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  • 1.
    Alakangas, Lena
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Nason, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Simulation of pyrite oxidation in fresh mine tailings under near-neutral conditions2012In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 14, no 8, p. 2245-2253Article in journal (Refereed)
    Abstract [en]

    Sulphidic residual products from ore processing may produce acid rock drainage, when exposed to oxygen and water. Predictions of the magnitude of ARD and sulphide oxidation rates are of great importance in mine planning because they can be used to minimize or eliminate ARD and the associated economic and environmental costs. To address the lack of field data of sulphide oxidation rate in fresh sulphide-rich tailings under near-neutral conditions, determination and simulation of the rate was performed in pilot-scale at Kristineberg, northern Sweden. The quality of the drainage water was monitored, along with oxygen and carbon dioxide concentrations. The chemical composition of the solid tailings was also determined. The field data were compared to predictions from simulations of pyrite oxidation using a 1-D numerical model. The simulations' estimates of the amount of Fe and S released over a seven year period (52 kg and 178 kg, respectively) were in reasonably good agreement with those obtained by analysing the tailings (34 kg and 155 kg, respectively). The discrepancy is probably due to the formation of secondary precipitates such as iron hydroxides and gypsum; which are not accounted for in the model. The observed mass transport of Fe and S (0.05 and 1.0 kg per year, respectively) was much lower than expected on the basis of the simulations and the core data. Neutralization reactions involving carbonates in the tailings result in a near-neutral pH at all depths except at the oxidation front (pH < 5), indicating that the dissolution of carbonates was too slow for the acid to be neutralized, which instead neutralized deeper down in the tailings. This was also indicated by the reduced abundance of solid Ca at greater depths and the high levels of carbon dioxide both of which are consistent with the dissolution of carbonates. It could be concluded that the near-neutral pH in the tailings has no decreasing effect on the rate of sulphide oxidation, but does reduce the concentrations of dissolved elements in the drainage water due to the formation of secondary minerals. This means that sulphide oxidation rates may be underestimated if determined from drainage alone.

  • 2.
    Alakangas, Lena
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lundberg, Angela
    Öhlander, Björn
    Changes of groundwater quality in sulphide-bearing mine-tailings as a result of remediation at Kristineberg, northern Sweden2007In: Mining and the Environment International Conference: proceedings, Centre for Environmental Monitoring, Laurentian University , 2007Conference paper (Refereed)
    Abstract [en]

    At the Kristineberg mine in northern Sweden, sulphide-rich tailings left open for 50 years were remediated in 1996 by applying double dry cover on one part of an impoundment, and raised groundwater level combined with simple till cover on the other part. Groundwater pipes installed in the impoundment were sampled from 1998 during a period of 6 years. The results showed that the groundwater quality varied considerably in the impoundment, even under the same type of cover. Secondarily retained Fe, S, Mg, Mn and Z were remobilised when the groundwater was raised. In the part with raised groundwater level, the average concentration of Fe ranged from 2700 to 9000mg/l in 1998, and the range for S was 2200 to 7000mg/l. During 2003 the average concentrations had decreased and ranged between 150 and 900 mg/l for Fe and between 130 and 900 mg/l for S. The improvement of the water quality was caused by inflow of less contaminated groundwater and decreasing sulphide oxidation rate. The redox potential generally decreased and pH increased. The concentrations of Cd, Cu and Pb in groundwater decreased rather rapidly all over the impoundment after remediation. In areas with relatively high pH and low redox potential, Al, Cd, Co, Cr, Cu, Fe, Ni, Pb and Zn were almost depleted.

  • 3.
    Alakangas, Lena
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lundberg, Angela
    Öhlander, Björn
    Pilot scale studies of different dry covers on sulphide-rich tailings in northern Sweden, oxygen diffusion2005In: Securing the future: international conference on mining and the environment, metals and energy recovery : proceedings, Stockholm: SweMin , 2005, p. 9-18Conference paper (Other academic)
  • 4. Alakangas, Lena
    et al.
    Lundberg, Angela
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Pilot-scale studies of different covers on unoxidised sulphide-rich tailings, northern Sweden: oxygen diffusion2010In: Mine Water and the Environment: proceedings of the 10th IMWA Congress 2008 : 2-5 June, 2008 - Karlovy Vary, Czech Republic / [ed] Nadia Rapantova; Zbyněk Hrkal, Ostrava: VSB - Technical University Ostrava, Faculty of Mining and Geology, Institute of Environmental Engineering , 2010, p. 347-350Conference paper (Refereed)
    Abstract [en]

