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  • 51. Andersson, Agneta
    et al.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Ripszam, Matyas
    Rowe, Owen
    Wikner, Johan
    Haglund, Peter
    Eilola, Kari
    SMHI, Research Department, Oceanography.
    Legrand, Catherine
    Figueroa, Daniela
    SMHI, Core Services.
    Paczkowska, Joanna
    Lindehoff, Elin
    Tysklind, Mats
    Elmgren, Ragnar
    Projected future climate change and Baltic Sea ecosystem management2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, p. S345-S356Article in journal (Refereed)
    Abstract [en]

    Climate change is likely to have large effects on the Baltic Sea ecosystem. Simulations indicate 2-4 degrees C warming and 50-80 % decrease in ice cover by 2100. Precipitation may increase similar to 30 % in the north, causing increased land runoff of allochthonous organic matter (AOM) and organic pollutants and decreased salinity. Coupled physical-biogeochemical models indicate that, in the south, bottom-water anoxia may spread, reducing cod recruitment and increasing sediment phosphorus release, thus promoting cyanobacterial blooms. In the north, heterotrophic bacteria will be favored by AOM, while phytoplankton production may be reduced. Extra trophic levels in the food web may increase energy losses and consequently reduce fish production. Future management of the Baltic Sea must consider the effects of climate change on the ecosystem dynamics and functions, as well as the effects of anthropogenic nutrient and pollutant load. Monitoring should have a holistic approach, encompassing both autotrophic (phytoplankton) and heterotrophic (e.g., bacterial) processes.

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  • 52.
    Andersson, Camilla
    et al.
    SMHI, Research Department, Air quality.
    Alpfjord, Helene
    SMHI, Professional Services.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Karlsson, Per Erik
    Miljöforskningsinstitutet.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Reanalysis of and attribution to near-surface ozone concentrations in Sweden during 1990-20132017In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 17, no 22Article in journal (Refereed)
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  • 53.
    Andersson, Camilla
    et al.
    SMHI, Research Department, Air quality.
    Alpfjord Wylde, Helene
    SMHI, Professional Services.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Long-term sulfur and nitrogen deposition in Sweden: 1983-2013 reanalysis2018Report (Other academic)
    Abstract [en]

    A unique long-term (1983-2013) dataset of sulfur and nitrogen deposition has been compiled for Sweden as well as the Baltic Sea and surrounding countries, based on quality controlled measurements and modelled fields, fused though advanced methods capturing spatial and temporal variations. The data set can be used for describing trends in deposition to various relevant surface types.Our reanalysis compares well to observations, but we have identified differences in dry deposition to coniferous forest. This calls for more in-depth studies of the dry deposition and improvements to the respective methods.We recommend more advanced methods of describing spatial variation than averaging or spatial interpolation of observed deposition.We estimate a significant decrease from the 1980s until today for both sulfur and nitrogen deposition (by ca. 80% and 30% respectively).Critical loads for coniferous and deciduous forests, mountain vegetation and wetlands have been surpassed mainly in the southwest Sweden, but also in southeast Sweden and the southern parts of Scandes Mountains. The situation is improving, but exceedances do still occur also in larger regions.

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  • 54.
    Andersson, Camilla
    et al.
    SMHI, Research Department, Air quality.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Bennet, Cecilia
    SMHI, Research Department, Air quality.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Thomas, Manu
    SMHI, Research Department, Air quality.
    Korhonen, H.
    Lehtinen, K. E. J.
    Kokkola, H.
    MATCH-SALSA - Multi-scale Atmospheric Transport and CHemistry model coupled to the SALSA aerosol microphysics model - Part 1: Model description and evaluation2015In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 8, no 2, p. 171-189Article in journal (Refereed)
    Abstract [en]

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

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  • 55.
    Andersson, Camilla
    et al.
    SMHI, Research Department, Air quality.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Johansson, Christer
    Population exposure and mortality due to regional background PM in Europe - Long-term simulations of source region and shipping contributions2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 22-23, p. 3614-3620Article in journal (Refereed)
    Abstract [en]

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

  • 56.
    Andersson, Camilla
    et al.
    SMHI, Research Department, Air quality.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    European ozone in a future climate: Importance of changes in dry deposition and isoprene emissions2010In: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 115, article id D02303Article in journal (Refereed)
    Abstract [en]

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

  • 57.
    Andersson, Camilla
    et al.
    SMHI, Research Department, Air quality.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Interannual variation and trends in air pollution over Europe due to climate variability during 1958-2001 simulated with a regional CTM coupled to the ERA40 reanalysis2007In: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 59, no 1, p. 77-98Article in journal (Refereed)
    Abstract [en]

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

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  • 58. Andersson, E.
    et al.
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    Devasthale, Abhay
    SMHI, Research Department, Atmospheric remote sensing.
    Methodology for evaluating lateral boundary conditions in the regional chemical transport model MATCH (v5.5.0) using combined satellite and ground-based observations2015In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 8, no 11, p. 3747-3763Article in journal (Refereed)
    Abstract [en]

