntade depositioner i omgivningen av en källa. För kraftverk kan behovet av information om depositionsfördelningen, som underlag för lokaliseringsbeslut, röra ett område med flera hundra kilometers utsträckning.

    Vid studier av den lokala spridningen runt en punktkälla har under lång tid den gaussiska plymmodellen varit allmänt använd. Den utgör ett enkelt och i många fall mycket bra hjälpmedel, men har avsevärda begränsningar i de fall då depositionsprocesser och kemiska omvandlingar måste inkluderas i beräkningarna. I modeller baserade på diffusionsekvationen, där vissa antaganden om den turbulenta diffusiviteten görs (sk K-teori), finns möjlighet att på ett väsentligt mer realistiskt sätt inkludera processer som rör deposition och kemiska omvandlingar. Nackdelen är dock att den matematiska behandlingen blir mer komplicerad.

    Numeriska lösningar av diffusionsekvationen har använts av tex Bo in & Persson (1975) och Omstedt & Rodhe (1977). I båda fallen gällde tillämpningarna föroreningsspridning på storregional skala. Maul (1977) har presenterat en analytisk lösning, som tillämpats på föroreningsspridning på mesoskala. Svårigheterna vid tillämpningen av K-teorin är framförallt att bestämma riktiga värden på de ingångsparametrar som fordras. För analytiska lösningar finns dessutom matematiska hinder för godtyckliga vind- och diffusivitetsprofiler. Detta har resulterat i att beräkningar med K-modeller hittills huvudsakligen utförts för några enkla medelprofiler.

    Avsikten med föreliggande projekt har varit att utveckla en för praktiskt brukanvändbar spridningsmodell för studier av torr- och våtdepositionen av föroreningar på lokal- och mesoskala, där godtyckliga vind- och diffusivitetsprofiler kan användas. Dessa genereras med hjälp av en gränsskiktsmodell för olika vädersituationer.

  • 257.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Ressner, Elisabet
    SMHI.
    Klein, Thomas
    SMHI, Core Services.
    Nationell miljöövervakning – MATCH-Sverige modellen: Metod- och resultatsammanställning för åren 1999-2002 samt diskussionav osäkerheter, trender och miljömål2004Report (Other academic)
    Abstract [en]

    National air pollution assessments based on the MATCH-Sweden model – Results for the period 1999-2002 The MATCH-Sweden model system is used as a tool for mapping of air pollution deposition and concentration over Sweden and for air pollution assessment studies.The system includes a simplified type of data assimilation of backgroundatmospheric chemistry observations in Sweden and Norway. Over the entire period 1999-2002 the annual sulphur and nitrogen deposition consistently shows a maximum over Southwest Götaland and decreases northwards. An annual air pollution budget for Sweden is determined. During the period of study the Swedish emissions account for 5-7% of the total annual deposition of sulphur in Sweden and for 11-13% of the corresponding NOx-deposition. The Swedish contribution to the total deposition of NHx-nitrogen is, according to the present calculations, about 16%. However, the uncertainty in this value is larger than for sulphur and NOx-nitrogen.Comparisons between results for the year 2000 obtained with MATCH-Sweden and the new “Unified EMEP Eulerian model” (EMEP, 2003) respectively, show good agreement for most parameters. The agreement is much better than observed in earlier comparisons with the old EMEP model. Large differences are found only for long-range transport contribution to the NHx-deposition over Northern Sweden, where MATCH-Sweden calculations indicate larger depositions than EMEP. However, the MATCH-Sweden system – including simplified data assimilation - suffers from a lack of representative air and precipitation NHx-measurements in that area. A tentative estimate of deposition trends over Sweden indicates a 50-55% decrease for sulphur between 1991 and 2002. For NOx- and NHx-nitrogen the corresponding decrease in deposition is only about 15%each.

  • 258.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Spridnings- och depositionsberäkningar för en sopförbränningsanläggning i Skövde1986Report (Other academic)
  • 259.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Spridningsberäkningar rörande gasutsläpp vid ScanDust i Landskrona - bestämning av cyanväte1987Report (Other academic)
  • 260.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Grennfelt, P.
    IVL.
    Kindbom, K.
    IVL.
    Lövblad, Gun
    IVL Swedish Environmental Research Institute.
    Svanberg, P-A
    IVL.
    Luftföroreningsepisoden över södra Sverige 2–4 februari 19871987Report (Other academic)
  • 261.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Häggkvist, Kenneth
    SMHI, Professional Services.
    Spridningsberäkningar, SSAB - Luleå-verken1986Report (Other academic)
    Abstract [sv]

    Spridningsberäkningar har utförts för ett par större utsläpp, av haveri­karaktär, från en större masugnsklocka. Utsläppen avser relativt stora gasflöden (20 000 m3 respektive 50 000 m3 ) under kort tid (5 respektive 15 min) och studien har syftat till att bestämma halter av CO och H2S i omgivningen samt områden där risk för explosion kan förekomma. Nedan ges en sammanfattande redovisning av resultaten. Av tabell 1 ( sid 2) framgår hur utsläppen specificerats, och de i tabellen angivna beteckning­arna för respektive fall utnyttjas i sammanfattningen nedan.

