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  • 2101. Liblik, Taavi
    et al.
    Naumann, Michael
    Alenius, Pekka
    Hansson, Martin
    SMHI, Core Services.
    Lips, Urmas
    Nausch, Gunther
    Tuomi, Laura
    Wesslander, Karin
    SMHI, Core Services.
    Laanemets, Jaan
    Viktorsson, Lena
    SMHI, Core Services.
    Propagation of Impact of the Recent Major Baltic Inflows From the Eastern Gotland Basin to the Gulf of Finland2018In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 5, article id UNSP 222Article in journal (Refereed)
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  • 2102.
    Lidman, Fredrik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Mörth, Carl-Magnus
    Björkvald, Louise
    Laudon, Hjalmar
    Selenium dynamics in boreal streams: the role of wetlands and changing groundwater tables2011In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 45, no 7, p. 2677-2683Article in journal (Refereed)
    Abstract [en]

    The concentrations of selenium in 10 catchments of a stream network in northern Sweden were monitored over two years, yielding almost 350 observations of selenium concentrations in streamwater. The export of selenium was found to be systematically greater from forests than from mires. Accounting for atmospheric deposition, which was monitored over four years, there was a net accumulation of selenium in mires, while the export from forest soils was approximately equal to the atmospheric deposition. In forest dominated catchments the concentrations of selenium oscillated rapidly back and forth from high to low levels during spring floods. High selenium concentrations coincided with rising groundwater tables in the riparian forest soils, while low selenium concentrations were associated with receding groundwater. Thermodynamic modeling indicated that precipitation of elemental selenium would occur under reducing conditions in the riparian soils. Since changes in the redox conditions are likely to occur near the transition from the unsaturated to the saturated zone, it is hypothesized that the transport of selenium from forest soils to streams is controlled by redox reactions in riparian soils.

  • 2103.
    Lidman, Johan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Olid, Carolina
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Forestry and Management, Swedish University of Agricultural Sciences, Umeå, Sweden; Department of Earth and Ocean Dynamics, University of Barcelona, Barcelona, Spain.
    Bigler, Christian
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Berglund, Åsa M. M.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Effect of past century mining activities on sediment properties and toxicity to freshwater organisms in northern Sweden2023In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 872, article id 162097Article in journal (Refereed)
    Abstract [en]

    The release of toxic metals from local mining activities often represents a severe environmental hazard for nearby lake ecosystems. Previous studies on the impact of mining have primarily focused on single lakes, with less emphasis on spatial and temporal recovery patterns of multiple lakes within the same catchment, but with different hydrological connection and distance to the pollutant source. This knowledge gap prevents us from assessing the real environmental risk of abandoned mines and understanding ecosystem recovery. This study explores the intensity and spatial patterns of sediment contamination and the potential for ecosystem recovery in three lakes in close vicinity of a lead (Pb) and zinc (Zn) mine in Sweden that has been inoperative for >20 years. Dated (210Pb and 137Cs) sediment cores from each lake were used to reconstruct temporal patterns in trace element deposition and relate those with past mining activities. Results show that all lakes were affected by mining, indicated by increasing Pb and Zn concentrations and decreasing organic matter content, at the onset of mining. However, the extent and timing of mining impact differed between lakes, which was partly ascribed to differences in the historical use of tailings and settling ponds. Assessment of toxicity levels in sediments, based on normalized Probable Effect Concentration Quotient (PEC-Q) to organic matter content, provided more consistent results with the historical mining than conventional methods, showing a decreasing impact in lakes once the operations ceased. Still, sediment Pb concentrations were > 10 times higher than pre-mining values, evidencing the urgent need for remediation actions in the study lakes. This study highlights the importance of considering spatial heterogeneity in metal deposition, sediment organic matter content, and hydrological connectivity with tailings when risk assessments are performed in mining-impacted lakes. The use of normalized PEC-Q in toxic assessments is also recommended.

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  • 2104.
    Lidström, Susanna
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History, History of Science, Technology and Environment.
    Sea-level rise in public science writing: History, science and reductionism2019Conference paper (Refereed)
  • 2105.
    Lidström, Susanna
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History, History of Science, Technology and Environment.
    Meyer, Tirza
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History, History of Science, Technology and Environment.
    Peterson, Jesse
    Department of Ecology, SLU Swedish University of Agricultural Sciences, Uppsala, Sweden.
    The metaphor of ocean “health” is problematic: “the ocean we want” is a better term2022In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 9Article in journal (Refereed)
  • 2106.
    Lidström, Susanna
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History, History of Science, Technology and Environment.
    Moriaki, Yasuhara
    et al.,
    Incoporating deep-ocean biodiversity into climate change policy2023Other (Other (popular science, discussion, etc.))
  • 2107.
    Lidström, Susanna
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History, History of Science, Technology and Environment.
    Sörlin, Sverker
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History, History of Science, Technology and Environment.
    Svedäng, Henrik
    Stockholm University; Gothenburg University.
    Decline and diversity in Swedish seas: Environmental narratives in marine history, science and policy2020In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 49, no 5, p. 1114-1121Article in journal (Refereed)
    Abstract [en]

    Before the mid-twentieth century, there was no comprehensive narrative about empirical conditions in Swedish seas. Around 1970, this view changed profoundly. In line with growing research and the emergence of ‘the environment’ as a defining concept, conditions in Swedish seas were framed as a ‘narrative of decline’. Marine scientists have since recorded more diverse developments than are described by an overall declensionist narrative. Data show trends of interrupted decline, variability and even recovery, taking place at least partly in response to effective policy and legislation. We suggest that beyond the specialised fields of marine sciences and marine environmental history, the overarching narrative of decline has persisted, paying little attention to local and regional particularities as well as cultural and political dimensions of the marine environment. This overly uniform narrative risks obscuring historical reality and, hence, fails to adequately inform policy and the public about developments and outcomes of interventions in Swedish seas.

  • 2108.
    Lidén, Rikard
    SMHI, Research Department, Hydrology.
    A new approach for estimating suspended sediment yield1999In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 3, no 2, p. 285-294Article in journal (Refereed)
    Abstract [en]

    A semi-distributed conceptual model, HBV-SED, for estimation of total suspended sediment concentration and yield at the outlet of a catchment was developed and tested through a case study. The base of the suspended sediment model is a dynamic hydrological model, which produces daily series of areal runoff and rainfall for each sub-basin as input to the sediment routine. A lumped measure of available sediment is accumulated continuously based on a linear relationship between log-transformed values of rainfall and erosion, while discharge of suspended sediment at the sub-basin outlet is dependent on runoff and amount of stored available sediment. Four model parameters are empirically determined through calibration against observed records of suspended sediment concentration. The model was applied to a 200 km(2) catchment with high altitude differences in the tropical parts of Bolivia, where recorded suspended sediment concentrations were available during a two-year period. 10,000 parameter sets were generated through a Monte Carlo procedure to evaluate the parameter sensitivity and interdependence. The predictability of the model was assessed through dividing the data record into a calibration and an independent period for which the model was validated and compared to the sediment rating curve technique. The results showed that the slope coefficients of the log-transformed model equations for accumulation and release were much stronger than the intercept coefficients. Despite an existing interdependence between the model parameters, the HBV-SED model gave clearly better results than the sediment rating curve technique for the validation period, indicating that the supply-based approach has a promising future as a tool for basic engineering applications.

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  • 2109.
    Lidén, Rikard
    et al.
    SMHI, Research Department, Hydrology.
    Harlin, Joakim
    SMHI.
    Analysis of conceptual rainfall-runoff modelling performance in different climates2000In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 238, no 3-4, p. 231-247Article in journal (Refereed)
    Abstract [en]

    With the objective of studying conceptual rainfall-runoff modelling performance in different climates, the HBV-96 model was applied on four catchments located in Europe, Africa and South America. Manual, automatic and Monte Carlo techniques were used for model calibration and parameter analyses. It was found that the magnitude of the water balance components had a significant influence on model performance. Performance decreased and demands of calibration period length increased with increased catchment dryness primarily because of a neater water balance and higher climatic variability in drier areas. A large degree of equifinality was discovered in all catchments where different calibration methods yielded equally good results but with different parameter combinations. Thus, it may be impossible to know if an optimum parameter set exists and to relate parameter values to physical properties of the catchment. On the other hand the validation results indicated that it might not matter if parameter values were not unique when studying runoff solely, provided the model application is within the same regime of flows. (C) 2000 Elsevier Science B.V. AU rights reserved.