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

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  • 59. Andersson, Emma
    et al.
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    Coupling aerosol optics to the MATCH (v5.5.0) chemical transport model and the SALSA (v1) aerosol microphysics module2016In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 9, no 5, p. 1803-1826Article in journal (Refereed)
    Abstract [en]

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

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  • 60. Andersson, Eva M.
    et al.
    Ogren, Mikael
    Molnar, Peter
    Segersson, David
    SMHI, Research Department, Air quality.
    Rosengren, Annika
    Stockfelt, Leo
    Road traffic noise, air pollution and cardiovascular events in a Swedish cohort2020In: Environmental Research, ISSN 0013-9351, E-ISSN 1096-0953, Vol. 185, article id 109446Article in journal (Refereed)
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  • 61.
    Andersson, Helén
    et al.
    SMHI, Research Department, Oceanography.
    Eriksson Bram, Lena
    SMHI, Core Services.
    Hjerdt, Niclas
    SMHI, Core Services.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Löptien, Ulrike
    SMHI, Research Department, Oceanography.
    Strömqvist, Johan
    SMHI, Research Department, Hydrology.
    Översikt av beräkningsmodeller för bedömning av fiskodlingars näringsämnesbelastning på sjöar, vattendrag, magasin och kustvatten2016Report (Other academic)
    Abstract [sv]

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

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

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

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

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

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

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  • 62.
    Andersson, Jafet
    et al.
    SMHI, Research Department, Hydrology.
    Ali, Abdou
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Gustafsson, David
    SMHI, Research Department, Hydrology.
    Minoungou, Bernard
    Providing peak river flow statistics and forecasting in the Niger River basin2017In: Physics and Chemistry of the Earth, ISSN 1474-7065, E-ISSN 1873-5193, Vol. 100, p. 3-12Article in journal (Refereed)
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  • 63.
    Andersson, Jafet
    et al.
    SMHI, Research Department, Hydrology.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Hjerdt, Niclas
    SMHI, Core Services.
    Combine and Share Essential Knowledge for Sustainable2016In: The Solutions Journal, ISSN 2154-0926, Vol. 7, no 3, p. 30-32Article in journal (Other (popular science, discussion, etc.))
  • 64.
    Andersson, Jafet
    et al.
    SMHI, Research Department, Hydrology.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Hjerdt, Niclas
    SMHI, Core Services.
    Combine and Share Essential Knowledge for Sustainable Water Management2016In: Solutions Journal, ISSN 2154-0896, E-ISSN 2154-0926, Vol. 7, no 3Article in journal (Other (popular science, discussion, etc.))
  • 65.
    Andersson, Jafet
    et al.
    SMHI, Research Department, Hydrology.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Traore, Farid
    Gustafsson, David
    SMHI, Research Department, Hydrology.
    Ali, Abdou
    Process refinements improve a hydrological model concept applied to the Niger River basin2017In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 31, no 25, p. 4540-4554Article in journal (Refereed)
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  • 66.
    Andersson, Jafet
    et al.
    SMHI, Research Department, Hydrology.
    Pechlivanidis, Ilias
    SMHI, Research Department, Hydrology.
    Gustafsson, David
    SMHI, Research Department, Hydrology.
    Donnelly, Chantal
    SMHI, Research Department, Hydrology.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Key factors for improving large-scale hydrological model performance2015In: European Water, ISSN 1792-085X, Vol. 49, p. 77-88Article in journal (Refereed)
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  • 67.
    Andersson, Jafet
    et al.
    SMHI, Research Department, Hydrology.
    Zehnder, Alexander J. B.
    Wehrli, Bernhard
    Jewitt, Graham P. W.
    Abbaspour, Karim C.
    Yang, Hong
    Improving Crop Yield and Water Productivity by Ecological Sanitation and Water Harvesting in South Africa2013In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 47, no 9, p. 4341-4348Article in journal (Refereed)
    Abstract [en]

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

  • 68.
    Andersson, Jan
    et al.
    SMHI, Core Services.
    Becker, Björn
    SMHI.
    Hillgren, Robert
    SMHI.
    Brofjordens kraftstation: Kylvattenspridning i Hanneviken1990Report (Other academic)
    Abstract [sv]

    Vattenfall planerar att lokalisera en restoljeförgasningsanläggning intill Scanraff vid Brofjorden. Anläggningens kylvattenutsläpp beräknas till 7,5 m3/s med eninitiell övertemperatur på cirka 10 °C. Alternativa utsläppspunkter är söder om Hanneviksholmen och södra Trommekilen.

    En frågeställning är huruvida man genom lämpligt val av utsläppsarrangemang kan få en gynnsam uppvärmning av Hanneviken och därigenom förbättra förutsättningarna för en produktion av växtplankton.Tillgången på växtplankton är en förutsättning för en tänkt ostronodling norr om Hanneviksholmen.

    SMHI har fått i uppdrag av Vattenfall Utveckling AB att utreda kylvattenspridningen för två alternativa utsläpp i Hanneviken. Arbetet har omfattat simuleringar av cirkulationsförhållandena och kylvattenspridningen samt fältundersökningar. Fältmätningarna har syftat till dels att verifiera modellens resultat dels att få en uppfattning om hur stor del av året man kan förvänta en gynnsam uppvärmning av Hanneviken.