    The efficiency of five cover systems to decrease oxygen intrusion into sulphide-rich tailings was studied in pilot-scale test cells (5x5x3 m(3)). The covers consisted of clayey till, sewage sludge, fine-grained apatite concentrate or Trisoplast (a mixture of a polymer, bentonite and tailings sand) as sealing layers and unspecified till as protective cover. In one reference cell, tailings were uncovered. Oxygen concentrations below the entire covers were highest below the Trisoplast and apatite layers, and lowest below the sewage sludge layer. Effective diffusion coefficients (D-eff) and oxygen fluxes were estimated in the covers with non-oxygen-consuming sealing layers (clayey till and apatite). For the protective covers the Deff ranged between E-09 and E-07 m(2)/s, and for the sealing layers between E-10 and E-09 m(2)/s, and for the entire covers between E-10 and E-08 m(2)/s. Seasonal variations in D-eff were larger within the covers than between the different cover systems. Oxygen fluxes through the entire covers with clayey till and apatite ranged between 0.2 and 4 mole m(2)/year, which was a reduction of more than 99% compared to uncovered dry tailings.

  • 5.
    Alakangas, Lena
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Öhlander, Björn
    Lundberg, Angela
    Changes of sulphide oxidation rates over time in mine tailings, Laver, Northern Sweden2009In: 8th International Conference on Acid Rock Drainage (ICARD) and Securing the Future: Mining, Metals & the Environment in a Sustainable Society 2009: Skelleftea, Sweden, 22 - 26 June 2009, Red Hook, NY: Curran Associates, Inc., 2009Conference paper (Refereed)
  • 6.
    Alakangas, Lena
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Öhlander, Björn
    Lundberg, Angela
    Estimation of temporal changes in oxidation rates of sulphides in copper mine tailings at Laver, Northern Sweden2010In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 408, no 6, p. 1386-1302Article in journal (Refereed)
    Abstract [en]

    Tailings containing pyrrhotite were deposited in an impoundment at a copper mine at Laver, Northern Sweden, which operated between 1936 and 1946. Since then the oxidation of sulphides has acidified recipient water courses and contaminated them with metals. Measurements from surface water sampled in 1993, 2001 and 2004-05 from a brook into which the tailing impoundment drains indicate that the amounts of sulphide-associated elements such as Cu, S and Zn released into the brook have decreased over time, while pH has increased. The mass transport of S in the brook during 1993 and 2001 corresponded well with the amount of S estimated to be released from the tailings by oxidation. Secondary precipitates such as covellite and gypsum, which can trap sulphur, were shown in earlier studies to be present in only low amounts. The annual release of elements from the tailings was estimated from the volume of tailings assumed to oxidise each year, which depends on movement of the oxidation front with time. The results indicate that the oxidation rate in the tailings has decreased over time, which may be due to the increased distance over which oxygen needs to diffuse to reach unoxidised sulphide grains, or their cores, in the tailings.

  • 7. Andersson, Christian
    et al.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Distribution of snow cover accumulation: airborne ground penetrating radar surveys2002In: Proceedings of the XXII Nordic Hydrological Conference / [ed] Å. Killingtveit, 2002, p. 517-526Conference paper (Refereed)
  • 8.
    Andreason, J
    et al.
    SMHI.
    Gyllander, A
    SMHI.
    Johansson, B
    SMHI.
    Källgården, J
    SMHI.
    Lindell, J
    SMHI.
    Olofsson, J
    SMHI.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Snötaxering med georadar: bättre vårflödesprognoser med HBV-modellen?2001Report (Other academic)
  • 9.
    Bengtsson, Lars
    et al.
    Luleå tekniska universitet.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Starius, Göran
    Luleå tekniska universitet.
    Beskrivning av vattenrörelser i den omättade markzonen: litteraturgenomgång, numerisk modell, simuleringar1982Report (Other academic)
  • 10.
    Feiccabrino, James
    et al.
    Lund University, Department of Water Resources Engineering.
    Graff, William
    21st Operational Weather Squadron, United States Air Forces in Europe, Kapuan Air Base, APO-AE 09021, Germany.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Sundström, Nils
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Gustafsson, David
    Kungliga tekniska högskolan, KTH, KTH Royal Institute of Technology, Land and Water Resources Engineering, KTH och SMHI, Research and Development (hydrology), Swedish Meteorological and Hydrological Institute, Norrköping.
    Meteorological Knowledge Useful for the Improvement of Snow Rain Separation in Surface Based Models2015In: Hydrology, ISSN 2306-5338, Vol. 2, no 4, p. 266-288Article in journal (Refereed)
    Abstract [en]

    An accurate precipitation phase determination—i.e., solid versus liquid—is of paramount importance in a number of hydrological, ecological, safety and climatic applications. Precipitation phase can be determined by hydrological, meteorological or combined approaches. Meteorological approaches require atmospheric data that is not often utilized in the primarily surface based hydrological or ecological models. Many surface based models assign precipitation phase from surface temperature dependent snow fractions, which assume that atmospheric conditions acting on hydrometeors falling through the lower atmosphere are invariant. This ignores differences in phase change probability caused by air mass boundaries which can introduce a warm air layer over cold air leading to more atmospheric melt energy than expected for a given surface temperature, differences in snow grain-size or precipitation rate which increases the magnitude of latent heat exchange between the hydrometers and atmosphere required to melt the snow resulting in snow at warmer temperatures, or earth surface properties near a surface observation point heating or cooling a shallow layer of air allowing rain at cooler temperatures or snow at warmer temperatures. These and other conditions can be observed or inferred from surface observations, and should therefore be used to improve precipitation phase determination in surface models.

