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  • 301.
    Sahlée, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science. Air and water sciences.
    Smedman, Ann-Sofi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Högström, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Rutgersson, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Bulk Exchange Coefficient for Humidity at Sea during Unstable and Neutral Conditions: A Re-evaluation based on new Field Data2006Conference paper (Other academic)
    Abstract [en]

    Analysis of the neutral exchange coefficient for latent heat, CEN, based on measurements from the Östergarnsholms site in the Baltic Sea has been made.

    CEN was found to be constant with wind speed during periods with an air-sea temperature difference, ΔT, larger than 3 K. However, for smaller ΔT it was demonstrated that CEN increased dramatically with wind speed.

    Through calculations with the spray-flux model of Andreas (2004) it was shown that spray-effects on the turbulent fluxes are relatively small. It was concluded that the increase of the exchange coefficients is due to dynamic effects.

    With the aid of spectral analysis it was demonstrated that there is a link between the strong increase of the exchange coefficients and the turbulence structure. During high winds and small ΔT, surface layer scale eddies gain importance on the turbulent transport of latent and sensible heat, at the expense of the larger scale eddies.

    The increase in CEN was found to be closely connected to a similar increase in the roughness length for humidity, z0q. It was demonstrated that this value deviated strongly from the z0q values calculated with surface renewal theory during high wind speeds and small ΔT. This result was taken as an indication of the failure of surface renewal theory for wind speeds above 10 ms-1. It is suggested that this is a result from the increasing importance of wave breaking with a possible link to changes in the turbulence structure.

    References

    Andreas, E. L, 2004: A bulk air-sea flux algorithm for high-wind, spray conditions, Version 2.0. Preprints, 13th Conf. on Interactions of the Sea and Atmosphere, Portland, ME, 9-13 August 2004, Amer. Meteor. Soc., CD-ROM P1.5, 8 pp.

  • 302.
    Sahlée, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Smedman, Ann-Sofi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Högström, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Rutgersson, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Re-evaluation of the bulk exchange coefficient for humidity at sea during unstable and neutral conditions2008In: Journal of Physical Oceanography, ISSN 0022-3670, E-ISSN 1520-0485, Vol. 38, no 1, p. 257-272Article in journal (Refereed)
    Abstract [en]

    Processes influencing the air-sea exchange of humidity during unstable and neutral stratification were studied using tower measurements from the island of Ostergarnsholm in the Baltic Sea. For small air-sea temperature differences, the neutral exchange coefficient for humidity C-EN was found to increase with increasing wind speed, attaining a value of approximately 1.8 x 10(-3) at 13 m s(-1). The high C-EN values were observed during situations when the characteristics of the turbulence structure differed from what would be expected from traditional theory. Results from spectral analysis point to a situation in which the vertical transport of humidity is dominated by smaller-scale eddies. Quadrant analysis showed that these eddies enhance the humidity flux by bringing down drier air from layers aloft. These findings are consistent with recent analyses of the neutral boundary layer in which a change of turbulence regime has been observed. The conclusion is made that this dynamic effect accounts for the observed increase in C-EN. Here, C-EN was calculated using a wave-dependent normalized wind gradient, which had the effect of reducing the value by about 10% during swell relative to calculations using a non-wave-dependent normalized wind gradient.

  • 303.
    Sahlée, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Smedman, Ann-Sofi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Rutgersson, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    A Comparison between Webb corrected Humidity and CO2 Spectra in the Marine Atmospheric Boundary Layer2007In: Fifth Study Conference on BALTEX, 2007, p. 212-Conference paper (Other academic)
  • 304.
    Sahlée, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Smedman, Ann-Sofi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Rutgersson, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Högström, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Spectra of CO2 and water vapour in the marine atmospheric surface layer2008In: Boundary-layer Meteorology, ISSN 0006-8314, E-ISSN 1573-1472, Vol. 126, no 2, p. 279-295Article in journal (Refereed)
    Abstract [en]

    Spectra of CO2 and water vapour fluctuations from measurements made in the marine atmospheric surface layer have been analyzed. A normalization of spectra based on Monin-Obukhov similarity theory, originally developed for wind speed and temperature, has been successfully extended also to CO2 and humidity spectra. The normalized CO2 spectra were observed to have somewhat larger contributions from low frequencies compared to humidity spectra during unstable stratification. However, overall, the CO2 and humidity spectra showed good agreement as did the cospectra of vertical velocity with water vapour and CO2 respectively. During stable stratification the spectra and cospectra displayed a well-defined spectral gap separating the mesoscale and small-scale turbulent fluctuations. Two-dimensional turbulence was suggested as a possible source for the mesoscale fluctuations, which in combination with wave activity in the vertical wind is likely to explain the increase in the cospectral energy for the corresponding frequency range. Prior to the analysis the turbulence time series of the density measurements were converted to time series of mixing ratios relative to dry air. Some differences were observed when the spectra based on the original density measurements were compared to the spectra based on the mixing ratio time series. It is thus recommended to always convert the density time series to mixing ratio before performing spectral analysis.