    Uppvärmningen av Hanneviken är starkt beroende av vindens riktning.För ostlig vind är temperaturhöjningen mindre än 2 °C,medan den är 3-5 °C för sydostlig eller sydvästlig vind.

    Uppvärmningen av vattnet längs kusten nordost om Kågarna blir 2-3 °C.

    Utsläppsalternativ 1 ger en något högre uppvärmning.

    Vindar från SE över S till W är mest gynnsamma för en inström väster om Hanneviksholmen och därmed en spridning av kylvatten in mot Hanneviken. Andelen av dessa vindar under året uppskattas till cirka 50%.

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  • 69.
    Andersson, Jan
    et al.
    SMHI, Core Services.
    Hillgren, Robert
    SMHI, Core Services.
    SMHIs undersökningar i Öregrundsgrepen 19861987Report (Other academic)
    Abstract [sv]

    1986 kan kraftverkets drift betraktas som normal med avseende på kylvattenflöde och värme. Samtliga tre block har haft ett högt driftutnyttjande.

    Kontrollprogrammets målsättning har varit att kontinuerligt övervaka kylvattnets spridning i tid och rum. Av särskilt intresse har varit att övervaka effekterna av läckaget från F 3:s kylvattenkanal. Tätningsarbetena påbörjades under F 3:s revisionsperiod under sensommaren och var avslutade i slutet av november. Följande slutsatser har dragits:

    • Tre-blocksdriften under december har inneburit avkylningsytor av storleken 6 - 8 km?Under två-blocksdrift är motsvarande ytor 4 - 7 km2
    • Området mellan St Sandgrund och vallen påverkas mest av läckaget.
    • 10°C övertemperatur har förekommit närmast vallen.
    • Vid driftstopp1 F 3:s revisionsperiod, avkyls det berörda läckageområdet.Ingen förekomst av uppvärmt kylvatten kan konstateras under revisionsperioden.
    • Vid idrifttagande av F 3 har omgående vattenområdet påverkats.
    • Drift under islagd period har medfört att öppet vatten förekommit utanför vallen hela tiden trots den svåra isvintern.
    • Ett extremt vattenstånd+ 143 cm över MW har förekommit (jfr med+ 150 cm vilket motsvarar "hundraårsvattenståndet").
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  • 70.
    Andersson, Jan
    et al.
    SMHI, Core Services.
    Hillgren, Robert
    SMHI, Core Services.
    SMHIs undersökningar utanför Forsmark 19871988Report (Other academic)
    Abstract [sv]

    1987 kan kraftverkets drift betraktas som normal med avseende på kylvattenflöde och värme. Samtliga tre block har haft ett högt drift utnyttjande.

    Kontrollprogrammets målsättning har varit att kontinuerligt övervaka kylvattnets spridning i tid och rum. Av särskilt intresse har varit att se effekten av kylvattentillskottet från block 3 via ordinarie utlopp.

    Följande slutsatser har dragits:

    • Treblocksdriften under året har inneburit avkylningsytor av storleksordningen 7 - 12 km2. Den tidigare bedömningen med endast karteringar från december 1986, var 6 - 8 km2.
    • Temperaturen i skärgårdsområdet har inte påverkats av treblocksdriften.
    • Något fortsatt läckage från F 3:s kylvattenkanal har inte observerats.
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  • 71.
    Andersson, Jan
    et al.
    SMHI, Core Services.
    Hillgren, Robert
    SMHI, Core Services.
    SMHIs undersökningar utanför Forsmark 19881989Report (Other academic)
    Abstract [sv]

    1988 kan kraftverkets drift betraktas som normal med avseende på kylvattenflöde och värme. Samtliga tre block har haft ett högt driftutnyttjande.

    Reservutskovet har dock nyttjats mer än föregående år, ca 3 månader.

    Kontrollprogrammets målsättning har varit att kontinuerligt övervaka kylvattnets spridning i tid och rum. Av särskilt intresse har varit att se effekten av  kylvattentillskottet från block 3 via ordinarie utlopp.

    Följande slutsatser har dragits:

    • Treblocksdriften under året har inneburit avkylningsytor av storleksordningen 8 - 16 km 2. Den tidigare bedömningen från 1987; var 7 - 12 km2.
    • Temperaturen i skärgårdsområdet har inte påverkats av treblocksdriften.
    • Något märkbart läckage från F 3:s kylvattenkanal har inte observerats.
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  • 72.
    Andersson, Jan
    et al.
    SMHI.
    Hillgren, Robert
    SMHI, Core Services.
    SMHIs undersökningar utanför Forsmark 19891990Report (Other academic)
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  • 73.
    Andersson, Jan
    et al.
    SMHI, Core Services.
    Hillgren, Robert
    SMHI, Core Services.
    SMHIs undersökningar utanför Forsmark 19921993Report (Other academic)
    Abstract [sv]

    1992 års kontrollprogram har haft som målsättning att:

    - kontinuerligt bevaka temperaturen i vertikal Si skärgårdsområdet.