  • 262.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Thaning, Lennart
    FOA.
    Model for Simulation of Air and Ground Contamination Associated with Nuclear Weapons. An Emergency Preparedness Model2000Report (Other academic)
  • 263.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Rodhe, H.
    MISU.
    De Geer, L-E
    FOA.
    The Chernobyl accident – A meteorological analysis of how radionucleides reached Sweden1986Report (Other academic)
  • 264.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    RODHE, H
    DE GEER, LE
    THE CHERNOBYL ACCIDENT - A METEOROLOGICAL ANALYSIS OF HOW RADIONUCLIDES REACHED AND WERE DEPOSITED IN SWEDEN1987In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 16, no 1, p. 20-31Article in journal (Refereed)
  • 265.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Rodhe, H.
    MISU.
    De Geer, L-E.
    FOA.
    Tjernobylolyckan - En meteorologisk analys av hur radioaktivitet spreds till Sverige1986Report (Other academic)
  • 266.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Ullerstig, Anders
    SMHI, Research Department, Climate research - Rossby Centre.
    Model calculations of dispersion of lindane over Europe: Pilot study with comparisons to easurements around the Baltic Sea and the Kattegat1996Report (Other academic)
  • 267.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Ullerstig, Anders
    SMHI, Research Department, Climate research - Rossby Centre.
    Regional luftmiljöanalys för Västmanlands län baserad på MATCH modell-beräkningar och mätdata: Analys av 1994 års data1997Report (Other academic)
  • 268.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Ullerstig, Anders
    SMHI, Research Department, Climate research - Rossby Centre.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Kindbom, Karin
    IVL Swedish Environmental Research Institute.
    Sjöberg, Karin
    IVL Swedish Environmental Research Institute.
    The Swedish Precipitation Chemistry Network: Studies in network design usting the MATCH modelling system and statistical methods1996Report (Other academic)
  • 269.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Wern, Lennart
    SMHI, Core Services.
    Beräkningar av svaveldepositionen i Stockholmsområdet1986Report (Other academic)
  • 270.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Wern, Lennart
    SMHI, Core Services.
    Luftvårdsstudie avseende industrikombinatet i Nynäshamn - depositionsberäkningar av koldamm1985Report (Other academic)
  • 271.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Wern, Lennart
    SMHI, Core Services.
    Spridnings- och depositionsberäkningar för avfalls- förbränningsanläggningar i Sofielund och Högdalen1985Report (Other academic)
  • 272.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Wern, Lennart
    SMHI, Core Services.
    Spridnings- och depositionsberäkningar för avfallsförbränningsanläggning i Högdalen1985Report (Other academic)
  • 273.
    Persson, Christer
    et al.
    SMHI, Research Department, Air quality.
    Wern, Lennart
    SMHI, Core Services.
    Spridnings- och depositionsberäkningar för avfallsförbränningsanläggning i Sofielund1985Report (Other academic)
  • 274.
    Persson, Gunn
    et al.
    SMHI, Professional Services.
    Wikberger, Christina
    Amorim, Jorge Humberto
    SMHI, Research Department, Air quality.
    Klimatanpassa nordiska städer med grön infrastruktur2018Report (Other academic)
    Abstract [sv]

    Förtätning av städer och pågående klimatförändring ökar behovet av anpassningsåtgärder. Grön infrastruktur och naturbaserade lösningar kan bidra till att skapa mer hälsosamma och långsiktigt hållbara städer. För att öka användningen av grön infrastruktur som en del i klimatanpassningen behöver vi förstå vilka kunskapsluckor och andra hinder som ligger i vägen för att grön infrastruktur ska användas i klimatanpassningsarbetet.

    SMHI har under år 2018 tillsammans med Stockholms stad drivit det av forskningsrådet Formas finansierade projektet ”Grön infrastruktur och klimat i nordiska städer: idag och i framtiden”. Sammanställningen av rapporter och workshops i projektet visar att det finns mycket kunskap och tillgängliga exempel på hur urbana gröna lösningar kan se ut. Det saknas dock svar på de kvantitativa effekterna av olika åtgärder avseende till exempel temperatur, luftkvalitet, påverkan på hälsa och sociala aspekter.

