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  • 1.
    Aldahan, Ala
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Alfimov, V.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    I-129 anthropogenic budget: major sources and sinks2007In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 22, no 3, 606-618 p.Article in journal (Refereed)
    Abstract [en]

    Data are presented here on the anthropogenic 129I inventory in regions that have been strongly affected by releases from European reprocessing facilities which, to the authors’ knowledge, presently account for >90% of the global isotope source in the Earth’s surface environment. The results show that >90% of the isotope inventory occurs in marine waters with the Nordic Seas and Eurasian basin of the Arctic Ocean containing most of the 129I. Within the terrestrial environment of Europe, soils contain the largest part of the isotope inventory. However, the inventory of the terrestrial system did not provide clues on the most plausible atmospheric source of 129I to Europe, thus supply from both gaseous and marine releases is proposed. The sum of the total inventory in both the marine and terrestrial environments did not match the estimated releases. This imbalance is likely to relate to unconstrained inventory estimates for marine basins (Irish Sea, English Channel and North Sea) close to the facilities, but also to the occurrence of 129I in the biosphere, and possible overestimated releases from the nuclear reprocessing facilities. There is no doubt that the available data on 129I distribution in the environment are far from representative and further research is urgently needed to construct a comprehensive picture.

  • 2.
    Alfimov, Vasily
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Measurements of Cl-36 with a gas-filled magnet at the Uppsala tandem laboratory2007In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 259, no 1, 199-203 p.Article in journal (Refereed)
    Abstract [en]

    The performance of a gas-filled magnet combined with a gas ionization detector for measurements of Cl-36 was systematically studied at the Uppsala tandem laboratory. Our tests were conducted at a terminal voltage of 4,6 MV using gas-foil stripping and a 37 MeV Cl-36(+7) ion beam. An optimal suppression of the interfering isobar S-36 in the stand-alone gas-filled magnet (2 mbar N-2 gas pressure) was found to be >= 300, and an additional >= 300 times reduction was achieved by the Eresidual signal of the two-anode gas ionization detector. The overall suppression in the order of >= 10(5) permits analysis of samples with a sulfur content of <= 5 ppm and Cl-36/Cl ratios of >= 10(-15). We have successfully measured samples with Cl-36/Cl ratios in the range of 10(-12)-10(-15) demonstrating the use of a mediumsized tandem accelerator system (similar to 1 MeV/amu) for Cl-36 AMS.

  • 3.
    Andreas C., Bryhn
    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.
    Improving the management of aquatic ecosystems through modelling.2005Licentiate thesis, monograph (Other scientific)
  • 4. Barthelmie, Rebecca
    et al.
    Larsen, G.
    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
    Hassan, U.
    Schlez, W.
    Rados, K.
    Lange, B.
    Waldl, I.
    Vølund, P.
    Neckelmann, S.
    Christensen, T.
    Nielsen, T.G.
    Højstrup, J.
    Schepers, G.
    Hegberg, T.
    Coelingh, J.
    Folkerts, L.
    Efficient Development of Offshore Windfarms: A New Project for Investigating Wake and Boundary-Layer Interactions2001In: EWEC2001 2-6 July 2001, Copenhagen, Denmark, 2001Conference paper (Other scientific)
  • 5. Barthelmie, Rebecca
    et al.
    Larsen, Gunner
    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
    Rados, Kostas
    Lange, Bernhard
    Vølund, Per
    Neckelmann, S.
    Christensen, L.
    Schepers, G.
    Hegberg, T.
    Folkerts, L.
    ENDOW:Efficient Development of Offshore Windfarms2001In: Wind Engineering, Vol. 25, no 5, 263-270 p.Article in journal (Refereed)
  • 6. Barthelmie, Rebecca
    et al.
    Larsen, Gunner
    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
    Schlez, Wolfgang
    Rados, Kostas
    Lange, Bernhard
    Vølund, Per
    Neckelmann, Søren
    Mogensen, Søren
    Schepers, Gerhard
    Hegberg, Terry
    Folkerts, Luuk
    ENDOW: Efficient Development of Offshore Windfarms: modelling wake and boundary-layer interactions2003In: European Geophysical Society/American Geophysical Society Joint Meeting, Nice, April 2003, 2003Conference paper (Other scientific)
  • 7. Barthelmie, Rebecca
    et al.
    Larsen, Gunner
    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
    Schlez, Wolfgang
    Rados, Kostas
    Lange, Bernhard
    Vølund, Per
    Neckelmann, Søren
    Mogensen, Søren
    Schepers, Gerhard
    Hegberg, Terry
    Folkerts, Luuk
    ENDOW: Efficient Development of Offshore Windfarms: modelling wake and boundary-layer interactions2003In: European Wind Energy Conference, Madrid, June 2003, 2003Conference paper (Other scientific)
  • 8. Barthelmie, Rebecca
    et al.
    Larsen, Gunner
    Pryor, Sara
    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
    Schlez, Wolfgang
    Rados, Kostas
    Lange, Bernhard
    Vølund, Per
    Neckelmann, Søren
    Morgensen, Søren
    Schepers, Gerhard
    Hegberg, Terry
    Folkerts, Luuk
    ENDOW: Efficient Development of Offshore Windfarms2003In: Proceedings from Offshore Wind Energy in Meditteranean and Other Seas OWEMES2003, Naples, Italy, 10-12 April 2003, 2003Conference paper (Other scientific)
  • 9. Barthelmie, Rebecca
    et al.
    Larsen, Gunner
    Pryor, Sara
    Jørgensen, Hans
    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. luft och vattenlära.
    ENDOW (efficient development of offshore wind farms): modelling wake and boundary layer interactions2004In: Wind Energy, Vol. 7, 225-245 p.Article in journal (Refereed)
    Abstract [en]

