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  • 51.
    Andersson, Kerstin
    SMHI, Samhälle och säkerhet.
    Vattenföring i Sverige. Del 3. Vattendrag till Egentliga Östersjön: Svenskt Vattenarkiv1993Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    En viktig uppgift för SMHI är att ge information om vattenföringen i Sveriges vattendrag. "Vattenföringen i Sveriges floder" utkom 1954. Den sammanställdes av Ragnar Melin och innehöll uppgifter tom är 1950. En ny utgåva, ''Vattenföring i Sverige", publicerades 1979. Den innehåller minst 10 år långa mätserier för de vattenföringsstationer som var i drift 1975 samt för vissa tidigare nedlagda stationer.

    Denna utgåva innehåller vattenföringsuppgifter t o m 1990 för de vattenföringsstationer som var i drift 1990 och som har en mätserie på minst 10 år.

    SMHI publicerar denna gång "Vattenföring i Sverige'' i fyra delar. Indelningen av Sverige är densamma som i "Arealer för avrinningsområden", som samtidigt är under utgivning. De olika delarna omfattar

    Del 1 vattendrag som mynnar i BottenvikenDel 2 vattendrag som mynnar i BottenhavetDel 3 vattendrag som mynnar i Egentliga ÖstersjönDel 4 vattendrag som mynnar i Västerhavet ( Öresund, Kattegatt, Skagerrak).

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  • 52.
    Andersson, Kerstin
    SMHI, Samhälle och säkerhet.
    Vattenföring i Sverige. Del 4. Vattendrag till Västerhavet: Svenskt Vattenarkiv1994Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    En viktig uppgift för SMH1 är att ge information om vattenföringen i Sveriges vattendrag. "Vattenföringen i Sveriges floder" utkom l954. Den sammanställdes av Ragnar Melin och innehöll uppgifter tom år 1950. En ny utgåva, "Vattenföring i Sverige", publicerades 1979. Den innehåller minst 10 är långa mätserier för de vattenföringsstationer som var i drift 1975 samt för vissa tidigare nedlagda stationer.Denna utgåva innehåller vattenföringsuppgifter tom 1990 för de vattenföringsstationer som var i drift 1990 och som har en rnätserie på minst 10 år.SMHI publicerar denna gäng ''Vattenföring i Sverige" i fyra delar. Indelningen av Sverige är densamma som i "Arealer för avrinningsområden'', som samtidigt är under utgivning.e olika delarna omfattarDel 1 vattendrag som mynnar i BottenvikenDel 2 vattendrag som mynnar i BottenhavetDel 3 vattendrag som mynnar i Egentliga ÖstersjönDel 4 vattendrag som mynnar i Västerhavet ( Öresund, Kattegatt, Skagerrak).

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  • 53.
    Andersson, Lars
    SMHI, Samhälle och säkerhet.
    Trends in nutrient and oxygen concentrations in the Skagerrak-Kattegat1996Ingår i: Journal of Sea Research, ISSN 1385-1101, E-ISSN 1873-1414, Vol. 35, nr 1-3, s. 63-71Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Skagerrak and Kattegat form a transition zone between the Baltic and the North Sea. Both areas are subject to increased nutrient loads. In this paper a non-parametric method is used to calculate the changes in nutrient and oxygen concentrations in the area. The period chosen was 1971 to 1990 and the parameters were dissolved inorganic nitrogen, phosphorus, silicate, total nitrogen and total phosphorus together with oxygen and oxygen saturation. Data have been sorted after salinity and the analyses have been carried out for different water masses and subareas. The results demonstrate that both surface and deep water in the Kattegat show increasing trends during winter for all nutrients except silicate. During summer there is an increase in total nitrogen and total phosphorus while silicate shows a decrease. In the Skagerrak the picture is more variable; in the eastern part, however, there is a clear increase for all inorganic nutrients during winter in the coastal water. Oxygen shows a declining trend in most areas.

  • 54.
    Andersson, Lars
    et al.
    SMHI, Samhälle och säkerhet.
    Carlberg, Stig
    SMHI, Samhälle och säkerhet.
    Fogelqvist, Elisabet
    SMHI.
    Fonselius, Stig
    SMHI, Forskningsavdelningen, Oceanografi.
    Fyrberg, Lotta
    SMHI, Samhälle och säkerhet.
    Palmén, Håkan
    SMHI.
    Zagradkin, Danuta
    SMHI.
    Yhlén, Bengt
    SMHI.
    Program för miljökvalitetsövervakning – PMK: Utsjöprogram under 19901991Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    ProjektI denna rapport beskrivs en verksamhet med miljöövervakning i de öppna havsområdena runt Sverige, från Kattegatt till nordligaste delen av  bottenhavet. SMHI utför arbetet på uppdrag av Naturvårdsverket, eftersom verksamheten ingår i det nationella programmet för övervakning av miljökvalitet - PMK. Större delen av resultaten överlämnas som ett svenskt bidrag till Helsingforskommissionens program för övervakning av Östersjöns marina miljö (BMP -Baltic Monitoring Programme).

    Övervakningen utförs genom att prover insamlas under regelbundna  expeditioner i Kattegatt, Öresund, Östersjön och Bottniska Viken. Fysikaliska, kemiska och biologiska parametrar bestäms i vattenprover, bottenfaunan studeras i sedimentprover och prover från fisk och mussla insamlas för bestämning av olika miljögifter.

    Arbetet utförs helt integrerat med den löpande oceanografiska verksamheten vid SMHI. Genom detta blir resultaten av SMHis eget undersökningsprogram tillgängliga för miljöövervakningen. Därför innehåller denna rapport betydligt mer information än vad PMK finansierar.

    ResultatVintern 1989-90 var mycket mild; det var faktiskt den fjärde osedvanligt milda vintern i rad. Utbredningen av havsis var liten i de svenska farvattnen. I stort sett var det bara Bottenviken som var istäckt och och detta istäcke bröt upp cirka två veckor tidigare än normalt.Början av 1990 var varm, blåsig och nederbördsrik, speciellt i sydsverige. Våren kom tidigt och var varmare än normalt. Från och med maj blev vädret instabilt och sommaren var sval och ostadig. Hösten var nederbördsrik men lugn, medan däremot december var blåsig och mild.

    Temperaturen i havsvattnet blev därför, liksom under 1989, högre än normalt under hela eller nästan hela året och mest märkbart under vinter- och höstmånaderna. Temperaturerna har inom hela havsområdet legat ca 1 - 3 °C högre än långtidsmedelvärdet för perioden 1979 - 89.

    Oxygenförhållandena i Kattegatt visade återigen en tillfällig nedgång i den sydöstra delen under sensommar och tidig höst. Trots att hösten var ovanligt lugn och omblandningen i vattenmassan relativt liten återgick oxygenhalterna till normala värden och någon riktigt utbredd oxygenbrist uppstod inte. I stora delar av Östersjön fortsatte dock de dåliga oxygenförhållandena i djupvattnet under hela året. Inte heller under 1990 inträffade något betydande inflöde av oxygenrikt vatten som kunde ventilera djupbassängerna.I Bornholmsbassängen fanns svavelväte i ett tunt skikt (med förgrening in i Hanöbukten) vid bottnen under hela året med undantag för augustiexpeditionen. I Gdanskbäckenet är skiktningen nu borta och inblandning av oxygen har kunnat ske från ytlagret, vilket haft en positiv effekt på bottenvattnet. I den östra Gotlandsbassängen är det nu mer än 13 år sedan det senast fanns oxygen i bottenvattnet. I motsats till detta har både norra centralbäckenet (med Landsortsdjupet) och djupområdet mellan Gotland och fastlandet varit helt fria från svavelväte under året.

    Närsalterna uppvisade inga ovanliga eller oväntade variationer under året. Under vinterperioden fanns fosfat och nitrat i ytvattnet i normala halter, som i samband med primärproduktionen under våren gick ned till låga eller knappt mätbara nivåer, för att sedan på nytt stiga under hösten.

    Analyserna av petroleumkolväten visar att halterna under våren 1990 var överlag något lägre än halterna under 1980-talet, vilket tyder på att belastningen med oljeföroreningar inte genomgått några påtagliga förändringar. Vid höstexpeditionen var halterna låga i ytan medan de på 10 m (och 30 m) djup var genomgående höga eller mycket höga inom hela havsområdet. Anledningen till detta har inte kunnat fastställas, men det torde inte röra sig om kontamination av proverna.