    De åtgärder som i dag görs i nordiska städer baseras huvudsakligen på behovet av att lösa dagvattenfrågor. Det finns få exempel på städer som använder grön infrastruktur och naturbaserade lösningar som klimatanpassningsåtgärder när det gäller värme. Samtidigt är aktörerna medvetna om övriga positiva effekter som tillkommer såsom trivsel, svalka och biologisk mångfald.

    Eftersom grön infrastruktur och naturbaserade lösningar är ganska nya åtgärder i klimatanpassningsarbetet så saknas oftast erfarenheter av långtidseffekter. Skötsel kan vara ett problem, trots bra anvisningar. Aktörerna pekar också på behovet av att engagera de boende kontinuerligt. Det tycks handla om att skapa en djupare förståelse för varför anläggningar ser ut som de gör och hur de ska skötas.

    Vid workshops och webbinarium efterfrågades vilka kunskapsluckor deltagarna såg. Ekonomi och kunskap om effekter lyftes fram tydligt i svaren. Dessutom önskades metoder för anläggning och drift, goda exempel, planeringsverktyg och underlag om temperatur och vatten.

    Ekonomi och kunskapsbrist ansågs som hinder för genomförande, vilket framkom vid workshops och webbinarium. Andra hinder som nämndes var politiska beslut, lagstiftning, avsaknad av riktlinjer, förtätning och konkurrens om mark liksom planerings- och samordningssvårigheter. En tröghet i att ändra traditionellt planerande och utförande pekades också ut som hinder. Många efterfrågar kunskap allmänt. Vår förhoppning är att denna rapport kan bidra till att inspirera och informera om var material finns. 

  • 275. Persson, K
    et al.
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    Lenner, M
    Sjodin, A
    Svanberg, P A
    Estimation of trends in urban traffic NOx emissions by an empirical model1999In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 235, no 1-3, p. 367-369Article in journal (Refereed)
    Abstract [en]

    A model has been developed to estimate trends in urban traffic NOx emissions by measured NO2 concentrations. (C) 1999 Elsevier Science B.V. All rights reserved.

  • 276. Pleijel, Hakan
    et al.
    Klingberg, Jenny
    Karlsson, Gunilla Pihl
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Karlsson, Per Erik
    Surface Ozone in the Marine Environment-Horizontal Ozone Concentration Gradients in Coastal Areas2013In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 224, no 7, article id 1603Article in journal (Refereed)
    Abstract [en]

    Spring/summer surface ozone concentrations, [O-3], in coastal environments were investigated: (1) by comparison of coastal and inland monitoring stations with data from a small island >5 km off the coast of southwest Sweden, (2) as a gradient from the coast towards inland in southernmost Sweden. Further, results from the chemical transport model MATCH were used to assess the marine influence on [O-3]. It was hypothesised that [O-3] is higher on the small island compared to the coast, especially during night and in offshore wind. Another hypothesis was that [O-3] declines from the coast towards inland. Our hypotheses were based on observations that the deposition velocity of O-3 to sea surfaces is lower than to terrestrial surfaces, and that vertical air mixing is stronger in the marine environment, especially during night. The island experienced 10 % higher [O-3] compared to the coast. This difference was larger with offshore (15 %) than onshore wind (9 %). The concentration difference between island and coast was larger during night, but prevailed during day and could not be explained by differences in [NO2] between the sites. The difference in [O-3] between the island and the inland site was 20 %. Higher [O-3] over the sea, especially during night, was reproduced by MATCH. In the gradient study, [O-3] declined from the coast towards inland. Both [O-3] and [NO2] were elevated at the coast, indicating that the gradient in [O-3] from the coast was not caused by NO titration. The conclusions were that surface [O-3] in marine environments is higher than in coastal, and higher in coastal than inland areas, especially during night.

  • 277. Politis, K
    et al.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Bayesian updating of atmospheric dispersion after a nuclear accident2004In: Journal of the Royal Statistic Society, Series C: Applied Statistics, ISSN 0035-9254, E-ISSN 1467-9876, Vol. 53, p. 583-600Article in journal (Refereed)
    Abstract [en]

    We consider a Bayesian forecasting. system to predict the dispersal of contamination on a large scale grid in the event of an accidental release of radioactivity. The statistical model is built on a physical model for atmospheric dispersion and transport called MATCH. Our spatiotemporal model is a dynamic linear model where the state parameters are the (essentially, deterministic) predictions of MATCH; the distributions of these are updated sequentially in the light of monitoring data. One of the distinguishing features of the model is that the number of these parameters is very large (typically several hundreds of thousands) and we discuss practical issues arising in its implementation as a realtime model. Our procedures have been checked against a variational approach which is used widely in the atmospheric sciences. The results of the model are applied to test data from a tracer experiment.