  • 2110.
    Liebenehm-Axmann, Anna Merle
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    The Role of Uni- and Multivariate Bias Adjustment Methods for Future Hydrological Projections and Subsequent Decision-Making2024Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Climate models are essential for generating future climate projections. However, due to simplifications, the models can produce systematic differences between output and reality, which is referred to as model bias. Bias adjustment methods aim to reduce this error, which is important for making future projections more reliable. Here, the suitability of four different bias adjustment methods was tested: distribution-based (Distribution Scaling (DS), Quantile Delta Mapping (QDM)) and non-distribution- based methods (Copula, Multivariate Bias Correction (MBCn)), of which each one univariate and one multivariate approach. The methods were assessed on climate future projections together with a non bias adjusted data set, focusing on their impacts on hydrological modelling simulations. For this, 16 hydrological signatures were analysed and categorized into: 1) water balance and flow dynamics, 2) seasonal behaviour of the flow, 3) low flow characteristics and 4) high flow characteristics. The assessment was carried out based on 50 catchments in Sweden, 10 climate models and one hydrological model. Most noticeable differences were observed between distribution-based and non-distribution-based methods, rather than between univariate and multivariate methods. Bias adjustment methods introduce half as much variation as climate models, catchments contribute substantially more to the projected signatures. Specific hydrological signatures differed regionally, such as changes in the average spring streamflow magnitude and greater bias adjustment variations in low- and high-flow frequencies, compared to varia- tions among catchments, suggesting a shift in the frequency of extreme streamflow events in the future. The choice of bias adjustment method impacted ’High flow characteristics’ the strongest. The Copula method deviated in the trend analysis by utilizing an existing trend. This research prompts further exploration of variation between current and projected future climate, or the inclusion of other variables that might impact projections, to determine the necessity of the methods. 

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    master623
  • 2111. Lienert, Judit
    et al.
    Andersson, Jafet
    SMHI, Research Department, Hydrology.
    Hofmann, Daniel
    Pinto, Francisco Silva
    Kuller, Martijn
    The role of multi-criteria decision analysis in a transdisciplinary process: co-developing a flood forecasting system in western Africa2022In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 26, no 11, p. 2899-2922Article in journal (Refereed)
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    The role of multi-criteria decision analysis in a transdisciplinary process: co-developing a flood forecasting system in western Africa
  • 2112.
    Ligtenberg, Jora
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Runoff changes due to urbanization: A review2017Student paper other, 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Urbanization causes changes in the water balance. Focusing on runoff, the aim of this report was to determine how both the magnitude and the form of this component change with urbanization. Also, solutions for decreasing the possible problems related to an increase in surface runoff were examined. Solutions were studied for both a general European situation and for the specific case of the Netherlands. Already after converting a forested area into agriculture, the runoff becomes more prominent, at the expense of evaporation and infiltration. When developing further into an urban area, its importance increases even more. In the last few years, various scientists have come up with suggestions of reducing the risks caused by increased runoff. Some examples are increasing the infiltration capacity or storing the excess water in cities. Considering the predicted future climate scenarios, water storage seems to be the best option. In the Netherlands, expanding the areas for water storage is the main subject of governmental research at the moment. On top of that, researchers advice to cooperate more between different stakeholders when considering water management. The main findings are thus that runoff increases with an increasing imperviousness of the surface, and the best solution to avoid problems caused by this enhanced amount of runoff seems to be the storage of excess water in cities. This solution is valid for both a general situation and in the Netherlands.

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  • 2113. Lilley, M. K. S.
    et al.
    Beggs, S. E.
    Doyle, T. K.
    Hobson, V. J.
    Strömberg, Patrik
    SMHI, Core Services.
    Hays, G. C.
    Global patterns of epipelagic gelatinous zooplankton biomass2011In: Marine Biology, ISSN 0025-3162, E-ISSN 1432-1793, Vol. 158, no 11, p. 2429-2436Article in journal (Refereed)
    Abstract [en]

    There is concern that overfishing may lead to a proliferation of jellyfish through a process known as fishing down the food web. However, there has been no global synthesis of patterns of gelatinous zooplankton biomass (GZB), an important first step in determining any future trends. A meta-analysis of epipelagic-GZB patterns was undertaken, encompassing 58 locations on a global scale, and spanning the years 1967-2009. Epipelagic-GZB decreased strongly with increasing total water column depth (r (2) = 0.543, p < 0.001, n = 58): in shallow (< 50 m) coastal waters, epipelagic-GZB was typically 742x the levels in deep ocean (> 2,000 m) sites. However, the ratio of GZB to primary productivity showed high values across a range of depths, i.e. this measure of the relative abundance of gelatinous zooplankton did not co-vary with depth.

  • 2114.
    Lim, Artem G.
    et al.
    BIO-GEO-CLIM Laboratory, Tomsk State University, Tomsk, Russian Federation.
    Krickov, Ivan V.
    BIO-GEO-CLIM Laboratory, Tomsk State University, Tomsk, Russian Federation.
    Vorobyev, Sergey N.
    BIO-GEO-CLIM Laboratory, Tomsk State University, Tomsk, Russian Federation.
    Korets, Mikhail A.
    V.N. Sukachev Institute of Forest, Siberian Branch of Russian Academy of Sciences, Separated Department of the KSC SB RAS, Krasnoyarsk, Russian Federation.
    Kopysov, Sergey
    BIO-GEO-CLIM Laboratory, Tomsk State University, Tomsk, Russian Federation.
    Shirokova, Liudmila S.
    N. Laverov Federal Center for Integrated Arctic Research, Russian Academy of Sciences, Arkhangelsk, Russian Federation.
    Karlsson, Jan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Pokrovsky, Oleg S.
    Geosciences and Environment Toulouse, UMR 5563 CNRS, 14 Avenue Edouard Belin, Toulouse, France.
    Carbon emission and export from the Ket River, western Siberia2022In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 19, no 24, p. 5859-5877Article in journal (Refereed)
    Abstract [en]

    Despite recent progress in the understanding of the carbon (C) cycle of Siberian permafrost-affected rivers, spatial and seasonal dynamics of C export and emission from medium-sized rivers (50 000-300 000 km2 watershed area) remain poorly known. Here we studied one of the largest tributaries of the Ob River, the Ket River (watershed Combining double low line 94 000 km2), which drains through pristine taiga forest of the boreal zone in the West Siberian Lowland (WSL). We combined continuous and discrete measurements of carbon dioxide (CO2) concentration using submersible CO2 sensor and floating chamber flux (FCO2), with methane (CH4), dissolved organic and inorganic C (DOC and DIC, respectively), particulate organic C and total bacterial concentrations over an 800 km transect of the Ket River main stem and its 26 tributaries during spring flood (May 2019) and 12 tributaries during summer baseflow (end of August-beginning of September 2019). The partial pressure of CO2 (pCO2) was lower and less variable in the main stem (2000 to 2500 μatm) compared to that in the tributaries (2000 to 5000 μatm). In the tributaries, the pCO2 was 40 % higher during baseflow compared to spring flood, whereas in the main stem, it did not vary significantly across the seasons. The methane concentration in the main stem and tributaries was a factor of 300 to 1900 (flood period) and 100 to 150 times lower than that of CO2 and ranged from 0.05 to 2.0 μmol L-1. The FCO2 ranged from 0.4 to 2.4 g C m-2 d-1 in the main channel and from 0.5 to 5.0 g C m-2 d-1 in the tributaries, being highest during August in the tributaries and weakly dependent on the season in the main channel. During summer baseflow, the DOC aromaticity, bacterial number, and needleleaf forest coverage of the watershed positively affected CO2 concentrations and fluxes. We hypothesize that relatively low spatial and seasonal variability in FCO2 of the Ket River is due to a flat homogeneous landscape (bogs and taiga forest) that results in long water residence times and stable input of allochthonous dissolved organic matter (DOM), which dominate the FCO2. The open water period (May to October) C emission from the fluvial network (main stem and tributaries) of the Ket River was estimated to 127 ± 11 Gg C yr-1, which is lower than the downstream dissolved and particulate C export during the same period. The estimated fluvial C emissions are highly conservative and contain uncertainties linked to ignoring hotspots and hot moments of emissions, notably in the floodplain zone. This stresses the need to improve the temporal resolution of FCO2 and water coverage across seasons and emphasizes the important role of WSL rivers in the release of CO2 into the atmosphere.