  • 11.
    Feiccabrino, James
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Precipitation phase discrimination by dew point and air temperature2008In: Proceedings of the Western Snow Conference, Kailua-Kona, Hawaii, April, 16 - 19, 2007: seventy-fifth annual meeting / [ed] Randall Julander, Soda Springs, Calif: Western Snow Conference , 2008, p. 141-145Conference paper (Refereed)
    Abstract [en]

    Correctly reported precipitation phases are crucial for estimation of snow storage in hydrological, regional and global climate models. Precipitation phase is especially critical for models simulating processes in tree canopies, since the canopy storage capacity is about one order of magnitude larger for snow than rain. The number of manned meteorological stations is decreasing, making determination of precipitation phase more difficult. Most hydrological models use an air temperature threshold to separate rain from snow, but there are indications that a dew-point temperature threshold might work better. This study utilized forty-five years of three-hour man-made observations for nineteen Swedish station ranging from 55˚N to 68˚N consisting of precipitation mass and phase, air and dew point temperatures. Precipitation events classed as snow or rain, excluding mixed precipitation, were used for the initial analysis.  Air temperature was found to be a better indicator of precipitation phase then dew point temperature. On occasion 0˚C is used as an air temperature threshold, but if the air temperature rain/snow threshold 0˚C is replaced by 1.0˚C the misclassified precipitation would be reduced by almost half in Sweden. Further analysis to identify mixed precipitation, totaling 16% of the precipitation is also included.

  • 12.
    Feiccabrino, James
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Precipitation phase discrimination in Sweden2009In: 65th Eastern Snow Conference, 2009, p. 239-254Conference paper (Refereed)
  • 13.
    Feiccabrino, James
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Gustafsson, David
    Kungliga tekniska högskolan, KTH.
    Improving surface based precipitation phase determination through air mass boundary identification2012In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 43, no 3, p. 179-191Article in journal (Refereed)
    Abstract [en]

    Most hydrological models apply one empirical formula based on surface air temperature for precipitation phase determination. This approach is flawed as surface precipitation phase results from energy exchanges between falling precipitation and air in the lower atmosphere. Different lower atmospheric conditions cause different precipitation phase probabilities for near-freezing temperatures. Often directly measured lower atmospheric conditions are not available for remote areas. However, meteorological observations occurring before/after similar air mass boundaries have similar atmospheric conditions that vary from most other observations. Therefore, hydrological models can indirectly account for lower atmospheric conditions. Twenty years of manual observations from eight United States weather stations were used to compare misclassified precipitation proportions when analyzing (a) all precipitation observations together and (b) identified cold air mass boundary observations (CAB) and non-CAB observations separately. The CAB observations were identified by a rapid surface air temperature decrease. A two-surface air temperature threshold method with one threshold all snow (T-S degrees C) and one all rain (T-R degrees C) having a linear snow fraction decrease between the thresholds was used. The T-S (0 degrees C), and T-R (4 degrees C) values for CAB were 1 degrees C warmer than for non-CAB (-1 degrees C, 3 degrees C). Analyzing CAB and non-CAB separately reduced misclassified precipitation 23%, from 7.0 to 5.4%.

  • 14.
    Feiccabrino, James
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Gustafsson, David
    Kungliga tekniska högskolan, KTH.
    Surface-based precipitation phase determination methods in hydrological models2013In: Hydrology Research, ISSN 1998-9563, Vol. 44, no 1, p. 44-57Article in journal (Refereed)
    Abstract [en]

    We compared solid and liquid precipitation mass output from three categories of common model precipitation phase determination schemes (PPDS) to the recorded precipitation phase in a set of 45 years of 3-hour manual meteorological observations from 19 Swedish meteorological stations. In the first category of rain/snow thresholds, it was found that rain/snow air temperature threshold (ATT) is a better precipitation phase indicator than a rain/snow dew point temperature threshold. When a rain/snow ATT of 0.0 °C (a default value used in some recent models) was replaced by 1.0 °C, misclassified precipitation was reduced by almost one half. A second category of PPDS use two ATTs, one snow and one rain, with a linear decrease in snow fraction between. This category identified precipitation phase better than a rain/snow ATT at 17 stations. Using all observations from all the meteorological stations, a final category using an air-temperature-dependent snow probability curve resulted in slightly lower misclassified precipitation mass at 13 of the 19 stations. However, schemes from the linear decrease in snow fraction category had the lowest misclassified precipitation mass at four meteorological stations.