  • 305.
    Sapota, Tomasz
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Håkanson, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. LUVA.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. ELD.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Sediment flux to Lake Baikal (Siberia, Russia): Modeling approach2006In: Geomorphology, Vol. 80, p. 105-113Article in journal (Refereed)
  • 306. Schippers, Axel
    et al.
    Herbert Jr., Roger
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Höglund, Lars Olof
    Geomicrobiological and geochemical investigation of pyrite – containing tailings from Kristineberg, Northern Sweden2005In: Proceedings, Securing the Future. Skellefteå, Sweden, 2005, p. 866-875Conference paper (Other (popular scientific, debate etc.))
    Abstract [en]

    Pyrite - containing tailings in Impoundment 1 in Kristineberg, northern Sweden were covered in 1996 with a soil cover consisting of 0.3 m compacted till and 1.5 m unspecified till. From the 1940s until 1996, the impoundment was unremediated and sulfide oxidation occurred to depths of 1 m in the tailings. This study focuses on the importance of microorganisms for pyrite oxidation and the release of oxidation products in the remediated tailings. Three cores containing material from the sealing layer and the zones of oxidized and unoxidized tailings were taken in September 2003 and geomicrobiologically and geochemically analyzed. Most-probable-number (MPN) numbers of pyrite-oxidizing, acidophilic Fe(II)-oxidizing microorganisms of the type Acidithiobacillus ferrooxidans were highest with up to 106 cells g-1 dw at the interface between the oxidized and unoxidized tailings, which correlates with maximum metal and sulfate pore water concentrations, a shift of pH and pe, as well as with high potential biological pyrite oxidation rates measured by microcalorimetry at atmospheric oxygen content. The mean proportion of biological pyrite oxidation was 80 % for the oxidized tailings. The potential pyrite oxidation rate for an assumed 0.3 m thick oxidation zone within the oxidized tailings was 4.7 x10-6 mol m-2 s-1 tailings surface (18 kg FeS2 m-2 year-1). The potential chemical pyrite oxidation rate was highest for the unoxidized tailings where Fe(II)-oxidizing microorganisms could not be detected and where the pyrite content was much higher than in the oxidized tailings. The results show that pyrite is biologically oxidized in particular zones of the mine tailings.

  • 307. Seibert, J.
    et al.
    Rodhe, Allan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Bishop, Kevin
    Simulating interactions between saturated and unsaturated storage in a conceptual runoff model2003In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 17, no 2, p. 379-390Article in journal (Refereed)
    Abstract [en]

    There is an increasing demand for modelling the fluxes of chemical constituents at the catchment scale. Conceptual runoff models provide a basis for such modelling tasks provided that they capture the essential hydrological processes. However, most conceptual models do not fully address interactions between unsaturated and saturated storage. This can lead to unrealistic simulations for watersheds with shallow groundwater, where a large part of the soil volume can contribute to both the unsaturated and the saturated storage, depending on groundwater levels. Adding a small amount of water to the saturated storage will cause a significant amount of water stored in the unsaturated zone to change its status to ‘saturated’. The maximum volume of the unsaturated storage also decreases with rising groundwater levels, i.e. increasing saturated storage. In this study, a new model concept was proposed in which special emphasis was put on the interaction between saturated and unsaturated storage. The total storage was divided into two compartments, representing saturated and unsaturated storage, with a boundary moving up and down in response to the water budget of the compartments. Groundwater dynamics show a distinct pattern along the hillslope studied. Groundwater levels in an area close to the stream had dynamics similar to runoff, whereas levels further upslope responded to rainfall with a delay. To represent these differences in the model, the hillslope was subdivided into a riparian and an upslope reservoir. The performance of the new model was compared with that of simpler model variants without spatial differentiation and with or without the new formulation allowing for interactions between unsaturated and saturated storage. The new model approach provided the best results for simulating both runoff and groundwater dynamics. The subdivision of the hillslope accounted for most of the performance increase. To test the model structure further, 18O concentrations in the stream were simulated and compared with measured values.

  • 308. Seibert, Jan
    et al.
    Bishop, Kevin
    McDonnell, Jeff
    Rodhe, Allan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Groundwater dynamics along a hillslope: A test of the steady state hypothesis2003In: Water Resources Research 39(1), pp 21-29, Vol. 39, no 1, p. 21-29Article in journal (Refereed)
  • 309. Shafer, Kristina
    et al.
    Hylander, Lars D.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Luft- och vatten (LUVA).
    Plath, David
    Novel solution to reduce or eliminate mercury pollution from artisanal and small scale gold mining.2006In: Abstracts of Eighth International Conference on Mercury as a Global Pollutant, 2006, p. 574-Conference paper (Other scientific)
    Abstract [en]

    In Suriname, mercury amalgamation is the favored method for recovering fine gold from sluice concentrates. An estimated 12-16,000 miners are releasing as much mercury to the environment as they are recovering in gold. A project is now underway to reduce or eliminate the use of mercury in gold mining. Funded by World Bank and in partnership between Artminers and World Wildlife-Guianas, this project introduces the Cleangold™

    sluice as an alternative to mercury. This patented method employs simple, inexpensive gravity separation. The University of British Columbia and University of Uppsala in Sweden have independently verified the efficacy of Cleangold. After field tests in Africa, Asia and South America, UNIDO’s Global Mercury Project has identified Cleangold as a mercury replacement method. A first round of training workshops were completed in

    December 2005 with over 70 miners attending. Interest is high in Cleangold because miners are paying upwards of $300/kg for mercury. Testing the ores and tailings of the operations in two areas confirmed anecdotal accounts from miners that they are

    recovering approximately 50% of the gold using their current practices. Using the Cleangold method, samples of gold, mercury, and amalgamated gold were recovered from tailings. The bulk of the gold recovered was found to be less than 150 microns in

    diameter. While the sluice boxes used by these miners are well built and operated, gold below 150 microns is not recovered by their expanded metal and looped carpet sluices. Evidence of losses of gold larger than 150 microns during the amalgamation process was noted and a mechanism for this loss is suggested. Methods to completely remove the use of mercury from these operations are described. Miners who attended workshops intend

    to employ Cleangold sluices to retrieve mercury, amalgam and fine gold from their tailings. This will be the first step in reclamation of abandoned mine sites. To reduce pollution from this process, WWF-Guianas will build simple retorts for distribution to miners to safely recover mercury from the concentrates of the Cleangold™ process until mercury free mining is established.

