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  • 101.
    Johansson, Barbro
    et al.
    SMHI, Professional Services.
    Persson, Magnus
    SMHI.
    Aranibar, Enrique
    ENDE Empresa Nacional de Electricidad.
    Llobet, Robert
    ENDE Empresa Nacional de Electricidad.
    Application of the HBV model to Bolivian basins1987Report (Other academic)
  • 102.
    Johansson, Lasse
    et al.
    SMHI, Professional Services.
    Gyllenram, Walter
    SMHI, Professional Services.
    Nerheim, Signild
    SMHI, Professional Services.
    Lokala effekter på extrema havsvattenstånd2018Report (Other academic)
    Abstract [sv]

    När havsvattennivån ska beräknas för en viss plats behöver hänsyn tas till lokala förhållanden. Vattenståndet lokalt kan avvika från det som observeras vid en av SMHI:s eller andras mätplatser. Geografin på platsen och vågor kan leda till högre vattennivåer än de som observeras vid mätplatserna.

    Denna rapport ger en kort beskrivning av hur vattenståndet längs Sveriges kuster byggs upp. Vi ger exempel på olika mekanismer för att läsaren ska få en uppfattning om skalorna i tid och höjd. Vågfenomen lokalt kan leda till att ytterligare högre nivåer kan beröras av vatten än vad vattenståndet anger.

    En översiktlig beskrivning görs av hur vågor interagerar med stränder ochkajer. Begreppen våguppstuvning och våguppsköljning förklaras. Några exempel ges på vilken effekt bottens lutning har och hur vågor utvecklas i hamnar.

    För att beräkna återkomstvärden för vattenstånd på en lokal plats beskrivs hur man kan utgå från de mätningar som SMHI gör sedan många år. Observationer från den närmaste eller de närmaste mätplatserna kan användas för att beräkna vattenstånd med olika återkomsttider för den önskade platsen. Ett exempel på en sådan beräkning presenteras där speciellt viktiga detaljer redovisas.

  • 103.
    Johnell, Anna
    et al.
    SMHI, Professional Services.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Deterministic evaluation of ensemble streamflow predictions in Sweden2007In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 38, no 4-5, p. 441-450Article in journal (Refereed)
    Abstract [en]

    A system for ensemble streamflow prediction, ESP, has been operational at SMHI since July 2004, based on 50 meteorological ensemble forecasts from ECMWF. Hydrological ensemble forecasts are produced daily for 51 basins in Sweden. All ensemble members, as well as statistics (minimum, 25% quartile, median, 75% quartile and maximum), are stored in a database. This paper presents an evaluation of the first 18 months of ESP median forecasts from this system, and in particular their performance in comparison with today's categorical forecast. The evaluation was made in terms of three statistical measures: bias B, root mean square error RMSE and absolute peak flow error PE. For ESP forecasts the bias ranged between -20% and 80% with a systematic overestimation for Sweden as a whole. A comparison between bias in input precipitation and ESP output, respectively, revealed only a weak relationship, but streamflow overestimation is likely related mainly to model properties. The results from the streamflow forecast comparison showed that the ESP median in deterministic terms performs overall as well as the presently used categorical forecast. Further, ESP has the advantage of providing at least a qualitative measure of the uncertainty in the forecasts, with probability forecasts being the ultimate goal.

  • 104. Kalantari, Zahra
    et al.
    Cavalli, Marco
    Cantone, Carolina
    SMHI, Professional Services.
    Crema, Stefano
    Destouni, Georgia
    Flood probability quantification for road infrastructure: Data-driven spatial-statistical approach and case study applications2017In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 581, p. 386-398Article in journal (Refereed)
  • 105.
    Kindell, Sven
    SMHI, Professional Services.
    Luften i Nässjö1987Report (Other academic)
  • 106.
    Kindell, Sven
    SMHI, Professional Services.
    Spridningsberäkningar för Ericsson, Ingelstafabriken1985Report (Other academic)
  • 107.
    Kindell, Sven
    SMHI, Professional Services.
    Spridningsberäkningar för SUPRAs anläggningar i Köping1985Report (Other academic)
  • 108.
    Kindell, Sven
    SMHI, Professional Services.
    Spridningsberäkningar för Uddevallas fjärrvärmecentral i Hovhult1986Report (Other academic)
  • 109.
    Kindell, Sven
    et al.
    SMHI, Professional Services.
    Ring, Sture
    SMHI, Professional Services.
    Spridningsberäkningar för SAABs planerade bilfabrik i Malmö1986Report (Other academic)
  • 110.
    Kindell, Sven
    et al.
    SMHI, Professional Services.
    Wern, Lennart
    SMHI, Core Services.
    Luftvårdsstudie avseende industrikombinatet i Nynäshamn (koncentrations- och luktberäkningar)1985Report (Other academic)
  • 111.
    Kjellström, Erik
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Bärring, Lars
    SMHI, Research Department, Climate research - Rossby Centre.
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Nilsson, Carin
    Lunds Universitet.
    Persson, Gunn
    SMHI, Professional Services.
    Strandberg, Gustav
    SMHI, Research Department, Climate research - Rossby Centre.
    Production and use of regional climate model projections – A Swedish perspective on building climate services2016In: Climate Services, ISSN 2405-8807, no 2-3, p. 15-29Article in journal (Refereed)
  • 112. Klutse, Nana Ama Browne
    et al.
    Ajayi, Vincent O.
    Gbobaniyi, Bode
    SMHI, Professional Services.
    Egbebiyi, Temitope S.
    Kouadio, Kouakou
    Nkrumah, Francis
    Quagraine, Kwesi Akumenyi
    Olusegun, Christiana
    Diasso, Ulrich
    Abiodun, Babatunde J.
    Lawal, Kamoru
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Lennard, Christopher
    Dosio, Alessandro
    Potential impact of 1.5 degrees C and 2 degrees C global warming on consecutive dry and wet days over West Africa2018In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 13, no 5, article id 055013Article in journal (Refereed)
  • 113.
    Langner, Joakim
    et al.
    SMHI, Research Department, Air quality.
    Alpfjord Wylde, Helene
    SMHI, Professional Services.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Mapping of phytotoxic ozone dose for birch, spruce, wheat and potato using the MATCH-Sweden system2019Report (Other academic)
    Abstract [en]

    We have added calculations of PODY for birch, spruce, wheat and potato to theMATCH-Sweden system. Several important updates compared to the previousimplementation for generic crops and generic deciduous trees have been made includingimproved calculations of canopy level ozone concentrations, updated calculations ofquasi-laminar and surface resistance and inclusion of soil moisture dependence forspecific vegetation species. 