  • 15.
    Feiccabrino, James
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skogsberg, Kjell
    Expected pollutant pathway differences between snow deposits and a permeable snow cooling pond2009In: Proceedings of the Annual Eastern Snow Conference: 28 - 30 May 2008, Fairlee, Vermont, USA, Fairlee, Vt, 2009, p. 47-62Conference paper (Refereed)
  • 16.
    Granlund, Nils
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    David, Gustafsson
    Feiccabrino, James
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Laboratory test of snow wetness influence on impulse radar amplitude2008In: Proceedings of the Western Snow Conference, Kailua-Kona, Hawaii, April, 16 - 19, 2007: seventy-fifth annual meeting / [ed] Randall Julander, Soda Springs, Calif: Western Snow Conference , 2008, p. 151-156Conference paper (Refereed)
  • 17.
    Granlund, Nils
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Gustafsson, David
    Kungliga tekniska högskolan, KTH.
    Lundberg, Angela
    Laboratory study of snow salinity influence on the relationship between electrical conductivity and wetness of snow2009In: 65th Eastern Snow Conference, 2009, p. 301-307Conference paper (Refereed)
  • 18.
    Granlund, Nils
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lundberg, Angela
    Feiccabrino, James
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Gustafsson, David
    Kungliga tekniska högskolan, KTH.
    Laboratory test of snow wetness influence on electrical conductivity measured with ground penetrating radar2009In: Hydrology Research, ISSN 1998-9563, Vol. 40, no 3, p. 33-44Article in journal (Refereed)
    Abstract [en]

    Ground penetrating radar operated from helicopters or snowmobiles is used to determine snow water equivalent (SWE) for annual snowpacks from radar wave two-way travel time. However, presence of liquid water in a snowpack is known to decrease the radar wave velocity, which for a typical snowpack with 5% (by volume) liquid water can lead to an overestimation of SWE by about 20%. It would therefore be beneficial if radar measurements could also be used to determine snow wetness. Our approach is to use radar wave attenuation in the snowpack, which depends on electrical properties of snow (permittivity and conductivity) which in turn depend on snow wetness. The relationship between radar wave attenuation and these electrical properties can be derived theoretically, while the relationship between electrical permittivity and snow wetness follows a known empirical formula, which also includes snow density. Snow wetness can therefore be determined from radar wave attenuation if the relationship between electrical conductivity and snow wetness is also known. In a laboratory test, three sets of measurements were made on initially dry 1m thick snowpacks. Snow wetness was controlled by stepwise addition of water between radar measurements, and a linear relationship between electrical conductivity and snow wetness was established.

  • 19. Granlund, Nils
    et al.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Gustafson, David
    KTH Royal Institute of Technology, Land and Water Resources Engineering.
    Laboratory study of the influence of salinity on the relationship between electrical conductivity and wetness of snow2010In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 24, no 14, p. 1981-1984Article in journal (Refereed)
    Abstract [en]

    Snow water equivalent of a snowpack can be estimated using ground-penetrating radar from the radar wave two-way travel time. However, such estimates often have low accuracy when the snowpack contains liquid water. If snow wetness is known, it is possible to take it into account in the estimates; it is therefore desirable to be able to determine snow wetness from already available radar data. Our approach is based on using radar wave attenuation, and it requires that the relationship between electrical conductivity and wetness of snow should be known. This relationship has been tentatively established in previous laboratory experiments, but only for a specific liquid water salinity and radar frequency. This article presents the results of new laboratory experiments conducted to investigate if and how this relationship is influenced by salinity. In each experiment, a certain amount of snow was melted and a known amount of salt (different for different experiments) was added to the water. Water salinity was measured, and the water was added step-wise to a one-meter thick snowpack, with radar measurements taken between additions of water. Our experiments have confirmed the earlier established linear relationship between electrical conductivity and wetness of snow, and they allow us to suggest that the influence of liquid water salinity on electrical conductivity is negligible when compared to the influence of liquid water content in snow

  • 20.
    Granlund, Nils
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lundberg, Angela
    Gustafsson, David
    Kungliga tekniska högskolan, KTH.
    Ahlberg, Jesper
    Kungliga tekniska högskolan, KTH.
    Wetterhall, Fredrik
    SMHI.
    Towards better predictions of snow melt runoffs: measuring snow depth and density using ground penetrating radar2009Conference paper (Other academic)
  • 21.
    Grelle, A.
    et al.
    SLU, Department of Production Ecology, Uppsala.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lindroth, A.
    SLU, Department of Production Ecology, Uppsala.
    Morén, A.-S.
    SLU, Department of Production Ecology, Uppsala.
    Cienciala, E.
    SLU, Department of Production Ecology, Uppsala.
    Evaporation components of a boreal forest: variations during the growing season1997In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 197, no 1-4, p. 70-87Article in journal (Refereed)
    Abstract [en]