  • 278. Potempski, S.
    et al.
    Galmarini, S.
    Addis, R.
    Astrup, P.
    Bader, S.
    Bellasio, R.
    Bianconi, R.
    Bonnardot, F.
    Buckley, R.
    D'Amours, R.
    van Dijk, A.
    Geertsema, G.
    Jones, A.
    Kaufmann, P.
    Pechinger, U.
    Persson, Christer
    SMHI, Research Department, Air quality.
    Polreich, E.
    Prodanova, M.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Sorensen, J.
    Syrakov, D.
    Multi-model ensemble analysis of the ETEX-2 experiment2008In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 42, no 31, p. 7250-7265Article in journal (Refereed)
    Abstract [en]

    In this paper we investigate the results of multi-model simulations performed on the ETEX-2 experiment by the ENSEMBLE modelling community. New sets of results were created by taking different percentiles of the distribution of the models' predicted values. Both single models and the new constructed sets of results have been compared with the observed data. While a similar comparison for the ETEX-1 case indicated the median model was superior to any single model, for the ETEX-2 case, the situation is more difficult due to complex meteorological conditions, and no absolute and clear conclusions can be obtained. However, for emergency response purposes the median model still can be considered the most viable option also for complicated meteorological situation such is the ETEX-2 experiment. (c) 2008 Elsevier Ltd. All rights reserved.

  • 279. Raisanen, P.
    et al.
    Haapanala, P.
    Chung, C. E.
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    Makkonen, R.
    Tonttila, J.
    Nousiainen, T.
    Impact of dust particle non-sphericity on climate simulations2013In: Quarterly Journal of the Royal Meteorological Society, ISSN 0035-9009, E-ISSN 1477-870X, Vol. 139, no 677, p. 2222-2232Article in journal (Refereed)
    Abstract [en]

    Although mineral aerosol (dust) particles are irregular in shape, they are treated as homogeneous spheres in climate model radiative transfer calculations. Here, we test the effect of dust particle non-sphericity in the ECHAM5.5-HAM2 global aerosol-climate model. The short-wave optical properties of the two insoluble dust modes in HAM2 are modelled using an ensemble of spheroids that has been optimized to reproduce the optical properties of dust-like aerosols, thereby providing a significant improvement over spheres. First, the direct radiative effects (DRE) of dust non-sphericity were evaluated diagnostically, by comparing spheroids with both volume-equivalent and volume-to-area (V/A) equivalent spheres. In the volume-equivalent case, the short-wave DRE of insoluble dust at the surface and at the top of the atmosphere (TOA) was slightly smaller (typically by 3-4%) for spheroidal than for spherical dust particles. This rather small difference stems from compensating non-sphericity effects on the dust optical thickness and asymmetry parameter. In the V/A-equivalent case, the difference in optical thickness was virtually eliminated and the DRE at the TOA (surface) was approximate to 20% (approximate to 13%) smaller for spheroids than for spheres, due to a larger asymmetry parameter. Even then, however, the global-mean DRE of non-sphericity was only 0.055 W m(-2) at the TOA and 0.070 W m(-2) at the surface. Subsequently, the effects of dust non-sphericity were tested interactively in simulations in which ECHAM5.5-HAM2 was coupled to a mixed-layer ocean model. Consistent with the rather small radiative effects noted above, the climatic differences from simulations with spherical dust optics were generally negligible.

  • 280. Reckermann, Marcus
    et al.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Omstedt, Anders
    Göteborgs Universitet.
    von Storch, Hans
    Keevallik, Sirje
    Schneider, Bernd
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Huenicke, Birgit
    BALTEX-an interdisciplinary research network for the Baltic Sea region2011In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 6, no 4, article id 045205Article in journal (Refereed)
    Abstract [en]

    BALTEX is an environmental research network dealing with the Earth system of the entire Baltic Sea drainage basin. Important elements include the water and energy cycle, climate variability and change, water management and extreme events, and related impacts on biogeochemical cycles. BALTEX was founded in 1993 as a GEWEX continental-scale experiment and is currently in its second 10 yr phase. Phase I (1993-2002) was primarily dedicated to hydrological, meteorological and oceanographic processes in the Baltic Sea drainage basin, hence mostly dealt with the physical aspects of the system. Scientific focus was on the hydrological cycle and the exchange of energy between the atmosphere, the Baltic Sea and the surface of its catchment. The BALTEX study area was hydrologically defined as the Baltic Sea drainage basin. The second 10 yr phase of BALTEX (Phase II: 2003-12) has strengthened regional climate research, water management issues, biogeochemical cycles and overarching efforts to reach out to stakeholders and decision makers, as well as to foster communication and education. Achievements of BALTEX Phase II have been the establishment of an assessment report of regional climate change and its impacts on the Baltic Sea basin (from hydrological to biological and socio-economic), the further development of regional physical climate models and the integration of biogeochemical and ecosystem models. BALTEX features a strong infrastructure, with an international secretariat and a publication series, and organizes various workshops and conferences. This article gives an overview of the BALTEX programme, with an emphasis on Phase II, with some examples from BALTEX-related research.