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  • 55.
    Andersson, Lars
    et al.
    SMHI, Samhälle och säkerhet.
    Rahm, Lars
    SMHI, Forskningsavdelningen, Oceanografi.
    THERMALLY DRIVEN CIRCULATION WITHIN AN EXPERIMENTAL ENCLOSURE1990Ingår i: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 30, nr 2, s. 111-129Artikel i tidskrift (Refereegranskat)
  • 56.
    Andersson, Lars
    et al.
    SMHI, Samhälle och säkerhet.
    RYDBERG, L
    EXCHANGE OF WATER AND NUTRIENTS BETWEEN THE SKAGERRAK AND THE KATTEGAT1993Ingår i: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 36, nr 2, s. 159-181Artikel i tidskrift (Refereegranskat)
  • 57.
    Andersson, Lotta
    SMHI, Samhälle och säkerhet.
    Experiences of the use of riverine nutrient models in stakeholder dialogues2004Ingår i: International Journal of Water Resources Development, ISSN 0790-0627, E-ISSN 1360-0648, Vol. 20, nr 3, s. 399-413Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The potential of models to assist in stakeholder dialogues is assessed regarding options for the reduction of riverine nitrogen loads in a 357-km(2) river basin in south central Sweden. Scenarios of remedies based on stakeholders' suggestions were used to stimulate discussions in a panel incorporating farmers, municipality staff, politicians and technical advisers. The farmers perceived the model-derived discussion material as valuable, although only average conditions at a generic farm were simulated. The panellists demonstrated caution when using regionalized information, but did not request quantitative uncertainty estimates. There was a desire to have phosphorus included in the model-derived discussion material and to include the impacts of other environmental goals than 'no eutrophication'. The inclusion of different stakeholder groups in the panel sessions was acknowledged as a way to establish a shared perception of the existing environmental status of the basin and to define the pros and cons of various remedies. This was seen by the panellists as a way to facilitate local implementation of the Water Framework Directive (WFD). Use of model-stimulated local stakeholder panels is also a way to ensure that involved stakeholders perceive local environmental goals as realistic and acceptable. However, to establish river-basin stakeholder dialogues as part of the nation-wide implementation of the WFD directive, it will be necessary to develop a model approach that can be used by local advisers. Perhaps the most critical factor is the moderators' ability to provide an atmosphere of mutual respect between all those involved in contrast to performing one-way lectures to the participants.

  • 58.
    Andersson, Lotta
    et al.
    SMHI, Samhälle och säkerhet.
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Consequences of changed wetness on riverine nitrogen - human impact on retention vs. natural climatic variability2001Ingår i: Regional Environmental Change, ISSN 1436-3798, E-ISSN 1436-378X, Vol. 2, nr 3, s. 93-105Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The HBV-N model was used for a scenario analysis of changes in nitrogen retention and transport caused by alterations of wetness due to land drainage, lowering of lakes, building of dams and climatic variability in a river basin in south-central Sweden (1885-1994). In general, dams were situated in locations more favourable for retention, compared to the lowered lakes. Rather modest conversions of water bodies only changed nitrogen transport by about 3%. The 180-times-larger increase of (mainly) tile-drained agricultural land had, according to simulations, increased the nitrogen transport by 17%, due to reduced retention. However, compared to human-induced alteration of the landscape N retention, the choice of 10-year periods of climatological data had the overriding effect on the calculated nitrogen transport. Weather-induced variations resulted in a 13% difference in nitrogen retention between various 10-year periods. When the model was driven by climatological data from the driest 10-year period (1905-1914), the estimated average annual load was only half of that obtained with climatological data from the wettest 10-year period (1975-1984).

  • 59.
    Andersson, Lotta
    et al.
    SMHI, Samhälle och säkerhet.
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Modelling of human and climatic impact on nitrogen load in a Swedish river 1885-19942003Ingår i: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 497, nr 1-3, s. 63-77Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Changes in environmental conditions within a river basin in South Central Sweden (1400 km(2)) and impacts on riverine nitrogen (N) transport were evaluated. A historical database was compiled and the process-based HBV-N model used to estimate flow normalised N loads in 1885, 1905, 1927, 1956, 1976, and 1994, using a standard climatological record (1985-1994). The study shows the value of process-based modelling in environmental impact assessment, by making it possible to assess and integrate the effect of a number of factors, both with regard to human impact and natural climatic variability. Factors taken into account include: the effects of land use, agricultural practices, atmospheric deposition, human dietary intake, use of flush toilets, lowering of lakes, building of dams, and climatic variability. For all years studied, agriculture was the overriding source of N, and changes in riverine N over time mainly reflected changes in land use and agricultural practices. In spite of decreasing N-leaching from agriculture, the net load remained fairly constant between 1885 and 1927, due to reduced N retention. Drainage of agricultural land had a dominating impact on reducing N retention, which increased the N loads, while the effects of the lowering of lake levels and dam building were less pronounced. Household N emission per capita was higher in 1994 than in 1927, as the increased consumption of meat and dairy products alone resulted in a higher increase of the emission than was compensated for with wastewater treatment improvement. In addition, introduction of flush toilets increased the emission from households. In total, the net load in 1976 was twofold higher than that in 1885, 1905 and 1927, due to increased leaching from agriculture, wastewater emission, and atmospheric deposition on lake surfaces. Finally, the impact of climatological variability was assessed, using a 110-yr climatological record. The choice of 10-yr period of climatological data was the factor that had the largest impact on calculated N load.

  • 60.
    Andersson, Lotta
    et al.
    SMHI, Samhälle och säkerhet.
    Bonell, M
    Moody, D W
    Special thematic issue: Hydrology for the environment. life and policy (Help) Programme - Foreword2004Ingår i: International Journal of Water Resources Development, ISSN 0790-0627, E-ISSN 1360-0648, Vol. 20, nr 3, s. 267-274Artikel i tidskrift (Övrigt vetenskapligt)
  • 61.
    Andersson, Lotta
    et al.
    SMHI, Samhälle och säkerhet.
    Olsson, Johanna Alkan
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Jonsson, Anna
    Use of participatory scenario modelling as platforms in stakeholder dialogues2008Ingår i: Water S.A., ISSN 0378-4738, E-ISSN 1816-7950, Vol. 34, nr 4, s. 439-447Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A participatory methodology, based on dialogues between stakeholders and experts has been developed and tested in the drainage area to Kaggebo Bay in the Baltic Sea. This study is focused on the EU Water Framework Directive, with emphasis on reduction of eutrophication. The drainage area is included in the WFD administrative area of the Motala Strom River basin. A similar approach is now applied in a recently initiated project in the Thukela River basin, with focus on impacts of climate change on water resources. The methodology is based on the idea that a catchment model serves as a platform for the establishment of a common view of present conditions and the causes behind these conditions. In the following steps, this is followed by model-assisted agreement on environmental goals (i.e. what do we want the future to look like?) and local agreement on a remedy or mitigation plans in order to reduce environmental impact (e. g. eutrophication); alternatively to adapt to conditions that cannot be determined by local actions (e. g. climate change). By involving stakeholder groups in this model-supported stepwise process, it is ensured that all stakeholder groups involved have a high degree of confidence in the presented model results, and thereby enable various actors involved to share a common view, regarding both present conditions, goals and the way to reach these goals. Although this is a process that is time-(and cost-) consuming, it is hypothesised that the use of this methodology is two-pronged: it increases the willingness to carry out remedies or necessary adaptations to a changing environment, and it increases the level of understanding between the various groups and therefore ameliorates the potential for future conflicts. Compared to traditional use of model results in environmental decision-making, the experts' role is transformed from a one-way communication of final results to assistance in the various steps of the participatory process.

  • 62.
    Andersson, Lotta
    et al.
    SMHI, Samhälle och säkerhet.
    Rosberg, Jörgen
    SMHI, Forskningsavdelningen, Hydrologi.
    Pers, Charlotta
    SMHI, Forskningsavdelningen, Hydrologi.
    Olsson, Jonas
    SMHI, Forskningsavdelningen, Hydrologi.
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Estimating catchment nutrient flow with the HBV-NP model: Sensitivity to input data2005Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 34, nr 7, s. 521-532Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamic catchment model HBV-N has been further developed by adding routines for phosphorus transport and is now called the HBV-NP model. The model was shown to satisfactorily simulate nutrient dynamics in the Ronnea catchment (1 900 km(2)). Its sensitivity to input data was tested, and results demonstrated the increased sensitivity to the selection of input data on a subcatchment scale when compared with the catchment scale. Selection of soil and land use databases was found to be critical in some subcatchments but did not have a significant impact on a catchment scale. Although acceptable on a catchment scale, using templates and generalization, with regards to emissions from point sources and rural households, significantly decreased model performance in certain subcatchments when compared with using more detailed local information. A division into 64 subcatchments resulted in similar model performance at the catchment outlet when compared with a lumped approach. Adjusting the imported matrixes of the regional leaching of nitrogen, from agricultural land, against mean subcatchment water percolation did not have a significant impact on the model performance.

