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  • 1. Carmichael, G R
    et al.
    Hayami, H
    Calori, G
    Uno, I
    Cho, S Y
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Kim, S B
    Ichikawa, Y
    Ikeda, Y
    Ueda, H
    Amann, M
    Model intercomparison study of long range transport and sulfur deposition in East Asia (MICS-ASIA)2001In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 130, no 1-4, p. 51-62Article in journal (Refereed)
    Abstract [en]

    To help improve the use of models in science & policy analysis in Asia it is necessary to have a better understanding of model performance and uncertainties. Towards this goal an intercomparison exercise has been initiated as a collaborative study of scientists interested in long-range transport in East Asia. An overview of this study is presented in this paper. The study consists of a set of prescribed test calculations with carefully controlled experiments. Models used the same domain, emission inventory, model parameters, meteorological conditions, etc. Two periods (January and May 1993) were selected to reflect long-range transport conditions under two distinct seasons. During these periods measurements of sulfur concentrations and deposition were made throughout the study region using identical sampling and analysis protocols. The intercomparison activity consists of four tasks (Blind Test, Fixed Parameter Test, Source Receptor test, and Tuning Test). All participants were asked to do Task A, and as many of the other tasks as possible. To date seven different models have participated in this study. Results and key findings are presented.

  • 2.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Sulphur simulations for East Asia using the match model with meteorological data from ECMWF2001In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 130, no 1-4, p. 289-294Article in journal (Refereed)
    Abstract [en]

    Sulphur transport and conversion calculations have been conducted over an East Asian domain as part of a model intercomparison exercise. We hereby describe the MATCH model, used in the study, and discuss the results achieved with different model configurations. We find that is often more critical to choose a representative gridbox value than selecting a specific parameter value from the suite available. The modelled, near-surface, atmospheric concentration of total-sulphur (SO2+sulphate) in eastern China is typically 5-10 mug S m(-3), with large areas exceeding 20 mug S m(3). In southern Japan the values range from 2-5 mug S m(-3). Atmospheric SO2 dominates over sulphate near the emission regions while sulphate concentrations are higher over e.g. the western Pacific. The sulphur deposition exceeds several g sulphur m(-2) year m(-1) in large areas of China. Southern Japan receives 0.5-1 S m(-2) year(-1).

  • 3. Kuylenstierna, J C I
    et al.
    Hicks, W K
    Cinderby, S
    Vallack, H W
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Variability in mapping acidification risk scenarios for terrestrial ecosystems in Asian countries2001In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 130, no 1-4, p. 1175-1180Article in journal (Refereed)
    Abstract [en]

    Acidification has the potential to become a widespread problem in parts of Asia. Just how widespread this risk may be is discussed by comparing sulphur deposition to critical load estimates, taking into account neutralising base cation deposition from soil dust. Two scenarios for the sulphur emission in 2025 are used as inputs to the MATCH atmospheric transfer model to estimate sulphur deposition scenarios. Net acidic deposition using a low and high base cation deposition input is compared to a map of sensitivity of terrestrial ecosystems to acidic deposition. Two ranges of critical loads assigned to this sensitivity reap are used. The variability in the maps showing risks of acidification using low and high estimates for critical loads and base cation deposition for two different development pathways is discussed. Certain areas are shown to be at risk in all cases whereas others are very sensitive to the values used to estimate risk.

  • 4.
    Langner, Joakim
    et al.
    SMHI, Research Department, Air quality.
    Persson, Christer
    SMHI, Research Department, Air quality.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Concentration and deposition of acidifying air pollutants over Sweden: Estimates for 1991 based on the match model and observations1995In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 85, no 4, p. 2021-2026Article in journal (Refereed)
    Abstract [en]

    The MATCH (Mesoscale Atmospheric Transport and CHemistry) model has been developed as a tool for air pollution assessment studies on different geographical scales. MATCH is an Eulerian atmospheric dispersion model, including physical and chemical processes governing sources, atmospheric transport and sinks of oxidized sulfur and oxidized and reduced nitrogen. Using a combination of air and precipitation chemistry measurements and the MATCH model, the national and long-range transport contributions to air pollution and deposition can be quantified in the model region. The calculations for the year 1991 show that the Swedish import was about 4.5 times larger than the export for sulfur and about six times larger for reduced nitrogen, while the Swedish import of oxidized nitrogen only exceeded the export by 10%. Using the MATCH system we estimate the long-range transport in an independent way compared to EMEP. Comparison between the EMEP and MATCH calculations for 1991 show that the total deposition of oxidized nitrogen over Sweden is similar, while the EMEP-values for total deposition of oxidized sulfur and reduced nitrogen are 25% respectively 40% smaller than what is obtained from MATCH.