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  • 2115.
    Lim, Nancy Joy
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Brandt, S. Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Are Feature Agreement Statistics Alone Sufficient to Validate Modelled Flood Extent Quality?: A Study on Three Swedish Rivers Using Different Digital Elevation Model Resolutions2019In: Mathematical problems in engineering (Print), ISSN 1024-123X, E-ISSN 1563-5147, Vol. 2019, article id 9816098Article in journal (Refereed)
    Abstract [en]

    Hydraulic modelling is now, at increasing rates, used all over the world to provide flood risk maps for spatial planning, flood insurance, etc. This puts heavy pressure on the modellers and analysts to not only produce the maps but also information on the accuracy and uncertainty of these maps. A common means to deliver this is through performance measures or feature statistics. These look at the global agreement between the modelled flood area and the reference flood that is used. Previous studies have shown that the feature agreement statistics do not differ much between models that have been based on digital elevation models (DEMs) of different resolutions, which is somewhat surprising since most researchers agree that high-resolution DEMs are to be preferred over poor resolution DEMs. Hence, the aim of this study was to look into how and under which conditions the different feature agreement statistics differ, in order to see when the full potential of high-resolution DEMs can be utilised. The results show that although poor resolution DEMs might produce high feature agreement scores (around F > 0.80), they may fail to provide good flood extent estimations locally, particularly when the terrain is flat. Therefore, when high-resolution DEMs (1 to 5 m) are used, it is important to carefully calibrate the models by the use of the roughness parameter. Furthermore, to get better estimates on the accuracy of the models, other performance measures such as distance disparities should be considered.

  • 2116.
    Lim, Nancy Joy
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Brandt, S. Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Division of Visual Information and Interaction, Department of Information Technology, Uppsala University, Uppsala, Sweden.
    Visualisation and evaluation of flood uncertainties based on ensemble modelling2016In: International Journal of Geographical Information Science, ISSN 1365-8816, E-ISSN 1365-8824, Vol. 30, no 2, p. 240-262Article in journal (Refereed)
    Abstract [en]

    This study evaluates how users incorporate visualisation of flood uncertainty information in decision-making. An experiment was conducted where participants were given the task to decide building locations, taking into account homeowners’ preferences as well as dilemmas imposed by flood risks at the site. Two general types of visualisations for presenting uncertainties from ensemble modelling were evaluated: (1) uncertainty maps, which used aggregated ensemble results; and (2) performance bars showing all individual simulation outputs from the ensemble. Both were supplemented with either two-dimensional (2D) or three-dimensional (3D) contextual information, to give an overview of the area.The results showed that the type of uncertainty visualisation was highly influential on users’ decisions, whereas the representation of the contextual information (2D or 3D) was not. Visualisation with performance bars was more intuitive and effective for the task performed than the uncertainty map. It clearly affected users’ decisions in avoiding certain-to-be-flooded areas. Patterns to which the distances were decided from the homeowners’ preferred positions and the uncertainties were similar, when the 2D and 3D map models were used side by side with the uncertainty map. On the other hand, contextual information affected the time to solve the task. With the 3D map, it took the participants longer time to decide the locations, compared with the other combinations using the 2D model.Designing the visualisation so as to provide more detailed information made respondents avoid dangerous decisions. This has also led to less variation in their overall responses.

  • 2117. Lin, C.
    et al.
    Kao, M. -J
    Wong, W. -Y
    Tsai, C. -P
    Chang, K. -T
    Yang, James
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Hydraulic Engineering.
    Characteristics of flow separation and hydraulic jump during run-down motion of shoaling solitary wave traveling over steep sloping bottom2016In: Proceedings of the International Offshore and Polar Engineering Conference, International Society of Offshore and Polar Engineers , 2016, p. 724-731Conference paper (Refereed)
    Abstract [en]

    The features of velocity fields for the evolution of shoaling solitary wave, having a wave-height to water-depth ratio of 0.363 and propagating over a 1:3 sloping bottom, are investigated experimentally. A flow visualization technique using particle trajectory method and a high-speed particle image velocimetry (HSPIV) system employing a high-speed digital camera were used. This study mainly focuses on the occurrence of separated shear layer from the sloping bottom, evolved vortex structure, subsequent hydraulic jump, and curling jet of the backward breaking wave impinging upon the free surface of retreated flow during the run-down motion of the shoaling solitary wave.

  • 2118. Lin, Mu
    et al.
    Qiao, Jixin
    Hou, Xiaolin
    Steier, Peter
    Golser, Robin
    Schmidt, Martin
    Dellwig, Olaf
    Hansson, Martin
    SMHI, Core Services.
    Bäck, Örjan
    SMHI, Core Services.
    Vartti, Vesa-Pekka
    Stedmon, Colin
    She, Jun
    Murawski, Jens
    Aldahan, Ala
    Schmied, Stefanie A. K.
    Anthropogenic U-236 and U-233 in the Baltic Sea: Distributions, source terms, and budgets2022In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 210, article id 117987Article in journal (Refereed)
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    Anthropogenic U-236 and U-233 in the Baltic Sea: Distributions, source terms, and budgets
  • 2119.
    Lin, Qi
    et al.
    College of Geography and Environment, Shandong Normal University, Ji'nan, China; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
    Liu, Enfeng
    College of Geography and Environment, Shandong Normal University, Ji'nan, China.
    Zhang, Enlou
    State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
    Nath, Bibhash
    Department of Geography, Hunter College of the City University of New York, NY, United States.
    Bindler, Richard
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Liu, Jian
    Water Research Institute of Shandong Province, Ji'nan, China.
    Shen, Ji
    School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing, China.
    Organic carbon burial in a large, deep alpine lake (southwest China) in response to changes in climate, land use and nutrient supply over the past ~100 years2021In: Catena (Cremlingen. Print), ISSN 0341-8162, E-ISSN 1872-6887, Vol. 202, article id 105240Article in journal (Refereed)
    Abstract [en]

    Inland waterbodies play an important role in the global carbon cycle, acting both as carbon sources with organic carbon (OC) mineralization and as sinks with OC burial in sediments. Under recent impacts of global warming, anthropogenic land-use change and nutrient supply, however, there is a limited knowledge regarding OC dynamics in sediments of large, deep lakes especially in subtropical alpine regions. Here, we studied the patterns of OC burial and the potential regulating factors using multiple sedimentary proxies and observational records in Lugu Lake (southwest China) over the past ~100 years. Comparisons of 15 sediment cores in different areas of the lake reveal similar temporal trends in OC content and other sediment parameters, indicating coherent patterns of whole-lake sedimentary environmental change dominated by watershed human perturbation. Based on C/N ratios and δ13Corg analyses, the sediment OC has primarily been autochthonous in source. OC accumulation rates (OCAR) increased during 1880–1980, from ~14 to 43 g C m−2 yr−1 in a central core (LGS), mainly resulting from elevated primary production under increased phosphorus input and soil erosion. Subsequently, OCAR decreased considerably to ~15 g C m−2 yr−1, although the phosphorus supply and lake primary productivity remained high. We infer the OCAR decline likely resulted from increased organic matter decomposition and OC mineralization in the water column because of climate warming and lake-water thermal stratification. This phenomenon might mask the positive contribution of primary production to OC burial. Our findings suggest that the commonly observed synergistically positive effects of warming and eutrophication on sediment OC burial may be impaired in deep lakes, which needs further investigations across ecological, climatic and land-use gradients.

  • 2120.
    Lin, Qi
    et al.
    State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
    Zhang, Ke
    State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
    McGowan, Suzanne
    School of Geography, University of Nottingham, Nottingham, United Kingdom.
    Capo, Eric
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Shen, Ji
    School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing, China.
    Synergistic impacts of nutrient enrichment and climate change on long-term water quality and ecological dynamics in contrasting shallow-lake zones2021In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 66, no 9, p. 3271-3286Article in journal (Refereed)
    Abstract [en]

    Anthropogenic and climatic stressors on freshwater ecosystems are of global concern. However, the interactions and effects of multiple stressors (e.g., nutrient enrichment, climate warming, altered wind and precipitation) acting over different spatial and temporal scales are often complex and remain controversial. Here, we reconstructed one-century dynamics of eutrophication and primary producer communities in algal-dominated and macrophyte-dominated zones of a large shallow lake (Taihu, China), by integrating sedimentary photosynthetic pigments and geochemical records with water monitoring and historical archives. We aimed to explore the long-term underlying mechanisms of the responses of water quality and lake biota to multiple environmental perturbations. We found that water quality degradation and algal community modification showed similar trends but distinct timings and trajectories in contrasting ecological zones. Onset and intensity of eutrophication in north Meiliang Bay (since the 1950s) exceeded far beyond that of macrophyte-dominated Eastern Taihu (~1990s). Anthropogenic nutrients overtook past climatic control on production and composition of phototrophic assemblages. More importantly, lake phytoplankton responded markedly to climate warming, decreasing wind speed, and extreme weathers after cultural eutrophication. Synergistic interactions of nutrients and climate on lake ecosystems became increasingly significant in promoting harmful algal blooms (HABs) dominated by Microcystis, close to the hyper-eutrophic north lake zones. The asynchronous limnological and ecological responses also indicated the modulating roles of lake ecological regime and catchment hydrogeomorphic characteristic. Collectively, our findings suggest that mitigation of eutrophication and HABs calls for a triple management strategy integrating anthropogenic nutrients, climate change, and lake-catchment setting.