    A comparison to results from the EMEP model for generic crops and generic deciduoustrees shows a better agreement than previously. Considering also that an error in theEMEP calculations has been identified, affecting primarily the PODY calculations forgeneric deciduous trees, MATCH-Sweden and EMEP model results now appear to bemore consistent.Year to year variability of PODY for birch and spruce are similar to that for genericdeciduous trees while numerical values are different, especially for birch, due to differentparameters in the PODY calculation and longer vegetation periods. Critical levelscorresponding to a 4 % growth reduction are exceeded for both birch and spruce in majorparts of Sweden for all years in the period 2013-2017.Year to year variability of PODY for wheat and potato are larger than for generic cropsdue to the higher threshold for PODY used in the calculations. Critical levelscorresponding to a 5 % reduction in crop yield are reached in four of five years insouthern Sweden for wheat and for two in five years for potato.The updated program package for PODY calculations could be used to calculateconsistent time series of PODY for different types of vegetation for the period 1990-2013based on reanalyzed ozone concentrations. The program package could also be developedto calculate PODY for the whole of Europe for different emission- or climate scenarios.The results presented in this report are also available in digital form at the SMHI homepage for environmental monitoring of air quality(www.smhi.se/klimatdata/miljo/atmosfarskemi).

  • 114.
    Leung, Wing
    et al.
    SMHI, Professional Services.
    Windmark, Fredrik
    SMHI, Professional Services.
    Brodl, Ludvik
    SMHI, Professional Services.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    A basis to estimate marginal cost for air traffic in Sweden.: Modelling of ozone, primary and secondary particles and deposition of sulfur and nitrogen.2018Report (Other academic)
    Abstract [en]

    In this study we have investigated the effects of emissions from aviation on air quality in both Swedish and European domains. The results will be used as a basis to estimate the marginal cost for air traffic in Sweden. The vertical, geographical and temporal distribution of aviation emissions over Sweden has been estimated using a newly developed methodology. The aviation emissions have been categorized by their emission altitude (LTO, low cruise and high cruise) and flight nationality (international, national and overflight). This aviation emission information was then used as input data to the regional atmospheric chemistry model MATCH to simulate the effects of aviation emissions on ecosystem, health and climate metrics. A total of 17 model simulations over three years have been performed. There is one simulation in which all emitted species from the surface and aviation emissions are included and eight simulations in which all aviation emissions from each combination of emission altitude and flight nationality are included. There are eight simulations in which NOx aviation emissions from each combination of emission altitude and flight nationality are included. Using these simulations, contributions from aviation emissions to deposition, concentrations and a range of different air pollution metrics has been calculated. The results are calculated in both the Europe and Swedish domains for all the simulations. 

    The following results are included in this report: . Deposition of oxidised and reduced nitrogen . Deposition of excess sulfur . AOT40 and SOMO35 and their exposures . Concentration and exposure of primary and secondary particles . Concentration of nitrate and sulfate particles . Concentration of surface and above surface ozone 

    In summary, contributions from aviation emissions in Sweden to the different concentrations, deposition and metrics for environmental effects are generally small, on the order of a few per mille or less. However the impacts can be traced in the simulations well beyond the Swedish borders. LTO emissions give the largest contribution to deposition of oxidised and reduced nitrogen, deposition of excess sulfur and concentrations of primary and secondary particles. In particular near the major airports like Stockholm-Arlanda and Gothenburg-Landvetter. High cruise emissions give insignificant contributions to deposition and concentrations at surface level. LTO emissions give a negative contribution to surface ozone concentration locally at the main Swedish airports but give an overall increased contribution in the regions around. Aviation emissions at low cruise and high cruise levels have the largest effect on ozone concentrations at higher levels. 

  • 115.
    Lindell, Sten
    SMHI, Professional Services.
    Realtidsbestämning av arealnederbörd1993Report (Other academic)
    Abstract [sv]

    Några vintrar under 80-talet gav HBV-modellen ett dåligt prognosresultat för vissa tillrinningsområden i norra Norrlands fjälltrakter. Samtidigt blev resultat av vårflödesvolymsprognosema för motsvarande områden bättre då arealnederbördsmetoden för prognosering av tilliinningsvolymer utnyttjades. För att utröna om det är möjligt att kombinera arealnederbördsmetodens nederbördsviktning med HBV-modellens tillrinningsberäkning finansierade arbetsgruppen för hydrologiskt utvecklingsarbet (HUVA) inom Vattenregleringsföretagens Samarbetsorgan (VASO) en studie budgetåret 1991-92 som avrapporterades i Mv PM Nr 3 (Lindell, 1992). I det arbetet användes ett PCprogram för tredimensionell interpolering, SURFER, för beräkning av den areella nederbörden. Arbetet med att läsa in nederbördsdata till det systemet var mycket omfattande och tog mesta tiden av projektet i anspråk. Däiför kunde endast ett prognosområde studeras med nederbördsdata under 15 månader

    Denna rapport redovisar en utveckling av SURFER-projektet från 1991-92. PC-programmet SURFER har ersatts med en av SMHI utvecklad modell för operationella korta väderprognoser, LAM-modellen (Ullerstig och Unden, 1981), (Unden, 1982) samt (Andersson et al., 1986).

    -talet gav HBV-modellen ett dåligt prognosresultat för vissa

    tillrinningsområden i norra Norrlands fjälltrakter

    . Samtidigt blev resultat av

    vårflödesvolymsprognosema för motsvarande områden bättre då arealnederbördsmetoden

    för prognosering av tilliinningsvolymer utnyttjades. För att utröna om det är möjligt att

    kombinera arealnederbördsmetodens nederbördsviktning med HBV-modellens

    tillrinningsberäkning finansierade arbetsgruppen för hydrologiskt utvecklingsarbete

    (HUVA) inom Vattenregleringsföretagens Samarbetsorgan (VASO) en studie budgetåret

    1991-92 som avrapporterades i Mv PM Nr 3 (Lindell, 1992). I det arbetet användes ett PCprogram

    för tredimensionell interpolering, SURFER, för beräkning av den areella

    nederbörden. Arbetet med att läsa in nederbördsdata till det systemet var mycket

    omfattande och tog mesta tiden av projektet i anspråk. Däiför kunde endast ett

    prognosområde studeras med nederbördsdata under 15 månader

    .

    Denna rapport redovisar en utveckling av SURFER-projektet från 1991-92. PC-programmet

    SURFER har ersatts med en av SMHI utvecklad modell för operationella korta

    väderprognoser, LAM-modellen (Ullerstig och Unden

    , 1981), (Unden, 1982) samt

    (Andersson et al., 1986).