  • 63.
    Andersson, Lotta
    et al.
    SMHI, Samhälle och säkerhet.
    Wilk, Julie
    Graham, Phil
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Warburton, Michele
    Design and test of a model-assisted participatory process for the formulation of a local climate adaptation plan2013Ingår i: Climate and Development, ISSN 1756-5529, E-ISSN 1756-5537, Vol. 5, nr 3, s. 217-228Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article presents the design and testing of a model-assisted participatory process for the formulation of a local adaptation plan to climate change. The pilot study focused on small-scale and commercial agriculture, water supply, housing, wildlife, livestock and biodiversity in the Thukela River basin, KwaZulu-Natal, South Africa. The methodology was based on stakeholders identifying and ranking the severity of climate-related challenges, and downscaled stakeholder-identified information provided by modellers, with the aim of addressing possible changes of exposure in the future. The methodology enables the integration of model-based information with experience and visions based on local realities. It includes stakeholders' own assessments of their vulnerability to prevailing climate variability and the severity, if specified, of climate-related problems that may occur more often in the future. The methodology made it possible to identify the main issues to focus on in the adaptation plan, including barriers to adaptation. We make recommendations for how to design a model-assisted participatory process, emphasizing the need for transparency, to recognize the interests of the stakeholders, good advance planning, local relevance, involvement of local champions, and adaptation of Information material to each group's previous experience and understanding.

  • 64.
    Andersson, Lotta
    et al.
    SMHI, Samhälle och säkerhet.
    Wilk, Julie
    Todd, Martin C.
    Hughes, Denis A.
    Earle, Anton
    Kniveton, Dominic
    Layberry, Russet
    Savenije, Hubert H. G.
    Impact of climate change and development scenarios on flow patterns in the Okavango River2006Ingår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 331, nr 1-2, s. 43-57Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper lays the foundation for the use of scenario modelling as a tool for integrated water resource management in the Okavango River basin. The Pitman hydrological model is used to assess the impact of various development and climate change scenarios on downstream river flow. The simulated impact on modelled river discharge of increased water use for domestic use, livestock, and informal irrigation (proportional to expected population increase) is very limited. Implementation of all likely potential formal irrigation schemes mentioned in available reports is expected to decrease the annual flow by 2% and the minimum monthly flow by 5%. The maximum possible impact of irrigation on annual average flow is estimated as 8%, with a reduction of minimum monthly flow by 17%. Deforestation of all areas within a 1 km buffer around the rivers is estimated to increase the flow by 6%. However, construction of all potential hydropower reservoirs in the basin may change the monthly mean flow distribution dramatically, although under the assumed operational rules, the impact of the dams is only substantial during wet years. The simulated impacts of climate change are considerable larger that those of the development scenarios (with exception of the high development scenario of hydropower schemes) although the results are sensitive to the choice of GCM and the IPCC SRES greenhouse gas (GHG) emission scenarios. The annual mean water flow predictions for the period 2020-2050 averaged over scenarios from all the four GCMs used in this study are close to the present situation for both the A2 and B2 GHG scenarios. For the 2050-2080 and 2070-2099 periods the all-GCM mean shows a flow decrease of 20% (14%) and 26% (17%), respectively, for the A2 (B2) GHG scenarios. However, the uncertainty in the magnitude of simulated future changes remains high. The simulated effect of climate change on minimum monthly flow is proportionally higher than the impact on the annual mean flow. (c) 2006 Elsevier B.V. All rights reserved.

  • 65.
    Andersson, Pia
    et al.
    SMHI, Samhälle och säkerhet.
    Hansson, Martin
    SMHI, Samhälle och säkerhet.
    Bjurström, Joel
    Simonsson, Daniel
    Naturtypsbestämning av miljöövervakningsstationer SMHI pelagial miljöövervakning2017Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Provtagningsstationerna i den nationella miljöövervakningen i havsmiljö är inte naturtypsbestämda. Detta innebär att insamlad miljöövervakningsdata inte kan användas fullt ut till bedömningar för artikel 17, art- och habitatdirektivet, samt för havsmiljödirektivet.  HaV har finansierat och uppdragit åt SMHI att undersöka möjligheterna att på ett enkelt sätt naturtypsklassa de månatliga miljöövervakningsstationerna som SMHI provtar. Uppdraget avsåg att testa utrustning och med hjälp av dropvideo undersöka om det är möjligt att, och i så fall, naturtypsbestämma stationer i utsjön under decemberexpeditionen 2016.  SMHI har konstruerat en rigg och utfört provtagning på 11 av 25 miljöövervakningsstationer. Belysningsproblematik och väder reducerade antalet provtagna stationer. SMHI anser att riggen, med justerad ljuskälla, är ett bra verktyg för visuell registrering av naturtyp på miljöövervakningsstationerna i utsjön.  Dock föreslås ett antal justeringar av riggen för att öka kvalitén på bildmaterialet samt att öka möjligheten att utföra ytterligare bedömningar av bildmaterialet.  Merparten av de undersökta bottnarna visar på väldigt finkornigt materiel, likt silt/lera. Ett fåtal arter har registrerats och ingen större mängd växtlighet. Merparten av de undersökta stationerna uppfyllde inte kriteriet för någon av habitatdirektivets naturtyper. På två stationer har naturtyp registreras som 1160 Vikar och sund, innehållandes1110 Sandbankar. För HUB Underwater biotopes har AB.H3O Baltic aphotic muddy sediment characterized by infaunal echinoderms registrerats på stationen P2 och AB.M4U Baltic aphotic mixed substrate characterized by no macrocommunity på stationerna BY5 och BY4.  SMHI rekommenderar en genomgång av det insamlade materialet med ArtDatabanken och/eller ytterligare expert för att säkerställa bedömning, utföra vissa rekommendationer samt säkerställa material som ska rapporteras till datavärd.SMHI rekommenderar ytterligare visuell provtagning på resterande stationer, samt kompletterande provtagning på stationer där kvalité på bild eller ljus varit bristfällig, eller där ArtDatabanken eller möjlig ytterligare expert rekommenderar ytterligare provtagning. Ytterligare expert kan komma att rekommendera hugg som kompletterande provtagning till den visuella metoden.En visuell undersökning på samtliga 25 stationer, med en landning per station, uppskattas förlänga en expedition med ca 11,5-13,5 timmar. 

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  • 66.
    Andreasson, Arnold
    et al.
    Arnold Andreasson Konsult AB.
    Strömberg, Patrik
    SMHI, Samhälle och säkerhet.
    Prager, Maria
    SMHI, Samhälle och säkerhet.
    Nexelius, Nils
    SMHI, Samhälle och säkerhet.
    Automatisering av nationellt dataflöde till ICES genom skördning - en förstudie2016Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    SMHI är, på uppdrag av Havs- och vattenmyndigheten (HaV), datavärd för svenska marina miljöövervakningsdata. En central del i uppdraget är att årligen rapportera nationellt insamlad data till nternationella Havsforskningsrådet, ICES.

    För biologiska data sker en årlig rapportering av data levererade från föregående års övervakning. Leveranserna sker på ett format definierat av ICES. Leveransernas innehåll valideras av SMHI mot ICES valideringstjänst DATSU via uppladdning till en webbsida. När samtliga fel är rättade skickas leveranserna till ICES via e-post.

    SMHI har fått ett uppdrag från HaV att utreda om det finns en möjlighet att låta ICES skörda data som ersättning för den nuvarande hanteringen med manuella leveranser. ICES har också ett intresse av att utreda om skördning av data är en lämplig metod för framtida inhämtande av data. ICES vill även testa möjligheterna att byta leveransformat till ett nytt XML-baserat format.