  • 2121.
    Lin, Shuqi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Environment and Climate Change Canada, Canada Centre for Inland Waters, Burlington, Canada.
    Pierson, Don
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Mesman, Jorrit P.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Département F.-A. Forel des sciences de l'environnement et de l'eau, Université de Genève, Geneva, Switzerland.
    Prediction of algal blooms via data-driven machine learning models: an evaluation using data from a well-monitored mesotrophic lake2023In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 16, no 1, p. 35-46Article in journal (Refereed)
    Abstract [en]

    With increasing lake monitoring data, data-drivenmachine learning (ML) models might be able to capture thecomplex algal bloom dynamics that cannot be completely described in process-based (PB) models. We applied two MLmodels, the gradient boost regressor (GBR) and long shortterm memory (LSTM) network, to predict algal blooms andseasonal changes in algal chlorophyll concentrations (Chl) ina mesotrophic lake. Three predictive workflows were tested,one based solely on available measurements and the othersapplying a two-step approach, first estimating lake nutrientsthat have limited observations and then predicting Chl usingobserved and pre-generated environmental factors. The thirdworkflow was developed using hydrodynamic data derivedfrom a PB model as additional training features in the twostep ML approach. The performance of the ML models wassuperior to a PB model in predicting nutrients and Chl. Thehybrid model further improved the prediction of the timingand magnitude of algal blooms. A data sparsity test based onshuffling the order of training and testing years showed theaccuracy of ML models decreased with increasing sampleinterval, and model performance varied with training–testingyear combinations.

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  • 2122.
    Lind, Lovisa
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Alfredsen, Knut
    Norwegian University of Science and Technology, Department of Hydraulic and Environmental Engineering.
    Kuglerová, Lenka
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Nilsson, Christer
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Hydrological and thermal controls of ice formation in 25 boreal stream reachesManuscript (preprint) (Other academic)
    Abstract [en]

    The Northern Hemisphere has a high density of fluvial freshwater ecosystems, many of which become ice-covered during winter. The formation and extent of ice have both ecological and socio-economic implications. For example, ice can cause freezing of riparian vegetation and fish eggs as well as influence hydropower production; however, when, where and why ice develops in small streams is poorly described. Data from 25 stream reaches were used to study the factors controlling ice formation during two consecutive winters. We addressed where in the catchment surface or anchor ice is most likely to develop, how stream morphology influences ice formation, and how climate influences ice processes. Reaches far away from lake outlets were most prone to form anchor ice, but many other factors also influenced ice formation. We found that anchor-ice was most common where water temperature and groundwater input were low and stream power high. The in-stream substrate was also important for the formation of anchor ice as well as the current velocity, which created turbulence and super-cooled conditions if high enough. We demonstrated that ice formation in the studied streams was complex, involving many variables, thus we constructed a conceptual model describing the likelihood of various ice types to develop, based on our large dataset. To our knowledge, this model is the first to describe the complexity of ice formation in steep boreal streams. As such it will be useful for practitioners and scientists working in small rivers in the Northern Hemisphere.

  • 2123.
    Lindahl, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Science.
    Modellering av avdunstning utgående från markfuktighetsmätningar i moränmark1996Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A one-dimensional SVAT-model (Soil-Vegetation-Atmosphere) was used to simulate evaporation and estimate the critical soil water potential where the reduction of the water uptake begins. This was done in a mixed pine and spruce forest in the north of Uppland, Sweden for the period 1 May to 31 October 1994. This period was unusually warm and dry and gave a unique chance to study the water uptake and the drought. Driving variables to the model were daily meteorological data and soil physical properties. The model was calibrated with TDR- (Time-Domain Reflectometry), tensiometer and ground water level measurements from the site for the same period. The critical water potential was estimated to -100 hPa and appeared to be a sensitive parameter in the model. The reduction of the water uptake began at the end of June. The surface resistance was calculated from the leaf area index and the Lohammar equation. The soil physical properties were shown to be significantly affecting the results of the simulation. The determination of these properties was uncertain because of the problems to measure in an inhomogenous till soil. The model simulations agreed generally well with the soil moisture measurements in some layers but a good agreement for all layers was not possible to obtain.

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    AnnaLindahl_1996
  • 2124.
    Lindberg, Sanna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Syresättning av grundvattnet i Badelundaåsen vid Lennhedens och Övre Tjärnas vattentäkter2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today, half of Sweden’s water supply comes from groundwater sources. Renewal of groundwater naturally happens most commonly through precipitation that seeps down to the groundwater table, but during special conditions renewal of groundwater through intrusion of surface water (e.g. river or lake) is possible. This will take place during saturated conditions, i.e. below the groundwater table, which will affect the quality of the groundwater. Surface water has a high content of organic matter, which will be degraded with the help of microorganisms. The microorganisms use oxygen during their respiration, and when the degradation takes place at saturated conditions the oxygen is being consumed at a higher rate than it is being added, since there is no contact with the atmosphere. This means that there is a risk that the organic matter will not degrade completely, which can cause problems in the drinking water plant, since organic matter can cause colour and smell to the water. Water with low oxygen content can also have higher concentrations of iron and manganese, which can lead to precipitation in pipes and to colour and smell as well.

    Last year, a new groundwater fed drinking water plant opened in Lennheden, situated northwest of Borlänge. It will, together with the old drinking water plant Övre Tjärna, supply both Borlänge and Falun with drinking water. Since it recently opened, it is suitable to examine possible changes in the groundwater quality, as it can cause problems in the future if the changes are not discovered in time. Both the drinking water plants are situated near the river Dalälven, where the intrusion of surface water is thought to have increased after the opening of the water plants.

    The aim of this study was therefore to determine how the operation of the two water plants will affect the groundwater quality, with regard to oxygenation and organic matter, due to the believed increased intrusion of surface water. In addition, possible changes in the groundwater flow directions were examined as well as how the situation can look like in the future. The results showed that there is a clear intrusion of surface water and increased organic content in the direction towards the old water plant, Övre Tjärna. No indications of increased intrusion due to the opening of Lennheden water plant could be seen, but a change in groundwater flow direction from southeast to northwest could be identified. The oxygen level was surprisingly low in the whole study area, which has lead to higher concentrations of iron and manganese in the groundwater. 

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  • 2125.
    Lindell, Sten
    SMHI, Professional Services.
    Realtidsbestämning av arealnederbörd1993Report (Other academic)
    Abstract [sv]

    Några vintrar under 80-talet gav HBV-modellen ett dåligt prognosresultat för vissa tillrinningsområden i norra Norrlands fjälltrakter. Samtidigt blev resultat av vårflödesvolymsprognosema för motsvarande områden bättre då arealnederbördsmetoden för prognosering av tilliinningsvolymer utnyttjades. För att utröna om det är möjligt att kombinera arealnederbördsmetodens nederbördsviktning med HBV-modellens tillrinningsberäkning finansierade arbetsgruppen för hydrologiskt utvecklingsarbet (HUVA) inom Vattenregleringsföretagens Samarbetsorgan (VASO) en studie budgetåret 1991-92 som avrapporterades i Mv PM Nr 3 (Lindell, 1992). I det arbetet användes ett PCprogram för tredimensionell interpolering, SURFER, för beräkning av den areella nederbörden. Arbetet med att läsa in nederbördsdata till det systemet var mycket omfattande och tog mesta tiden av projektet i anspråk. Däiför kunde endast ett prognosområde studeras med nederbördsdata under 15 månader

    Denna rapport redovisar en utveckling av SURFER-projektet från 1991-92. PC-programmet SURFER har ersatts med en av SMHI utvecklad modell för operationella korta väderprognoser, LAM-modellen (Ullerstig och Unden, 1981), (Unden, 1982) samt (Andersson et al., 1986).

    -talet gav HBV-modellen ett dåligt prognosresultat för vissa

    tillrinningsområden i norra Norrlands fjälltrakter

    . Samtidigt blev resultat av

    vårflödesvolymsprognosema för motsvarande områden bättre då arealnederbördsmetoden

    för prognosering av tilliinningsvolymer utnyttjades. För att utröna om det är möjligt att

    kombinera arealnederbördsmetodens nederbördsviktning med HBV-modellens

    tillrinningsberäkning finansierade arbetsgruppen för hydrologiskt utvecklingsarbete

    (HUVA) inom Vattenregleringsföretagens Samarbetsorgan (VASO) en studie budgetåret

    1991-92 som avrapporterades i Mv PM Nr 3 (Lindell, 1992). I det arbetet användes ett PCprogram

    för tredimensionell interpolering, SURFER, för beräkning av den areella

    nederbörden. Arbetet med att läsa in nederbördsdata till det systemet var mycket

    omfattande och tog mesta tiden av projektet i anspråk. Däiför kunde endast ett

    prognosområde studeras med nederbördsdata under 15 månader

    .