    While experience gained through the offshore wind energy projects currently operating is valuable, a major uncertainty in estimating power production lies in the prediction of the dynamic links between the atmosphere and wind turbines in offshore regimes. The objective of the ENDOW project was to evaluate, enhance and interface wake and boundary layer models for utilization offshore. The project resulted in a significant advance in the state of the art in both wake and marine boundary layer models, leading to improved prediction of wind speed and turbulence profiles within large offshore wind farms. Use of new databases from existing offshore wind farms and detailed wake profiles collected using sodar provided a unique opportunity to undertake the first comprehensive evaluation of wake models in the offshore environment. The results of wake model performance in different wind speed, stability and roughness conditions relative to observations provided criteria for their improvement. Mesoscale model simulations were used to evaluate the impact of thermal flows, roughness and topography on offshore wind speeds. The model hierarchy developed under ENDOW forms the basis of design tools for use by wind energy developers and turbine manufacturers to optimize power output from offshore wind farms through minimized wake effects and optimal grid connections. The design tools are being built onto existing regional-scale models and wind farm design software which was developed with EU funding and is in use currently by wind energy developers.

  • 10.
    Beldring, Stein
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Rodhe, Allan
    Tallaksen, Lena
    Kinematic wave approximations to hillslope hydrological processes in till soils2000In: Hydrological Processes, Vol. 14, 727-745 p.Article in journal (Refereed)
  • 11.
    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.
    Boundary-layer modelling for wind climate estimates2001In: Wind Engineering, Vol. 25, no 5, 289-299 p.Article in journal (Refereed)
  • 12.
    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.
    Estimating Offshore Wind Potential – a more complex task than expected?2001In: EWEC’2001, Copenhagen 3rd - 7th July 2001, 2001Conference paper (Other scientific)
  • 13.
    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. luft och vattenlära.
    Higher-order closure meso-scale modelling for wind resource estimates in Sweden2004In: 2004 European Wind Energy Conference and Exhibition, 2004Conference paper (Other scientific)
    Abstract [en]

    The wind climate over Sweden is investigated using the three-dimensional higher-order closure MIUU-model from Uppsala University. A technique for estimating the wind resource with this type of model is presented, and the resulting wind climate is verified against measurements.

    Statistics of the geostrophic wind is used for weighting model output together into the final wind climate. Comparisons are made between estimates of geostrophic wind from observed surface pressure data, and from ERA40/NCEP reanalysis sea level pressure data and 850 hPa geopotential height data.

    The results presented are based on data from an ongoing project aiming at mapping the wind climate over Sweden on a 1 km horizontal resolution, but here only results on a 5 km horizontal resolution are presented.

  • 14.
    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.
    Nya svenska vindkarteringen2006Other (Other (popular scientific, debate etc.))
  • 15.
    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.
    The wind climate in an Arctic mountain valley, II2002Report (Other scientific)
  • 16.
    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.
    Wind measurements at Lyse Wind Power Station1995Report (Other scientific)
  • 17.
    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. LUVAL.
    Wind Resource Mapping Of Sweden Using The Miuu-Model2007Report (Other scientific)
    Abstract [en]

    A method to simulate the climatological wind field using the MIUU-model (Meteorological Institute Uppsala University model) has been developed at Uppsala University, reducing the total number of simulations needed. With this method a limited number of climato¬logically relevant simulations are performed, with different wind and temperature conditions, and a weighting based on climato¬logi¬cal data for the geostrophic wind (horizontal pressure gradient) is made in order to fi¬nally estimate the wind climate. The method is applicable for mapping the wind resources with a resolution of 0.5-10 km. To use this method geostrophic wind (strength and direction), sea and land temperatures, topography, roughness, and land use are needed. No observed boundary-layer winds are needed other than for verification. Comparisons between model results and measurements show good agreement.