  • 281.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Extended back-trajectories by means of adjoint equations2004Report (Other academic)
  • 282.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Koncentrations- och depositionsberäkningar för en sopförbrännings anläggning vid Ryaverken i Borås1986Report (Other academic)
  • 283.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Koncentrations- och depositionsberäkningar för Halmstads avfallsförbränningsanläggning vid Kristinehed1986Report (Other academic)
  • 284.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Modelling of anthropogenic sulfur deposition to the African and South American continents1996Report (Other academic)
  • 285.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Spridningsberäkningar för Varbergs kommun: Bestämning av halter av SO2, CO, NOx samt några kolväten1987Report (Other academic)
  • 286.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Spridningsberäkningar rörande gasutsläpp vid ScanDust i Landskrona – bestämning av cyanvätehalter1986Report (Other academic)
  • 287.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Spridningsberäkningar rörande utsläpp av NOx inom Fagersta kommun1986Report (Other academic)
  • 288.
    Robertson, Lennart
    et al.
    SMHI, Research Department, Air quality.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Source function estimate by means of variational data assimilation applied to the ETEX-I tracer experiment1998In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 32, no 24, p. 4219-4225Article in journal (Refereed)
    Abstract [en]

    The ETEX data set opens new possibilities to develop data assimilation procedures in the area of long-range transport. This paper illustrates the possibilities using a variational approach, where the source term for ETEX-I was reconstructed. The MATCH model (Robertson et at., 1996) has been the basis for this attempt. The timing of the derived emission rates are in accordance with the time period for the ETEX-I release, and a cross validation, with observations beyond the selected assimilation period, shows that the source term gained holds for the entire ETEX-I experiment. A poor-man variational approach was shown to perform nearly as good as a fully variational data assimilation. The issue of quality control has not been considered in this attempt but will be an important part that has to be addressed in future work. (C) 1998 Elsevier Science Ltd. All rights reserved.

  • 289.
    Robertson, Lennart
    et al.
    SMHI, Research Department, Air quality.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    An Eulerian limited-area atmospheric transport model1999In: Journal of applied meteorology (1988), ISSN 0894-8763, E-ISSN 1520-0450, Vol. 38, no 2, p. 190-210Article in journal (Refereed)
    Abstract [en]

    A limited-area, offline, Eulerian atmospheric transport model has been developed. The model is based on a terrain-following vertical coordinate and a mass-conserving, positive definite advection scheme with small phase and amplitude errors. The objective has been to develop a flexible, all purpose offline model. The model includes modules for emission input, vertical turbulent diffusion, and deposition processes. The model can handle an arbitrary number of chemical components and provides a framework for inclusion of modules describing physical and chemical transformation processes between different components. Idealized test cases, as well as simulations of the atmospheric distribution of Rn-222, demonstrate the ability of the model to meet the requirements of mass conservation and positiveness and to produce realistic simulations of a simple atmospheric tracer.

  • 290.
    Robertson, Lennart
    et al.
    SMHI, Research Department, Air quality.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    MATCH - Meso-scale Atmospheric Transport and Chemistry modelling system1996Report (Other academic)
  • 291.
    Robertson, Lennart
    et al.
    SMHI, Research Department, Air quality.
    Persson, Christer
    SMHI, Research Department, Air quality.
    ATTEMPTS TO APPLY 4-DIMENSIONAL DATA ASSIMILATION OF RADIOLOGICAL DATA USING THE ADJOINT TECHNIQUE1993In: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 50, no 2-4, p. 333-337Article in journal (Refereed)
    Abstract [en]

    A data assimilation procedure is presented. By feeding measurements into a dispersion model. using the adjoint technique, it is shown that the proper transport level as well as the source intensity can he found. The technique is tested on a fictitious accidental release. and thus fictitious measurements are used.