    Denna rapport redovisar en utveckling av SURFER-projektet från 1991-92. PC-programmet

    SURFER har ersatts med en av SMHI utvecklad modell för operationella korta

    väderprognoser, LAM-modellen (Ullerstig och Unden

    , 1981), (Unden, 1982) samt

    (Andersson et al., 1986).

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  • 2126.
    Lindell, Sten
    et al.
    SMHI, Professional Services.
    Carlsson, Bengt
    SMHI, Research Department, Hydrology.
    Sanner, Håkan
    SMHI, Core Services.
    Reihan, Alvina
    SMHI.
    Vedom, Rimma
    Application of the integrated hydrological modelling system IHMS-HBV to pilot basin in Estonia1996Report (Other academic)
    Abstract [en]

    This report describes calibration and application of the IHMS-HBV model on a daily time step to Kasari River basin in Estonia. The Swedish Meteorological and Hydrological Institute (SMHI) have as consultant been responsible for the set-up, calibration, training and delivery of the Integrated Hydrological Model System with the HBV-model (IHMSHBV). The Swedish Board for lnvestment and Technical Support (BITS) financed the project. The training and transfer of technology were addressed to the Estonian Meteorological and Hydrological Institute (EMHI).

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  • 2127.
    Lindell, Sten
    et al.
    SMHI, Professional Services.
    Ericsson, Lars O.
    SMHI.
    Sanner, Håkan
    SMHI, Core Services.
    Göransson, Karin
    SMHI.
    Integrated Hydrological Monitoring and Forecasting System for the Vistula River Basin1997Report (Other academic)
    Abstract [en]

    This report is a technical description on the project Integrated Hydrological Monitoring and Forecasting System for the Vistula River Basin. The Swedish Meteorological and Hydrological lnstitute in Nonköping, Sweden, (hereinafter called SMHI) and Institute of Meteorology and Water Management in Warsaw, Poland, (hereinafter called IMWM) has fulfilled and co-operated in this project. SMHI have as consultants been responsible for design and development of the Vistula River Monitoring and Forecasting System, for on-the-job training and education in Windows programming and development as well as in set-up, calibration and applications of the HBV-model. IMWM responsibilities has been to provide the project with hydrometeorological data and information on land use for the calibration activities and to supply the project with the hydrodynamic model in use at the polish institute. IMWM has been deeply involved in the design and development of the Vistula River Monitoring and Forecasting System and bad the main responsibility in the HBV-model calibration activities.

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  • 2128.
    Lindell, Sten
    et al.
    SMHI, Professional Services.
    Sanner, Håkan
    SMHI, Core Services.
    Nikolushkina, Irena
    SMHI.
    Stikute, Inita
    SMHI.
    Application of the integrated hydrological modelling system IHMS-HBV to pilot basin in Latvia1996Report (Other academic)
    Abstract [en]

    This report describes calibration and application of the IHMS-HBV model on daily time step to Lielupe River basin in Latvia. The Swedish Meteorological and Hydrologicalnstitute (SMHI) have as consultant been responsible for the set-up, calibration, training and delivery of the Integrated Hydrological Model System with the HBV-model (IHMSHBV). The Swedish Board for Investment and Technical Support (BITS) financed the project. The training and transfer of technology were addressed to the Latvia Hydrometeorological Agency (LHMA)

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  • 2129. Lindenschmidt, Karl-Erich
    et al.
    Alfredsen, Knut
    Carstensen, Dirk
    Chorynski, Adam
    Gustafsson, David
    SMHI, Research Department, Hydrology.
    Halicki, Michal
    Hentschel, Bernd
    Karjalainen, Niina
    Koegel, Michael
    Kolerski, Tomasz
    Kornas-Dynia, Marika
    Kubicki, Michal
    Kundzewicz, Zbigniew W.
    Lauschke, Cornelia
    Malinger, Albert
    Marszelewski, Wlodzimierz
    Moeldner, Fabian
    Naslund-Landenmark, Barbro
    Niedzielski, Tomasz
    Parjanne, Antti
    Pawlowski, Boguslaw
    Pinskwar, Iwona
    Remisz, Joanna
    Renner, Maik
    Roers, Michael
    Rybacki, Maksymilian
    Szalkiewicz, Ewelina
    Szydlowski, Michal
    Walusiak, Grzegorz
    Witek, Matylda
    Zagata, Mateusz
    Zdralewicz, Maciej
    Assessing and Mitigating Ice-Jam Flood Hazards and Risks: A European Perspective2023In: Water, E-ISSN 2073-4441, Vol. 15, no 1, article id 76Article in journal (Refereed)
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    Assessing and Mitigating Ice-Jam Flood Hazards and Risks_A European Perspective: A European Perspective
  • 2130.
    Linders, Torsten
    et al.
    Institutionen för geovetenskaper, Göteborgs Universitet.
    Saetra, Øyvind
    Meteorologisk Institutt, Norge.
    Bracegirdle, Thomas J.
    British Antarctic Survey, Cambridge, UK.
    Limited polar low sensitivity to sea-surface temperature2011In: Quarterly Journal of the Royal Meteorological Society, ISSN 0035-9009, E-ISSN 1477-870X, Vol. 137, no 654, p. 58-69Article in journal (Refereed)
  • 2131.
    Lindersson, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    The use of global data to uncover how humans shape flood and drought risk2023Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The human consequences of flood and drought disasters are widespread and detrimental. Large-scale studies, drawing on global geodata products and international databases, can systematically examine how anthropogenic megatrends shape disaster risk and test the generalisability of findings from other scientific methodologies. However, the top-down lens of these global studies often misses the pivotal role that human societies play in shaping disaster risk, including how water management influences physical hazards and how political factors shape social vulnerability. It is precisely this tension – characterised by the need for global perspectives alongside the need to incorporate human influences in the study of disaster risk – that motivates my research.

    This thesis specifically examines how observations from global data can leverage our understanding of how humans shape hydrological disaster risk, in terms of the hazard, human exposure and social vulnerability. To this end, the thesis draws on multiple methodologies across four individual studies, including one scoping review and three quantitative geospatial studies. The findings of this thesis provide insights into 1) how the landscape of global data shapes disaster studies and 2) how human societies shape disaster risk.

    For the former, my thesis shows that key data opportunities and challenges vary across disaster types and risk dimensions. Addressing each of these limitations is important because of the interrelated nature of disaster risk. The thesis also underlines how the pursuit of transforming fragmented disaster knowledge into holistic and useful information would encounter fewer obstacles if the global datasets were more integrated or, at the very least, more compatible. Databases recording past disaster losses serve as a natural place for such an integration.

    For the latter, this thesis brings to light the heterogeneous impact that large-scale infrastructure projects can have on disaster risk, by showing that river regulation does not serve as a universal solution for reducing long-term drought risk. The thesis also highlights the central role of human exposure and economic inequality in shaping human losses during severe flood disasters. Taken together, this underlines the importance of addressing root causes of vulnerability to reduce fatalities during disasters.

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  • 2132.
    Lindersson, Sara
    et al.
    Uppsala Univ, Dept Earth Sci, Ctr Nat Hazards & Disaster Sci, Uppsala, Sweden..
    Brandimarte, Luigia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Mard, Johanna
    Uppsala Univ, Dept Earth Sci, Ctr Nat Hazards & Disaster Sci, Uppsala, Sweden..
    Di Baldassarre, Giuliano
    Uppsala Univ, Dept Earth Sci, Ctr Nat Hazards & Disaster Sci, Uppsala, Sweden..
    Global riverine flood risk - how do hydrogeomorphic floodplain maps compare to flood hazard maps?2021In: Natural hazards and earth system sciences, ISSN 1561-8633, E-ISSN 1684-9981, Vol. 21, no 10, p. 2921-2948Article in journal (Refereed)
    Abstract [en]

    Riverine flood risk studies often require the identification of areas prone to potential flooding. This modelling process can be based on either (hydrologically derived) flood hazard maps or (topography-based) hydrogeomorphic floodplain maps. In this paper, we derive and compare riverine flood exposure from three global products: a hydrogeomorphic floodplain map (GFPLAIN250m, hereinafter GFPLAIN) and two flood hazard maps (Flood Hazard Map of the World by the European Commission's Joint Research Centre, hereinafter JRC, and the flood hazard maps produced for the Global Assessment Report on Disaster Risk Reduction 2015, hereinafter GAR). We find an average spatial agreement between these maps of around 30 % at the river basin level on a global scale. This agreement is highly variable across model combinations and geographic conditions, influenced by climatic humidity, river volume, topography, and coastal proximity. Contrary to expectations, the agreement between the two flood hazard maps is lower compared to their agreement with the hydrogeomorphic floodplain map. We also map riverine flood exposure for 26 countries across the global south by intersecting these maps with three human population maps (Global Human Settlement population grid, hereinafter GHS; High Resolution Settlement Layer, hereinafter HRSL; and WorldPop). The findings of this study indicate that hydrogeomorphic floodplain maps can be a valuable way of producing high-resolution maps of flood-prone zones to support riverine flood risk studies, but caution should be taken in regions that are dry, steep, very flat, or near the coast.