    - kontrollera vattenområdet vid F3:s kylvattenkanal (tidigare läckaget).

    Kraftverkets drift under 1992 kan betraktas som normal med avseende på kylvattenflöde och värme.

    Reservutskovet har använts i drygt 1 månad. Under 1990 och 1991 var motsvarande tid cirka 6 månader. Att perioden varit så mycket längre under de två föregående åren har berott på att Kustlaboratoriet i Öregrund bedrivit ett försök att skapa möjligheter för en förbättrad fiskreproduktion.

    Kommentarer:

    * Tendensen av något förhöjda temperaturer under åren 1990 - 91 i skärgårdsområdet vid vertikal S har brutits. Temperaturen ligger på en mer normal nivå genom att reservutskovet utnyttjats betydligt mindre under 1992.

    * Det fanns inga spår av det tidigare läckaget utanför F3:s kylvattenkanal.

    Statistiskt sett var årsmedeltemperaturen (april - november) under -92 i vertikal Spå 1 m djup 0.23°C över medelvärdet för perioden 1977-91. För 1991 och 1990 låg årsmedeltemp. 2.2°C resp l.8°C över medelvärdet.

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  • 74.
    Andersson, Jan
    et al.
    SMHI, Core Services.
    Hillgren, Robert
    SMHI, Core Services.
    SMHIs undersökningar utanför Forsmark 19931994Report (Other academic)
    Abstract [sv]

    1993 års kontrollprogram har haft som målsättning att:

    - kontinuerligt bevaka temperaturen i vertikal S i skärgårdsområdet

    - kontrollera vattenområdet vid F3:s kylvattenkanal (tidigare läckaget).

    Kraftverkets drift under 1993 kan betraktas som normal med avseende på kylvattenflöde och värme.

    Reservutskovet har använts i drygt 1 månad. Under 1990 och 1991 var motsvarande tid cirka 6 månader. Att perioden varit så mycket längre under de två åren har berott på att Kustlaboratoriet i Öregrund bedrivit ett försök att skapa möjligheter för en förbättrad fiskreproduktion.

    Kommentarer:

    * Temperaturen ligger på en fortsatt normal nivå genom att reservutskovet   utnyttjats betydligt mindre under 1992.

    * Det fanns inga spår av det tidigare läckaget utanför F3:s kylvattenkanal.

    Statististiskt sett var årsmedeltemperaturen (april - november) under -93 i vertikal Spå 1 m djup 0.l8°C under medelvärdet för perioden 1977-92.

    För 1991 och 1990 låg årsmedeltemp. 2.2°C resp l.8°C över medelvärdet, samt för 1992 låg årsmedeltemp. 0.23°C över medelvärdet.

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  • 75.
    Andersson, Jan
    et al.
    SMHI, Core Services.
    Hillgren, Robert
    SMHI, Core Services.
    SMHIs undersökningar utanför Forsmark 19941995Report (Other academic)
    Abstract [sv]

    Kraftverkets drift under 1994 kan betraktas som normal med avseende på kylvattenflöde och värme.

    Kylvatten från Fl och F2 har släppts via reservutskovet under 5 månader. Detta på grund av problem med rensningen av fiskspärren vid biotestsjöns utlopp. Den sammantagna effekten av kylvatten från reservutskovet och en värmebölja medförde att den hittills högsta uppmätta temperaturen i vertikal S, 25.2°C noterades den 2 augusti. Årsmedeltemperaturen (april - november) under 1994 i vertikal S på 1 m djup låg 1.7 °C över medelvärdet för perioden 1977 - 1993 (april - november).

    1994 års temperaturöverskott uppstod framförallt under sommaren, under senhösten ökade vattenutbytet med det utanförliggande havsområdet och någon ackumulering av kylvatten kunde inte registreras.

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  • 76.
    Andersson, Jan
    et al.
    SMHI, Core Services.
    Hillgren, Robert
    SMHI, Core Services.
    SMHIs undersökningar utanför Forsmark 19951996Report (Other academic)
    Abstract [sv]

    Målsättning för 1995 års kontrollprogram har varit att kontinuerligt bevaka temperaturen i vertikal S i skärgårdsområdet.

    Kylvatten har släppts via reservutskovet vid olika tillfällen under sammanlagt 5 månader. Största delen av utsläppen har skett under andra halvåret. Detta pga problem med rensningen av fiskspärren vid Biotestsjöns utlopp. För 1994 rådde liknande förhållanden.

    Effekten av kylvatten från reservutskovet och en vann inledning på hösten ("brittsommar") medförde att den hittills högsta månadsmedeltemperaturen för oktober noterades (vertikal S på 1 m djup 11.82°C). Årsmedeltemperaturen (april-nov) under 1995 låg 1 °C över medelvärdet för perioden 1977-94 (april-nov ). Motsvarande siffra för 1994 var 1. 7°C.

    1995 års temperaturöverskott uppstod framförallt under augusti-september- oktober. I  november ökade vattenutbytet med det utanförliggande havsområdet och någon ackumulering av kylvatten kunde inte registreras.