  • 292.
    Robertson, Lennart
    et al.
    SMHI, Research Department, Air quality.
    Ring, Sture
    SMHI, Professional Services.
    Spridningsberäkningar för bromcyan2009Report (Other academic)
  • 293.
    Robertson, Lennart
    et al.
    SMHI, Research Department, Air quality.
    Rodhe, H
    Granat, L
    Modelling of sulfur deposition in the southern Asian region1995In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 85, no 4, p. 2337-2343Article in journal (Refereed)
    Abstract [en]

    Acidification problems in developing countries are expected to become more prevalent in the coming decades. Assessments of means of abatement strategies are likely to become of vital interest. This paper presents some preliminary results of modelling of acidic deposition due to anthropogenic emissions of sulfur in the Southern Asian region. It is concluded that the study has some shortcomings, that has to be addressed in future work, such as lack of treatment of deep convection and that deposition and transformation rates used are not adapted to the tropics. Only very limited validation has been possible due to the lack of relevant measurements. Wet deposition data from rural Thailand are in fair agreement with calculated values. The study is one part of a larger project encompassing mapping ecosystem sensitivity to acid deposition, wet chemistry measurements and atmospheric transfer modelling.

  • 294. Rodhe, H
    et al.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Gallardo, L
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Global scale transport of acidifying pollutants1995In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 85, no 1, p. 37-50Article in journal (Refereed)
    Abstract [en]

    During the past few years several attempts have been made to use three-dimensional tracer transport models to simulate the global distribution of sulfur and nitrogen compounds from both natural and anthropogenic sources. We review these studies and show examples of estimated distributions of the total deposition of sulfur, oxidized nitrogen and ammonium as well as the pH of precipitation. The simulated patterns are compared with observations. Weaknesses in these estimates resulting from lack of knowledge of emissions, chemical transformations and removal processes are emphasized and discussed. We also show examples of how the models can be used to estimate past and future deposition patterns. In particular, we use the IPCC scenario IS92a to estimate the possible sulfur deposition around the world in the year 2050. A comparison with critical load values for sulfur deposition indicates that substantial parts of South and East Asia are at risk for acidification problems in the future.

  • 295.
    Rummukainen, Markku
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Johansson, Daniel J.A.
    Institutionen för energi och miljö, avdelningen för fysisk resursteori, Chalmers.
    Azar, Christian
    Institutionen för energi och miljö, avdelningen för fysisk resursteori, Chalmers.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Doescher, Ralf
    SMHI, Research Department, Climate research - Rossby Centre.
    Smith, Henrik
    Centrum för miljö och klimatforskning, Lunds universitet.
    Uppdatering av den vetenskapliga grunden för klimatarbetet2011Report (Other academic)
    Abstract [sv]