    To improve the understanding of interactions between the boreal forest and the climate system as a key issue for global climate change, the water budget of a mixed pine and spruce forest in central Sweden was estimated by measurements of the water flux components and the total evaporation flux during the period 16 May-31 October 1995. Total evaporation was measured using eddy correlation and the components were obtained using measurements of precipitation, throughfall, tree transpiration, and forest floor evaporation. On a daily basis, tree transpiration was the dominant evaporation component during the vegetation period. However, it could be efficiently blocked by a wet canopy associated with large interception evaporation. The accumulated total evaporation was 399 mm, transpiration was 243 mm, forest floor evaporation was 56 mm and interception evaporation was 74 mm. The accumulated sum of interception, transpiration, and floor evaporation was 51 mm larger than the actual measured total evaporation. This difference was mainly attributed to the fact that transpiration was measured in a rather dense 50-year-old stand while total evaporation represented the average conditions of older, roughly 100-year-old stands. To compare eddy-correlation measurements with small-scale measurements of evaporation components, a source area analysis was made to select the flux data that give the best representation of the investigated stand. Especially under stable atmospheric conditions the requirements for surface homogeneity were very high and extreme care had to be taken to be aware of the flux source areas. Canopy water storage was determined by two methods: by the water balance of the canopy, which gave a result of 3.3 mm; and by the so-called minimum method based on plots of throughfall versus precipitation, which gave a much lower value of 1.5 mm. Seasonal interception evaporation constituted 30% of the precipitation.

  • 22.
    Gustafsson, D.
    et al.
    Kungliga tekniska högskolan, KTH.
    Stähli, M.
    Swiss Federal Research Institute.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Multi-criteria parameterisation of a numerical forest snow processes model: analysis of parameter uncertainty and governing processes2006In: Geophysical Research Abstracts, European Geosciences Union (EGU), 2006, Vol. 8Conference paper (Other academic)
    Abstract [en]

    Forest snow processes such as snow interception evaporation and the influence of the canopy on snow cover melt are important for the land surface water and heat balance. Difficulties to model snow interception are due to both limitation in the understanding of the governing processes and in parameter estimations. In this study we parameterise a numerical simulation model (Alpine3D) using multiple calibration variables - snow water equivalent, snowmelt, throughfall, and runoff - through a Monte-Carlo procedure, which enables parameter uncertainty estimations and identification of the sensitivity in the model to different processes. The analysis is based on a data from a sub-alpine spruce forest in Alptal, Switzerland. Results show how the multi-criteria approach is able to reduce the number of parameter combinations that fulfil the critera. Further more, it is shown that parameters governing the turbulent exchange from the canopy and the snow cover were most important for the simulation of the snow cover evolution, whereas the runoff and throughfall was more sensitive to direct throughfall and interception capacity parameterisations.

  • 23.
    Gustafsson, David
    et al.
    KTH och SMHI.
    Ahlberg, Jesper
    Kungliga tekniska högskolan, KTH.
    Feiccabrino, James
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lindström, Göran
    SMHI.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Sundström, Nils
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Wetterhall, Fredrik
    SMHI.
    Distribuerade system för förbättrade snö- och avrinningsprognoser: Integration i hydrologiska modeller. Slutrapport2012Report (Other academic)
    Abstract [sv]