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  • 77.
    Andersson, Jan
    et al.
    SMHI, Core Services.
    Hillgren, Robert
    SMHI, Core Services.
    Westring, Gustaf
    SMHI.
    Strömmar, skiktningsförhållanden, vattenståndsvariationer mellan Cebu och Leyte, Filippinerna.: -En förstudie inför sjökabelläggning i områdetTyp: Rapport1992Report (Other academic)
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  • 78.
    Andersson, Kerstin
    SMHI, Core Services.
    Svenskt sjöregister. 2 delar: Svenskt Vattenarkiv1996Report (Other academic)
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  • 79.
    Andersson, Kerstin
    SMHI, Core Services.
    Vattenföring i Sverige. Del 1. Vattendrag till Bottenviken: Svenskt Vattenarkiv1995Report (Other academic)
    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 gäng "Vattenföring i Sverige" i fyra delar. Indelningen av Sverige är densamma som i "Arealer för avrinningsområden", som samtidigt är under utgivning. De 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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  • 80.
    Andersson, Kerstin
    SMHI, Core Services.
    Vattenföring i Sverige. Del 2. Vattendrag till Bottenhavet: Svenskt Vattenarkiv1995Report (Other academic)
    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 år 1950. En nyutgåva, "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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  • 81.
    Andersson, Kerstin
    SMHI, Core Services.
    Vattenföring i Sverige. Del 3. Vattendrag till Egentliga Östersjön: Svenskt Vattenarkiv1993Report (Other academic)
    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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  • 82.
    Andersson, Kerstin
    SMHI, Core Services.
    Vattenföring i Sverige. Del 4. Vattendrag till Västerhavet: Svenskt Vattenarkiv1994Report (Other academic)
    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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  • 83.
    Andersson, Lars
    SMHI, Core Services.
    Trends in nutrient and oxygen concentrations in the Skagerrak-Kattegat1996In: Journal of Sea Research, ISSN 1385-1101, E-ISSN 1873-1414, Vol. 35, no 1-3, p. 63-71Article in journal (Refereed)
    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.

  • 84.
    Andersson, Lars
    et al.
    SMHI, Core Services.
    Carlberg, Stig
    SMHI, Core Services.
    Fogelqvist, Elisabet
    SMHI.
    Fonselius, Stig
    SMHI, Research Department, Oceanography.
    Fyrberg, Lotta
    SMHI, Core Services.
    Palmén, Håkan
    SMHI.
    Zagradkin, Danuta
    SMHI.
    Yhlén, Bengt
    SMHI.
    Program för miljökvalitetsövervakning – PMK: Utsjöprogram under 19901991Report (Other academic)
    Abstract [en]

    The projectThis report describes a project for environmental monitoring in the sea areas around Sweden, from the Kattegat to the northern part of the Bothnian Sea. SMHI carries out this project based on a contractual arrangement with the National Swedish Environment Protection Agency (SEPA) and the project is part of the national programme for environmental monitoring (PMK). The greater part of the results from the project described here is also reported as a national Swedish contribution to the Baltic Monitoring Programme (BMP) of the Helsinki Commission (HELCOM).

    The monitoring is carried out through a number of regular cruises in the Kattegat, the Sound (Öresund), the Baltic Proper and the Gulf ofBothnia. Physical, chemical and biological parameters are studied in water samples, zoobenthos is studied in sediment grab samples and samples of fish and mussels are collected for the determination of harmful substances.

    The work is entirely integrated with the regular oceanographical programme of SMHI. By this arrangement the result of the SMHI programme is made available also for the national monitoring. Consequently, this report contains a lot more information than is really financed by the SEPA monitoring budget.

    ResultsThe winter of 1989 - 90 was very mild; it was in fact the fourth mild winter in sequence! The sea ice cover was small; By and large, it was only the Bothnian Bay that was covered and this ice broke up about two weeks earlier than usual. The first part of 1990 was warm and windy and yielded at lot of  precipitation, particularly in the southern part of Sweden. The spring was early and warmer than normal. In May and later the weather was more unstable and the summer had changing weather and somewhat low temperatures. The autumn started as calm and rainy, but ended in December as mild and windy.

    The temperature of the sea surface layer was higher than normal most part of the year, just as it was in 1989. lnfact, the temperatures were 1- 3 °C above the long term mean value for the period 1979- 1989 in the entire area.

    The oxygen conditions in the south eastern Kattegat once again turned into an unfavorable situation in late summer and early autumn. However, despite the unusually calm autumn with only weak mixing of the water masses the oxygen concentrations increased again and the situation never was serious. Also in the Baltic Proper the bad oxygen situation in the deep water prevailed in several basins the whole year. No major infiow of oxygen rich water occurred to ventilate the deep basins. In the Bornholm Basin hydrogen sulphide was present under the halocline (with an extension into the Hanö Bight) the whole year with the exception of the August cruise. In the Gdansk Basin there is no longer any stratification and oxygen is mixed into hte water from the surfacelayer. This has improved the conditions int he bottom water. However, in the Eastern Gotland Basin hydrogen sulphide has been present in the bottom water for more than 13 years continuously. The Northern Central Basin, including the Landsort Deep, and the Western Central Basin were free from hydrogen sulphide the whole year.