    Det naturvetenskapliga kunskapsläget om klimatförändringarna förbättrats ständigt genom forskningen om klimatsystemet, klimatpåverkan, klimatets variationer och förändringar samt klimateffekter. Kunskapsläget är väletablerat när det gäller den grundläggande fysiken bakom växthuseffekten, liksom att genomsnittstemperaturen vid jordytan stigit de senaste femtio åren. Det är också mycket sannolikt att det mesta av den observerade uppvärmningen beror på mänsklig klimatpåverkan. Samtidigt finns det betydande osäkerheter när det gäller konsekvenserna av klimatförändringarna samt hur mycket utsläppen behöver minska för att man ska nå ett givet klimatmål. Värdet på klimatkänsligheten är den viktigaste faktorn för beräkningar av hur mycket växthusgaser vi kan släppa ut, givet ett visst temperaturmål. Forskningen visar att det behövs stora och snabba utsläppsminskningar för att uppnå tvågradersmålet. För att nå ett lägre temperaturmål, till exempel ett 1,5-gradersmål, är de nödvändiga utsläppsminskningarna än mer omfattande.  För att nå tvågradersmålet med en sannolikhet runt 70 % krävs uppskattningsvis att de globala växthusgasutsläppen minskar i storleksordningen 50‒60 % från år 2000 till 2050, och minskar med nära 100 % till 2100.  För att nå ett 1,5-gradersmål med en sannolikhet runt 70 % krävs globala nollutsläpp redan runt år 2050.  För att nå ett 1,5-gradersmål med en sannolikhet runt 50 % krävs uppskattningsvis att de globala växthusgasutsläppen minskar i storleksordningen 80 % från år 2000 till 2050, och med nära 100 % till 2100. Det är framför allt de kumulativa utsläppen av koldioxid och andra långlivade växthusgaser som räknas när det gäller hur stora klimatförändringarna blir bortom 2100. Ju senare de globala utsläppen kulminerar, och ju högre nivå de då är på, desto större blir utmaningen för att åstadkomma en tillräckligt snabb påföljande utsläppsminskningstakt. Reducerade utsläpp av kortlivade klimatpåverkande ämnen är viktigt främst i ett kortare perspektiv. Det finns olika modeller för hur de globala utsläppsminskningarna kan fördelas mellan olika regioner och länder. Dessa baseras inte på naturvetenskapliga principer utan är beroende av politiska och andra ställningstaganden. För en del länder skiljer sig resultaten mycket beroende på valet av fördelningsmodell. För de flesta industriländer är slutsatsen dock generellt sett densamma: jämfört med idag behöver deras utsläpp minska mycket kraftigt.  För att nå tvågradersmålet med i storleksordningen 70 % sannolikhet krävs, givet en globalt lika per capita fördelning av utsläppen från och med 2050, att utsläppen i Sverige minskar med cirka 70 % från år 2005 till 2050. Den motsvarande siffran för EU är cirka 80 %.  För att nå ett 1,5-gradersmål med i storleksordningen 70 % sannolikhet krävs, givet en globalt lika per capita fördelning av utsläppen från och med 2050, att utsläppen minskar från år 2005 till år 2050 med runt 100 % i Sverige och i EU, och i andra länder.  För att nå ett 1,5-gradersmål med i storleksordningen 50 % sannolikhet krävs, givet en globalt lika per capita fördelning av utsläppen från och med 2050, att utsläppen i Sverige och EU minskar med drygt 90 % från år 2005 till 2050. Nettoutsläpp av koldioxid från avskogning och utrikes luft- och sjöfart ingår inte i dessa uppskattningar. Generellt blir riskerna för allvarliga klimateffekter mindre ju mer ambitiöst temperaturmål som väljs, men riskerna försvinner inte med tvågradersmålet, och inte ens med ett 1,5-gradersmål. Jämfört med IPCC:s AR4 från 2007, har nya forskningsresultat publicerats om klimateffekter. I denna rapport har vi fokuserat på havsnivåhöjningen, havsförsurningen, den biologiska mångfalden samt klimateffekter i Arktis. Jämfört med genomgången av kunskapsläget i AR4 visar nya resultat att den framtida havsnivåhöjningen kan bli större, havsförsurningens effekter på marina ekosystem omfattande och även om en del arter kan vara anpassningsbara, kan världens ekosystem påverkas av skillnader i olika arters sårbarhet för klimatförändringarna. I Arktis sker snabba förändringar. Sammantaget ter sig riskerna för allvarliga klimateffekter större jämfört med AR4. Denna rapport utgår från naturvetenskaplig klimatforskning sedan 2007. Rapporten förordar inte något specifikt temperaturmål, någon specifik utsläppsbana eller specifika policybeslut. Dessa är föremål för politiska avgöranden.

  • 296. Saaroni, H.
    et al.
    Amorim, Jorge Humberto
    SMHI, Research Department, Air quality.
    Hiemstra, J. A.
    Pearlmutter, D.
    Urban Green Infrastructure as a tool for urban heat mitigation: Survey of research methodologies and findings across different climatic regions2018In: Urban Climate, ISSN 2212-0955, E-ISSN 2212-0955, Vol. 24, p. 94-110Article in journal (Refereed)
  • 297. Samson, Roeland
    et al.
    Moretti, Marco
    Amorim, Jorge Humberto
    SMHI, Research Department, Air quality.
    Branquinho, Cristina
    Fares, Silvano
    Morelli, Federico
    Niinemets, Ülo
    Paolett, Elena
    Pinho, Pedro
    Sgrigna, Gregorio
    Stojanovski, Vladimir
    Tiwary, Abhishek
    Sicard, Pierre
    Calfapietra, Carlo
    Towards an integrative approach to evaluate the environmental ecosystem services provided by urban forest2019In: Journal of Forestry Research, ISSN 1007-662X, E-ISSN 1993-0607, p. 1-16Article in journal (Refereed)
  • 298. Sand, M.
    et al.
    Berntsen, T. K.
    von Salzen, K.
    Flanner, M. G.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Victor, D. G.
    Response of Arctic temperature to changes in emissions of short-lived climate forcers2016In: Nature Climate Change, ISSN 1758-678X, E-ISSN 1758-6798, Vol. 6, no 3, p. 286-+Article in journal (Refereed)
    Abstract [en]