  • 116.
    Lindell, Sten
    et al.
    SMHI, Professional Services.
    Carlsson, Bengt
    SMHI, Research Department, Hydrology.
    Sanner, Håkan
    SMHI, Core Services.
    Reihan, Alvina
    SMHI.
    Vedom, Rimma
    Application of the integrated hydrological modelling system IHMS-HBV to pilot basin in Estonia1996Report (Other academic)
    Abstract [en]

    This report describes calibration and application of the IHMS-HBV model on a daily time step to Kasari River basin in Estonia. The Swedish Meteorological and Hydrological Institute (SMHI) have as consultant been responsible for the set-up, calibration, training and delivery of the Integrated Hydrological Model System with the HBV-model (IHMSHBV). The Swedish Board for lnvestment and Technical Support (BITS) financed the project. The training and transfer of technology were addressed to the Estonian Meteorological and Hydrological Institute (EMHI).

  • 117.
    Lindell, Sten
    et al.
    SMHI, Professional Services.
    Ericsson, Lars O.
    SMHI.
    Sanner, Håkan
    SMHI, Core Services.
    Göransson, Karin
    SMHI.
    Integrated Hydrological Monitoring and Forecasting System for the Vistula River Basin1997Report (Other academic)
    Abstract [en]

    This report is a technical description on the project Integrated Hydrological Monitoring and Forecasting System for the Vistula River Basin. The Swedish Meteorological and Hydrological lnstitute in Nonköping, Sweden, (hereinafter called SMHI) and Institute of Meteorology and Water Management in Warsaw, Poland, (hereinafter called IMWM) has fulfilled and co-operated in this project. SMHI have as consultants been responsible for design and development of the Vistula River Monitoring and Forecasting System, for on-the-job training and education in Windows programming and development as well as in set-up, calibration and applications of the HBV-model. IMWM responsibilities has been to provide the project with hydrometeorological data and information on land use for the calibration activities and to supply the project with the hydrodynamic model in use at the polish institute. IMWM has been deeply involved in the design and development of the Vistula River Monitoring and Forecasting System and bad the main responsibility in the HBV-model calibration activities.

  • 118.
    Lindell, Sten
    et al.
    SMHI, Professional Services.
    Sanner, Håkan
    SMHI, Core Services.
    Nikolushkina, Irena
    SMHI.
    Stikute, Inita
    SMHI.
    Application of the integrated hydrological modelling system IHMS-HBV to pilot basin in Latvia1996Report (Other academic)
    Abstract [en]

    This report describes calibration and application of the IHMS-HBV model on daily time step to Lielupe River basin in Latvia. The Swedish Meteorological and Hydrologicalnstitute (SMHI) have as consultant been responsible for the set-up, calibration, training and delivery of the Integrated Hydrological Model System with the HBV-model (IHMSHBV). The Swedish Board for Investment and Technical Support (BITS) financed the project. The training and transfer of technology were addressed to the Latvia Hydrometeorological Agency (LHMA)

  • 119.
    Lindström, Göran
    et al.
    SMHI, Research Department, Hydrology.
    Gardelin, Marie
    SMHI, Professional Services.
    Johansson, Barbro
    SMHI, Professional Services.
    Persson, Magnus
    SMHI.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    HBV-96 – En areellt fördelad modell för vattenkrafthydrologin1996Report (Other academic)
  • 120.
    Lindström, Göran
    et al.
    SMHI, Research Department, Hydrology.
    Gardelin, Marie
    SMHI, Professional Services.
    Persson, Magnus
    SMHI.
    Conceptual modelling of evapotranspiration for simulations of climate change effects1994Report (Other academic)
    Abstract [en]

    The evapotranspiration routines in existing conceptual hydrological models have been identified as one of the weaknesses which appear when these rnodels are used for the simulation of hydrological effects of a changing clirnate. The hydrological models in operational use today usually have a very superficial description of evapotranspiration. They have, nevertheless, been able to yield reasonable results. The objective of this paper is to analyse and suggest modifications of existing evapotranspiration routines in conceptual hydrological models to make them more appropriate for use in simulation of the effects of a changing climate on water resources.

    The following rnodifications of the evapotranspiration routine were formulated and tested in the HBV model: Ternperature anomaly correction of evapotranspiration, potential evapotranspiration by a simplified Thornthwaite type formula, interception submodel, spatially distributed evapotranspiration routine and alternative forrnulations of lake evapotranspiration. Sensitivity analyses were thereafter rnade to illustrate the effects of uncertainty in the hydrological model structure versus those of the uncertainty in the climate change predictions.

  • 121.
    Lindström, Göran
    et al.
    SMHI, Research Department, Hydrology.
    Johansson, Barbro
    SMHI, Professional Services.
    Persson, Magnus
    SMHI.
    Gardelin, Marie
    SMHI, Professional Services.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    Development and test of the distributed HBV-96 hydrological model1997In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 201, no 1-4, p. 272-288Article in journal (Refereed)
    Abstract [en]

    A comprehensive re-evaluation of the HBV hydrological model has been carried out. The objectives were to improve its potential for making use of spatially distributed data, to make it more physically sound and to improve the model performance. The new version, HBV-96, uses subbasin division with a typical resolution of 40 km(2), although any resolution can be used. In addition, each subbasin is divided into elevation bands, vegetation and snow classes. Automatic weighting of precipitation and temperature stations was introduced and a new automatic calibration scheme was developed. The modifications led to significant improvements in model performance. In seven test basins the average value of the efficiency criterion R-2 increased from 86 to 89%, with improvements in both the calibration and verification periods. (C) 1997 Elsevier Science B.V.

  • 122.
    Losjö, Katarina
    et al.
    SMHI, Professional Services.
    Södling, Johan
    SMHI, Professional Services.
    Wern, Lennart
    SMHI, Core Services.
    German, Jonas
    SMHI, Professional Services.
    Uppföljning av de svenska riktlinjerna för bestämning av dimensionerande flöden för dammanläggningar2019Report (Other academic)
    Abstract [en]

    Commissioned by Svenska kraftnät, the Swedish Meteorological and Hydrological Institute has carried out a follow-up study on the Swedish guidelines for determination of designs floods for dams. The main purpose was to investigate whether the Swedish meteorological and hydrological observation data show any signs of climatic change, which could affect the validity of the guidelines, formulated in 1990 (Flödeskommittén, 1990), later updated twice, in which the edition of 2015 (Svensk Energi et.al., 2015), emphasize the application also in a changing climate . The first follow-up study was performed in 2008 (Bergström m.fl., 2008), and the present study has used longer time series, both after 2008 and earlier than in the study of 2008.

    The guidelines prescribe that the calculation of design flood should be carried out using a hydrological model, and the following parameters are decided to be used in the simulations:

    • a snow cover with a statistical return period of 30 years
    • a 14-day precipitation sequence over 1000 km2
    • corrections of this sequence regarding the area of the catchment
    • corrections of the sequence regarding elevation above sea level and month of the year
    • extreme wind speed

    The present analyses have used long series of observation data from SMHI climatological and hydrological databases, mostly using the division of Sweden into five regions, described in the guidelines.