  • 18.
    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. LUVAL.
    Wind Statistics Mapping Using a Higher-order Closure Meso-scale Model2007In: European Wind Energy Conference 2007 Proceedings, 2007Conference paper (Other scientific)
    Abstract [en]

    The use of meso-scale models for wind resource assessments has increased as this type of model reproduce the complex and inhomogeneous wind fields often seen not only in complex terrain but also offshore. Here the higher-order closure MIUU-model developed at Uppsala University has been used to map the wind climate over Sweden. This type of model is, however, computer-time consuming to run. A method to estimate the climatological wind field using the MIUU model has been developed, reducing the total number of simulations needed. With this method only a limited number of climatologically relevant simulations are made. Weighting based on climatological data for the horizontal pressure gradient (geostrophic wind) is made in order to finally estimate the wind resource. The method is applicable for mapping the wind potential with a resolution of 0.5-10 km. To use this method geostrophic wind (strength and direction), sea and land temperatures, topography, roughness, and land-use are needed. Comparisons between model results and measurements show good agreement. The paper gives details on the technique and show wind statistics arrived at within a project where the wind climate over Sweden on a 1 km resolution is calculated. Wind distributions may be estimated both for speed and direction giving the two Weibull parameters as function of location and height. Turbulent kinetic energy, which is also an output parameter from the model calculations, has been used to estimate the climatology of turbulence intensity.

  • 19.
    Bergström, Hans
    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.
    Juuso, Nikolaus
    A Study of Valley Winds Using the MIUU Meso-scale Model2006In: Wind Energy, Vol. 9, 109-129 p.Article in journal (Refereed)
    Abstract [en]

    High winds are sometimes found in low-altitude terrain in mountain valleys. The reasons for this and the possibilities to find such sites from modelled wind fields are investigated. The higher-order closure MIUU model developed at Uppsala University is used for a general study of channelling of winds in mountain valleys. The importance of length, width and depth of the valley is investigated. Comparisons are made with wind measurements.

  • 20.
    Bergström, Hans
    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. Luft och vattenlära.
    Juuso, Nikolaus
    A study of valley winds using the MIUU meso-scale model2004In: 2004 European Wind Energy Conference and Exhibition, 2004Conference paper (Other scientific)
    Abstract [en]

    High winds are sometimes found in low altitude terrain in mountain valleys. The reasons for this and the possibilities to find such sites from modelled wind fields are investigated. The higher-order closure MIUU-model, developed at Uppsala University, is used for a general study of channelling of winds in mountain valleys. The importance of length, width and depth of the valley is investigated. Comparisons are made with wind measurements.

  • 21.
    Bergström, Hans
    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.
    Källstrand, Birgitta
    Estimating Wind Potential in a Complex Terrain Arctic Mountain Valley2001In: EWEC’2001, Copenhagen 3rd - 7th July 2001, 2001Conference paper (Other scientific)
  • 22.
    Bergström, Hans
    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.
    Källstrand, Birgitta
    Measuring and modelling the wind climate in a mountain valley in northern Sweden2000In: Proceedings from BOREAS V, Wind Energy Production in Cold Climates, 29 Nov. – 1 Dec. 2000, Levi, Finland, 2000Conference paper (Other scientific)
  • 23.
    Bergström, Hans
    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.
    Lindholm, Magnus
    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.
    Higher-order closure meso-scale modelling for wind climate estimates2003In: Proceedings from World Wind Energy Conference, WWEC2003, 23-26 November 2003, Cape Town, South Africa, 2003Conference paper (Other scientific)
  • 24.
    Bergström, Hans
    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.
    Moberg, Anders
    Daily air temperature and pressure series for Uppsala 1722-19982002In: Climatic Change, no 53, 231-252 p.Article in journal (Refereed)
  • 25.
    Bergström, Hans
    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.
    Boundary layer temperature, wind and humidity2001In: Theor. Appl. Climatol., Vol. 70, CD- p.Article in journal (Refereed)
  • 26.
    Bergström, Hans
    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.
    Micrometeorological measurements at an agricultural site during late winter conditions2001In: Theor. Appl. Climato., Vol. 70, CD- p.Article in journal (Refereed)
  • 27.
    Beven, Keith J
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Smith, P.
    Freer, J.
    Comment on “Hydrological forecasting uncertainty assessment: Incoherence of the GLUE methodology” by Pietro Mantovan and Ezio Todini2007In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 338, no 3-4, 315-318 p.Article in journal (Refereed)
    Abstract [en]