    Nutrient conditions did not show any remarkable or unexpected changes during 1990. During the winter period phosphate and nitrate were present in about normal concentrations, which decreased to near detection limit during the production period in the spring and early summer and then increased again during autumn.

    The analyses of petroleum hydrocarbons showed slightly lower concentrations for the spring as compared to the results from the 1980-ties. This indicates that the load of oil pollution of the Baltic and the Kattegat had not changed significantly. However, the results from the autumn sampling were strikingly different. Although the surface samples showed normal concentrations the results from 10 m (and 30 m) were higher. The reason for this could not be identified but it is unlikely to be a contamination of the samples.

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  • 85.
    Andersson, Lars
    et al.
    SMHI, Core Services.
    Rahm, Lars
    SMHI, Research Department, Oceanography.
    THERMALLY DRIVEN CIRCULATION WITHIN AN EXPERIMENTAL ENCLOSURE1990In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 30, no 2, p. 111-129Article in journal (Refereed)
  • 86.
    Andersson, Lars
    et al.
    SMHI, Core Services.
    RYDBERG, L
    EXCHANGE OF WATER AND NUTRIENTS BETWEEN THE SKAGERRAK AND THE KATTEGAT1993In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 36, no 2, p. 159-181Article in journal (Refereed)
  • 87.
    Andersson, Lotta
    SMHI, Core Services.
    Experiences of the use of riverine nutrient models in stakeholder dialogues2004In: International Journal of Water Resources Development, ISSN 0790-0627, E-ISSN 1360-0648, Vol. 20, no 3, p. 399-413Article in journal (Refereed)
    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.

  • 88.
    Andersson, Lotta
    et al.
    SMHI, Core Services.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Consequences of changed wetness on riverine nitrogen - human impact on retention vs. natural climatic variability2001In: Regional Environmental Change, ISSN 1436-3798, E-ISSN 1436-378X, Vol. 2, no 3, p. 93-105Article in journal (Refereed)
    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).

  • 89.
    Andersson, Lotta
    et al.
    SMHI, Core Services.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Modelling of human and climatic impact on nitrogen load in a Swedish river 1885-19942003In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 497, no 1-3, p. 63-77Article in journal (Refereed)
    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.

  • 90.
    Andersson, Lotta
    et al.
    SMHI, Core Services.
    Bonell, M
    Moody, D W
    Special thematic issue: Hydrology for the environment. life and policy (Help) Programme - Foreword2004In: International Journal of Water Resources Development, ISSN 0790-0627, E-ISSN 1360-0648, Vol. 20, no 3, p. 267-274Article in journal (Other academic)
  • 91.
    Andersson, Lotta
    et al.
    SMHI, Core Services.
    Olsson, Johanna Alkan
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Jonsson, Anna
    Use of participatory scenario modelling as platforms in stakeholder dialogues2008In: Water S.A., ISSN 0378-4738, E-ISSN 1816-7950, Vol. 34, no 4, p. 439-447Article in journal (Refereed)
    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.

  • 92.
    Andersson, Lotta
    et al.
    SMHI, Core Services.
    Rosberg, Jörgen
    SMHI, Research Department, Hydrology.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Estimating catchment nutrient flow with the HBV-NP model: Sensitivity to input data2005In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 34, no 7, p. 521-532Article in journal (Refereed)
    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.

  • 93.
    Andersson, Lotta
    et al.
    SMHI, Research Department, Hydrology.
    Samuelsson, Patrick
    SMHI, Research Department, Climate research - Rossby Centre.
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Assessment of climate change impact on water resources in the Pungwe river basin2011In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 63, no 1, p. 138-157Article in journal (Refereed)
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  • 94.
    Andersson, Lotta
    et al.
    SMHI, Core Services.
    Wilk, Julie
    Graham, Phil
    SMHI, Research Department, Climate research - Rossby Centre.
    Warburton, Michele
    Design and test of a model-assisted participatory process for the formulation of a local climate adaptation plan2013In: Climate and Development, ISSN 1756-5529, E-ISSN 1756-5537, Vol. 5, no 3, p. 217-228Article in journal (Refereed)
    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.