    Det övergripande målet med projektet har varit att minska totala volymfelet i prognoser för vårflödesavrinningen samt att förbättra tids- och volym-bestämningen av flödespikarna för dessa. Projektet har fokuserat på att kombinera utveckling av modell- och mätteknik för att studera hur modellstrukturer och metoder för att integrera mätinformation (data-assimilering) kan optimeras i förhållande till tillgänglig snöinformation. Ett syfte har också varit att de utvecklade metoderna skall vara operationellt användbara och baserade på kostnads- och tidseffektiva mättekniker och modelleringsverktyg, samtidigt som de skall ge en betydande förbättring av prognoserna. I projektet har en rad mättekniker testats och vidareutvecklas (tex snökuddar, automatiska sensorer för snödjup- och densitet, samt markradartekniker). Störst fokus har varit på vidareutveckling av radarteknik för linjemätning av snötäckets djup, densitet och fuktighet. För torr snö har djup och densitet uppskattats med hjälp av radarvågornas snöutbredningshastighet direkt från radardata med ett flerkanalradarsystem, [så kallad ”common-mid point” (CMP) metod)]. För blöt snö krävs förutom utbrednings-hastigheten också information om snöns fuktighet för korrigering av uppskattningen av snöns densitet. Inom projektet har därför en ny metod utvecklats för bestämning av snös fuktighet baserad på det faktum att utsläckningen av radarsignalens amplitud beror på snöns fuktighet. Två olika hydrologiska modeller har använts inom projektet: SMHI:s nya vattenbalans- och vattenkvalitetsmodell HYPE samt en egenutvecklad modell. Den senare modellen har utvecklats för att kunna jämföra tillrinnings-prognosernas känslighet för val av snömodellstruktur (representation av processer och distribution i tid och rum). Modellen består av en rumsligt distribuerad snömodell kopplad till en odistribuerad avrinningsmodell (en förenklad variant av HBV-modellen). Modellen utvecklades inom det hydrologiska modelleringssystemet HYSS utvecklat på SMHI, men kan i princip kopplas till vilken modellplattform som helst. Snö-smältningen kan beräknas antingen med temperatur- och strålnings-indexmetod eller med energibalansmetod. Den rumsliga distribueringen kan göras antingen med ett 2-dimensionellt nät eller genom uppdelning av avrinningsområdet i representativa enheter baserad på klassificering av topografi (höjd, lutning väderstreck) och vegetation. HYPE-modellen har för närvarande en enklare snömodell än den egenutvecklade modellen, men erbjuder istället hög rumslig uppdelning, öppen källkod (HYPE Open Source Community) och en enkel hantering av drivdata och modelluppsättningar för nya områden genom den operationella sverigeapplikationen (S-HYPE). HYPE-modellen har därför använts för att göra projektets modellutveckling lättare tillgänglig för andra. Den har också använts för att jämföra värdet av assimilering av snödata med värdet av val av prognosdata för nederbörd och temperatur. På sikt kan den egenutvecklade snömodellen göras tillgänglig som en valbar modul i HYPE. En dataassimileringsrutin baserad på Ensemble Kalmanfilter (EnKF) har utvecklats för integrering av snöinformation i simuleringarna och har implementerats som en modul i HYPE. Med EnKF metoden uppdateras modelltillstånd som funktion av kovariansen mellan modelltillstånd och modellfel. Uppdateringen sker sekventiellt, det vill säga under simuleringens gång vartefter nya observationer tillkommer. Kovariansen mellan modelltillstånd och modellfel uppskattas genom att skapa en ensemble av modeller med en viss spridning i modelltillstånden. Spridningen genereras genom att köra flera parallella modeller med slumpmässiga avvikelser i drivvariabler och parametervärden. En styrka med metoden är att osäkerheter i observationer, modellparametrar och indata kan uppskattas var för sig och användas för en automatisk uppdatering av modelltillstånden. Resterande spridning i den uppdaterade prognosen nyttjas för skattning av osäkerheten i resultaten. Beräkningsbördan ökar jämfört med en enskild simulering (ca 100 ensemblemedlemmar behövs), men jämfört med andra dataassimileringsmetoder är EnKF metoden mycket effektiv. De flesta hydrologiska modeller använder samma tröskeltemperatur för att skilja på regn och snö för alla nederbördstillfällen Förhållanden högre upp i atmosfären påverkar emellertid också hur stor andel av nederbörden som faller som snö respektive regn vid en viss markytetemperatur. Situationen i atmosfären beror i sin tur till stor del på vilken typ av front (gräns mellan luftmassor med olika temperatur) som producerar nederbörden. Vi har visat att man kan minska andelen felklassad nederbörd genom att identifiera vilken typ av front (varm- eller kall) som orsakar nederbörden vid ett specifikt tillfälle och anpassa tröskeltemperaturen efter fronttypen. Simuleringar med det nyutvecklade modellsystemet för testområdet Kultsjön i Västerbotten visar att assimilering med EnKF av distribuerade snödata förbättrade vårflodsprognoserna samtliga 4 år i delområdet Kultsjön och 3 av 4 år i delområdet Ransarn. Den relativa förbättringen var i medel 10-15 % beroende på vilka drivdata som användes. Störst förbättring av vårflodsprognosen, jämfört med den traditionella metoden med ensembler av historiska år, erhölls emellertid genom att använda säsongsprognoser från ECMWF (European Centre for Medium Range Weather Forecasts) som drivdata. Det var överraskande att dessa simuleringar gav bättre resultat än simuleringar med stationsmätningar. En möjlig förklaring kan vara att den interpolation av stationsdata som ligger till grund för SMHIs operationella drivdata (nederbörd och temperatur, PTHBV) kan ge både över- och underskattning av nederbörd i fjällområden beroende på om vädersystemen kommer från väster eller öster. Medelvolymfelet för Kultsjön förbättrades från 17 % till 8 % för de undersökta åren när en kombination av säsongsprognoser från ECMWF och assimilering av snöradardata användes istället för en deterministisk PTHBV-simulering. Den utvecklade dataassimileringstekniken har således visats sig vara ett effektivt sätt att automatiskt uppdatera modellerna inför vårflodsprognosen, och bör enkelt kunna anpassas för operationell användning. Det är också tydligt att assimilering av väderprognosdata från ECWMF gav en bättre prognos för Kultsjöns avrinningsområde än nuvarande PTHBV data. Mer arbete med att förstå hur osäkerheter och korrelationer i såväl snödata som modelldata krävs dock för att med säkerhet slå fast att målsättningarna i projektet har uppnåtts. Användningen av väderprognosdata som input i kombination med assimilering av snödata var mycket lovande och bör vidareutvecklas.