    This comment is a response to the criticisms of the GLUE methodology by [Mantovan, P., Todini, E., 2006. Hydrological forecasting uncertainty assessment: Incoherence of the GLUE methodology, J. Hydrology, 2006]. In this comment it is shown that the formal Bayesian identification of models is a special case of GLUE that can be used where the modeller is prepared to make very strong assumptions about the nature of the modelling errors. For the hypothetical study of Mantovan and Todini, exact assumptions were assumed known for the formal Bayesian identification, but were then ignored in the application of GLUE to the same data. We show that a more reasonable application of GLUE to this problem using similar prior knowledge shows that gives equally coherent results to the formal Bayes identification. In real applications, subject to input and model structural error it is suggested that the coherency condition of MT06 cannot hold at the single observation level and that the choice of a formal Bayesian likelihood function may then be incoherent. In these (more interesting) cases, GLUE can be coherent in the application of likelihood measures based on blocks of data, but different choices of measures and blocks effectively represent different beliefs about the information content of data in real applications with input and model structural errors.

  • 28.
    Blenckner, Thorsten
    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 conceptual model of climate-related effects on lake ecosystems2005In: Hydrobiologia, Vol. 553, 1-14 p.Article in journal (Refereed)
  • 29.
    Blenckner, Thorsten
    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.
    Klimatisch bedingte Gefährdung der Wasserqualität2004In: Warnsignal Klima:: Genug Wasser für alle?, Wissenschaftliche Auswertungen, Hamburg, Germany , 2004, 400- p.Chapter in book (Refereed)
  • 30.
    Bockgård, N.
    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.
    Niemi, A.
    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.
    Role of soil-rock interaction on recharge into fractured rock2003In: Proceedings of TOUGH Symposium 2003 , May 12–14, 2003, 2003Conference paper (Refereed)
  • 31.
    Bockgård, Niclas
    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.
    Niemi, Auli
    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.
    Role of rock heterogeneity on lateral diversion of water flow at the soil-rock interface2004In: Vadose Zone Journal, ISSN 1539-1663, Vol. 3, no 3, 786-795 p.Article in journal (Refereed)
  • 32.
    Bockgård, Niclas
    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.
    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. Air and Water Science.
    Experiences of CFC dating of groundwater in central Sweden2004Report (Other scientific)
  • 33.
    Bockgård, Niclas
    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.
    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. Air and Water Science.
    Olsson, K Anders
    Accuracy of CFC groundwater dating in a crystalline bedrock aquifer: Data from a site in southern Sweden2004In: Hydrogeology Journal, ISSN 1431-2174, Vol. 12, no 2, 171-183 p.Article in journal (Refereed)
    Abstract [en]

    The concentrations of chlorofluorocarbons (CFC-11, CFC-12, and CFC-113) and tritium were determined in groundwater in fractured crystalline bedrock at Finnsjon, Sweden. The specific goal was to investigate the accuracy of CFC dating in such an environment, taking potential degradation and mixing of water into consideration. The water was sampled to a depth of 42 m in three boreholes along an 800-m transect, from a recharge area to a local discharge area. The CFC-113 concentration was at the detection limit in most samples. The apparent recharge date obtained from CFC-11 was earlier than from CFC-12 for all samples, with a difference of over 20 years for some samples. The difference was probably caused by degradation of CFC-11. The CFC-12 dating of the samples ranged from before 1945 to 1975, with the exception of a sample from the water table, which had a present-day concentration. Conclusions about flow paths or groundwater velocity could not be drawn from the CFCs. The comparison between CFC-12 and tritium concentrations showed that most samples could be unmixed or mixtures of waters with different ages, and the binary mixtures that matched the measured concentrations were determined. The mixing model approach can be extended with additional tracers.

  • 34. Braun, Matthias
    et al.
    Schuler, Thomas V.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Hock, Regine
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Brown, Ian
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Jackson, Miriam
    Comparison of remote sensing derived glacier facies maps with distributed mass balance modelling at Engabreen, northern Norway2007In: Glacier Mass Balance Changes and Meltwater Discharge / [ed] Patrick Ginot & Jean-Emmanuel Sicart, Wallingford: IAHS , 2007, Vol. 318, 126-134 p.Conference paper (Refereed)
    Abstract [en]

    Calibration and validation of glacier mass balance models typically rely on mass balance data derived from measurements at individual points, often along altitudinal gradients, thus neglecting much of the spatial variability of mass balance. Remote sensing data can provide useful additional spatially distributed information, e.g. on surface conditions such as bare ice area, firn cover extent, or snow. We developed a semi-automated procedure to derive glacier-facies maps from Landsat satellite images, and applied it to Engabreen, an outlet glacier from the Svartisen ice cap in northern Norway. These maps, discriminating between firn, snow and ice surfaces, are then used as a reference for mass balance modelling. Facies information shows a general agreement with the available few field observations and results obtained by distributed mass balance modelling. We conclude that Earth Observation products provide a powerful, although as yet poorly exploited tool, for calibration and validation of distributed mass balance models.