    There is growing scientific(1,2) and political(3,4) interest in the impacts of climate change and anthropogenic emissions on the Arctic. Over recent decades temperatures in the Arctic have increased at twice the global rate, largely as a result of ice-albedo and temperature feedbacks(5-8). Although deep cuts in global CO2 emissions are required to slow this warming, there is also growing interest in the potential for reducing short-lived climate forcers (SLCFs; refs 9,10). Politically, action on SLCFs may be particularly promising because the benefits of mitigation are seen more quickly than for mitigation of CO2 and there are large co-benefits in terms of improved air quality(11). This Letter is one of the first to systematically quantify the Arctic climate impact of regional SLCFs emissions, taking into account black carbon (BC), sulphur dioxide (SO2), nitrogen oxides (NOx), volatile organic compounds (VOCs), organic carbon (OC) and tropospheric ozone (O-3), and their transport processes and transformations in the atmosphere. This study extends the scope of previous works(2,12) by including more detailed calculations of Arctic radiative forcing and quantifying the Arctic temperature response. We find that the largest Arctic warming source is from emissions within the Asian nations owing to the large absolute amount of emissions. However, the Arctic is most sensitive, per unit mass emitted, to SLCFs emissions from a small number of activities within the Arctic nations themselves. Astringent, but technically feasible mitigation scenario for SLCFs, phased in from 2015 to 2030, could cut warming by 0.2 (+/- 0.17) K in 2050.

  • 299. Schmidt, Karsten
    et al.
    Yurkin, Maxim A.
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    A case study on the reciprocity in light scattering computations2012In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 20, no 21, p. 23253-23274Article in journal (Refereed)
    Abstract [en]

    The fulfillment of the reciprocity by five publicly available scattering programs is investigated for a number of different particles. Reciprocity means that the source and the observation point of a given scattering configuration can be interchanged without changing the result. The programs under consideration are either implementations of T-matrix methods or of the discrete dipole approximation. Similarities and differences concerning their reciprocity behavior are discussed. In particular, it is investigated whether and under which conditions reciprocity tests can be used to evaluate the scattering results obtained by the different programs for the given particles. (c) 2012 Optical Society of America

  • 300.
    Segersson, David
    SMHI, Research Department, Air quality.
    A dynamic model for shipping emissions: Adaptation of Airviro and application in the Baltic Sea2014Report (Other academic)
    Abstract [en]

    In many countries, shipping is an important contributor to emissions of air pollutants. For sulphur, shipping is nowadays often considered the most important source of emissions. Shipping also emits significant amounts of nitric oxides, particles and volatile organic compounds. From a climate change perspective, shipping is an important source of green house gases, and also contributes significantly to emissions of short lived climate pollutants, such as soot. Emissions to air from shipping have impact on air quality, climate change and acidification. To understand the impact of shipping emissions on the environment, human health and the climate, it is necessary to quantify, map and describe the emissions. Due to lack of data and knowledge, estimates of emissions from shipping have always been very uncertain. One reason to the uncertainties has been difficulties to locate the large number of ships travelling at sea, another reason has been uncertainties regarding emission factors. Since year 2007 AIS (Automatic Identification System) has been a standard for positioning and identification of ships at sea. AIS is complementary to radar and describes location, speed and identity of ships with high precision. This development creates new possibilities to improve information regarding emissions. A system that makes use of data from AIS to estimate emissions from shipping has been developed. The system allows emissions to be calculated for shipping based on the latest knowledge regarding emission factors and makes use of ship specific data as far as possible. The general motivation is to improve the quality of estimations of emissions of air pollutants, green house gases and SLCP (Short Lived Climate Pollutants) as well as to provide a flexible tool to be used for related questions. The system is an integrated part of the Air Quality Management system Airviro. The developed system has been applied for the Baltic Sea. This application of the system is called Shipair. Shipair contains AIS information for the whole Baltic Sea, and the North Sea up to the southern coast of Norway. The AIS information comes from the international AIS database operated by HELCOM. Besides AIS, the Shipair application also makes use of a web service operated by Swedish Maritime Administration to acquire and estimate ship specific parameters needed for emission calculations. The Shipair application of Airviro has been validated by comparing calculated and measured fuel consumption for a small number of ships. The differences between measured and calculated fuel consumption are below 10 % for the individual ships, which is considered well within what could be expected. Comparisons have also been made with results from other ship emission inventories. The results are similar to those of the STEAM2 model published by FMI (Finnish Meteorological Institute), which are based on a similar methodology. Emissions used by from EMEP (Environmental Monitoring and Evaluation Programme) on the other hand can be seen to give significantly higher emissions than both Shipair and STEAM2. Finally, indirect verification has been made by comparing results from dispersion models with concentrations measured in ambient air. Due to a large number of other emission sources that dominate the concentrations in ambient air, these results can confirm that the Shipair calculations are reasonable, but does not provide any closer evaluation of the quality of the results. To investigate if estimates based on fuel statistics, currently used in international reporting of Swedish shipping emissions, are reasonable, a comparison has also been made with estimations based on national fuel statistics. The results indicate that estimations based on the fuel statistics could be underestimating the emissions of CO2 from domestic shipping with approximately 50 %.

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