  • 5.
    Lindström, Göran
    et al.
    SMHI, Research Department, Hydrology.
    RODHE, A
    TRANSIT TIMES OF WATER IN SOIL LYSIMETERS FROM MODELING OF O-181992In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 65, no 1-2, p. 83-100Article in journal (Refereed)
    Abstract [en]

    A proper description of water pathways and transit times is important in the simulation of groundwater acidification using hydrochemical models. A simple water balance model, describing water flow and transit times in different soil layers, was developed and tested by the use of the stable isotope O-18 as a natural tracer in soil lysimeters. Drainage was collected from lysimeters of three depths: 15, 40, and 80 cm, from two sites in the Stubbetorp research basin in south-eastern Sweden. The content of O-18 in the precipitation and in the drainage from the lysimeters was measured during 2 yr. O-18 was regarded as an ideal tracer, and its concentration in the drainage was modeled using the concentration in the precipitation as input. The percolation from each soil layer was assumed to depend on the inflow and the soil moisture storage in the layer. The most important model parameter, the field capacity, was derived from field information. Sensitivity analysis showed that the model was rather insensitive to other parameter values. Although simple, the model gave good results, both for the flow of water and O-18. The best results were obtained, when ideal mixing in the upper horizons of the soil was combined with piston flow at greater depths. Preferential flow was not found to be of great importance, nor was immobile water. Particle flow velocities and transit times in the soil lysimeters were simulated. The average particle flow velocities were about 0.6 cm d-1. The use of a dynamic model made it possible to simulate the temporal variations in transit times for water in the soil lysimeters. The mean transit times for the 80 cm lysimeter ranged from about 3 to 6 mo with an average value of 4 mo.

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

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

  • 7.
    Rahm, Lars
    et al.
    SMHI, Research Department, Oceanography.
    Håkansson, Bertil
    SMHI, Research Department, Oceanography.
    LARSSON, P
    FOGELQVIST, E
    BREMLE, G
    Valderaama, Jorge
    SMHI.
    NUTRIENT AND PERSISTENT POLLUTANT DEPOSITION ON THE BOTHNIAN BAY ICE AND SNOW FIELDS1995In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 84, no 1-2, p. 187-201Article in journal (Refereed)
    Abstract [en]

    A study of atmospheric deposited nutrients and some persistent pollutants has been carried out on the ice and snow fields of the subarctic Bothnian Bay, the northernmost basin of the Baltic Sea. Total amounts of 600, 500 and 400 tons NO3-N, NH4-N and N-org-N, respectively are deposited in the snow while the corresponding amounts for P-tot-P is 40 tons. The corresponding amount for PCB and lindane are 1.0 and 0.2 kg, respectively. The measurements were carried out on the snow-covered ice four to six weeks old. A part of the deposited snow has been incorporated into the snow-ice and an attempt to estimate its mean thickness and its amount of nutrients has been made. The total amounts now reach 1700, 1300 and 1100 tons of NO3-N and NH4-N and N-org-N, respectively in the snow and ice together. The results obtained support the use of land-based stations in estimates of seasonal atmospheric nutrient deposition to the Bothnian Bay. The observed concentrations of chloroorganic compounds correspond to those land-based observations reported from the same latitude in the northern hemisphere and reported in literature.

  • 8.
    Robertson, Lennart
    et al.
    SMHI, Research Department, Air quality.
    Rodhe, H
    Granat, L
    Modelling of sulfur deposition in the southern Asian region1995In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 85, no 4, p. 2337-2343Article in journal (Refereed)
    Abstract [en]

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

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

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

  • 10.
    Sandén, Per
    SMHI, Research Department, Hydrology.
    ESTIMATION AND SIMULATION OF METAL MASS-TRANSPORT IN AN OLD MINING AREA1991In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 57-8, p. 387-397Article in journal (Refereed)
    Abstract [en]

    In a watershed with an old mine tailings deposit, mass transport of Cu, Zn and Cd was studied. An extensive sampling program and the use of the PULSE model for the simulation of water flow made it feasible to simulate and compare the dynamics of metal transport at different sites in the study area. Close to the tailings deposit, the weathering rate in the deposit had a large impact on the dynamics of the mass transport, and interannual variation in mass transport was considerably lower than the variation in runoff. Further downstream, the mass transport was almost exclusively determined by the water flow and, thus far unidentified, mechanisms maintained fairly constant metal concentrations in the stream water. The usefulness of the PULSE model for simulating metal concentrations may still be questioned. However, it is noteworthy that a hydrochemical model based on a fairly simple description of the mixing of water from different sources and a very simple pH dependence of the concentration of metals, at least semi-quantitatively, can reproduce the dynamics of metal concentrations and mass transport of metals.

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