  • 2133.
    Lindersson, Sara
    et al.
    Uppsala Univ, Dept Earth Sci, Uppsala, Sweden..
    Brandimarte, Luigia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Mård, Johanna
    Uppsala Univ, Dept Earth Sci, Uppsala, Sweden..
    Di Baldassarre, Giuliano
    Uppsala Univ, Dept Earth Sci, Uppsala, Sweden..
    A review of freely accessible global datasets for the study of floods, droughts and their interactions with human societies2020In: WIREs Water, E-ISSN 2049-1948, Vol. 7, no 3, article id e1424Article, review/survey (Refereed)
    Abstract [en]

    The availability of planetary-scale geospatial datasets that can support the study of water-related disasters in the Anthropocene is rapidly growing. We review 124 global and free datasets allowing spatial (and temporal) analyses of floods, droughts and their interactions with human societies. Our collection of datasets is available in a descriptive list for download at . The purpose of providing an overview of datasets across a wide range of hydrological and socioeconomic variables is to highlight research opportunities across scientific disciplines for the study of the water-society interplay. Our collection of datasets confirms that the availability of geospatial data capturing hydrological hazards and exposure is far more mature than those capturing vulnerability aspects. We do not only highlight the unprecedented opportunities associated with these global datasets for the study of water-related disasters in the Anthropocene, but also discuss the challenges associated with their exploitation. These challenges include: (a) time varying datasets advised not to be used in time series analyses; (b) fine spatial resolution datasets advised not to be used in local scale studies; (c), datasets built by a wide variety of data sources prohibiting systematic uncertainty assessments; and (d) datasets built by covariate variables preventing interaction studies. This article is categorized under: Engineering Water > Planning Water Engineering Water > Sustainable Engineering of Water Science of Water > Water Extremes

  • 2134.
    Lindersson, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Brandimarte, Luigia
    KTH Royal Inst Technol, Sch Architecture & Built Environm, Stockholm, Sweden..
    Mård, Johanna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Di Baldassarre, Giuliano
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    A review of freely accessible global datasets for the study of floods, droughts and their interactions with human societies2020In: WIREs Water, E-ISSN 2049-1948, Vol. 7, no 3, article id e1424Article, review/survey (Refereed)
    Abstract [en]

    The availability of planetary-scale geospatial datasets that can support the study of water-related disasters in the Anthropocene is rapidly growing. We review 124 global and free datasets allowing spatial (and temporal) analyses of floods, droughts and their interactions with human societies. Our collection of datasets is available in a descriptive list for download at . The purpose of providing an overview of datasets across a wide range of hydrological and socioeconomic variables is to highlight research opportunities across scientific disciplines for the study of the water-society interplay. Our collection of datasets confirms that the availability of geospatial data capturing hydrological hazards and exposure is far more mature than those capturing vulnerability aspects. We do not only highlight the unprecedented opportunities associated with these global datasets for the study of water-related disasters in the Anthropocene, but also discuss the challenges associated with their exploitation. These challenges include: (a) time varying datasets advised not to be used in time series analyses; (b) fine spatial resolution datasets advised not to be used in local scale studies; (c), datasets built by a wide variety of data sources prohibiting systematic uncertainty assessments; and (d) datasets built by covariate variables preventing interaction studies.

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  • 2135.
    Lindersson, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Brandimarte, Luigia
    KTH Royal Inst Technol, Dept Sustainable Dev Environm Sci & Engn, Stockholm, Sweden..
    Mård, Johanna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Di Baldassarre, Giuliano
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Global riverine flood risk - how do hydrogeomorphic floodplain maps compare to flood hazard maps?2021In: Natural hazards and earth system sciences, ISSN 1561-8633, E-ISSN 1684-9981, Vol. 21, no 10, p. 2921-2948Article in journal (Refereed)
    Abstract [en]

    Riverine flood risk studies often require the identification of areas prone to potential flooding. This modelling process can be based on either (hydrologically derived) flood hazard maps or (topography-based) hydrogeomorphic floodplain maps. In this paper, we derive and compare riverine flood exposure from three global products: a hydrogeomorphic floodplain map (GFPLAIN250m, hereinafter GFPLAIN) and two flood hazard maps (Flood Hazard Map of the World by the European Commission's Joint Research Centre, hereinafter JRC, and the flood hazard maps produced for the Global Assessment Report on Disaster Risk Reduction 2015, hereinafter GAR). We find an average spatial agreement between these maps of around 30 % at the river basin level on a global scale. This agreement is highly variable across model combinations and geographic conditions, influenced by climatic humidity, river volume, topography, and coastal proximity. Contrary to expectations, the agreement between the two flood hazard maps is lower compared to their agreement with the hydrogeomorphic floodplain map. We also map riverine flood exposure for 26 countries across the global south by intersecting these maps with three human population maps (Global Human Settlement population grid, hereinafter GHS; High Resolution Settlement Layer, hereinafter HRSL; and WorldPop). The findings of this study indicate that hydrogeomorphic floodplain maps can be a valuable way of producing high-resolution maps of flood-prone zones to support riverine flood risk studies, but caution should be taken in regions that are dry, steep, very flat, or near the coast.

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    FULLTEXT01
  • 2136.
    Lindersson, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Centre of Natural Hazards and Disaster Science.
    Jonsson, Elise
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Centre of Natural Hazards and Disaster Science.
    Di Baldassarre, Giuliano
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Centre of Natural Hazards and Disaster Science.
    The two-faced impact of dams and reservoirs on hydrological droughtManuscript (preprint) (Other academic)
    Abstract [en]

    Rivers around the world are increasingly regulated by dams and reservoirs. As a result, hydrological drought conditions are more and more characterised by a complex anthropogenic dimension. Understanding how human activities influence the propagation of drought is particularly crucial in the face of climatic and societal changes. In this work, we explore how large dams change the way in which atmospheric water deficit propagates through river basins and result (or not) in hydrological drought. To this end, we analysed geocoded records of 15 large dams in five countries with weather and streamflow observations. Our study reveals a heterogeneous pattern of dam-induced drought propagation shifts. A slight majority of the dams reduced the duration of hydrological drought (i.e. below-normal river flows) compared to the unregulated state. However, most dams contributed to an increased streamflow deficit, both in terms of the median deficit per event and the total deficit over a 10-year period. Our findings also highlight the presence of dams that severely exacerbated hydrological drought conditions downstream, as indicated by more frequent, longer, and more intense drought events. This study significantly contributes to the existing literature showing that river regulation through dams is by no means a panacea for reducing drought risk.

  • 2137.
    Lindersson, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Centre of Natural Hazards and Disaster Science, Uppsala University, Uppsala, Sweden.
    Raffetti, Elena
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Centre of Natural Hazards and Disaster Science, Uppsala University, Uppsala, Sweden;British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK;Heart and Lung Research Institute, University of Cambridge, Cambridge, UK;Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden.
    Rusca, Maria
    Global Development Institute, University of Manchester, Manchester, UK.
    Brandimarte, Luigia
    Sustainable Development, Environmental Sciences and Engineering Department, KTH Royal Institute of Technology, Stockholm, Sweden.
    Mård, Johanna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Centre of Natural Hazards and Disaster Science, Uppsala University, Uppsala, Sweden.
    Di Baldassarre, Giuliano
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Centre of Natural Hazards and Disaster Science, Uppsala University, Uppsala, Sweden.
    The wider the gap between rich and poor the higher the flood mortality2023In: Nature Sustainability, E-ISSN 2398-9629Article in journal (Refereed)
    Abstract [en]

    Economic inequality is rising within many countries globally, and this can significantly influence the social vulnerability to natural hazards. We analysed income inequality and flood disasters in 67 middle- and high-income countries between 1990 and 2018 and found that unequal countries tend to suffer more flood fatalities. This study integrates geocoded mortality records from 573 major flood disasters with population and economic data to perform generalized linear mixed regression modelling. Our results show that the significant association between income inequality and flood mortality persists after accounting for the per-capita real gross domestic product, population size in flood-affected regions and other potentially confounding variables. The protective effect of increasing gross domestic product disappeared when accounting for income inequality and population size in flood-affected regions. On the basis of our results, we argue that the increasingly uneven distribution of wealth deserves more attention within international disaster-risk research and policy arenas.