    SMHI föreslår en lösning där SMHI:s tjänst för maskin-maskin-kommunikation, SHARKdata, används. SHARKdata kommer att utökas för att kunna generera exportpaket i enlighet med ICES nya XML-baserade format. ICES har även kompletterat sin valideringstjänst DATSU med ett gränssnitt för maskin-maskinkommunikation så att man med automatik kan anropa DATSU och validera exportpaket. En prototyp har utvecklats för att visa hur SHARKdata kan användas för denna typ av hantering med skördning. I prototypen ingår även konvertering till en inledande testversion av XML-formatet för datatypen Zoobenthos.

    Det fortsatta projektet efter denna förstudie planeras som ett samarbete mellan SMHI och ICES. SMHI utvecklar fortlöpande SHARKdata i takt med att ICES släpper specifikationer på format för nya datatyper, parallellt med att data rapporteras på nuvarande sätt. Detta arbete beräknas pågå under 2016 och 2017, med varierande intensitet. Efter denna test- och utvecklingsperiod antas ICES släppa en ny version av sitt rapporteringformat och då kan SMHI gå över till det nya rapporteringssättet.

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  • 67.
    Andréasson, Johan
    et al.
    SMHI, Affärsverksamhet.
    Bergström, Sten
    SMHI, Forskningsavdelningen, Hydrologi.
    Carlsson, Bengt
    SMHI, Forskningsavdelningen, Hydrologi.
    Graham, Phil
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Hydrological change - Climate change impact simulations for Sweden2004Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 33, nr 4-5, s. 228-234Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Climate change resulting from the enhanced greenhouse effect is expected to give rise to changes in hydrological systems. This hydrological change, as with the change in climate variables, will vary regionally around the globe. Impact studies at local and regional scales are needed to assess how different regions will be affected. This study focuses on assessment of hydrological impacts of climate change over a wide range of Swedish basins. Different methods of transferring the signal of climate change from climate models to hydrological models were used. Several hydrological model simulations using regional climate model scenarios from Swedish Regional Climate Modelling Programme (SWECLIM) are presented. A principal conclusion is that subregional impacts to river flow vary considerably according to whether a basin is in northern or southern Sweden. Furthermore, projected hydrological change is just as dependent on the choice of the global climate model used for regional climate model boundary conditions as the choice of anthropogenic emissions scenario.

  • 68. Archfield, Stacey A.
    et al.
    Clark, Martyn
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Hay, Lauren E.
    McMillan, Hilary
    Kiang, Julie E.
    Seibert, Jan
    Hakala, Kirsti
    Bock, Andrew
    Wagener, Thorsten
    Farmer, William H.
    Andreassian, Vazken
    Attinger, Sabine
    Viglione, Alberto
    Knight, Rodney
    Markstrom, Steven
    Over, Thomas
    Accelerating advances in continental domain hydrologic modeling2015Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 51, nr 12, s. 10078-10091Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the past, hydrologic modeling of surface water resources has mainly focused on simulating the hydrologic cycle at local to regional catchment modeling domains. There now exists a level of maturity among the catchment, global water security, and land surface modeling communities such that these communities are converging toward continental domain hydrologic models. This commentary, written from a catchment hydrology community perspective, provides a review of progress in each community toward this achievement, identifies common challenges the communities face, and details immediate and specific areas in which these communities can mutually benefit one another from the convergence of their research perspectives. Those include: (1) creating new incentives and infrastructure to report and share model inputs, outputs, and parameters in data services and open access, machine-independent formats for model replication or reanalysis; (2) ensuring that hydrologic models have: sufficient complexity to represent the dominant physical processes and adequate representation of anthropogenic impacts on the terrestrial water cycle, a process-based approach to model parameter estimation, and appropriate parameterizations to represent large-scale fluxes and scaling behavior; (3) maintaining a balance between model complexity and data availability as well as uncertainties; and (4) quantifying and communicating significant advancements toward these modeling goals.

  • 69.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Andersson, Lotta
    SMHI, Samhälle och säkerhet.
    Alkan-Olsson, J.
    Jonsson, A.
    Using catchment models to establish measure plans according to the Water Framework Directive2007Ingår i: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 56, nr 1, s. 21-28Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A participatory modelling process (DEMO) has been developed and applied in a 350 km(2) catchment in southern Sweden. The overall goal is to improve the dialogues between experts and local stakeholders by using numerical models as a platform for discussions. The study is focused on reducing nutrient load and on the development of a locally established measure plan, which is requested by the European Water Framework Directive. The HBV-NP model was chosen as it can calculate effects and costs for different allocations of several combined measures in a catchment. This paper shows the impact of including local data in the modelling process vs. using more general data. It was found that modelled diffuse nutrient pollution was highly modified when including local know-how, soft information and more detailed field investigations. Leaching from arable land was found to be 35% higher using more detailed information on for instance, agricultural practices, crop and soil distribution. Moreover, the stakeholders' acceptance of model results and reliance on experts was increased by applying the participatory process and involving stakeholders in the modelling procedure.

  • 70.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Andersson, Lotta
    SMHI, Samhälle och säkerhet.
    Larsson, M
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Olsson, Jonas
    SMHI, Forskningsavdelningen, Hydrologi.
    Pers, Charlotta
    SMHI, Forskningsavdelningen, Hydrologi.
    Modelling diffuse nutrient flow in eutrophication control scenarios2004Ingår i: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 49, nr 3, s. 37-45Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Swedish Water Management Research Programme (VASTRA) focuses on the development and demonstration of tools for more efficient eutrophication control when implementing the EU water framework directive in Sweden. During the first half of the programme, models for nitrogen flow were developed, and at present, similar models for phosphorus are under construction (e.g. HBV-P). The programme is interdisciplinary, and scientists are collaborating in actor-games and focus group evaluations including scenario analysis. The scenarios modelled in VASTRA phase 1, show that (i) changed agricultural practices can be the most effective and-least expensive way to reduce nitrogen transport from land to, the sea; (ii) constructed agricultural wetlands may only have small impact on riverine nitrogen transport in some regions, due to natural hydrometeorological dynamics; (iii) removing planktivorous fish may be an efficient way of reducing the algal concentrations in lakes without the undesired side-effect of increased nutrient load to the down-stream river system. In VASTRA phase 11, one of the highlights will be interdisciplinary scenario-modelling of different measure strategies in a pilot catchment of southern Sweden (Ronne a).

  • 71.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Andreasson, Johan
    SMHI, Affärsverksamhet.
    Fogelberg, S
    Johnsson, H
    Pers, Charlotta
    SMHI, Forskningsavdelningen, Hydrologi.
    Persson, K
    Climate change impact on water quality: Model results from southern Sweden2005Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 34, nr 7, s. 559-566Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Starting from six regional climate change scenarios, nitrogen leaching from arable-soil, water discharge, and nitrogen retention was modeled in the Ronnea catchment. Additionally, biological response was modeled in the eutrophic Lake Ringsjon. The results are compared with similar studies on other catchments. All scenarios gave similar impact on water quality but varied in quantities. However, one scenario resulted in a different transport pattern due to less-pronounced seasonal variations in the hydrology. On average, the study shows that, in a future climate, we might expect: i) increased concentrations of nitrogen in the arable root zone (+50%) and in the river (+13%); ii) increased annual load of nitrogen from land to sea (+22%) due to more pronounced winter high flow; moreover, remote areas in the catchment may start to contribute to the outlet load; iii) radical changes in lake biochemistry with increased concentrations of total phosphorus (+50%), total nitrogen (+20%), and planktonic algae such as cyanobacteria (+80%).

  • 72.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Brandt, Maja
    SMHI, Forskningsavdelningen, Hydrologi.
    Modelling nitrogen transport and retention in the catchments of southern Sweden1998Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 27, nr 6, s. 471-480Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Baltic Sea is suffering from eutrophication and attempts are being made to reduce nutrient loads. This article focuses on nitrogen transport from southern Sweden (145 000 km(2)), and presents a model approach (HBV-N) that has been used in the national decision-making process for best management practices. Calculations of nitrogen leaching, retention in the freshwater system, net transport to the sea, and source apportionment are presented for the period 1985-1994. Input data were handled in GIS, including results from SOIL-N and MATCH. Daily simulations were made in 3725 subbasins with calibration against measured time series at 722 sites. Diffuse source pollution was normally retained by 10-25% before entering the river network. Lakes normally reduced nitrogen transport by 30-40 kg ha(-1) yr(-1) of lake area. On average, 45% of the annual gross load was reduced during transport, but temporal and spatial variations were great. 75 000 tonnes N yr(-1) reached the sea.