    • The analyses of the 14-day precipitation sequence has been made by analysing precipitation higher than 90 mm over 1000 km2 during 24 hours and 2 days during the period 1930-2018, as well as the 14-day precipitation sum 1961-2018. Also the highest point precipitation values have been analysed for the period 1945-2018.
    • It is not possible to find a trend in the data for neither of these analyses, in contrary to the findings in the previous follow-up, where an increase in the highest point precipitation was seen for the period 1961-2007.
    • Two adaptations of accumulated 14-day precipitation over three areas: 100, 100 and 10 000 km, to the areal correction curve in the guidelines show some discrepancies. However, the present analyses are made using another database than the basis of the original curve, and the results indicate that there is no immediate need for adjustment of the areal correction in the guidelines.
    • The distribution of high precipitation over the year has been studied, and it shows the same pattern as the monthly corrections of the sequence in the guidelines. The pattern is similar for the periods 1961-90 and 1991-2018.
    • The mean values of yearly largest snow cover have been analysed for the period 1904/05-2017/18. The results do not indicate any trend, only shorter time variations, neither for the whole period nor for the period 1961-2018. As the determination of snow cover with a return period of 30 years should be made using frequency analysis, the recommendations in the guidelines to use a long data period for the analyses are still valid.
    • An analysis of the daily highest flood peaks was made for data from 60 unregulated or very slightly regulated discharge stations. No long time trend that could reveal changes in flood risks can be seen in the results.
    • The geostrophic wind, an idealized average wind speed, computed from observations of air pressure, has been studied 1940-2017. For geostrophic wind of at least 25 m/s no signs of long term trend can be seen.
    • The analyses of the ratio between the design flood for flood design category I and the flood of a 100-year return period indicates increasing ratio with decreasing catchment area. This could

    The overall conclusion of the study is that there is presently no need for adjusting the parameters in the guidelines. The importance of using long time series for trend analyses is revealed.

  • 123.
    Lärke, Agne
    et al.
    SMHI.
    Sanner, Håkan
    SMHI, Core Services.
    Johnell, Anna
    SMHI, Professional Services.
    Utvärdering av SMHIs prognos och varningstjänsts verksamhet under flödena januari t o m mars 2002 i sydvästra Sverige2003Report (Other academic)
    Abstract [sv]

    Mellan den 16 januari och 13 februari föll rikligt med regn över sydvästra Sverige. I kombination med viss snösmältning orsakade detta kraftigt stigande flöden och översvämningar som följd. Flödena kulminerade på många håll i början av februari. I slutet av februari och början av mars ökade återigen flödena kraftigt till följd av nya regnväder. På de flesta håll nåddes dock inte flöden lika höga som i början av februari.

  • 124.
    Marmefelt, Eleonor
    SMHI, Professional Services.
    Currents in the Gulf of Bothnia During the Field Year of 19911994Report (Other academic)
  • 125.
    Marmefelt, Eleonor
    et al.
    SMHI, Professional Services.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    An integrated biogeochemical model system for the Baltic Sea1999In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 393, p. 45-56Article in journal (Refereed)
    Abstract [en]

    The Swedish Meteorological and Hydrological Institute (SMHI) is developing an integrated biogeochemical model system for the Baltic Sea. It consists of three coupled models; a marine biogeochemical-hydrodynamical model (SCOBI), a continuous riverine nitrogen transport model (HBV-N) and an atmospheric transport and chemical model (MATCH). It is supplied with a tool for presentation and analysis. The SCOBI model is a coupled one-dimensional model with high vertical resolution. Horizontal variations are taken into account by dividing the area into smaller boxes. The model includes primary phytoplankton production, nitrogen fixation and secondary zooplankton production. Nitrogen load from land is obtained through the HBV-N model, which simulates organic and inorganic nitrogen separately in catchments. The model is based on the hydrological model HBV, and the subbasin runoff is simulated on a daily basis. The HBV-N model is calibrated and validated against measured concentrations and water flow in rivers. The atmospheric input of oxidised and reduced nitrogen is taken from the annual assessments carried out with the MATCH-Sweden modelling system. MATCH-Sweden combines model calculations, using an atmospheric transport and chemical model, with observations of air- and precipitation chemistry data to give a detailed mapping of concentrations and deposition of nitrogen compounds over Sweden. Supplemented with monitoring data for the specific area of interest, the integrated biogeochemical model system makes a useful tool for environmental protection analyses; e.g. for interpretation of monitoring data as well as creating scenarios for studies of effects in changes of the nutrient loads.

  • 126.
    Marmefelt, Eleonor
    et al.
    SMHI, Professional Services.
    Håkansson, Bertil
    SMHI, Research Department, Oceanography.
    Erichsen, Anders Christan
    Sehested Hansen, Ian
    Institute of Marine Research, Bergen, Norway..
    Development of an Ecological Model System for the Kattegat and the Southern Baltic: Final Report to the Nordic Councils of Ministers2000Report (Other academic)
  • 127.
    Marmefelt, Eleonor
    et al.
    SMHI, Professional Services.
    Olsson, Håkan
    SMHI, Core Services.
    Integrerat Kustzonssystem för Hallandskusten2005Report (Other academic)
    Abstract [sv]

    Kustzonssystemet är ett integrerat modellsystem där såväl belastningen på kusten från land och atmosfär som tillståndet i kustzonen beräknas med hjälp av modeller. Tillrinningen från land har beräknats med hjälp av den hydrologiska modellen HBV och koncentrationerna har fastställts med hjälp av observerade data. Atmosfärsdepositionen både på land och i kustområdet beräknas av den atmosfärskemiska MATCH-modellen. Kustzonsmodellen (PROBE-SCOBI), som är en biogeokemisk modell, beräknar tillståndet i kustvattnen.Syftet med Kustzonssystemet är att modellerna skall vara så beskaffade att det är möjligt att skapa långa tidsserier främst av näringsämnen och syrgashalt, samtidigt som miljötillståndet i kustzonen genom modellerna beskrivs med så hög kvalité att modellsystemet kan användas i analyssyfte, exempelvis vid scenariostudier. Kustzonsmodellen är en s.k. en-dimensionell modell, som löser upp modellvariablerna i djupled med hög noggrannhet, men beräknar ett horisontellt medelvärde i sitt område. För att kunna lösa upp de horisontella gradienterna i området måste modellområdet delas in i flertalet delbassänger. Beräkningar görs i alla bassänger, vilka är kopplade med varandra och utbyter egenskaper mellan varandra. Indelningen av Kustzonsmodellens delbassänger längs Hallandskusten följer SVAR-indelningen. Detta innebär att Kustzonsmodellen längs Hallandskusten består av 20 delbassänger.