  • 310.
    Sjöblom, Anna
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Nilsson, Charlotta
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Bergström, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    A modified inertial dissipation method applied on light weight cup anemometers2005Report (Other (popular scientific, debate etc.))
  • 311.
    Sjöblom, Anna
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Smedman, Ann-Sofi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Comparison between eddy-correlation and inertial dissipation methods in the marine atmospheric boundary layer2004In: Boundary-Layer Meteorology, Vol. 110, p. 141-164Article in journal (Refereed)
  • 312.
    Sjöblom, Anna
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Smedman, Ann-Sofi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    The turbulent kinetic budget over the sea2002In: J. Geophys. Res., Vol. 107, no C10Article in journal (Refereed)
  • 313.
    Sjöblom, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Smedman, Ann-Sofi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    The turbulent kinetic energy budget in the marine atmospheric surface layer2002In: Journal of Geophysical Research - Oceans, ISSN 2169-9275, E-ISSN 2169-9291, Vol. 107, no C10, article id 3142Article in journal (Refereed)
  • 314.
    Sjöblom, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Smedman, Ann-Sofi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Vertical Structure in the Marine Atmospheric Boundary Layer and its Implication for the Inertial Dissipation Method2003In: Boundary-layer Meteorology, ISSN 0006-8314, E-ISSN 1573-1472, Vol. 109, no 1, p. 1-25Article in journal (Refereed)
    Abstract [en]

    The structure of the marine atmospheric boundarylayer and the validity ofMonin–Obukhov similarity theory over the seahave been investigated using longterm measurements. Three levels of turbulencemeasurements (at 10 m, 18 mand 26 m) at Östergarnsholm in themiddle of the Baltic Sea have beenanalysed. The results show that turbulentparameters have a strong dependenceon the actual height due to wave influence.The wind profile and thus thenormalised wind gradient are very sensitiveto wave state. The lower part of theboundary layer can be divided into three heightlayers, a wave influenced layerclose to the surface, a transition layer andan undisturbed ‘ordinary’ surfacelayer; the depth of the layers is determinedby the wave state. This heightstructure can, however, not be found for thenormalised dissipation, which is onlya function of the stability, except duringpronounced swell where the actualheight also has to be accounted for. Theresults have implications for the heightvariation of the turbulent kinetic energy(TKE) budget. Thus, the imbalancebetween production and dissipation willalso vary with height according to thevariation of wave state. This, in turn,will of course have strong implicationsfor the inertial dissipation method, inwhich a parameterisation of the TKEbudget is used.

  • 315.
    Sjögren, Björn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Brandt, Ola
    Nuth, Chris
    Isaksson, Elisabeth
    Pohjola, Veijo
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Kohler, Jack
    van de Waal, Roderik S.W.
    Determination of firn density in ice cores using image analysis2007In: Journal of Glaciology, ISSN 0022-1430, E-ISSN 1727-5652, Vol. 53, no 182, p. 413-419Article in journal (Refereed)
    Abstract [en]

    This study presents a simple and inexpensive method for deriving a high-resolution density proxy record for the firn part of an ice core using digital images. The image data have better resolution and are less sensitive to core quality than is density derived through di-electric profiling (DEP). Simple image analysis is thus suitable to derive a density proxy record in the firn section of ice cores drilled in the percolation or wet snow zone, and to better interpret the results of a DEP record. The images may be used as a permanent record when evaluating other types of ice-core data. Suggestions are provided to improve data quality and decrease post-processing time of the image analysis in future studies.

  • 316. Slånberg, Lena
    et al.
    Hylander, Lars
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Luft- och vatten.
    Appropriate classification of three Swedish soils for agrarian and environmental management2004In: Agricultural and Food Science, Vol. 13, no 4, p. 378-389Article in journal (Refereed)
    Abstract [en]

    Classification of soils according to internationally agreed criteria forms a valuable base for scientific and political analyses. The objectives of this study were to evaluate two soil classification systems and relate them to agricultural and environmental concerns, principally phosphorus leakage, by classifying three Swedish, arable soils. The Bjärröd soil was classified as a Rupti-Endogleyic Phaeozem according to the World Reference Base for Soil Resources and as a coarse-loamy, mesic Oxiaquic Hapludoll according to the Soil Taxonomy. Bjelkesta was classified as an Orthieutric Gleysol and a fine, frigid, Typic Endoaquept, respectively, and Götala as a Haplic Arenosol and a frigid Typic Udipsamment. We evaluated some changes to the classification systems proposed by Nordic scientists and found the classification of Bjärröd misleading and suggest it being classified as a Cambisol/Inceptisol and that information of the characteristically high base saturation in Bjelkesta and the spodic character in Götala being included in their names. This information is useful for decisions regarding agrarian and environmental management of the soils.

  • 317. Slånberg, Lena
    et al.
    Hylander, Lars D.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Appropriate classification of three Swedish soils for agrarian and environmental management.2005In: Focus on Soils Symposium 14—16 September 2005 in Uppsala, ‘Managing Soils for the Future’, 2005Conference paper (Other scientific)
  • 318.
    Smedman, A., Guo-Larsén, X., Högström, U., Kahma, K. and Pettersson. H.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. AIR AND WATER SCIENCE.
    Smedman, Ann-Sofi
    The effect of sea state on the monmentum exchange over the sea during neutral conditions2003In: Journal of Geophysical Research, Vol. 108, no C11, p. 3367-Article in journal (Refereed)
  • 319.
    Smedman, Ann-Sofi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Precipetation and Evaporation Budgets over the Baltic Proper:Observations and Modelling2006In: J. of Atmospheric and Ocean Science, Vol. 30, no 4, p. 269-286Article in journal (Refereed)
  • 320.
    Smedman, Ann-Sofi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    The marine atmospheric boundary layer during swell, according to recent studies in the Baltic Sea1999In: Air-Sea exchange, 1999Chapter in book (Refereed)
  • 321.
    Smedman, Ann-Sofi
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. LUVA.
    Gryning, Sven-Erik
    Bumke, Karl
    Högström, Ulf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. LUVA.
    Rutgersson, Anna
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. LUVA.
    Batchvarova, Ekaterina
    Peters, Gerhard
    Hennemuth, Barbara
    Tammelin, Bengt
    Hyvönen, Reijo
    Omstedt, Anders
    Michelson, Daniel
    Andersson, Tage
    Clemens, Marco
    Precipitation and evaporation budgets over the Baltic Proper: observations and modelling2005In: Journal of Atmospheric and Ocean Science, ISSN 1741-7538, Vol. 10, no 3, p. 163-191Article in journal (Refereed)
    Abstract [en]