  • 73.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Brandt, Maja
    SMHI, Forskningsavdelningen, Hydrologi.
    Watershed modelling of nonpoint nitrogen losses from arable land to the Swedish coast in 1985 and 19942000Ingår i: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 14, nr 4, s. 389-404Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Eutrophication problems in the Baltic Sea have drawn attention to the contribution of nutrients from surrounding countries. By using the HBV-N model in southern Sweden (145 000 km(2)) daily nitrogen leaching, reduction in rivers and lakes, net transport to the sea and source apportionment have been calculated in 3725 subbasins for the period 1985-1994, with calibration at 722 sites against measured time series. On average, 48% of the nonpoint losses from agriculture were reduced during the transport towards the sea, which left about 33 500 tonnes in annual mean net transport. This represents 45% of the total land-based load. Land cover and emissions for the years of 1985 and 1994 were used in two separate simulations of the 10-year period. The normalized gross leakage from arable land in 1985 was estimated to 29 kg N ha(-1) year(-1), which corresponds to 15 kg N ha(-1) year(-1) in net leakage to the sea. In 1994 these transports were reduced by 20 and 15%, and thereby the total load on the sea was decreased by 7%. This is still far from the Swedish goal of 50% reduction. The article presents the spatial variation of nitrogen leakage and retention within the southern half of Sweden, and emphasizes the importance of allocating measures where down-stream retention is low in order to achieve efficiency with respect to the sea. It is shown that the model approach may be used in the decision making process for best management practices in watersheds. (C) 2000 Elsevier Science B.V. All rights reserved.

  • 74.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Dahne, Joel
    SMHI, Affärsverksamhet.
    Donnelly, Chantal
    SMHI, Forskningsavdelningen, Hydrologi.
    Climate Change Impact on Riverine Nutrient Load and Land-Based Remedial Measures of the Baltic Sea Action Plan2012Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, nr 6, s. 600-612Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To reduce eutrophication of the Baltic Sea, all nine surrounding countries have agreed upon reduction targets in the HELCOM Baltic Sea Action Plan (BSAP). Yet, monitoring sites and model concepts for decision support are few. To provide one more tool for analysis of water and nutrient fluxes in the Baltic Sea basin, the HYPE model has been applied to the region (called Balt-HYPE). It was used here for experimenting with land-based remedial measures and future climate projections to quantify the impacts of these on water and nutrient loads to the sea. The results suggest that there is a possibility to reach the BSAP nutrient reduction targets by 2100, and that climate change may both aggravate and help in some aspects. Uncertainties in the model results are large, mainly due to the spread of the climate model projections, but also due to the hydrological model.

  • 75.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Dahne, Joel
    SMHI, Affärsverksamhet.
    Donnelly, Chantal
    SMHI, Forskningsavdelningen, Hydrologi.
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Strömqvist, Johan
    SMHI, Forskningsavdelningen, Hydrologi.
    Water and nutrient simulations using the HYPE model for Sweden vs. the Baltic Sea basin - influence of input-data quality and scale2012Ingår i: HYDROLOGY RESEARCH, ISSN 1998-9563, Vol. 43, nr 4, s. 315-329Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Water resource management is often based on numerical models, and large-scale models are sometimes used for international strategic agreements. Sometimes the modelled area entails several political entities and river basins. To avoid methodological bias in results, methods and databases should be homogenous across political and geophysical boundaries, but this may involve fewer details and more assumptions. This paper quantifies the uncertainty when the same model code is applied using two different input datasets; a more detailed one for the country of Sweden (S-HYPE) and a more general one for the entire Baltic Sea basin (Balt-HYPE). Results from the two model applications were compared for the Swedish landmass and for two specific Swedish river basins. The results show that both model applications may be useful in providing spatial information of water and nutrients at various scales. For water discharge, most relative errors are <10% for S-HYPE and <25% for Balt-HYPE. Both applications reproduced the most mean concentration for nitrogen within 25% of the observed mean values, but phosphorus showed a larger scatter. Differences in model set-up were reflected in the simulation of both spatial and temporal dynamics. The most sensitive data were precipitation/temperature, agriculture and model parameter values.

  • 76.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Donnelly, Chantal
    SMHI, Forskningsavdelningen, Hydrologi.
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Regulation of snow-fed rivers affects flow regimes more than climate change2017Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, artikel-id 62Artikel i tidskrift (Refereegranskat)
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  • 77.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Hjerdt, Niclas
    SMHI, Samhälle och säkerhet.
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Artificially Induced Floods to Manage Forest Habitats Under Climate Change2018Ingår i: FRONTIERS IN ENVIRONMENTAL SCIENCE, ISSN 2296-665X, Vol. 6, artikel-id 102Artikel i tidskrift (Refereegranskat)
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  • 78.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Lidén, R.
    SMHI.
    Nitrogen and phosphorus concentrations from agricultural catchments - influence of spatial and temporal variables2000Ingår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 227, nr 1-4, s. 140-159Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The eutrophication problem has drawn attention to nutrient leaching from arable land in southern Sweden, and further understanding of spatial and temporal variability is needed in order to develop decision-making tools. Thus, the influence of spatial and temporal variables was analysed statistically using empirical time series of different nutrient species from 35 well-documented catchments (2-35 km(2)), which have been monitored for an average of 5 years. In the spatial analysis several significant correlations between winter median concentrations and catchment characteristics were found. The strongest correlation was found between inorganic nitrogen and land use, while concentrations of different phosphorus species were highly correlated to soil texture. Multiple linear regression models gave satisfactory results for prediction of median winter concentrations in unmeasured catchments, especially for inorganic nitrogen and phosphate. In the analysis of temporal variability within catchments, internal variables from a dynamic hydrological model (HBV) were linked to concentration fluxes. It was found that phosphorus and inorganic nitrogen concentrations were elevated during flow increase at low-Bow conditions, while they were diluted as the wetness in the catchment increased. During unmonitored periods regression models were successful in predicting temporal variability of total phosphorus, phosphate and inorganic nitrogen, while organic nitrogen and particulate phosphorus could not be predicted with this approach. Dividing the data into different flow categories did not improve the prediction of nutrient concentration dynamics. The results and literature review presented, confirm parts of the present HBV-W model approach and will be useful for further development of nutrient routines linked to dynamic hydrological models. (C) 2000 Elsevier Science B.V. All rights reserved.

  • 79.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Climate impact on floods: changes in high flows in Sweden in the past and the future (1911-2100)2015Ingår i: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 19, nr 2, s. 771-784Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is an ongoing discussion whether floods occur more frequently today than in the past, and whether they will increase in number and magnitude in the future. To explore this issue in Sweden, we merged observed time series for the past century from 69 gauging sites throughout the country (450 000 km(2)) with high-resolution dynamic model projections of the upcoming century. The results show that the changes in annual maximum daily flows in Sweden oscillate between dry and wet periods but exhibit no significant trend over the past 100 years. Temperature was found to be the strongest climate driver of changes in river high flows, which are related primarily to snowmelt in Sweden. Annual daily high flows may decrease by on average -1% per decade in the future, mainly due to lower peaks from snowmelt in the spring (-2% per decade) as a result of higher temperatures and a shorter snow season. In contrast, autumn flows may increase by + 3% per decade due to more intense rainfall. This indicates a shift in floodgenerating processes in the future, with greater influence of rain-fed floods. Changes in climate may have a more significant impact on some specific rivers than on the average for the whole country. Our results suggest that the temporal pattern in future daily high flow in some catchments will shift in time, with spring floods in the northern-central part of Sweden occurring about 1 month earlier than today. High flows in the southern part of the country may become more frequent. Moreover, the current boundary between snow-driven floods in northern-central Sweden and rain-driven floods in the south may move toward higher latitudes due to less snow accumulation in the south and at low altitudes. The findings also indicate a tendency in observations toward the modeled projections for timing of daily high flows over the last 25 years. Uncertainties related to both the observed data and the complex model chain of climate impact assessments in hydrology are discussed.