  • 95.
    Andersson, Lotta
    et al.
    SMHI, Research Department, Hydrology.
    Wilk, Julie
    SMHI, Research Department, Hydrology.
    Graham, Phil
    SMHI, Professional Services.
    Warburton, Michele
    School of Bioresources Engineering & Environmental HydrologyUniversity of KwaZulu-NatalPrivate Bag X01, Scottsville, 3209 South Africa.
    Local Assessment of Vulnerability to Climate Change Impacts on Water Resources in the Upper Thukela River Basin, South Africa - Recommendations for Adaptation2009Report (Other academic)
    Abstract [en]

    This report originates from a project entitled Participatory Modelling for Assessment of Local Impacts of Climate Variability and Change on Water Resources (PAMO), financed by the Swedish Development Agency and Research Links cooperation (NRF and the Swedish Research Council). The project is based on interactions between stakeholders in the Mhlwazini/Bergville area of the Thukela River basin, climate and water researchers from the University of KwaZulu-Natal (Pietermaritzburg Campus) and the Swedish Meteorological and Hydrological Institute (SMHI) during a series of workshops held in 2007-2009. Between the workshops, the researcher’s compiled locally relevant climate change related information, based on requests from the workshop participants, as a basis for this adaptation plan. The aim is to provide a local assessment of vulnerability to climate change impacts on water resources and adaptation strategies. The assessment identifies existing climate-water related problems, current adaptation strategies and recommendations for future action based on likelihoods for change and the severity if such changes will occur.Denna rapport har sitt ursprung i projektet Deltagande modellering för bedömning av lokal inverkan av klimatvariabilitet och förändringar på vattenresurser (PAMO), finansierat av Sida och Research Links (NFR i Sydafrika, samt VR i Sverige). Projektet baseras på interaktion mellan vattenintressenter i Mhlwazini/Bergville området av Thukelas avrinningsområde och klimat och vattenforskare från University of KwaZulu-Natal (Pietermaritzburg Campus) och SMHI under en serie av workshops under 2007-2009. Mellan workshops har forskarna tagit fram klimatförändringsrelaterad information med lokal relevans, baserat på önskemål från deltagarna i workshops. Denna information har sedan använts som ett underlag till framtagandet av en anpassningsplan. Syftet är att tillhandahålla en lokal bedömning av sårbarhet relaterad till påverkan på vattenresurser av klimatförändringar, samt en lokalt föreslagen anpassningsstrategi. Existerande klimatrelaterade problem och nuvarande anpassningsstrategier har identifierats och rekommendationer för framtida aktioner, baserade på sannolikhet för förändringar och kännbarheten av konsekvenserna om dessa förändringar inträffar.

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  • 96.
    Andersson, Lotta
    et al.
    SMHI, Core Services.
    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 River2006In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 331, no 1-2, p. 43-57Article in journal (Refereed)
    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.

  • 97.
    Andersson, Pia
    et al.
    SMHI, Core Services.
    Hansson, Martin
    SMHI, Core Services.
    Bjurström, Joel
    Simonsson, Daniel
    Naturtypsbestämning av miljöövervakningsstationer SMHI pelagial miljöövervakning2017Report (Other academic)
    Abstract [en]

    Sampling stations in the national environmental monitoring in the marine environment is not defined when it comes to habitat. This means that the environmental monitoring data collected cannot be properly used in the assessments connected to the Habitats Directive or the Marine Framework Strategy Directive. SwAM has funded and commissioned SMHI to explore the possibilities to in a simple manner classify the habitats for the SMHI monitoring stations. The project was intended to test the equipment and through drop video examine if it is possible, and if so, determine habitats for the open sea stations during the expedition in December, 2016. SMHI has designed a rig and conducted sampling at 11 of 25 monitoring stations. Lighting problems and weather conditions reduced the number of sampled stations. SMHI:s opinion is that the rig, with adjusted light source, is a good tool for visual investigation of the habitats at the monitoring stations in the open sea. However, we have proposed a number of adjustments to the rig to increase the quality of the images and videos and to increase the possibility to carry out further assessments of the material. Most of the images show very fine-grained material like silt / clay. A few species have been recorded and almost no vegetation. Most of the stations did not meet the criteria for the Habitat Directive . At two stations habitat was registered as 1160 Bays and sounds, containing1110 Sandbanks. For HUB Underwater biotopes, AB.H3O Baltic aphotic muddy sediments Characterized by infaunal echinoderms was registered at the station P2 and AB.M4U Baltic aphotic mixed substrate Characterized by no macro community was registered on stations BY5 and BY4. SMHI recommends a review of the collected material together with ArtDatabanken and / or additional expert to ensure the performed assessment, to ensure recommendations and to quality control and define the material to be reported to a data host. SMHI recommend additional visual sampling of the remaining stations, as well as additional sampling on stations where the quality of the image was inadequate, or where ArtDatabanken or a possible additional expert recommend additional sampling. Additional experts may recommend adding sediment sampling to the visual method at some stations. Performing visual sampling of all 25 stations, with one landing per station, will extend the expedition with approximately 11,5-13, hours.

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  • 98.
    Andersson, Stefan
    et al.
    SMHI, Professional Services.
    Arvelius, Johan
    SMHI, Professional Services.
    Jones, Jörgen
    SMHI, Professional Services.
    Kindell, Sven
    SMHI, Professional Services.
    Leung, Wing
    SMHI, Professional Services.
    Beräkningar av emissioner och halter avbenso(a)pyren och partiklar frånsmåskalig vedeldning: Luftkvalitetsmodellering för Skellefteå, Strömsunds och Alingsås kommuner2019Report (Other academic)
    Abstract [sv]

    I denna studie har emissioner och halter i utomhusluften av benso(a)pyren (B(a)P) samt partiklar (PM2.5) beräknats för Skellefteå, Strömsunds och Alingsås kommuner avseende småskalig uppvärmning. Emissioner har beräknats för hela kommunerna, medan luftkvalitet har modellerats för två tätorter i varje kommun; Boliden och Bureå i Skellefteå kommun, Backe och Hoting i Strömsunds kommun samt Alingsås och Sollebrunn i Alingsås kommun. De tre kommunerna valdes då de identifierades ha höga B(a)P-halter i den tidigare nationella B(a)P-kartläggningen samt tillgång till sotarregister av tillräcklig bra kvalitet; tätorterna valdes genom att analysera emissionsberäkningarna i varje kommun och välja ut tätorter med de högsta emissionerna.