  • 35.
    Bryhn, Andreas C.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Håkanson, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    A comparison of predictive phosphorus load-concentration models for lakes2007In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 10, no 7, 1084-1099 p.Article in journal (Refereed)
    Abstract [en]

    Lake models that predict phosphorus (P) concentrations from P-loading have provided important knowledge enabling successful restoration of many eutrophic lakes during the last decades. However, the first-generation (static) models were rather imprecise and some nutrient abatement programs have therefore produced disappointingly modest results. This study compares 12 first-generation models with three newer ones. These newer models are dynamic (time-dependent), and general in the sense that they work without any further calibration for lakes from a wide limnological domain. However, static models are more accessible to non-specialists. Predictions of P concentrations were compared with empirical long-term data from a multi-lake survey, as well as to data from transient conditions in six lakes. Dynamic models were found to predict P concentrations with much higher certainty than static models. One general dynamic model, LakeMab, works for both deep and shallow lakes and can, in contrast to static models, predict P fluxes and particulate and dissolved P, both in surface waters and deep waters. PCLake, another general dynamic model, has advantages that resemble those of LakeMab, except that it needs three or four more input variables and is only valid for shallow lakes.

  • 36.
    Bryhn, Andreas C.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Håkanson, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Eutrophication: Model Before Acting2009In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 324, no 5928, 723-723 p.Article in journal (Refereed)
  • 37.
    Bryhn, Andreas C.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Håkanson, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Eklund, Jenny
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Variabilities and uncertainties in key coastal water variables as a basis for understanding changes and obtaining predictice power in modelling2008In: Vatten, ISSN 0042-2886, Vol. 64, 259-272 p.Article in journal (Refereed)
    Abstract [en]

    The focus of this work is on general patterns in uncertainty as well as temporal and spatial variability in keywater variables in coastal science and management. These patterns are essential since they regulate how manysamples must be taken to get reliable mean or median values characterising coastal water quality and whichvariables are most suitable for monitoring and predictive modelling. We present results concerning coefficientsof variation, correlations, regressions, variations in data from different time periods, and confidence intervalsfor empirical mean values. We use data from Ringkøbing Fjord (Denmark, N. Europe), Chesapeake Bay(Eastern U.S.) and other coastal marine sites to illustrate the basic principles related to patterns in variability.We have shown that total and particulate N and P generally have much lower coefficients of variability (CV)than dissolved inorganic nutrient fractions. The latter are, hence, of limited use in predictive models for coastalmanagement. Total nitrogen (N) and phosphorus (P) were, on the other hand, found to be useful predictors oftwo standard bioindicators, the Secchi depth (a measure of water clarity) and chlorophyll-a concentrations(a measure of phytoplankton biomass or production)

  • 38.
    Bryhn, Andreas C.
    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. LUVAL.
    Håkanson, 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. LUVAL.
    Eklund, Jenny M.
    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.
    Variabilities and uncertainties in management-related coastal water variables.: Deliverable D2.3.3.2007Report (Other scientific)
  • 39.
    Bryhn, Andreas Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Hessen, Dag O
    Blenckner, Thorsten
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Predicting particulate pools of nitrogen, phosphorus and organic carbon in lakes2007In: Aquatic Sciences, ISSN 1015-1621, E-ISSN 1420-9055, Vol. 69, no 4, 484-494 p.Article in journal (Refereed)
    Abstract [en]

    The variation between lakes with respect to concentrations of particulate nutrient pools was studied in 126 Norwegian lakes covering a wide range in lake-specific properties. Particulate phosphorus (P) always constituted close to 60% of total P (TP) concentrations. Particulate nitrogen (N) and organic carbon (C) concentrations, on the other hand, were sensitive to several lake characteristics, particularly to TP concentrations. Through optimisation procedures and multivariate regression, the present study presents general empirical models for predicting particulate nutrient concentrations. Furthermore, significant trend shifts in the relationships between TP vs. particulate N and TP vs. particulate organic C were observed at TP = 6 mu g l(-1) and TP = 80 mu g l(-1), suggesting non-linearities in these relationships along the TP gradient. A trend shift in the TP vs. chlorophyll relationship was observed at TP = 90. Taking such non-linearities into account may decrease the uncertainty in predicting particulate N, particulate organic C and chlorophyll.