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  • 80.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Detecting Changes in River Flow Caused by Wildfires, Storms, Urbanization, Regulation, and Climate Across Sweden2019Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973Artikel i tidskrift (Refereegranskat)
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  • 81.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Olsson, Jonas
    SMHI, Forskningsavdelningen, Hydrologi.
    A systematic review of sensitivities in the Swedish flood-forecasting system2011Ingår i: Atmospheric research, ISSN 0169-8095, E-ISSN 1873-2895, Vol. 100, nr 2-3, s. 275-284Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Since the early 1970s operational flood forecasts in Sweden have been based on the hydrological HBV model. However, the model is only one component in a chain of processes for production of hydrological forecasts. During the last 35 years there has been considerable work on improving different parts of the forecast procedure and results from specific studies have been reported frequently. Yet, the results have not been compared in any overall assessment of potential for improvements. Therefore we formulated and applied a method for translating results from different studies to a common criterion of error reduction. The aim was to quantify potential improvements in a systems perspective and to identify in which part of the production chain efforts would result in significantly better forecasts. The most sensitive (> 20% error reduction) components were identified for three different operational-forecast types. From the analyses of historical efforts to minimise the errors in the Swedish flood-forecasting system, it was concluded that 1) general runoff simulations and predictions could be significantly improved by model structure and calibration, model equations (e.g. evapotranspiration expression), and new precipitation input using radar data as a complement to station gauges; 2) annual spring-flood forecasts could be significantly improved by better seasonal meteorological forecast, fresh re-calibration of the hydrological model based on long time-series, and data assimilation of snow-pack measurements using georadar or gamma-ray technique; 3) short-term (2 days) forecasts could be significantly improved by up-dating using an auto-regressive method for discharge, and by ensembles of meteorological forecasts using the median at occasions when the deterministic forecast is out of the ensemble range. The study emphasises the importance of continuously evaluating the entire production chain to search for potential improvements of hydrological forecasts in the operational environment. (C) 2010 Elsevier B.V. All rights reserved.

  • 82.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Lowgren, M
    Pers, Charlotta
    SMHI, Forskningsavdelningen, Hydrologi.
    Rosberg, Jörgen
    SMHI, Forskningsavdelningen, Hydrologi.
    Integrated catchment modeling for nutrient reduction: Scenarios showing impacts, potential, and cost of measures2005Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 34, nr 7, s. 513-520Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A hydrological-based model (HBV-NP) was applied to a catchment (1900 km(2)) in the southern part of Sweden. Careful characterization of the present load situation and the potential for improved treatment or reduced soil leaching were analyzed. Several scenarios were modeled to find strategies to reach the Swedish environmental goals of reducing anthropogenic nitrogen load by 30% and phosphorus load by 20%. It was stated that the goals could be reached by different approaches that would affect different polluters and social sectors. However, no single measure was enough by itself. Instead, a combination of measures was necessary to achieve the goals. The nitrogen goal was the most difficult to attain. In order to be cost-effective, these measures should be applied to areas contributing the most to the net loading of the sea. This strategy could reduce the costs by 70%-80% when compared with implementing the measures in the entire catchment. Integrated catchment models may thus be helpful tools for reducing costs in environmental control programs.

  • 83.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Nilsson, Johanna
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Experimenting with Coupled Hydro-Ecological Models to Explore Measure Plans and Water Quality Goals in a Semi-Enclosed Swedish Bay2015Ingår i: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 7, nr 7, s. 3906-3924Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Measure plans are currently being developed for the Water Framework Directive (WFD) by European water authorities. In Sweden, such plans include measures for good ecological status in the coastal ecosystem. However, the effect of suggested measures is not yet known. We therefore experimented with different nutrient reduction measures on land and in the sea, using a model system of two coupled dynamic models for a semi-enclosed bay and its catchment. The science question was whether it is worthwhile to implement measures in the local catchment area to reach local environmental goals, or if the status of the Bay is more governed by the water exchange with the Sea. The results indicate that by combining several measures in the catchment, the nutrient load can be reduced by 15%-20%. To reach the same effect on nutrient concentrations in the Bay, the concentrations of the sea must be reduced by 80%. Hence, in this case, local measures have a stronger impact on coastal water quality. The experiment also show that the present targets for good ecological status set up by the Swedish water authorities may be unrealistic for this Bay. Finally, we discuss when and how to use hydro-ecological models for societal needs.

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  • 84.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Pers, Charlotta
    SMHI, Forskningsavdelningen, Hydrologi.
    Lessons learned? Effects of nutrient reductions from constructing wetlands in 1996–2006 across Sweden2016Ingår i: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, s. 1-11Artikel i tidskrift (Refereegranskat)
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  • 85.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Pimentel, Rafael
    SMHI, Forskningsavdelningen, Hydrologi.
    Isberg, Kristina
    SMHI, Forskningsavdelningen, Hydrologi.
    Crochemore, Louise
    SMHI, Forskningsavdelningen, Hydrologi.
    Andersson, Jafet
    SMHI, Forskningsavdelningen, Hydrologi.
    Hasan, Abdulghani
    Pineda, Luis
    Global catchment modelling usingWorld-Wide HYPE (WWH), open data, and stepwise parameter estimation2020Ingår i: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 24, nr 2, s. 535-559Artikel i tidskrift (Refereegranskat)
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  • 86.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Torstensson, G
    Wittgren, Hans Bertil
    SMHI, Forskningsavdelningen.
    Landscape planning to reduce coastal eutrophication: agricultural practices and constructed wetlands2004Ingår i: Landscape and Urban Planning, ISSN 0169-2046, E-ISSN 1872-6062, Vol. 67, nr 1-4, s. 205-215Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Southern Sweden suffers from coastal eutrophication and one reason is the high nitrogen load through rivers. The major part of this load originates from diffuse land-based sources, e.g. arable soil leaching. Effective reduction of load from such sources demand careful landscape analysis, combined with changed behaviour of the stakeholders. This study describes a chain of methods to achieve trustworthy management plans that are based on numerical modelling and stakeholders participation and acceptance. The effect of some measures was unexpected when modelling their impact on the catchment scale. Management scenarios to reduce riverine nitrogen load were constructed in an actor game (i.e. role-play) for the Genevadsan catchment in southern Sweden. The game included stakeholders for implementation of a loading standard for maximum nitrogen transport at the river mouth. Scenarios were defined after negotiation among involved actors and included changes in agricultural practices, improved wastewater treatment, and establishment of wetlands. Numerical models were used to calculate the nitrogen reduction for different measures in each scenario. An index model (STANK) calculated the root zone leaching of nitrogen from crops at four type farms. This generated input to a catchment scale model (HBV-N) and farm economics. The economic impact of different sets of remedial measures was evaluated for each type farm and then extrapolated to the catchment. The results from scenario modelling show that possible changes in agricultural practices (such as tuning, timing of fertilisation and ploughing, changed crop cultivation) could reduce the nitrogen load to the sea by some 30%, while wetland construction only reduced the original load by some 5%. In the most cost-effective scenario agricultural practices could reduce the riverine load by 86 t per year at a cost of 1.0 million SEK, while constructed wetlands only reduced the load by 14 t per year at a cost of 1.7 million SEK. Thus, changed agricultural practices can be the most effective and less expensive way to reduce nitrogen transport from land to the sea, while constructed wetlands with realistic allocations and sizes may only have small impact on riverine nitrogen transport from land to sea. The overall experience is that actor games and numerical modelling are useful tools in landscape planning for analysing stakeholders' behaviour and the impact of measures to reduce coastal eutrophication. (C) 2003 Elsevier Science B.V. All rights reserved.

  • 87.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Wittgren, H B
    Modelling nitrogen removal in potential wetlands at the catchment scale2002Ingår i: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 19, nr 1, s. 63-80Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The reduction of nitrogen fluxes from land to sea is an important task in areas with estuarine or marine eutrophication. Wetland creation has been proposed as one method to reduce nitrogen from streams draining agricultural areas. In this study, a scenario of nitrogen removal in created wetlands was evaluated by mathematical modelling of nitrogen fluxes in a catchment (224 km(2)) in southern Sweden. The scenario was based on topographically realistic siting of 40 potential wetlands with a total area of 0.92 km(2) (0.4% of the catchment area). Nitrogen removal in the wetlands was described with a simple and robust first-order model, which was modified and evaluated against data from eight monitored surface-flow wetlands. However, the modifications gave no substantial support for changing the basic model. For catchment-scale modelling this wetland model was incorporated into a dynamic process-based catchment model (HBV-N). The catchment was then divided to several coupled subbasins, so that the wetland influence on nitrogen load could be estimated separately for each potential wetland. The modelling showed that the 40 potential wetlands would reduce the nitrogen transport to the coast with approximately 6%. Specific removal rates ranged between 57 and 466 kg ha(-1) yr(-1) for the different wetlands, depending on residence time (size and hydraulic loading) and nitrogen concentration in inflow. Due to temperature dependence and seasonal variation in water discharge, significant decrease in nitrogen concentrations mainly occurred during summer periods with low loading. The study illustrates that catchment modelling is a useful method for analysing wetland creation plans, and that wetland creation must cover fairly large areas and be combined with other measures in order to achieve substantial reduction of nitrogen fluxes to coastal waters. Further monitoring of existing wetlands will improve the removal expression and decrease uncertainty. For instance, at present it could not be deducted whether wetlands with low average residence times ( < 2 days) have net removal or net resuspension on an annual basis. (C) 2002 Elsevier Science B.V. All rights reserved.