  • 24.
    Gustafsson, David
    et al.
    Kungliga tekniska högskolan, KTH.
    Ahlberg, Jesper
    Kungliga tekniska högskolan, KTH.
    Sundström, Nils
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lindström, Göran
    SMHI.
    Wetterhall, Fredrik
    SMHI.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Distribuerade system för förbättrade snö- och avrinningsprognoser: Integration i hydrologiska modeller - Delrapport 12009Report (Other academic)
    Abstract [sv]

    Ambitionen med projektet är att minska volymfelet i avrinningsprognoser samt att förbättra tidsbestämningen av den första avrinningen och av flödespikarna i samband med snösmältning. Projektet fokuserar på att kombinera modell- och mättekniksutveckling för att utforska hur mo-dellstruktur och metod för att integrera mätinformation (dataassimilering) kan optimeras i förhållande till tillgängliga snödata. Syftet är att utveckla en operationellt användbar metod baserad på kostnads- och tidseffektiva mättekniker och modelleringsverktyg. Metoden skall anpassas för användning av både stora och små vattenreglerande företag, och den skall ge en betydande förbättring av prognoserna. I projektet testats och vidareutvecklas en rad mättekniker, som tex snökuddar, automatiska snödjups- och snödensitetssensorer, och mark-radartekniker. Radartekniken vidareutvecklas för bestämning av snötäckets djup, densitet och våthet genom att utnyttja informationen som fås från radarvågornas utbredningshastighet, av att ett flerkanalssystem används och från amplitudutsläckning. En ny snömodell har utvecklats för att kunna testa olika val av modellstruktur för processrepresentation och distribution i tid och rum. Modellen är programmerad som en subrutin till SMHI:s nya hydrologiska simulerings-system HYSS, men kan i princip kopplas till vilken hydrologisk modellplattform som helst. Kärnan i modellen är en modell av snö- och markskiktet, där snösmältning och avdunstning från marken kan beräknas antingen med graddagarsmetoden eller med energibalansmetoden. En enkel variant av HBV-modellens grundvatten- och sjörepresentation används för att simulera avrinningen. Den rumsliga distributionen av snö- och markmodellen kan väljas fritt. I projektet testas både distribuering i gridnät med olika upplösning, samt distribuering i klasser uppdelade enligt höjd, lutning, vädersträck och vegetation. En dataassimileringsrutin baserad på Ensemble Kalmanfilter (EnKF) har utvecklats för integrering av snöinformation i simuleringarna. EnKF metoden uppdaterar parametervärden och modelltillstånd, som funktion av kovariansen mellan modellfel och modelltillstånd, parametrar och inputvariabler. Exempel på sådana parametrar och variabler är graddagsfaktorn för smältning och snömängd. Kovariansmatrisen genereras genom slumpmässiga störningar på inputvariabler och parametrar. EnKF ger förutom en automatisk uppdatering och kalibrering även en uppskattning av osäkerheter i resultaten. Resultaten av simuleringarna med det nyutvecklade modellsystemet visar att dataassimilering med EnKF av distribuerade snödata kan förbättra avrinnings-prognoserna och uppskatta osäkerheter i resultaten. För enstaka år visades även att de markburna radarmätningarna av snömängden minskade osäkerheterna och förbättrade prognoserna mer än motsvarande manuella mätningar. En systematisk undersökning av förtjänsten av olika modell-strukturer och av rumslig distribuering i förhållande till datakvalitet och data-mängd återstår dock som en viktig uppgift för projektets avslutande hälft.