  • 40.
    Carlson, Karin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology, Microbiology. Earth Sciences, Department of Earth Sciences, Air and Water Science. Mikrobiologi.
    Halldin, Sven
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology, Microbiology. Earth Sciences, Department of Earth Sciences, Air and Water Science. Luft- och vattenlära.
    Naturvetarsvenskan förtvinar2006In: Språkvård, no 2006/2, 36-38 p.Article in journal (Other (popular scientific, debate etc.))
    Abstract [en]

    Engelska för forskningen, svenskan för forskningsinformationen och båda språken i utbildningen. Ungefär så ville Kerstin Norén, prorektor vid Göteborgs universitet, ordna högskolans språkval i en artikel i Språkvård 2006/1. Karin Carlson och Sven Halldin, båda verksamma i Uppsala uiversitets naturvetenskapliga språkgrupp, tycker att det inte är så enkelt.

  • 41.
    Carlson, Karin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Earth Sciences, Department of Earth Sciences, Air and Water Science. Physics, Department of Physics and Materials Science, Theoretical Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology, Microbiology. Mathematics and Computer Science, Department of Mathematics, Mathematics I -V.
    Kiselman, Christer
    Earth Sciences, Department of Earth Sciences, Air and Water Science. Physics, Department of Physics and Materials Science, Theoretical Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology, Microbiology. Mathematics and Computer Science, Department of Mathematics, Mathematics I -V.
    Danielsson, Ulf
    Department of Theoretical Physics. Earth Sciences, Department of Earth Sciences, Air and Water Science. Physics, Department of Physics and Materials Science, Theoretical Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology, Microbiology. Mathematics and Computer Science, Department of Mathematics, Mathematics I -V.
    Halldin, Sven
    Earth Sciences, Department of Earth Sciences, Air and Water Science. Physics, Department of Physics and Materials Science, Theoretical Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology, Microbiology. Mathematics and Computer Science, Department of Mathematics, Mathematics I -V.
    Mattsson, Amalia
    Language policy for a bilingual faculty2005In: Bi- and multilingual universities, Helsinki, Finland, Sept 1-3, 2005, 2005Conference paper (Refereed)
    Abstract [en]

    The Faculty of Science and Technology of Uppsala University is for all practical purposes a bilingual institution, using both Swedish and English in education and research. Extensive use of English in teaching, and also in intrauniversity communication, permits recruitment of nonSwedishspeaking students, researchers and professors, and also prepares our students for

    international careers. However, the introduction of English has been somewhat haphazard, not taking into account possible negative effects on communication in Swedish, nor on students'

    learning.

    In order to improve students' and professors' language skills, and achieve a good balance between Swedish and English, the faculty board appointed a language committee in 2003 whose task was to propose a language policy for the faculty. A first part, stating as a main goal that all communication from and within the faculty should have the highest quality possible, has been adopted by the board. A second part including language planning with respect to status, corpus, and acquisition for both Swedish and English to accomplish this goal was sent to the board of the faculty in May, 2005. Implementation of this policy will affect all faculty activities, especially education. Suggested

    annual reports on language status will raise our present minimal knowledge about possible domain losses and allow for relevant countermeasures.

  • 42. Carstensen, J.
    et al.
    Hernandez-Garcia, E.
    Håkanson, Lars
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. 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.
    Terminology list for threshold modelling, identification and uncertainty evaluation.: Deliverable D2.4.1.2006Report (Other scientific)
  • 43. Chen, D.
    et al.
    Gao, G.
    Xu, Chong-yu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Guo, J.
    Ren, G.
    Comparison of the Thornthwaite method and pan data with the standard Penman-Monteith estimates of reference evapotranspiration in China2005In: Climate Research (CR), ISSN 0936-577X, E-ISSN 1616-1572, Vol. 28, 123-132 p.Article in journal (Refereed)
  • 44. Chen, D.
    et al.
    Gong, Lebing
    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.
    Halldin, Sven
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    A high-resolution, gridded dataset for monthly temperature normals (1971 – 2000) in Sweden2007In: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 89, no 4, 249-261 p.Article in journal (Refereed)
    Abstract [en]