  • 88.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Wittgren, Hans Bertil
    SMHI, Forskningsavdelningen.
    MODELING THE EFFECTS OF WETLANDS ON REGIONAL NITROGEN TRANSPORT1994Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 23, nr 6, s. 378-386Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Created wetlands have been suggested as a method to reduce nitrogen transport to the Baltic Sea. This paper presents a dynamic conceptual model for simulation of the hypothetical effect of wetlands on nitrogen export to the coastal zone. The study was performed in the Soder-kopingsan drainage basin (882 km(2)) in southeastern Sweden, discharging into the Baltic Sea. An empirically based routine for wetland retention was calibrated separately and incorporated in the model. Scenarios with different location and size of wetlands were analyzed. It was estimated that conversion of 1% (8.8 km(2)) of this basin into wetlands would reduce the nitrogen transport by 10-16% and that more than 5% (45 km(2)) conversion to wetlands is required to reduce the transport by 50%. It was concluded that creation of wetlands should be considered, primarily, downstream from major lakes, in coastal areas, and where the summer load is a significant portion of the annual load. Some further conclusions from the study were that: i) the net reduction of nitrogen transport per unit area of wetland decreases with increasing total area of wetlands in a drainage basin; ii) the wetland retention efficiency obtained in studies of individual wetlands can not be extrapolated in a linear fashion to estimate the net reduction of nitrogen transport at the mouth of a whole drainage basin; iii) the seasonal hydrological and hydrochemical dynamics are of fundamental importance for wetland retention efficiency, which complicates comparison and extrapolation of results from one region to another.

  • 89. Arnbjerg-Nielsen, K.
    et al.
    Willems, P.
    Olsson, Jonas
    SMHI, Forskningsavdelningen, Hydrologi.
    Beecham, S.
    Pathirana, A.
    Gregersen, I. Bulow
    Madsen, H.
    Nguyen, V. -T-V
    Impacts of climate change on rainfall extremes and urban drainage systems: a review2013Ingår i: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 68, nr 1, s. 16-28Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    A review is made of current methods for assessing future changes in urban rainfall extremes and their effects on urban drainage systems, due to anthropogenic-induced climate change. The review concludes that in spite of significant advances there are still many limitations in our understanding of how to describe precipitation patterns in a changing climate in order to design and operate urban drainage infrastructure. Climate change may well be the driver that ensures that changes in urban drainage paradigms are identified and suitable solutions implemented. Design and optimization of urban drainage infrastructure considering climate change impacts and co-optimizing these with other objectives will become ever more important to keep our cities habitable into the future.

  • 90.
    Arneborg, Lars
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Axell, Lars
    SMHI, Forskningsavdelningen, Oceanografi.
    Lensu, Mikko
    Ljungman, Olof
    Mattsson, Johan
    Oil drift modeling in pack ice - Sensitivity to oil-in-ice parameters2017Ingår i: Ocean Engineering, ISSN 0029-8018, E-ISSN 1873-5258, Vol. 144, s. 340-350Artikel i tidskrift (Refereegranskat)
  • 91.
    Arneborg, Lars
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Jansson, Par
    Staalstrom, Andre
    Broström, Göran
    Tidal Energy Loss, Internal Tide Radiation, and Local Dissipation for Two-Layer Tidal Flow over a Sill2017Ingår i: Journal of Physical Oceanography, ISSN 0022-3670, E-ISSN 1520-0485, Vol. 47, nr 7, s. 1521-1538Artikel i tidskrift (Refereegranskat)
  • 92.
    Arnér, Erik
    SMHI.
    Simulering av vårflöden med HBV-modellen1991Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    För att förbättra HBV-modellens snörutin, och i synnerhet dess prognoser över vårflodens start, prövas en graddagmetod som använder sig av dygnets extremtemperaturer för att beräkna snöackumulation och snösmältning. Temperaturen under dygnet antas variera linjärt mellan maximum- och minimumtemperaturen, och nederbörden fördelas på regn och snö i förhållande till den tid som temperaturen varit över respektive under en tröskeltemperatur. Snöackumulering och snösmältning beräknas separat under de tidssteg då tröskeltemperaturen ligger inom dygnets temperaturintervall. Resultaten från simuleringarna jämförs med resultaten från den ursprungliga HBV-modellen, vilken endast använder dygnsmedeltempcraturen. Sex svenska avrinningsområden med varierande storlek och klimat undersöks, och sammanlagt 88 år simuleras och jämförs.

    Det konstateras att den nya modellen ger något bättre simulering av flödet vid vårflodens start för de undersökta områdena, men att den samtidigt ger något sämre värden på den förklarade variansen, R2-värdet. Detta resultat är inte generellt för alla områdena, men sammantaget bedöms det att de båda modellerna är i stort sett likvärdiga.

    Återfrysningsfaktrns betydelse i den nya modellen prövas i två små områden för att se om dess storlek har någon inverkan på resultatet. Den varieras stegvis från 0.00 upp till 0.21, och för varje steg kalibreras de andra snöparametrarna om. Det konstateras att det värde som återfrysningsfaktorm  har kan ha en viss betydelse, men det viktigaste är att den finns så att snön är torr då smältningen börjar på våren. Återfrysningens storlek kan till en del regleras av andra parametrar.

    I ett område undersöks den roll som kvaliten på temperaturdata har i de båda modellerna, genom att temperaturdata från en klimatstation i taget används. Indata från tre olika stationer används och för varje station kalibreras          snöparametrarna om. Resultaten visar att simuleringsresultaten förändras ungefär lika mycket då temperaturstation byts som då man byter modell. De indikerar också att den nya modellen är mer beroende av representativa temperaturdata än den vanliga HBV-modellen.

    Den automatiska kalibreringsmetoden utvecklad av Harlin 1991 har använts genomgående i detta arbete, och totalt har nästan 50 kalibreringar utförts. Erfarenheterna från denna nya metod är goda.

    Rapporten innehåller också en beskrivning av HBV-modellen och en litteraturgenomgång inom området snömodellering.

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  • 93. ASKNE, J
    et al.
    LEPPARANTA, M
    Thompson, Thomas
    SMHI.
    THE BOTHNIAN EXPERIMENT IN PREPARATION FOR ERS-1, 1988 (BEPERS-88) - AN OVERVIEW1992Ingår i: International Journal of Remote Sensing, ISSN 0143-1161, E-ISSN 1366-5901, Vol. 13, nr 13, s. 2377-2398Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BEPERS-88 was an extensive field campaign on the use of Synthetic Aperture Radar (SAR) in sea ice remote sensing in the Baltic Sea. This experiment was performed in order to study the possibilities of using the ERS-1 satellite SAR (and radar altimeter) in connection with the brackish ice in the Baltic Sea. The Canada Centre for Remote Sensing CV-580 C/X-band SAR was flown and an extensive validation programme was carried out. The data have been used for SAR image analysis, backscatter investigations, geophysical validation of SAR over sea ice, and evaluation of the potentials of SAR in operational ice information services. The results indicate that SAR can be used to discriminate between ice and open water, classify ice types into three categories, quantify ice ridging intensity, and determine the ice drift. As an operational tool SAR is expected to be an excellent complement to NOAA imagery and ground truth.

  • 94.
    Axell, Lars
    SMHI, Forskningsavdelningen, Oceanografi.
    On the variability of Baltic Sea deepwater mixing1998Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, Vol. 103, nr C10, s. 21667-21682Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Historical oceanographic data from the period 1964-1997 from two deep subbasins (the Gotland Deep and the Landsort Deep) in the Baltic Sea have been analyzed, by using a budget method on stagnant periods, with respect to vertical diffusion and vertical energy flux density in the deep water. It was found that the rate of deepwater mixing varied with the seasons, with higher rates in fall and winter compared to spring and summer. Further, according to the analyzed data, the downward flux density of energy available for vertical diffusion decreased with increasing depth in the Gotland Deep. In the Landsort Deep, however, the flux density increased somewhat, probably because of topographic concentration of the energy, before decreasing toward the bottom. Moreover, the vertical energy flux densities were compared with the expected flux density from the local wind. It is proposed that in the Gotland Deep, which is outside the coastal boundary layer, the observed deepwater mixing is dominated by the energy input from the wind via inertial currents and internal waves. In the Landsort Deep, however, which is within the coastal boundary layer, the expected flux density of energy from the local wind cannot explain the observed rate of work against the buoyancy forces. It is proposed that the active coastal boundary layer plays a central role in the transfer of energy to mixing processes in the deep water.