    Precipitation and evaporation budgets over the Baltic Sea were studied in a concerted project called PEP in BALTEX, combining extensive field measurements and modelling efforts. Eddy-correlation-measurements of turbulent heat flux were made on a semi-continuous basis for a 12 months period at four well-exposed coastal sites in the Baltic Proper. Precipitation was measured at land-based sites with standard gauges and on four merchant ships travelling between Germany and Finland with the aid of specially designed ship rain gauges (SRG).

    The evaporation and precipitation regime of the Baltic Sea was modelled for a 12 months period by applying a wide range of numerical models: The operational atmospheric High Resolution Limited Area Model HIRLAM (Swedish and Finnish versions), the German atmospheric REgional-scale MOdel, REMO, the operational German Europe-Model (only precipitation), the oceanographic model PROBE-Baltic, and two models that use interpolation of ground-based data, the Swedish MESAN model of SMHI and a German model of IFM-GEOMAR Kiel.

    Modelled precipitation was compared with ship rain gauge measurements on board the ships. A reasonable correlation was obtained, but the regional scale models and MESAN give some 20 percent higher precipitation over the sea than measured.

    Bulk parameterisation schemes for evaporation were evaluated against measurements. A constant value of CHN and CEN with wind speed underestimated large fluxes of both sensible and latent heat flux. The limited area models do not resolve the influence of the height of the marine boundary layer in coastal zones and the entrainment processes, which may explain the observed low correlations between modelled and measured latent heat fluxes.

    Estimates of evaporation, E, and precipitation, P, for the entire Baltic Proper were made with several models for a 12 months period. While the annual variation was well represented by all predictions, there are still important differences in the total mean. Evaporation ranges from 509 to 625 mm/year and precipitation between 624 and 805 mm/year for the particular 12 months period. Taking the results of model verification from the present study into account, the best estimate of P - E is about 100 50 mm for the particular 12 months period. But the annual mean of P - E varies considerably from year to year. This is reflected in simulations with the PROBE-Baltic model for an 18 years period, which gave 95 mm/year for the 12 months period studied here and 32 mm/year as an average for 18 years.

  • 322.
    Smedman, Ann-Sofi
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Högström, Ulf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Effect of sea state on the momentum exchange2006In: GTP Conference on Turbulence and Scalar Transport in Roughness Sublayers, Boulder, USA,26-28 September 2006, 2006Conference paper (Refereed)
  • 323.
    Smedman, Ann-Sofi
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Högström, Ulf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Effects of shear sheltering in a slightly stable atmospheric boundary layer with strong shear2005In: Quarterly Journal of the Royal Meteorological Society, Vol. 130, p. 31-50Article in journal (Refereed)
  • 324.
    Smedman, Ann-Sofi
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. LUVA.
    Högström, Ulf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. LUVA.
    Effects of shear sheltering in Atmosperic surface layer flow2004In: IUTAM Symposium on Reynolds Number Scaling in Turbulent Flow, Kluwer Academic Publisher , 2004, p. 375-Chapter in book (Refereed)
  • 325.
    Smedman, Ann-Sofi
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Högström, Ulf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Towards a fundamentally new understanding of the marine atmospheric boundary layer2004In: AMS conference 16th Symposium on Boudary Layers and Turbulence, Portland, Maine, USA, 2004, 2004Conference paper (Refereed)
  • 326.
    Smedman, Ann-Sofi
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Högström, Ulf
    Wind climatology at a well-exposed site in the Baltic Sea.1999In: Journal of Wind Engineering, Vol. 23, no 2, p. 133-142Article in journal (Refereed)
  • 327.
    Smedman, Ann-Sofi
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. AIR AND WATER SCIENCE.
    Högström, Ulf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Bergström, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Johansson, Cecilia
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Sjöblom, Anna
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Guo-Larsén, Xiaoli
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    New findings concerning the structure of the marine atmospheric boundary layer over the Baltic Sea – possible implications for wind energy installations2003In: Wind Engineering, Vol. 27, no 6Article in journal (Refereed)
  • 328.
    Smedman, Ann-Sofi
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Högström, Ulf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Bergström, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Rutgersson, Anna
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Kahma, K. K.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Pettersson, H.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    A case study of air-sea interaction during swell conditions1999In: J. Geophys. Res.: C, Vol. 104, p. 25833-25851Article in journal (Refereed)
  • 329.
    Smedman, Ann-Sofi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Högström, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Sahleé, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Johansson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Critical re-evaluation of the bulk transfer coefficient for sensible heat over the ocean during unstable and neutral conditions2007In: Quarterly Journal of the Royal Meteorological Society, ISSN 0035-9009, E-ISSN 1477-870X, Vol. 133, no 622, p. 227-250Article in journal (Refereed)
    Abstract [en]