  • 128.
    Marmefelt, Eleonor
    et al.
    SMHI, Professional Services.
    Olsson, Håkan
    SMHI, Core Services.
    Lindow, Helma
    SMHI, Core Services.
    Svensson, Jonny
    Thalassos Computations.
    Integrerat Kustzonssystem för Bohusläns skärgård2004Report (Other academic)
    Abstract [sv]

    SMHIs Kustzonssystem har implementerats längs Bohuskusten i två etapper. Första etappen omfattar skärgården från Gullmaren i söder upp till riksgränsen i norr. Den andra etappen sträcker sig från fjordsystemet kring Orust och Tjörn och ner till Onsala kustvatten. Tillrinningen från land har beräknats med hjälp av den hydrologiska modellen HBV och koncentrationerna har fastställt m.h.a. observerade data. Atmosfärsdepositionen både på land och i kustområdet beräknas av den atmosfärskemiska MATCH-modellen. Kustzonsmodellen (PROBE-SCOBI), som är en biogeokemisk modell, beräknar tillståndet i skärgårdsvattnen.Med hjälp av Kustzonsmodellen har skärgårdens miljötillstånd kunnat beräknats för en längre tidsperiod. Validering av modellen visar på en god överensstämmelse mellan observationer och modellens resultat både i den norra respektive den södra delen.Kustzonssystemet är ett utmärkt modellredskap för beräkning av långtidsscenarier genom att studera effekter på planktontillväxt, syrgasförhållanden och övergödning/siktdjup för olika åtgärder på land. Med hjälp av Kustzonssystemet kan man även beräkna hur stor del av belastningen på ett havsområde som kommer från öppna havet och hur stor del som kommer från andra källor, vilket gör modellsystemet mycket användbart i arbetet med Vattendirektivet.

  • 129.
    Marmefelt, Eleonor
    et al.
    SMHI, Professional Services.
    Omstedt, Anders
    SMHI, Research Department, Oceanography.
    DEEP-WATER PROPERTIES IN THE GULF OF BOTHNIA1993In: Continental Shelf Research, ISSN 0278-4343, E-ISSN 1873-6955, Vol. 13, no 2-3, p. 169-187Article in journal (Refereed)
    Abstract [en]

    The northern extension of the Baltic Sea, the Gulf of Bothnia, is a weakly stratified sea. One would therefore expect that the deep water of the Gulf is easily renewed through deep thermal convection, or even through deep haline convection, as the Gulf is more or less covered with ice every winter. However, the present study shows, through analysis of historical temperature, salinity and density data, that the deep water in the Gulf of Bothnia is mainly renewed by major inflows of Baltic Proper surface water. The penetrating water forms a dense bottom current in the Gulf. In the southern part of the Gulf, the Bothnian Sea, the volume flow of the bottom current is found to increase by 10%. It is therefore not likely that the bottom current properties are changed to any appreciable extent. The bottom current properties in the Bothnian Bay, on the other hand, are highly affected, as the volume flow is estimated to increase by 150% in this basin.

  • 130.
    Marmefelt, Eleonor
    et al.
    SMHI, Professional Services.
    Sahlberg, Jörgen
    SMHI, Professional Services.
    Bergstrand, Marie
    SMHI, Core Services.
    HOME Vatten i södra Östersjöns vattendistrikt: Integrerat modellsystem för vattenkvalitetsberäkningar2007Report (Other academic)
    Abstract [sv]

    SMHI har utvecklat ett interaktivt modellsystem för vattenkvalitetberäkningar i mark, sjöar, vattendrag och kustvatten, HOME Vatten. Ett av de första områden som systemet implementerades i var Östergötlands skärgård, med tillhörande avrinningsområde. I detta uppdrag har HOME Vatten implementerats i resterande områden i södra Östersjöns vattendistrikt, dvs. i Kalmar, Blekinge, Skåne och Gotlands län. De ingående modellerna i HOME Vatten är HBV-N (TRK) modellen för mark, sjöar och vattendrag samt Kustzonsmodellen för kustvattnen. Atmosfärsdepositionen både på land och i kustområdet beräknas av den atmosfärskemiska MATCH-modellen.HOME Vatten har utvecklats för att vara ett verktyg i svensk vattenförvaltning med speciellt fokus på EUs ramdirektiv för vatten. Modelluppsättningarna i Kalmar och Skåne-Blekinge läns kustvatten har validerats mot tillgängliga mätdata, och visar en god överrensstämmelse med data.I Gotlands län förekommer inget kustvattenkontrollprogram, varför modellen inte har kunnat valideras i detta område.

  • 131.
    Marmefelt, Eleonor
    et al.
    SMHI, Professional Services.
    Svensson, Jonny
    SMHI.
    Numerical circulation models for the Skagerrak - Kattegat: Preparatory study1990Report (Other academic)
  • 132.
    Meier, Markus
    et al.
    SMHI, Research Department, Oceanography.
    Andréasson, Johan
    SMHI, Professional Services.
    Broman, Barry
    SMHI, Research Department, Climate research - Rossby Centre.
    Graham, Phil
    SMHI, Professional Services.
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Persson, Gunn
    SMHI, Professional Services.
    Climate change scenario simulations of wind, sea level, and river discharge in the Baltic Sea and Lake Mälaren region – a dynamical downscaling approach from global to local scales2006Report (Other academic)
    Abstract [en]

    A regional climate model (RCM) and oceanographic, hydrological and digital elevation models were applied to study the impact of climate change on surface wind, sea level, river discharge, and flood prone areas in the Baltic Sea region. The RCM was driven by two global models and two emission scenarios. According to the four investigated regional scenario simulations, wind speed in winter is projected to increase between 3 and 19% as an area average over the Baltic Sea. Although extremes of the wind speed will increase about as much as the mean wind speed, sea level extremes will increase more than the mean sea level, especially along the eastern Baltic coasts. In these areas projected storm events and global average sea level rise may cause an increased risk for flooding. However, the Swedish east coast will be less affected because mainly the west wind component in winter would increase and because land uplift would compensate for increased sea levels, at least in the northern parts of the Baltic. One of the aims of the downscaling approach was to investigate the future risk of flooding in the Lake Mälaren region including Stockholm city. In Stockholm the 100-year surge is projected to change between -51 and 53 cm relative to present mean sea level suggesting that in the city the risk of flooding from the Baltic Sea is relatively small because the critical height of the jetty walls will not be exceeded. Lake Mälaren lies just to the west of Stockholm and flows directly into the Baltic Sea to the east. This study addresses also the question of how the water level in Lake Mälaren may be affected by climate change by incorporating the following three contributing components into an analysis: 1) projected changes to hydrological inflows to Lake Mälaren, 2) changes to downstream water levels in the Baltic Sea, and 3) changes in outflow regulation from the lake. The first component is analyzed using hydrological modeling. The second and third components employ the use of a lake discharge model. An important conclusion is that projected changes to hydrological inflows show a stronger impact on lake levels than projected changes in water level for the Baltic Sea. Furthermore, an identified need for increased outflow capacity from the lake for the present climate does not diminish with projections of future climate change. The tools developed in this work provide valuable inputs to planning for both present and future operations of water level in Lake Mälaren. Based on the oceanographic and hydrological scenario simulations, flood prone areas were analysed in detail for two municipalities, namely Ekerö and Stockholm. The GIS analysis of both municipalities indicates a series of affected areas. However, in case of the 100-year flood (0.65 m above the mean lake level) in present climate or even in case of the maximum probable flood (1.48 m above the mean lake level) the potential risks will be relatively low.