    A baseline climatology is required in evaluating climate variability and changes on regional and local scales. Gridded climate normals, i.e. averages over a 30-year period, are of special interest since they can be readily used for validation of climate models. This study is aimed at creating an updated gridded dataset for Swedish monthly temperature normals over the period 1971–2000, based on standard 2-m air temperature records at 510 stations in mainland Sweden. Spatial trends of the normal temperatures were modelled as functions of latitude, longitude and elevation by multiple linear regression. The study shows that the temperature normals are strongly correlated with latitude throughout the year and especially in cold months, while elevation was a more important factor in June and July. Longitude played a minor role and was only significant in April and May. Regression equations linking temperature to latitude, longitude and elevation were set up for each month. Monthly temperature normals were detrended by subtracting spatial trends given by the regressions. Ordinary kriging was then applied to both original data (simple method) and de-trended data (composite method) to model the spatial variability and to perform spatial gridding. The multiple regressions showed that between 82% (summer) and 96% (winter) of the variance in monthly temperature normals could be explained by latitude and elevation. Unexplained variances, i.e. the residuals, were modelled with ordinary kriging with exponential semivariograms. The composite grid estimates were calculated by adding the multiple linear trends back to the interpolated residuals at each grid point. Kriged original temperature normals provided a performance benchmark. The cross–validation shows that the interpolation errors of the normals are significantly reduced if the composite method rather than the simple one was used. A gridded monthly dataset with 30-arcsecond spacing was created using the established trends, the kriging model and a digital topographic dataset.

  • 45. Chen, H.
    et al.
    Guo, S.L.
    Xu, Chong-yu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Singh, V.P.
    Historical temporal trends of hydro-climatic variables and runoff response to climate variability and their relevance in water resource management in the Hanjiang basin2007In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 344, no 3-4, 171-184 p.Article in journal (Refereed)
    Abstract [en]

    The Danjiangkou reservoir lies in the upper Hanjiang basin and is the source of water for the middle route of the South-to-North Water Diversion Project (SNWDP) in China. Any significant change in the magnitude or timing of runoff from the Danjiangkou reservoir induced by changes in climatic variables would have significant implications for the economic prosperity of the area in the Hanjiang basin as well as for the South-to-North Water Diversion Project. In this paper the following issues are investigated: (1) Temporal trends of annual and seasonal precipitation and temperature from 1951 to 2003 in the Hanjiang basin are analyzed using the Mann–Kendall and the linear regression methods; spatial distributions of precipitation and temperature are interpolated by the inverse distance weighted interpolation method. (2) Temporal trends of runoff, precipitation and temperature from 1951 to 2003 in the Danjiangkou reservoir, an upper stream basin of the Hanjiang River, are further tested. (3) To assess the impact of climate change on water resources and predict the future runoff change in the Danjiangkou reservoir basin, a two-parameter water balance model is used to simulate the hydrological response for the climate change predicted by GCMs for the region for the period of 2021–2050.

    The results indicate that (1) at the α = 0.05 significance level precipitation in the Hanjiang basin has no trend, but the temperature in the same region has significant upward trends in most parts of the Hanjiang basin. (2) The mean annual, spring, and winter runoffs in the Danjiangkou reservoir basin have decreasing trends. (3) The results simulated for the period 2021–2050 show that runoff of the Danjiangkou reservoir would increase in all the seasons, mainly in response to the predicted precipitation increase in the region. Sensitivity analysis shows that a 1 °C and 2 °C increase in temperature would reduce the mean annual runoff to about 3.5% and 7%, respectively. A decrease/increase of the mean monthly precipitation of 20% and 10% would decrease/increase the mean annual runoff to about 30% and 15%, respectively. The results of this study provide a scientific reference not only for assessing the impact of the climate change on water resources and the flood prevention in the Hanjiang basin, but also for dimensioning the middle route of the SNWDP in China.

  • 46. Chen, X.
    et al.
    Chen, Y. D.
    Xu, Chong-yu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    A distributed Monthly Hydrological Model for water balance simulation2005Conference paper (Other academic)
  • 47. Chen, X.
    et al.
    Chen, Y.D.
    Xu, Chong-yu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    A distributed monthly hydrological model for integrating spatial variations of basin topography and rainfall2007In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 21, no 2, 242-252 p.Article in journal (Refereed)
    Abstract [en]