    A new analysis of the neutral heat transfer coefficient CHN on data from Östergarnsholm is presented, which is primarily based on a limited set of measurements with the very accurate MIUU (Meteorological Institute of the University of Uppsala) instrument, but with additional information from an extensive set of measurements with Solent sonic R2. Sonic data are, however, used with great caution, since for wind speed U above 10 m s-1, a strongly wind-speed-dependent correction is shown to be required. This error is roughly proportional to (U-10) for sea-air temperature differences less than 4-5 K. For a larger temperature difference, no correction appears to be necessary in the wind speed range 10-15 m s-1. We infer from our data that for conditions when unstable and near-neutral conditions prevail, measurements of the sea surface - air temperature difference are accurate to within 0.1 K at our site. This means that data for a range of relatively small temperature differences (0.5-1.5 K) which were often rejected in previous studies could be retained. It is observed that a rapid increase of CH and CHN occurs in that range. For wind speed above 10 m s-1, CHN is observed to increase rapidly with U10. During those conditions, the wave field at the site is known to have characteristics very similar to those in deep-sea conditions. In a previous analysis of data from Östergarnsholm, it was speculated that observed high CHN values could be due to spray. Calculations with a spray model showed, however, conclusively that for wind speeds less than 14 m s-1, the spray effect on the sensible heat flux is expected to be small. The high CHN values must instead be due to dynamic effects. It is demonstrated that when the Obukhov length L is less than about -150 m a regime with very specific characteristics ensues. This regime is dominated by surface-layer scale eddies, which cause Monin-Obukhov relations for the exchange of sensible heat to break down. The characteristics of this surface-layer regime are treated in detail in the companion paper. The rise of CHN with wind speed is shown to be closely related to a corresponding increase of ZOTwith roughness Reynolds number for winds above 10 m s-1. This means that during those conditions, traditional surface renewal theory for heat is no longer valid. It is suggested that this, in turn, is a result of increasing importance of wave-breaking with increasing wind and with a possible link to processes in near-surface atmospheric layers in the regime with -L > 150 m.

  • 330. Sokolik, Adrian S.
    et al.
    Hillström, Lars
    Hylander, Lars D.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Luft- och vattenlära (LUVA).
    Mercury concentrations in sediment and fish from Nanay River, Peru – a small-scale gold mining area.2006In: Abstracts of Eighth International Conference on Mercury as a Global Pollutant, 2006, p. 574-Conference paper (Other scientific)
    Abstract [en]

    Nanay River in the peruvian Amazonian rain forest supports 300 000 inhabitants in the city of Iquitos and surrounding villages with drinking water and fish for consumption. The river has been polluted with mercury, due to the use of the amalgamation method for gold extraction. This has resulted in that local people have got increased levels of mercury, up to 45 mg mercury per litre of blood. The aim of this study was to evaluate the concentrations of mercury in sediment and fish in the Nanay River, Peru, and to study eventual relation between fish mercury concentrations and mercury concentrations in sediment and water parameters such as dissolved organic matter, pH, dissolved oxygen and turbidity. In October 2005, eleven sample points for river water and sediment were established, from the gold mining activities close to Pucaurco westwards (18M 0605010, UTM 9579526) to Pampa Chica eastwards, drinking water source for Iquitos, (18M 0691053, UTM 9585255) in the region Loreto in Peru. Water temperature, conductivity,

    total dissolved ions, turbidity, dissolved oxygen and pH was measured in the field. Five species of predatory fishes were collected within the study area, where Pintuyacu River

    joins Nanay River. The samples are currently subject to analyses in Sweden and results will be obtained during the spring. Based on the results, information will be sent to the Regional Government in the region of Loreto about the current state and recommended actions to prevent further contamination.

  • 331.
    Stemström -Khalili, Maria
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. LUVAL.
    Salt, water and nutrient fluxes to Himmerfjärden bay2007Other (Other scientific)
  • 332. Stålnacke, P.
    et al.
    Pengerud, A.
    Garnier, J.
    Reumann, J.
    Holmer, M.
    Håkanson, L.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. LUVAL.
    Bechmann, M.
    Nutrient driver and pressure relationships: Deliverable D6.2.5.2008Report (Other scientific)
  • 333.
    Subramanian, V.
    et al.
    School of Environmental Sciences, Jawaharlal Nehru University New Delhi, India.
    Madhavan, N.
    School of Environmental Sciences, Jawaharlal Nehru University New Delhi, India.
    Lundin, Lars-Christer
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science. Hydrology.
    Saxena, Rajinder
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science. Hydrology.
    Nature of distribution of mercury in the sediments of the River Yamuna (tributary of the Ganges), India2003In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 5, no 3, p. 427-434Article in journal (Refereed)
    Abstract [en]

    Suspended Particulate Matter (SPM), surface (bed sediments) and short length cores of sediments collected from the largest tributary of the river Ganges, namely the river Yamuna, were analysed for total mercury as well as its fractionation in various size and chemical sites in the sediments following standard procedures. Also, attempts were made to determine the vertical distribution in sediments in relation to the recent timescale of a few decades. Our observations indicate that the SPM in general showed higher levels of total mercury compared to the surface sediments while at places the enhancement could be by a factor of 10, say around 25 microg g(-1) in the downstream region that integrates the industrial midstream and agricultural downstream terrain near its confluence with the Ganges. Surface sediments in the upstream direction near the Himalayan foothills and SPM in the lower reaches showed significant high Index of Geoaccumulation (Igeo) as defined by Müller. Size fractionation studies indicate that the finer fraction preferentially showed higher levels of mercury while in the lower reaches of the river, the total mercury is equitably distributed among all size fractions. The proportion of the residual fraction of mercury in relation to mobile fractions, in general decreases downstream towards its confluence with the Ganges river. In sediment cores, the vertical distribution show systematic peaks of mercury indicating that addition of this toxic metal to the aquatic system is in direct proportion to the increase in various types of human activities such as thermal power plants, land use changes (urbanisation) in the midstream region and intensive fertiliser application in lower reaches of this vast river basin.