  • 133. Milano, Marianne
    et al.
    Reynard, Emmanuel
    Bosshard, Nina
    SMHI, Professional Services.
    Weingartner, Rolf
    In light of seasonal climatic and anthropogenic changes, is the Vaud canton (Switzerland) vulnerable to water stress by the medium-term?2016In: La houille blanche, ISSN 0018-6368, E-ISSN 1958-5551, no 5, p. 17-24Article in journal (Refereed)
  • 134.
    Nerheim, Signild
    et al.
    SMHI, Professional Services.
    Schöld, Sofie
    SMHI, Core Services.
    Persson, Gunn
    SMHI, Professional Services.
    Sjöström, Åsa
    SMHI, Core Services.
    Framtida havsnivåer i Sverige2018Report (Other academic)
    Abstract [sv]

    Sveriges kustområden drabbas ibland av tillfälliga översvämningar i samband med stormar eller då kraftiga lågtryck passerar. Översvämningar kan orsaka allvarliga samhällsstörningar och vatteninträngning i byggnader kan ge upphov till stora kostnader. Den pågående globala uppvärmningen, med stigande havsnivåer som följd, aktualiserar frågan om hur vattenståndet kring svenska kusten kan förändras, idag och i framtiden. Havet stiger och det kommer att pågå under hundratals eller kanske till och med tusentals år framöver.

    SMHI startade 2015 ett projekt för att beskriva havsnivåer längs svenska kusten i dagens och framtidens klimat. Projektet har levererat:

    • Beräknade medelvattenstånd för hela Sveriges kust för år 2050 och år 2100 utifrån tre olika framtida klimatscenarier.
    • En visningstjänst för framtida medelvattenstånd.
    • En beskrivning av hur höga havsvattenstånd kan beräknas för en specifik plats.
    • Höga vattenstånd för SMHI:s mätstationer samt en visualisering av dessa.
    • En översikt över statistisk metodik.
    • En vägledning för utvärdering av lokala effekter.
    • En beskrivning av kända högvattenhändelser i olika kustområden och parametrar och processer relaterade till dessa.

    Denna rapport presenterar en översikt över resultaten som tagits fram i projektet och avslutas med en beskrivning av hur framtidens höga havsnivåer kan bedömas i planeringssyfte. SMHI har i rapporten inte tagit ställning till vilket klimatscenario eller vilken tidshorisont som är mest lämpligt att använda för samhällsplanering. Detta måste bestämmas i ett situationsspecifikt sammanhang där risk och kostnader beaktas. SMHI vill betona att även om år 2100 ofta anges som slutår för klimatscenarier, så kommer havets nivå att fortsätta att stiga längre än så.

    Rapporten summerar resultat från övriga rapporter som framtagits inom projektet. För ytterligare detaljer hänvisas till dessa (se Förord).

  • 135.
    Nylén, Linda
    et al.
    SMHI, Professional Services.
    Asp, Magnus
    SMHI, Professional Services.
    Berggreen-Clausen, Steve
    SMHI, Professional Services.
    Berglöv, Gitte
    SMHI, Professional Services.
    Björck, Emil
    SMHI, Professional Services.
    Axén Mårtensson, Jenny
    SMHI, Core Services.
    Persson, Håkan
    SMHI, Professional Services.
    Sjökvist, Elin
    SMHI, Professional Services.
    Framtidsklimat i Gävleborgs län - enligt RCP-scenarier2015Report (Other academic)
    Abstract [en]

    The report describes todays and future climate in Gävleborg County based on observations and climate modelling. Regional modelled RCP4.5 and RCP8.5 scenarios have been further downscaled to 4×4 km2 resolution. The results are presented as meteorological and hydrological indices based on statistically processed model data.

  • 136.
    Nylén, Linda
    et al.
    SMHI, Professional Services.
    Asp, Magnus
    SMHI, Professional Services.
    Berggreen-Clausen, Steve
    SMHI, Professional Services.
    Berglöv, Gitte
    SMHI, Professional Services.
    Björck, Emil
    SMHI, Professional Services.
    Axén Mårtensson, Jenny
    SMHI, Core Services.
    Persson, Håkan
    SMHI, Professional Services.
    Sjökvist, Elin
    SMHI, Professional Services.
    Framtidsklimat i Jämtlands län - enligt RCP-scenarier2015Report (Other academic)
    Abstract [en]

    The report describes todays and future climate in Jämtland County based on observations and climate modelling. Regional modelled RCP4.5 and RCP8.5 scenarios have been further downscaled to 4×4 km2 resolution. The results are presented as meteorological and hydrological indices based on statistically processed model data.

  • 137.
    Nylén, Linda
    et al.
    SMHI, Professional Services.
    Asp, Magnus
    SMHI, Professional Services.
    Berggreen-Clausen, Steve
    SMHI, Professional Services.
    Berglöv, Gitte
    SMHI, Professional Services.
    Björck, Emil
    SMHI, Professional Services.
    Axén Mårtensson, Jenny
    SMHI, Core Services.
    Persson, Håkan
    SMHI, Professional Services.
    Sjökvist, Elin
    SMHI, Professional Services.
    Framtidsklimat i Värmlands län - enligt RCP-scenarier2015Report (Other academic)
    Abstract [en]

    The report describes todays and future climate in Värmland County based on observations and climate modelling. Regional modelled RCP4.5 and RCP8.5 scenarios have been further downscaled to 4×4 km2 resolution. The results are presented as meteorological and hydrological indices based on statistically processed model data.

  • 138.
    Nylén, Linda
    et al.
    SMHI, Professional Services.
    Asp, Magnus
    SMHI, Professional Services.
    Berggreen-Clausen, Steve
    SMHI, Professional Services.
    Berglöv, Gitte
    SMHI, Professional Services.
    Björck, Emil
    SMHI, Professional Services.
    Axén Mårtensson, Jenny
    SMHI, Core Services.
    Persson, Håkan
    SMHI, Professional Services.
    Sjökvist, Elin
    SMHI, Professional Services.
    Framtidsklimat i Västernorrlands län - enligt RCP-scenarier2015Report (Other academic)
    Abstract [en]

    The report describes todays and future climate in Västernorrland County based on observations and climate modelling. Regional modelled RCP4.5 and RCP8.5 scenarios have been further downscaled to 4×4 km2 resolution. The results are presented as meteorological and hydrological indices based on statistically processed model data.