    Hydrological models at a monthly time-scale are important tools for hydrological analysis, such as in impact assessment of climate change and regional water resources planning. Traditionally, monthly models adopt a conceptual, lumped-parameter approach and cannot account for spatial variations of basin characteristics and climatic inputs. A large requirement for data often severely limits the utility of physically based, distributed-parameter models. Based on the variable-source-area concept, we considered basin topography and rainfall to be two major factors whose spatial variations play a dominant role in runoff generation and developed a monthly model that is able to account for their influences in the spatial and temporal dynamics of water balance. As a hybrid of the Xinanjiang model and TOPMODEL, the new model is constructed by innovatively making use of the highly acclaimed simulation techniques in the two existing models. A major contribution of this model development study is to adopt the technique of implicit representation of soil moisture characteristics in the Xinanjiang model and use the TOPMODEL concept to integrate terrain variations into runoff simulation. Specifically, the TOPMODEL topographic index ln(a/tan) is converted into an index of relative difficulty in runoff generation (IRDG) and then the cumulative frequency distribution of IRDG is used to substitute the parabolic curve, which represents the spatial variation of soil storage capacity in the Xinanjiang model. Digital elevation model data play a key role in the modelling procedures on a geographical information system platform, including basin segmentation, estimation of rainfall for each sub-basin and computation of terrain characteristics. Other monthly data for model calibration and validation are rainfall, pan evaporation and runoff. The new model has only three parameters to be estimated, i.e. watershed-average field capacity WM, pan coefficient and runoff generation coefficient . Sensitivity analysis demonstrates that runoff is least sensitive to WM and, therefore, it can be determined by a prior estimation based on the climate and soil properties of the study basin. The other two parameters can be determined using optimization methods. Model testing was carried out in a number of nested sub-basins of two watersheds (Yuanjiang River and Dongjiang River) in the humid region in central and southern China. Simulation results show that the model is capable of describing spatial and temporal variations of water balance components, including soil moisture content, evapotranspiration and runoff, over the watershed. With a minimal requirement for input data and parameterization, this terrain-based distributed model is a valuable contribution to the ever-advancing technology of hydrological modelling.

  • 48. Chen, Y. D.
    et al.
    Chen, X.
    Xu, Chong-yu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    A Monthly Hydrological Model for Integrating Spatial Variations of Basin Topography and Rainfall2005Conference paper (Other academic)
  • 49. Chen, Y. D.
    et al.
    Huang, G.
    Shao, Q.
    Xu, Chong-yu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Regional analysis of low flow using L-moments for Dongjiang basin, South China2006In: Hydrological Sciences Journal, Vol. 51, no 6, 1051-1064 p.Article in journal (Refereed)
    Abstract [en]

    Dongjiang water has been the key source of water supplies for Hong Kong and its neighbouring cities in the Pearl River Delta in South China since the mid-1960s. Rapid economic development and population growth in this region have caused serious concerns over the adequacy of the quantity and quality of water withdrawn from the Dongjiang River in the future. Information on the magnitude and frequency of low flows in the basin is needed for planning of water resources at present and in the near future. The L-moment method is used to analyse the regional frequency of low flows, since recent studies have shown that it is superior to other methods that have been used previously, and is now being adopted by many organizations worldwide. In this study, basin-wide analysis of low flows

    is conducted for Dongjiang basin using five distributions: generalized logistic, generalized extreme value, lognormal, Pearson type III and generalized Pareto. Each of these has three parameters estimated by the L-moment method. The discordancy index and homogeneity testing show that 14 out of the 16 study sites belong to a homogenous region; these are used for further analysis. Based on the L-moment ratios diagram, the Hosking and Wallis goodness-of-fit statistical criterion and the L-kurtosis criterion, the three-parameter lognormal distribution is identified as the most appropriate distribution for the homogeneous study region. The regional low-flow estimates for each return period are obtained using

    the index flood procedure. Examination of the observed and simulated low flows by regional frequency analysis shows a good agreement in general, and the results may satisfy practical application. Furthermore, the regional low-flow relationship between mean annual 7-day low flows and basin area is

    developed using linear regression, providing a simple and effective method for estimation of low flows of desired return periods for ungauged catchments.

  • 50. Choi, H.T.
    et al.
    Beven, Keith J
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Multi-period and Multi-criteria Model Conditioning to Reduce Prediction Uncertainty in Distributed Rainfall-Runoff Modelling within GLUE framework2007In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 332, no 3-4, 316-336 p.Article in journal (Refereed)
    Abstract [en]

    A new approach to multi-criteria model evaluation is presented. The approach is consistent with the equifinality thesis and is developed within the Generalised Likelihood Uncertainty Estimation (GLUE) framework. The predictions of Monte Carlo realisations of TOPMODEL parameter sets are evaluated using a number of performance measures calibrated for both global (annual) and seasonal (30 day) periods. The seasonal periods were clustered using a Fuzzy C-means algorithm, into 15 types representing different hydrological conditions. The model shows good performance on a classical efficiency measure at the global level, but no model realizations were found that were behavioural over all multi-period clusters and all performance measures, raising questions about what should be considered as an acceptable model performance. Prediction uncertainties can still be calculated by allowing that different clusters require different parameter sets. Variations in parameter distributions between clusters, as well as examination of where observed discharges depart from model prediction bounds, give some indication of model structure deficiencies.

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