  • 334. Tammelin, Bengt
    et al.
    Hyvönen, R.
    Bergström, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Magnusson, Mikael
    Botta, G.
    Douvikas, D.
    Rathman, O.
    Strack, M.
    Verification on Wind Energy Predictions Produced by WAsP and Some Mesoscale Models in European Mountains2001In: EWEC2001, 2-6 July 2001, Copenhagen, Denmark, 2001Conference paper (Other scientific)
  • 335.
    Tuomola, Leena
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Terese, Niklasson
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Silva, Edinaldo de Castro
    Hylander, Lars D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Fish mercury development in relation to abiotic characteristics and carbon sources in a six-year-old, Brazilian reservoir2008In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 390, no 1, p. 177-187Article in journal (Refereed)
    Abstract [en]

    Time series on fish mercury (Hg) development are rare for hydroelectric reservoirs in the tropics. In the central-western part of Brazil, a hydroelectric reservoir, called Lago Manso, was completed in 1999 after that background levels of fish Hg concentrations had been determined. The development for the first 3 years was studied in 2002. The objective of the present study was to determine development of fish Hg concentrations for a second threeyear period after flooding. The bioaccumulation factor and certain abiotic and biotic factors, possibly affecting the availability and accumulation of Hg, were also examined. The results show that Hg levels in fish from Lago Manso have increased more than five times compared to the background levels observed before construction of the reservoir. At the same time, dissolved organic carbon has increased while dissolved oxygen has decreased indicating enhanced bioavailability of Hg. In the reservoir, Salminus brasiliensis had in average a Hg content of 1.1 μg g−1 f.w., Pseudoplatystoma fasciatum 1.2, Serrasalmus marginatus/spilopleura 0.9, and Brycon hilarii 0.6 μg g−1 f.w. The average fish Hg contents were higher downstream, except for B. hilarii. In the reservoir, the average Hg content of each species was in 2005 always over the consumption limit (0.55 μg total Hg g−1 f.w.) recommended by WHO. Therefore, the people living around Lago Manso should be informed of the health effects of Hg, and fish consumption recommendations should be carried out. The accumulation of Hg varies widely between species as shown by the bioaccumulation factor which ranges between 5.08 and 5.59 log units. The observed variation is explained by differences in diet and trophic position with piscivorous fish exhibiting the highest mean Hg concentration, followed by carnivorous and omnivorous species. Carbon isotope analyses imply that trophic position is not the only cause of the observed differences in Hg levels between omnivorous B. hilarii, having a diet partly based on C4 plants, and carnivorous S. marginatus as well as piscivorous S. brasiliensis, whose carbon sources are depleted in 13C. The fact that the species have different carbon sources indicates that they belong to different food chains.

  • 336.
    Törnblom, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Thermally driven wind modification in coastal areas and its influence on sound propagation with application to wind power2006Licentiate thesis, monograph (Other scientific)
    Abstract [en]

    The objective of the current study is to investigate the wind modifications in coastal areas and also to see the impact of atmospheric conditions on long-range sound propagation over sea. This is important when planning where to place wind turbines. Atmospheric measurements (wind, temperature, humidity) were performed in the Baltic Sea area, and a numerical meso-γ-scale atmospheric model (the MIUU-model) was used. The study was performed in early summer when it is common for thermally driven flows e.g. sea breezes and low level jets to evolve, resulting in supergeostrophic winds. The most important parameters for these winds were found to be temperature and roughness differences between land and sea. Even though the wind climatologically increases over sea, a case where the wind decreases when advected out over a cold sea is investigated.

    This happens if the stable boundary layer (SBL) over sea is deep enough. Parameters that have a great positive influence on the increase in depth of the SBL are strong thermal winds in combination with large temperature differences between land and sea. With a shallower SBL the wind increases over sea. During one week, the sound level from a siren, placed on a lighthouse in the Baltic Sea, was measured 9.5 km away from the source. This was performed simultaneously with the atmospheric measurements. The influence of atmospheric changes on the sound propagation is studied in details. Higher sound levels are found when low level jets occur and the sound level also seems to be dependent on the height to the jet.

  • 337.
    Törnblom, Karin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Bergström, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Johansson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Thermally driven mesoscale flows - simulations and measurements2007In: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 12, no 6, p. 623-641Article in journal (Refereed)
    Abstract [en]

    The wind climate shows often large local variations in coastal areas. The present study was based on measurements at several sites on the island of Gotland in the Baltic Sea and on simulations with a numerical meso-gamma-scale atmosphere model (the MIUU model). It is common for thermally driven flows, e.g. sea breezes and low level jets, to evolve resulting in supergeostrophic winds. The most important parameters affecting these flows were found to be temperature and roughness differences between the land and sea. Although the wind speed increases climatologically over a see, a case where the wind speed decreased when advected out over a cold sea was investigated. This happens if the stable boundary layer (SBL) over the sea is deep enough. A deep SBL is favoured by strong thermal winds in combination with large temperature differences between the land and sea. With a shallow SBL the wind speed increases over the sea.