    Syftet med studien är undersöka hur B(a)P- och PM2.5-halterna i Sverige förhåller sig till miljökvalitetsnormer, utvärderingströsklar samt preciseringen av miljökvalitetsmålet Frisk luft och analysera hur stort gapet är för att klara dessa. Detta genom spridningsmodellering samt utvärdering mot mätningar i fem av tätorterna. Osäkerheterna i den tidigare gjorda nationella karteringen av B(a)Phalter från småskalig vedeldning (Andersson et al., 2015), som ska ses som en preliminär bedömning av halterna, utvärderas också. Vidare undersöks, genom känslighetsanalys, hur antaganden om emissionsfaktorer och eldvanor påverkar luftkvaliteten i områdena. En av de åtgärder som utreds är att byta ut gamla vedpannor mot moderna eldstäder. Luftmiljövinsterna av detta undersöks också genomspridningsmodellering.

    Emissionerna från eldstäderna har beräknats utifrån information från sotarregister i de olika kommunerna, där eldstäderna har klassificerats som vedpannor (miljögodkända och ickemiljögodkända), lokaleldstäder, flis- och pelletspannor samt övriga pannor (mest oljepannor). Geolokalisering, dvs. framtagandet av koordinater, har gjorts för de olika eldstäderna i registren baserat på adresser. Med hjälp av modellerade energibehov för ett genomsnittligt meteorologiskt kalenderår för perioden 1960-1990, för ett genomsnittligt småhus, samt antaganden om emissionsfaktorer, eldstäders nyttjandegrad samt verkningsgrad har sedan emissionerna beräknats.

    Lokalskalig spridningsmodellering med en rumslig upplösning om 20 m × 20 m har genomförts för de utvalda tätorterna med den Gaussiska lokalskaliga spridningsmodellen Dispersion, som är samma lokala modell som finns i modellsystemet SIMAIR-ved. Vid spridningsmodelleringen har meteorologiska data från Mesan för kalenderår 2016 och 2017 använts. Bakgrundshalter har inkluderats för PM2.5, men enbart lokalt haltbidrag från småskalig uppvärmning har beräknats för B(a)P; ett schablontillägg av bakgrundshalter för B(a)P har gjorts för varje tätort. Modelleringen har också utvärderats mot preliminära mätresultat (månadsprovtagning) av B(a)P avseende juni- december 2017 i Boliden, Bureå, Backe, Hoting samt Alingsås tätort samt mätningar av PM2.5 i Bureå och Backe (mätningarna har utförts av Svenska Miljöinstitutet IVL på uppdrag av Naturvårdsverket)

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  • 99.
    Andersson, Tage
    SMHI, Research Department, Atmospheric remote sensing.
    A HEAVY MESOSCALE SNOWFALL EVENT IN NORTHERN GERMANY1991In: METEOROLOGICAL MAGAZINE, ISSN 0026-1149, Vol. 120, no 1425, p. 67-68Article in journal (Refereed)
  • 100.
    Andersson, Tage
    SMHI, Research Department.
    Aeronautic wind shear and turbulence. A review for forecasts1989Report (Other academic)
    Abstract [en]

    'Turbulence' in flight operations means all inhomogeneities in the wind field which cause unexpected deviations from the aircraft's intended flight path. It utters itself as bumpiness, which in extreme cases also may cause severe discomfort to passengers and crew, and even be dangerous because persons and loose objects may be tossed around. Even more serious is that in extreme cases the pilot may lose his control of the aircraft, and/or the aircraft may be damaged.

    This is most serious when an aircraft is heavy loaded and flying at a speed just above its stalling speed, as in take-off.

    'Turbulence' is related to the shear of the wind. A sharp wind shear by itself affects the aircraft; due to its inertia the aircraft tries to keep its speed relative to the ground also when the surrounding air has changed it. This affects the lifting forece, causing an acceleration and a change in the aircraft's attitude.

    lf the air flow is laminar, shear does not produce turbulence. However, even if turbulence needs not to be present in strong shear at low altitudes ( NCR, 1983, after Lee and Beckwith, 1981 ) laminary flow belongs to the laboratory, not the atmosphere. In this manual we will mainly talk about wind shear, since this is a meteorological parameter that at least in principle is possible to measure. It has to be understood that wind shear is nearly always accompanied by turbulence (or bumpiness).

    Some forecasting hints will be given in the text. The most important one will, however, be given already here:

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