  • 139.
    Ohlsson, Alexandra
    et al.
    SMHI, Professional Services.
    Asp, Magnus
    SMHI, Professional Services.
    Berggreen-Clausen, Steve
    SMHI, Professional Services.
    Berglöv, Gitte
    SMHI, Professional Services.
    Björck, Emil
    SMHI, Professional Services.
    Johnell, Anna
    SMHI, Professional Services.
    Nylén, Linda
    SMHI, Professional Services.
    Persson, Håkan
    SMHI, Professional Services.
    Sjökvist, Elin
    SMHI, Professional Services.
    Framtidsklimat i Blekinge län - enligt RCP-scenarier2015Report (Other academic)
    Abstract [en]

    The report describes todays and future climate in Blekinge County based on observations and climate modelling. Regional modelled RCP4.5 and RCP8.5 scenarios have been further downscaled to 4×4 km2 resolution. The results are presented as meteorological and hydrological indices based on statistically processed model data.

  • 140.
    Ohlsson, Alexandra
    et al.
    SMHI, Professional Services.
    Asp, Magnus
    SMHI, Professional Services.
    Berggreen-Clausen, Steve
    SMHI, Professional Services.
    Berglöv, Gitte
    SMHI, Professional Services.
    Björck, Emil
    SMHI, Professional Services.
    Johnell, Anna
    SMHI, Professional Services.
    Nylén, Linda
    SMHI, Professional Services.
    Persson, Håkan
    SMHI, Professional Services.
    Sjökvist, Elin
    SMHI, Professional Services.
    Framtidsklimat i Jönköpings län - enligt RCP-scenarier2015Report (Other academic)
    Abstract [en]

    The report describes todays and future climate in Jönköping County based on observations and climate modelling. Regional modelled RCP4.5 and RCP8.5 scenarios have been further downscaled to 4×4 km2 resolution. The results are presented as meteorological and hydrological indices based on statistically processed model data.

  • 141.
    Ohlsson, Alexandra
    et al.
    SMHI, Professional Services.
    Asp, Magnus
    SMHI, Professional Services.
    Berggreen-Clausen, Steve
    SMHI, Professional Services.
    Berglöv, Gitte
    SMHI, Professional Services.
    Björck, Emil
    SMHI, Professional Services.
    Johnell, Anna
    SMHI, Professional Services.
    Nylén, Linda
    SMHI, Professional Services.
    Persson, Håkan
    SMHI, Professional Services.
    Sjökvist, Elin
    SMHI, Professional Services.
    Framtidsklimat i Skånes län - enligt RCP-scenarier2015Report (Other academic)
    Abstract [en]

    The report describes todays and future climate in Skåne County based on observations and climate modelling. Regional modelled RCP4.5 and RCP8.5 scenarios have been further downscaled to 4×4 km2 resolution. The results are presented as meteorological and hydrological indices based on statistically processed model data.

  • 142.
    Ohlsson, Alexandra
    et al.
    SMHI, Professional Services.
    Asp, Magnus
    SMHI, Professional Services.
    Berggreen-Clausen, Steve
    SMHI, Professional Services.
    Berglöv, Gitte
    SMHI, Professional Services.
    Björck, Emil
    SMHI, Professional Services.
    Johnell, Anna
    SMHI, Professional Services.
    Nylén, Linda
    SMHI, Professional Services.
    Persson, Håkan
    SMHI, Professional Services.
    Sjökvist, Elin
    SMHI, Professional Services.
    Framtidsklimat i Västmanlands län - enligt RCP-scenarier2015Report (Other academic)
    Abstract [en]

    The report describes todays and future climate in Västmanland County based on observations and climate modelling. Regional modelled RCP4.5 and RCP8.5 scenarios have been further downscaled to 4×4 km2 resolution. The results are presented as meteorological and hydrological indices based on statistically processed model data.

  • 143.
    Olsson, Jonas
    et al.
    SMHI, Research Department, Hydrology.
    Berg, Peter
    SMHI, Research Department, Hydrology.
    Eronn, Anna
    SMHI, Research Department, Climate research - Rossby Centre.
    Simonsson, Lennart
    SMHI, Research Department, Hydrology.
    Södling, Johan
    SMHI, Professional Services.
    Wern, Lennart
    SMHI, Core Services.
    Yang, Wei
    SMHI, Research Department, Hydrology.
    Extremregn i nuvarande och framtida klimat Analyser av observationer och framtidsscenarier2018Report (Other academic)
    Abstract [sv]

    Studien har främst omfattat analyser av extrem korttidsnederbörd i observationer från SMHIs nät av automatiska meteorologiska stationer. Även analyser av korttidsnederbörd från kommunala mätare, manuella meteorologiska stationer, väderradar och klimatmodeller har genomförts. De huvudsakliga slutsatserna från detta uppdrag kan sammanfattas enligt följande.

    • En regionalisering av extrem korttidsnederbörd (skyfall) i Sverige gav fyra regioner: sydvästra (SV), sydöstra (SÖ), mellersta (M) och norra (N) Sverige. Ytterligare indelning kan göras men i denna studie prioriterades att ha regioner av denna storleksordning för att få ett ordentligt underlag för regional statistik. Regionaliseringen gäller enbart korttidsnederbörd, upp till maximalt 12 tim varaktighet.
    • Den regionala statistiken uppvisar tämligen distinkta geografiska skillnader, med högst värden i region SV och lägst i region N. Det är inte förvånande att vårt avlånga land uppvisar regionala skillnader då varmare och fuktigare luftmassor förekommer mer i söder än i norr, och därmed ökar förutsättningarna för intensiv nederbörd. Den regionala statistiken överensstämmer överlag väl med motsvarande statistik i våra grannländer.
    • Under perioden 1996-2017 finns inga tydliga tidsmässiga tendenser vad gäller skyfallens storlek och frekvens i de olika regionerna, utan dessa ligger överlag på en konstant nivå. Inte heller extrem dygnsnederbörd sedan 1900 uppvisar några tydliga tendenser på regional nivå. På nationell nivå indikeras en svag ökning av dels landets högsta årliga nederbörd sedan 1881, dels förekomsten av stora, utbredda 2-dygnsregn sedan 1961.
    • Skyfallsstatistik baserad på nederbördsobservationer från väderradar som justerats mot interpolerade stationsdata (HIPRAD) överensstämmer väl med stationsbaserad statistik för korta varaktigheter (upp till 2 tim) i södra Sverige. För längre varaktigheter och i mellersta och norra Sverige överskattar HIPRAD regnvolymerna.
    • Analyser av de senaste klimatmodellerna (Euro-CORDEX) indikerar en underskattning av extrema regnvolymer för korta varaktigheter (1 tim) men överlag en realistisk beskrivning av observerad skyfallsstatistik. Den framtida ökningen av volymerna beräknas ligga mellan 10% och 40% beroende på tidshorisont och koncentration av växthusgaser, vilket överlag ligger nära tidigare bedömningar.