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  • 2138.
    Lindgren, Carl
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Estimating groundwater changes in the Rufiji basin by using data from the GRACE satellites2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
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  • 2139.
    Lindgren, Georg
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Physical process effects on catchment-scale pollutant transport-attenuation, coastal loading and abatement efficiency2006Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Pollutants follow various subsurface and surface water pathways from sources within a catchment to its outlet and may cause detrimental effects on downstream water quality and ecosystems. Along their different transport pathways through a catchment, pollutants may be attenuated subject to different physical and biogeochemical processes. In this thesis, physical process effects on such catchment-scale pollutant transport and attenuation, resulting coastal pollutant loading and its efficient abatement are investigated. For this purpose, pollutant transport-attenuation is modeled both generically using a Lagrangian Stochastic Advective-Reactive (LaSAR) approach and site specifically for the Swedish Norrström basin using the GIS-based dynamic nitrogen transport-attenuation model POLFLOW. Furthermore, the role of such modeling for catchment-scale pollutant abatement is also investigated by use of economic optimization modeling.

    Results indicate that appropriate characterization of catchment-scale solute transport and attenuation processes requires accurate quantification of the specific solute pathways from different sources in a catchment, through the subsurface and surface water systems of the catchment, to the catchment outlet. The various physical processes that act on solute transported along these pathways may be quantified appropriately by use of relevant solute travel time distributions for each water subsystem that the pathways cross through the catchment. Such distributions capture the physical solute travel time variability from source to catchment outlet and its effects on reactive pollutant transport. Results of this thesis show specifically that neglect of such physical solute travel time variability in large-scale models of nitrogen transport and attenuation in catchments may yield misleading model estimates of nitrogen attenuation rates.

    Results for nitrogen abatement optimization in catchments further indicate that inefficient solutions for coastal nitrogen load reduction may result from simplifying physical transport assumptions made in different catchment-scale nitrogen transport-attenuation models. Modeling of possible future nitrogen management scenarios show also that slow nitrogen transport and reversible mass transfer processes in the subsurface water systems of catchments may greatly delay and temporally redistribute coastal nitrogen load effects of inland nitrogen source abatement over decades or much longer. Achievement of the national Swedish environmental objective to reduce the anthropogenic coastal nitrogen loading by 30% may therefore require up to a 40% reduction of both point sources, for achieving a fast coastal load response, and diffuse sources, for maintaining the coastal load reduction also in the long term.

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  • 2140. Lindgren, Georg A.
    et al.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Darracq, Amelie
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Inland subsurface water system role for coastal nitrogen load dynamics and abatement responses2007In: Environmental Science & Technology, Vol. 41, no 7, p. 2159-2164Article in journal (Refereed)
    Abstract [en]

    We simulate and analyze long-term dynamics of coastal

    nitrogen (N) loading and the inland source changes and

    processes that may have determined its development over

    the past 60-year period and may govern its possible

    future responses to variousNsource management scenarios.

    With regard to processes, the results show that average

    basin-scale N delivery fractions to the coast may not be

    representative of the coastal impacts of either diffuse or

    point inland sources. The effects of inland source changes

    may be greatly redistributed in space-time and delayed

    by slow N transport and mass transfer processes in the

    subsurface water system of coastal catchments. Extrapolation

    of current N transport-attenuation conditions

    for quantification of future abatement effects may therefore

    be misleading if the extrapolation models do not realistically

    represent delayed long-term influences of slow subsurface

    processes. With regard to policy, the results show that and

    why national Swedish and international Baltic Sea

    region policies for coastal N load abatement may be

    difficult or impossible to achieve by inland source abatement

    only. Large mitigation of both point and diffuse sources

    may be necessary to achieve targeted coastal N load

    reductions fast and maintain them also in the long term.

  • 2141.
    Lindgren, Georg
    et al.
    KTH, Superseded Departments (pre-2005), Land and Water Resources Engineering.
    Destouni, Georgia
    Miller, Adrienne
    Solute transport through the integrated groundwater-stream system of a catchment2004In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 40, no 3, p. W03511-Article in journal (Refereed)
    Abstract [en]

    We present a coupled groundwater-stream model of catchment-scale solute transport, using a Lagrangian stochastic advective-sorptive travel time approach. We consider distributed solute input over an entire catchment and investigate the resulting stream solute breakthrough, subject to the possible solute spreading mechanisms: (1) variable groundwater advection and solute mass transfer between mobile and immobile groundwater zones and (2) in-stream advection, mixing, and solute mass transfer between stream water and hyporheic zone. Among these mechanisms we show that fractal solute spreading over a wide timescale range is, for realistic parameter values, obtained in the stream only for the condition combination of both variable solute advection and solute mass transfer in the groundwater, with mean groundwater advection to mass transfer rate ratio that falls within a certain value range and with only a small fraction of solute input mass following fast overland and/or storm soil water flow to the stream

  • 2142.
    Lindh, Markus
    et al.
    SMHI, Core Services.
    Pinhassi, Jarone
    Sensitivity of Bacterioplankton to Environmental Disturbance: A Review of Baltic Sea Field Studies and Experiments2018In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 5, article id UNSP 361Article in journal (Refereed)
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  • 2143.
    Lindquist, Armin
    Perfomers of environmental monitoring, Government Agencies, National Board of Fisheries.
    Anteckningar om äldre svenska marina fiskerivetenskapliga undersökningar: Glimtar från 200 år av fiskeriundersökningar1998Report (Other academic)
    Abstract [en]

    The annotations cover the time from the middle of the 18th century to the end of the 1970’s. Three periods can be distinguished. -During the first period, from the middle of the 18th century until the beginning of the present century, taxonomic studies (PetrusArtedi) and descriptions of fish species occurring in Swedish waters were the dominating activities. From this period, annual reports are available on fisheries, at that time coastal only, from Norrland in the Baltic Sea to Bohuslän, in the Skagerrack. The first marine environmental issue was the question whether train oil waste was dangerous for the fishery during the herring period in the 18thcentury in Bohuslän. Herring periods, during which herring occurred in enormous quantities in the archipelago of Bohuslän, were considered to be caused, at least partly, by major oceanographic changes. Swedish oceanographers took the initiative for an international coordination of marine research.

    During the second period, from the beginning of this century until 1948, the International Council for the Exploration of the Sea, ICES, was established, whereby efforts became internationally coordinated. Numerous biological investigations were carried out on herring, sprat, codfishes and flatfishes. Studies were also made on benthos and plankton, and a network of oceanographic observations was established in the Skagerrack/Kattegatt and in the Baltic. A number of experiments were conducted with fishing gear. Results from fishery investigations were used as background material i.a. for management measures. A comprehensive study on fish and fisheries in northern countries was published in two volumes of “Fiskar och Fiske i Norden”, edited by K.A. Anderssson, 3 edns.

    The third period, starting in 1948 when the Royal Fishery Board (now the Swedish National Board of Fisheries) was established, commenced with a large number of taggings of herring and cod, in order to study migrations and growth. Through excavations of sub fossile waste the origin of the herring, present during the herring period of the eighteenth century, could be identified. In the context of environmental issues in the sea, it was found that our long term series on biological and oceanographical data was the most valuable material available. The oceanographic situation was monitored particularly in the Baltic. Following the increased exploitation of fish stocks, there was a pronounced shift of focus towards stock assessments. Some socio-economic studies were also made.

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  • 2144.
    Lindqvist, Andreas
    et al.
    RISE Research Institutes of Sweden. SLU Swedish University of Agricultural Sciences, Sweden.
    Fornell, Rickard
    RISE Research Institutes of Sweden, Built Environment, Energy and Resources.
    Prade, Thomas
    SLU Swedish University of Agricultural Sciences, Sweden.
    Tufvesson, Linda
    SLU Swedish University of Agricultural Sciences, Sweden.
    Khalil, Sammar
    SLU Swedish University of Agricultural Sciences, Sweden.
    Kopainsky, Birgit
    University of Bergen, Sweden.
    Human-Water Dynamics and their Role for Seasonal Water Scarcity – a Case Study2021In: Water resources management, ISSN 0920-4741, E-ISSN 1573-1650, Vol. 35, no 10, p. 3043-3061Article in journal (Refereed)
    Abstract [en]

    Ensuring sustainable management and an adequate supply of freshwater resources is a growing challenge around the world. Even in historically water abundant regions climate change together with population growth and economic development are processes that are expected to contribute to an increase in permanent and seasonal water scarcity in the coming decades. Previous studies have shown how policies to address water scarcity often fail to deliver lasting improvements because they do not account for how these processes influence, and are influenced by, human-water interactions shaping water supply and demand. Despite significant progress in recent years, place-specific understanding of the mechanisms behind human-water feedbacks remain limited, particularly in historically water abundant regions. To this end, we here present a Swedish case study where we, by use of a qualitative system dynamics approach, explore how human-water interactions have contributed to seasonal water scarcity at the local-to-regional scale. Our results suggest that the current approach to address water scarcity by inter-basin water transports contributes to increasing demand by creating a gap between the perceived and actual state of water resources among consumers. This has resulted in escalating water use and put the region in a state of systemic lock-in where demand-regulating policies are mitigated by increases in water use enabled by water transports. We discuss a combination of information and economic policy instruments to combat water scarcity, and we propose the use of quantitative simulation methods to further assess these strategies in future studies. © 2021, The Author(s).