  • 95.
    Axell, Lars
    SMHI, Forskningsavdelningen, Oceanografi.
    Wind-driven internal waves and Langmuir circulations in a numerical ocean model of the southern Baltic Sea2002Ingår i: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 107, nr C11, artikel-id 3204Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    [1] A one-dimensional numerical ocean model of the southern Baltic Sea is used to investigate suitable parameterizations of unresolved turbulence and compare with available observations. The turbulence model is a k-epsilon model that includes extra source terms P-IW and P-LC of turbulent kinetic energy (TKE) due to unresolved, breaking internal waves and Langmuir circulations, respectively. As tides are negligible in the Baltic Sea, topographic generation of internal wave energy (IWE) is neglected. Instead, the energy for deepwater mixing in the Baltic Sea is provided by the wind. At each level the source term P-IW is assumed to be related to a vertically integrated pool of IWE, E-0, and the buoyancy frequency N at the same level, according to P-IW (z) proportional to E0Ndelta (z). This results in vertical profiles of epsilon (the dissipation rate of TKE) and K-h (the eddy diffusivity) according to epsilon proportional to N-delta and K-h proportional to Ndelta-2 below the main pycnocline. Earlier observations are inconclusive as to the proper value of delta, and here a range of values of delta is tested in hundreds of 10-year simulations of the southern Baltic Sea. It is concluded that delta = 1.0 +/- 0.3 and that a mean energy flux density to the internal wave field of about (0.9 +/- 0.3) x 10(-3) W m(-2) is needed to explain the observed salinity field. In addition, a simple wind-dependent formulation of the energy flux to the internal wave field is tested, which has some success in describing the short- and long-term variability of the deepwater turbulence. The model suggests that similar to16% of the energy supplied to the surface layer by the wind is used for deepwater mixing. Finally, it is also shown that Langmuir circulations are important to include when modeling the oceanic boundary layer. A simple parameterization of Langmuir circulations is tuned against large-eddy simulation data and verified for the Baltic Sea.

  • 96.
    Axell, Lars
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Liu, Ye
    SMHI, Forskningsavdelningen, Oceanografi.
    Application of 3-D ensemble variational data assimilation to a Baltic Sea reanalysis 1989-20132016Ingår i: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 68, artikel-id 24220Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A 3-D ensemble variational (3DEnVar) data assimilation method has been implemented and tested for oceanographic data assimilation of sea surface temperature (SST), sea surface salinity (SSS), sea ice concentration (SIC), and salinity and temperature profiles. To damp spurious long-range correlations in the ensemble statistics, horizontal and vertical localisation was implemented using empirical orthogonal functions. The results show that the 3DEnVar method is indeed possible to use in oceanographic data assimilation. So far, only a seasonally dependent ensemble has been used, based on historical model simulations. Near-surface experiments showed that the ensemble statistics gave inhomogeneous and anisotropic horizontal structure functions, and assimilation of real SST and SIC fields gave smooth, realistic increment fields. The implementation was multivariate, and results showed that the cross-correlations between variables work in an intuitive way, for example, decreasing SST where SIC was increased and vice versa. The profile data assimilation also gave good results. The results from a 25-year reanalysis showed that the vertical salinity and temperature structure were significantly improved, compared to both dependent and independent data.

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  • 97.
    Axell, Lars
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Ljungman, Olof
    SMHI, Forskningsavdelningen, Oceanografi.
    A One-Equation Turbulence Model for Geophysical Applications: Comparison with Data and the k - epsilon Model2001Ingår i: Environmental Fluid Mechanics, ISSN 1567-7419, E-ISSN 1573-1510, Vol. 1, nr 1, s. 71-106Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A one-equation turbulence model is presented, in which the turbulent kinetic energy k is calculated with a transport equation whereas the turbulent length scale l is calculated with an algebraic expression. The value of l depends on the local stratification and reduces to the classical kappa vertical bar z vertical bar scaling for unstratified flows near a wall, where vertical bar z vertical bar is the distance to the wall. The length scale decreases during stable stratification, and increases for unstable stratification compared to the neutral case. In the limit of strong stable stratification, the so-called buoyancy length scale proportional to k(1/2)N(-1) is obtained, where N is the buoyancy frequency. The length scale formulation introduces a single model parameter which is calibrated against experimental data. The model is verified extensively against laboratory measurements and oceanic data, and comparisons are made with the two-equation k-epsilon model. It is shown that the performance of the proposed k model is almost identical to that of the k-epsilon model. In addition, the stability functions of Launder are revisited and adjusted to obtain better agreement with recent data.

  • 98. Bailey, Helen
    et al.
    Fossette, Sabrina
    Bograd, Steven J.
    Shillinger, George L.
    Swithenbank, Alan M.
    Georges, Jean-Yves
    Gaspar, Philippe
    Strömberg, Patrik
    SMHI, Samhälle och säkerhet.
    Paladino, Frank V.
    Spotila, James R.
    Block, Barbara A.
    Hays, Graeme C.
    Movement Patterns for a Critically Endangered Species, the Leatherback Turtle (Dermochelys coriacea), Linked to Foraging Success and Population Status2012Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, nr 5, artikel-id e36401Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Foraging success for pelagic vertebrates may be revealed by horizontal and vertical movement patterns. We show markedly different patterns for leatherback turtles in the North Atlantic versus Eastern Pacific, which feed on gelatinous zooplankton that are only occasionally found in high densities. In the Atlantic, travel speed was characterized by two modes, indicative of high foraging success at low speeds (<15 km d(-1)) and transit at high speeds (20-45 km d(-1)). Only a single mode was evident in the Pacific, which occurred at speeds of 21 km d(-1) indicative of transit. The mean dive depth was more variable in relation to latitude but closer to the mean annual depth of the thermocline and nutricline for North Atlantic than Eastern Pacific turtles. The most parsimonious explanation for these findings is that Eastern Pacific turtles rarely achieve high foraging success. This is the first support for foraging behaviour differences between populations of this critically endangered species and suggests that longer periods searching for prey may be hindering population recovery in the Pacific while aiding population maintenance in the Atlantic.

  • 99. Bal, S.
    et al.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Spangehl, T.
    Cubasch, U.
    On the robustness of the solar cycle signal in the Pacific region2011Ingår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 38, artikel-id L14809Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The potential role of the stratosphere for the 11-year solar cycle signal in the Pacific region is investigated by idealized simulations using a coupled atmosphere-ocean general circulation model. The model includes a detailed representation of the stratosphere and accounts for changes in stratospheric heating rates from prescribed time dependent variations of ozone and spectrally high resolved solar irradiance. Three transient simulations are performed spanning 21 solar cycles each. The simulations use slightly different ozone perturbations representing uncertainties of solar induced ozone variations. The model reproduces the main features of the 20th century observed solar response. A persistent mean sea level pressure response to solar forcing is found for the eastern North Pacific extending over North America. Moreover, there is evidence for a La Nina-like response assigned to solar maximum conditions with below normal SSTs in the equatorial eastern Pacific, reduced equatorial precipitation, enhanced off-equatorial precipitation and an El Nino-like response a couple of years later, thus confirming the response to solar forcing at the surface seen in earlier studies. The amplitude of the solar signal in the Pacific region depends to a great extent on the choice of the centennial period averaged. Citation: Bal, S., S. Schimanke, T. Spangehl, and U. Cubasch (2011), On the robustness of the solar cycle signal in the Pacific region, Geophys. Res. Lett., 38, L14809, doi:10.1029/2011GL047964.

  • 100. Bal, Sourabh
    et al.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Spangehl, Thomas
    Cubasch, Ulrich
    Enhanced residual mean circulation during the evolution of split type sudden stratospheric warming in observations and model simulations2018Ingår i: Proceedings of the Indian Academy of Sciences, Earth and Planetary Sciences, ISSN 0253-4126, E-ISSN 0973-774X, Vol. 127, nr 5, artikel-id 68Artikel i tidskrift (Refereegranskat)
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