    Både för bedömningen av regionala skillnader och historiska klimateffekter är det av största vikt att bibehålla, eller ännu hellre utöka, observationerna av korttidsnederbörd i Sverige. Nederbördsmätning via alternativa tekniker bör kunna användas i allt högre utsträckning framöver för förbättrad kunskap och statistik. Väderradar är redan etablerat och den digitala utvecklingen öppnar även möjligheter till insamling av nederbördsdata och relaterad information via mobilmaster, uppkopplade privata väderstationer, sociala medier, etc. Denna utveckling måste bevakas, utvärderas och i största möjliga utsträckning utnyttjas.

  • 144.
    Olsson, Jonas
    et al.
    SMHI, Research Department, Hydrology.
    Dahné, Joel
    SMHI, Professional Services.
    German, Jonas
    SMHI.
    Westergren, Bo
    Stockholm Vatten AB.
    von Scherling, Mathias
    Stockholm Vatten AB.
    Kjellson, Lena
    Stockholm Vatten AB.
    Olsson, Alf
    Sweco AB.
    En studie av framtida flödesbelastning på Stockholms huvudavloppssystem2011Report (Other academic)
    Abstract [en]

    This study was performed within the SWEdish research programme on Climate, Impacts and Adaptation (SWECIA), funded by the Foundation for Strategic Environmental Research (MISTRA), with additional funding from Stockholm Vatten AB. The aim of the study was to assess the discharge load on Stockholm's main sewer system during the rest of this century in light of both climate change and population increase. For this assessment, flow simulations with MIKE Urban were performed. Reference simulations for today's climate were done both for a representative year (1984) and for some 200 selected rainfall events between 1983 and 2007. In future simulations the climate effect was taken into account by rescaling input data (temperature, precipitation, evaporation) in line with climate model scenarios and the population effect by an increase in line with official estimations. The results indicate in particular that the spill volumes to Lake Mälaren and Saltsjön will increase substantially, but also an increased inflow to the treatment plant, and thus an increased need for treatment, and an increased flood risk.

  • 145.
    Olsson, Jonas
    et al.
    SMHI, Research Department, Hydrology.
    Graham, Phil
    SMHI, Professional Services.
    Rosberg, Jörgen
    SMHI, Research Department, Hydrology.
    Hellström, Sara-Sofia
    SMHI, Research Department, Hydrology.
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Berndtsson, Ronny
    Lund University, Department of Water Resources Engineering, .
    Simulation of Runoff in the Baltic Sea Drainage Basin During the Past Millennium2007Conference paper (Other academic)
  • 146.
    Olsson, Jonas
    et al.
    SMHI, Research Department, Hydrology.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Johnell, Anna
    SMHI, Professional Services.
    Jacobsson, Karin
    SMHI, Professional Services.
    Hydrologiska ensembleprognoser2006Report (Other academic)
    Abstract [en]

    Since July 2004, a system for hydrological ensemble forecasting has been operational at SMHI. The system uses meteorological ensemble forecasts of precipitation and temperature from ECMWF as input to the hydrological HBV model, which generates an ensemble of discharge forecasts. In this report, the hydrological ensemble prediction system (EPS) is firstly described, along with some general features of the forecasts. Some preparatory analyses of the ECMWF meteorological forecasts and spring flood EPS forecasts are made. The main part of the report is an evaluation of 18 months of 9-day hydrological ensemble forecasts in 45 Swedish catchments. In the deterministic evaluation, the EPS median forecast is compared with the categorical PMP forecast. The results indicate an overall similar performance of the two forecast types. It is also shown that the spread of the EPS forecasts is related to the forecast error. In the probabilistic evaluation, the accuracy of probabilities calculated from the EPS spread is investigated. A percentile-based evaluation shows that the spread is underestimated. A threshold-based evaluation shows that the probability of exceeding some high discharge threshold level is overestimated. Finally, a simple method to correct the EPS spread is developed and tested, and different ways to present EPS forecasts are discussed.

  • 147.
    Olsson, Jonas
    et al.
    SMHI, Research Department, Hydrology.
    Södling, Johan
    SMHI, Professional Services.
    Berg, Peter
    SMHI, Research Department, Hydrology.
    Wern, Lennart
    SMHI, Core Services.
    Eronn, Anna
    SMHI, Research Department, Climate research - Rossby Centre.
    Short-duration rainfall extremes in Sweden: a regional analysis2019In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 50, no 3, p. 945-960Article in journal (Refereed)
  • 148.
    Olsson, Jonas
    et al.
    SMHI, Research Department, Hydrology.
    Södling, Johan
    SMHI, Professional Services.
    Wetterhall, Fredrik
    SMHI, Research Department, Hydrology.
    Högupplösta nederbördsdata för hydrologisk modellering: en förstudie2013Report (Other academic)
    Abstract [en]

    Hydrological modeling at SMHI is generally done with a daily time step. However, today simulation and forecasting with a shorter time step is possible, through a spatially highly resolved hydrological model (S-HYPE) as well as high-resolution input data. In this preliminary study, different types of observation-based, high-resolution input data (mainly precipitation) have been invented, compiled and evaluated at different temporal and spatial scales: automatic stations, PTHBV, MESAN, radar data. A new product called PTHBV-radar has been developed by distributing the daily precipitation in PTHBV over the day using radar observations. The different types of data were tested in hydrological simulation by the HYPE model in a small catchment.For long accumulation times (year, month) PTHBV gives higher values than MESAN. Radar data have distinct artifacts, e.g. in the border between radars, but regional mean values agree with other sources. Concerning 1-h precipitation, the overall agreement with automatic station data is best in MESAN, followed by PTHBV-radar and radar. The spatial smoothing in MESAN however generates lower values of maximum intensities, in this respect PTHBV-radar and radar are closer to the station data.The hydrological 1-h simulations with MESAN and PTHBV-radar as input data improved performance evaluated on a daily basis, as compared with a reference simulation with PTHBV as input data. Using radar precipitation as input generated an overestimated discharge. The differences between 1-d and 1-h simulations were illustrated for single high flows and in terms of maximum daily values.

  • 149.
    Olsson, L-E
    et al.
    SMHI.
    Kindell, Sven
    SMHI, Professional Services.
    Air pollution impact assessment for the SABAH timber, pulp and paper complex1986Report (Other academic)
  • 150. Olusegun, Christiana Funmilola
    et al.
    Oguntunde, Philip G.
    Gbobaniyi, Bode
    SMHI, Research Department, Climate research - Rossby Centre. SMHI, Professional Services.
    Simulating the Impacts of Tree, C3, and C4 Plant Functional Types on the Future Climate of West Africa2018In: Climate, ISSN 2053-7565, E-ISSN 2225-1154, Vol. 6, no 2, article id 35Article in journal (Refereed)
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