  • 338. van der Perk, M.
    et al.
    Owens, P.N.
    Deeks, L.K.
    Rawlins, B.G.
    Haygarth, P.M.
    Beven, Keith J
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Controls on catchment-scale patterns of phosphorus in soil, streambed sediment, and stream water2007In: Journal of Environmental Quality, ISSN 0047-2425, E-ISSN 1537-2537, Vol. 36, p. 694-708Article in journal (Refereed)
    Abstract [en]

    Many models of phosphorus (P) transfer at the catchment scale rely on input from generic databases including, amongst others, soil and land use maps. Spatially detailed geochemical data sets have the potential to improve the accuracy of the input parameters of catchment-scale nutrient transfer models. Furthermore, they enable the assessment of the utility of available, generic spatial data sets for the modeling and prediction of soil nutrient status and nutrient transfer at the catchment scale. This study aims to quantify the unique and joint contribution of soil and sediment properties, land cover, and point-source emissions to the spatial variation of P concentrations in soil, streambed sediments, and stream water at the scale of a medium-sized catchment. Soil parent material and soil chemical properties were identified as major factors controlling the catchment-scale spatial variation in soil total P and Olsen P concentrations. Soil type and land cover as derived from the generic spatial database explain 33.7% of the variation in soil total P concentrations and 17.4% of the variation in Olsen P concentrations. Streambed P concentrations are principally related to the major element concentrations in streambed sediment and P delivery from the hillslopes due to sediment erosion. During base flow conditions, the total phosphorus (<0.45 µm) concentrations in stream water are mainly controlled by the concentrations of P and the major elements in the streambed sediment.

  • 339. Veiga, Marcello M.
    et al.
    Maxson, Peter
    Hylander, Lars D.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Luft- och vattenlära (LUVA).
    Origin of mercury in artisanal and small-scale gold mining.2006In: J. of Cleaner Production., Vol. 14, p. 436-447Article in journal (Refereed)
    Abstract [en]

    Mercury (Hg) is used by small-scale gold miners in more than 50 developing countries, where the accompanied releases affect human health and the environment. The objectives of this paper are to summarize present use of Hg in artisanal and small-scale mining (ASM) worldwide, reveal the origin of part of the Hg used by the gold miners, and propose appropriate actions to reduce the resulting Hg emissions. Significant releases of mercury are associated with inefficient amalgamation techniques. Releases are estimated to range from 800 to 1000 tonne/annum. Of this total, approximately 200e250 tonne of Hg are released in China, 100e150 tonne in Indonesia, and 10e30 tonne each in Bolivia, Brazil, Colombia, Peru, Philippines, Venezuela and Zimbabwe. Mercury usually enters these countries legally e typically imported from countries in the European Union e although in some cases and in some years (e.g., Indonesia, Venezuela, etc.), the reported imports of Hg are far below estimated consumption. Meanwhile, the EU, while gradually replacing Hg products and processes with more environmentally benign alternatives, paradoxically continues to produce virgin Hg at government-owned mines, further exacerbating a general global oversupply of Hg e evident from its historically low market price. Political leadership is needed to avoid the transfer of excess Hg, and related health and environmental risks from the EU to third countries. Otherwise, the present situation will continue or even worsen, with no oversight or control of the global Hg trade in which the transfer of excess EU Hg to artisanal miners is favoured by low Hg prices relative to gold prices.

  • 340. Virkkunen, K
    et al.
    Moore, J
    Isaksson, E
    Pohjola, Veijo
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Kekonen, T.
    Warm summers and ion concentrations in snow: comparison of present day with Medieval Warm Epoch from snow pits and an ice core from Lomonosovfonna, Svalbard2007In: Journal of Glaciology, ISSN 0022-1430, E-ISSN 1727-5652, Vol. 53, no 183, p. 623-634Article in journal (Refereed)
    Abstract [en]

    Snow pits sampled during two consecutive years (2001, 2002) at the summit of Lomonosovfonna ice cap in central Spitsbergen, Svalbard, showed that ion concentrations were spatially homogeneous. The snowpack on Lomonosovfonna shows no evidence of aerosol deposition from Arctic haze, in contrast to Holtedahlfonna (a glacier at a similar altitude in northern Spitsbergen) where there is a clear signature. In common with many other ice caps in the Arctic, Lomonosovfonna experiences periodic melting, and the deepest of the snow pits contained a record of one exceptionally warm (2001) and one long summer (2000). The most easily eluted species are nitrate and the divalent ions. Very low ion concentrations and high values of a melt indicator log ([Na+]/[Mg2+]) were a result of either deep percolation or runoff of ions during melting. Comparing the snow-pit record with the ion record of more than 800 years from an ice core drilled on Lomonosovfonna in 1997 reveals some layers with similar composition to those that suffered significant melting in the snowpack: a few years in the 20th century and around AD 1750, and all of the core from before AD 1200 show unusually heavy melting.

  • 341. Wang, Y. J.
    et al.
    Jiang, T.
    Xu, Chong-yu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Observed trends of pan evaporation and its impact factors over the Yangtze River basin between 1961 and 20002005In: Journal of Natural Resources, Vol. 20, no 6, p. 864-870Article in journal (Refereed)
  • 342.
    Westerberg, Ida
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Halldin, Sven
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Lundin, lars-Christer
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Xu, Chong-Yu
    Department of Geosciences, University of Oslo, Oslo, Norway.
    Seibert, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Beven, Keith
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Evaluation of performance measures for water-balance modelling focusing on low flows in a mountainous Honduran catchment, with uncertainty2007In: Internacional Estimación del Caudal de Compensación, San José, Costa Rica: Instituto Costarricense de Electricidad (ICE) , 2007Conference paper (Other academic)
  • 343.
    Wetterhall, Fredrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Air and Water Science.
    Statistical Downscaling of Precipitation in Central Sweden2004Licentiate thesis, monograph (Other scientific)
  • 344.
    Wetterhall, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Bardossy, A.
    Halldin, Sven
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Xu, Chong-yu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Downscaling of daily precipitation in the Baltic Sea catchment2005In: Geophysical Research Abstracts 7, 2005, p. 08065-Conference paper (Other academic)
  • 345.
    Wetterhall, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Bardossy, Andras
    Chen, Deliang
    Halldin, Sven
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Xu, Chong-yu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Statistical downscaling of daily precipitation over Sweden using GCM output2009In: Journal of Theoretical and Applied Climatology, ISSN 0177-798X, E-ISSN 1434-4483, Vol. 96, no 1-2, p. 95-103Article in journal (Refereed)
    Abstract [en]