  • 2145.
    Lindqvist, Klara
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Modelling the Effects of Climate Change on Future DOC Export to Lake Mälaren Using a Generalized Watershed Loading Functions (GWLF) Model2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Browning of boreal freshwaters due to an increased export of terrestrial dissolved organic carbon (DOC) has been observed for some decennia. Drivers include recovery from acid deposition and changing climate and land cover. Lake Mälaren provides the Swedish capital Stockholm with drinking water and an increased future browning of the lake could demand more treatment to produce acceptable drinking water. Knowledge of what can be expected in a changing climate is therefore needed. The aim of this study was to evaluate; (1) The performance of the GWLF model simulations of hydrology and DOC export for 13 catchments draining into the Galten and Ekoln basins in lake Mälaren; (2) How simulated DOC export from the 13 catchments would change in response to climate scenarios RCP2.6, 6.0 and 8.5; and (3) If climate change impact on DOC export to lake Mälaren potentially will demand more treatment of the lake water in the future to produce acceptable drinking water to the Stockholm area. All data used were open access and include temperature, precipitation, discharge, total organic carbon (TOC) and water colour, land cover and soil types. In comparison to other studies, good model performance was found when simulating daily streamflow, baseflow, surface runoff, daily DOC loads and monthly DOC loads. Model simulations of DOC concentrations were less certain, but for some catchments similar results were obtained as in other studies. Increased air temperature resulted in higher simulated soil temperatures and a longer growing season. An increase in both annual precipitation and evapotranspiration resulted in only slight increase in simulated annual streamflow. There were, however, large seasonal impacts on streamflow with higher winter flows and lower spring flood. Annual DOC loads increased, mainly due to increased DOC concentrations over the whole year, as the annual streamflow did not change greatly. Increased winter streamflow and DOC concentrations resulted in large increases in DOC loads. The impact was larger for the higher emission scenarios. DOC loading to Galten and Ekoln increased in all future scenarios during winter, with a likely impact on DOC concentrations in the eastern basins as well. Increased loads to Ekoln are likely to impact the drinking water production of Stockholm more direct than the increases in Galten, as the Ekoln water has a shorter transit time to the drinking water withdrawals. The GWLF model shows much promise in predicting DOC concentrations and loads to lake Mälaren in a changing climate. To estimate the effects of DOC export to lake Mälaren on future drinking water production, further work also needs to be done on in-lake transport and processes.

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  • 2146.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    A simple automatic calibration routine for the HBV model1997In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 28, no 3, p. 153-168Article in journal (Refereed)
    Abstract [en]

    A simple, but efficient, method for automatic calibration of the conceptual HBV rainfall-runoff model was developed. A new criterion, which combines the commonly used efficiency criterion R-2 and the relative volume error was introduced. 2 values nearly as high as those Optimising this combined criterion resulted in R-2 for optimising only R-2, but With much smaller volume errors. An earlier automatic calibration method for the HBV model relied on the use of different criteria for different parameters. With the simplification to one single criterion, the optimum search method could be made more efficient. The optimisation is made for one parameter at a time, while the others are kept constant. This one-dimensional optimisation is repeated in a loop for all parameters. A new loop is performed as long as there is a sufficiently large improvement since the last one. After each loop a search is made in the direction which is defined by the differences in parameter values between the two latest loops. The calibration routine was developed for, and tested with, the HBV model, but it should be general enough to be applicable to other models as well.

  • 2147.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Analys av avrinningsserier för uppskattning av effektivt regn1987Report (Other academic)
    Abstract [sv]

    En metod för beräkning av effektiv nederbörd ur avrinningsserier presenteras. Metoden innebär, att hela avrinningsområdet betraktas som en effektiv regnmätare, vilken analyseras via sin avrinningsserie. Resultaten inkluderar bidrag från regn, snösmältning och förluster pga magasinering i marken samt tar hänsyn till den areella variationen i alla dessa faktorer.Den föreslagna metoden har tillämpats på 31 avrinningsserier, företrädesvis från områden i norra Sverige, totalt omfattande1 365 observationsår. De erhållna uppskattningarna av effektiva regn är för nederbördstillfällen med enbart regn i allmänhet avsevärt lägre än den nederbördsmängd, som fallit över området. Dessutom kan i flera områden en viss reduktion av risken för höga effektiva regn sommartid skönjas. Orsaken till detta är i första hand effekten av ett markfuktighetsunderskott sommartid. I utpräglade fjällområden är detta förhållande ej lika framträdande.En viss minskning av den största påträffade effektiva regnmängden med ökande areal framgår av materialet.Stora effektiva regn, orsakade av snösmältning under våren, är mer frekventa än stora regntillfällen under sommar och höst, i synnerhet om flerdygnsvärden analyseras.

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  • 2148.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Floods in Sweden – Trends and occurrence1993Report (Other academic)
    Abstract [en]

    Sweden experienced a number of large floods in the 1980-ies. This raised the question of whether floods were becoming more frequent. A systematic study on floods was carried out, to provide a perspective to past and future floods. Frequency analysis was made using 16 methods. A split-sample test was used for evaluation of the predictive power of the methods. Numerical criteria were used for measuring the goodness of fit. The return periods of observed floods were estirnated by use of plotting positions.

    No convincing evidence of trends was found. The 1980-ies had larger floods than usual, where as the 1970-ies had few high floods, especially, in the auturnn. This may have led to the, irnpression of a trend. No evidence of autocorrelation or periodicity was found. For most of Sweden, the spring was found to be the season with highest extremes. The flood-moderating effect of regulation was illustrated, although floods were also found to occur in regulated systems. The results from the frequency analysis depended on the choice of criteria. In general, however, distributions with two parameters performed best. Neither a two component model treating spring and autumn separately, three parameter distributions, nor regional analyses gave any irnprovements. The spatial correlation within the data was considerable.

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  • 2149.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Hydrologiska aspekter på åtgärder mot vattenbrist och torka inom avrinningsområden2019Report (Other academic)
    Abstract [sv]

    Vattenbrist och torka har varit i fokus i Sverige under senare åren. 2016-2018 var särskilt torra i södra Sverige. Syftet med denna rapport är främst att jämföra de senaste åren med tidigare förhållanden och att anlysera effekten av olika åtgärder mot vattenbrist och torka. Hydrologiska mätserier analyserades, ända sedan 1807 fram till och med 2018. Tonvikten är på perioden från och med 1900, eftersom få stationer var igång innan dess. Vattenföringen minskar inte generellt i Sverige. Lågflödena har ökat i norra Sverige, troligen beroende på milda vintrar på senare år. I sydöstra Sverige har lågflödena i stället minskat, eventuellt delvis på grund av regleringar. 2016-2018 var mycket torra i sydost. Vilket år som har varit torrast beror på var i landet man avser och vad man menar med torrt. Lågflöden analyserades både med statistiska metoder och med den hydrologiska modellen S-HYPE. Osäkerheten i uppskattningar av lågflöden är stor i båda metodvalen. Några sätt att förbättra metodiken föreslås i rapporten. Effekten av olika scenarier beräknades både med en statistisk metod och med S-HYPE. Den faktor som har störst effekt för att höja lågflödena är att man sparar vatten i sjöar, särskilt om man reglerar dem så att vatten sparas till sommaren. De flesta av de simulerade förändringarna i landskapet gav mindre effekt. Sammanfattningsvis är det framförallt vädret och klimatet som avgör vattenflödet. Att det var så torrt åren 2016-2018 beror främst på att det regnade så lite. Effekterna av torrperioder kan mildras genom att man sparar vatten i till exempel sjöar eller dammar.

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  • 2150.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Lake water levels for calibration of the S-HYPE model2016In: HYDROLOGY RESEARCH, ISSN 1998-9563, Vol. 47, no 4, p. 672-682Article in journal (Refereed)
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