    A classification of Swedish weather patterns (SWP) was developed by applying a multi-objective fuzzy-rule-based classification method (MOFRBC) to large-scale-circulation predictors in the context of statistical downscaling of daily precipitation at the station level. The predictor data was mean sea level pressure (MSLP) and geopotential heights at 850 (H850) and 700 hPa (H700) from the NCEP/NCAR reanalysis and from the HadAM3 GCM. The MOFRBC was used to evaluate effects of two future climate scenarios (A2 and B2) on precipitation patterns on two regions in south-central and northern Sweden. The precipitation series were generated with a stochastic, autoregressive model conditioned on SWP. H850 was found to be the optimum predictor for SWP, and SWP could be used instead of local classifications with little information lost. The results in the climate projection indicated an increase in maximum 5-day precipitation and precipitation amount on a wet day for the scenarios A2 and B2 for the period 2070-2100 compared to 1961-1990. The relative increase was largest in the northern region and could be attributed to an increase in the specific humidity rather than to changes in the circulation patterns.

  • 346.
    Wetterhall, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Bárdossy, András
    Chen, Deliang
    Halldin, Sven
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Xu, Chong-Yu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Daily precipitation-downscaling techniques in three Chinese regions2006In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 42, no 11, p. W11423-Article in journal (Refereed)
    Abstract [en]

    Four methods of statistical downscaling of daily precipitation were evaluated on three catchments located in southern, eastern, and central China. The evaluation focused on seasonal variation of statistical properties of precipitation and indices describing the precipitation regime, e. g., maximum length of dry spell and maximum 5-day precipitation, as well as interannual and intra-annual variations of precipitation. The predictors used in this study were mean sea level pressure, geopotential heights at 1000, 850, 700, and 500 hPa, and specific humidity as well as horizontal winds at 850, 700, and 500 hPa levels from the NCEP/NCAR reanalysis with 2.5 degrees x 2.5 degrees resolution for 1961 - 2000. The predictand was daily precipitation from 13 stations. Two analogue methods, one using principal components analysis (PCA) and the other Teweles-Wobus scores (TWS), a multiregression technique with a weather generator producing precipitation (SDSM) and a fuzzy-rule-based weather-pattern-classification method (MOFRBC), were used. Temporal and spatial properties of the predictors were carefully evaluated to derive the optimum setting for each method, and MOFRBC and SDSM were implemented in two modes, with and without humidity as predictor. The results showed that ( 1) precipitation was most successfully downscaled in the southern and eastern catchments located close to the coast, ( 2) winter properties were generally better downscaled, ( 3) MOFRBC and SDSM performed overall better than the analogue methods, ( 4) the modeled interannual variation in precipitation was improved when humidity was added to the predictor set, and ( 5), the annual precipitation cycle was well captured with all methods.

  • 347.
    Wetterhall, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Chen, D.
    Halldin, Sven
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Xu, Chong-yu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Statistical downscaling of daily precipitation in two catchments in eastern China2005In: Geophysical Research Abstracts 7, 2005, p. 01374-Conference paper (Other academic)
  • 348.
    Wetterhall, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Halldin, Sven
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Xu, Chong-Yu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Seasonality properties of four statistical-downscaling methods in central Sweden2007In: Journal of Theoretical and Applied Climatology, ISSN 0177-798X, E-ISSN 1434-4483, Vol. 87, no 1-4, p. 123-137Article in journal (Refereed)
    Abstract [en]

    Daily precipitation in northern Europe has different statistical properties depending on season. In this study, four statistical downscaling methods were evaluated in terms of their ability to capture statistical properties of daily precipitation in different seasons. Two of the methods were analogue downscaling methods; one using principal component analysis (PCA) and one using gradients in the pressure field (Teweles-Wobus scores, TWS) to select the analogues in the predictor field. The other two methods were conditional-probability methods; one using classification of weather patterns (MOFRBC) and the other using a regression method conditioning a stochastic weather generator (SDSM). The two analogue methods were used as benchmark methods. The study was performed on seven precipitation stations in south-central Sweden and the large-scale predictor was gridded mean-sea-level pressure over Northern Europe. The four methods were trained and calibrated on 25 years of data (1961–1978, 1994–2000) and validated on 15 years (1979–1993). Temporal and spatial limitations were imposed on the methods to find the optimum predictor settings for the downscaling. The quality measures used for evaluating the downscaling methods were the residuals of a number of key statistical properties, and the ranked probability scores (RPS) for precipitation and maximum length of dry and wet spells. The results showed that (1) the MOFRBC and SDSM outperformed the other methods for the RPS, (2) the statistical properties for the analogue methods were better during winter and autumn; for SDSM and TWS during spring; and for MOFRBC during summer, (3) larger predictor areas were needed for summer and autumn precipitation than winter and spring, and (4) no method could well capture the difference between dry and wet summers.

  • 349.
    Wetterhall, Fredrik
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Air and Water Science.
    Halldin, Sven
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Air and Water Science.
    Xu, Chong-yu
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Air and Water Science.
    Statistical Downscaling of Precipitation in Central Sweden. Intercomparison of different approaches2004In: Fourth Study Conference on BALTEX, Conference Proceedings, 2004Conference paper (Refereed)
  • 350.
    Wetterhall, Fredrik
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Air and Water Science.
    Halldin, Sven
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Air and Water Science.
    Xu, Chong-yu
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Air and Water Science.
    Statistical Downscaling of Precipitation in Central Sweden. Intercomparison of different approaches2004In: EGU 1st General Assembly: Nice, France, 25-30 April 2004, 2004Conference paper (Refereed)
45678 301 - 350 of 387
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