  • 25.
    Gustafsson, David
    et al.
    Kungliga tekniska högskolan, KTH.
    Sundström, Nils
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Friborg, Johan
    Malags.
    Multi-offset impulse radar for snow water equivalent measuerments2008Conference paper (Other academic)
  • 26.
    Kløve, Bjørn
    et al.
    Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, University of Oulu.
    Ala-Aho, Pertti
    Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, University of Oulu.
    Bertrand, Guillaume
    University of Neuchâtel.
    Boukalova, Zuzana
    GIS-Geoindustry s.r.o..
    Ertürk, Ali
    Istanbul Technical University.
    Goldscheider, Nico
    Karlsruhe Institute of Technology (KIT), Institute for Applied Geosciences, Department of Hydrogeology.
    Ilmonen, Jari
    Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, University of Oulu.
    Karakaya, Nusret
    Abant Izzet Baysal University.
    Kupfersberger, Hans
    Joanneum Research Forschungsgesellschaft mbH Elisabethsr.
    Kvœrner, Jens
    Bioforsk - Norwegian Institute for Agricultural and Environmental Research.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Mileusnić, Marta
    University of Zagreb.
    Moszczynska, Agnieszka
    Universita Cattolica del SacroCuore.
    Muotka, Timo
    Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, University of Oulu.
    Preda, Elena
    University of Bucharest.
    Rossi, Pekka
    Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, University of Oulu.
    Siergieiev, Dmytro
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Šimek, Josef
    GIS-Geoindustry s.r.o..
    Wachniew, Przemysław
    AGH University of Science and Technology, Mickiewicza.
    Angheluta, Vadineanu
    University of Bucharest.
    Widerlund, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Groundwater dependent ecosystems: Part I: Hydroecological status and trends2011In: Environmental Science and Policy, ISSN 1462-9011, E-ISSN 1873-6416, Vol. 14, no 7, p. 770-781Article in journal (Refereed)
    Abstract [en]

    Groundwater dependent ecosystems (GDEs) include valuable ecosystems such as springs, wetlands, rivers, lakes and lagoons. The protection of these systems and services they provide is highlighted by international agreements, i.e. Ramsar convention on wetlands, and regional legislation, i.e. the European Water Framework Directive. Groundwater provides water, nutrients and a relatively stable temperature. However, the role of groundwater in surface ecosystems is not fully understood. The ecosystem can depend on groundwater directly or indirectly, and the reliance can be continuous, seasonal or occasional. This has implications for the vulnerability of ecosystems, as some may be easily affected by external pressure. Conceptual models and quantitative assessments of how groundwater interacts with the environment are needed. GDEs are also threatened by different land use activities and climate change. Hence, we need to understand how GDEs are affected by changes in groundwater quantity and quality, as severe groundwater changes have been observed in many regions. This study examines key aspects of GDEs (hydrogeology, geochemistry and biodiversity) in order to improve conceptual understanding of the role of groundwater in such ecosystems. The status and baseline of different types of GDEs are discussed, with particular emphasis on past evidence of environmental change and potential thresholds and threats in GDEs in various parts of Europe with different land use, climate and geology

  • 27.
    Kløve, Bjørn
    et al.
    University of Oulu.
    Allan, Andrew
    University of Dundee.
    Bertrand, Guillaume
    University of Neuchâtel.
    Druzynska, Elzbieta
    Cracow University of Technology.
    Ertürk, Ali
    Istanbul Technical University.
    Goldscheider, Nico
    Karlsruhe Institute of Technology (KIT), Institute for Applied Geosciences, Department of Hydrogeology.
    Henry, Sarah
    University of Dundee.
    Karakaya, Nusret
    Abant Izzet Baysal University.
    Karjalainen, Timo P.
    University of Oulu.
    Koundouri, Phoebe
    Athens University of Economics and Business.
    Kupfersberger, Hans
    Joanneum Research Forschungsgesellschaft mbH.
    Kvœrner, Jens
    Bioforsk - Norwegian Institute for Agricultural and Environmental Research.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Muotka, Timo
    University of Oulu.
    Preda, Elena
    University of Bucharest.
    Velázquez, Manuel Pulido
    Universidad Politécnica de Valencia.
    Schipper, Peter
    Alterra, Droevendaalsesteeg 3a, P.O. Box 47, 6700 AA Wageningen.
    Groundwater dependent ecosystems: Part II. Ecosystem services and management in Europe under risk of climate change and land use intensification2011In: Environmental Science and Policy, ISSN 1462-9011, E-ISSN 1873-6416, Vol. 14, no 7, p. 782-793Article in journal (Refereed)
    Abstract [en]

    Groundwater in sufficient amounts and of suitable quality is essential for potable water supplies, crop irrigation and healthy habitats for plant and animal biocenoses. The groundwater resource is currently under severe pressure from land use and pollution and there is evidence of dramatic changes in aquifer resources in Europe and elsewhere, despite numerous policy measures on sustainable use and protection of groundwater. Little is known about how such changes affect groundwater dependent ecosystems (GDEs), which include various aquatic and terrestrial ecosystems above ground and inside the aquifer. Future management must take this uncertainty into account. This paper focuses on multiple aspects of groundwater science, policy and sustainable management. Examples of current management methods and practices are presented for selected aquifers in Europe and an assessment is made of the effectiveness of existing policies such as the European Water Framework Directive and the Habitat Directive in practice and of how groundwaters and GDEs are managed in various conditions. The paper highlights a number of issues that should be considered in an integrated and holistic approach to future management of groundwater and its dependent ecosystems

  • 28.
    Kløve, Bjørn
    et al.
    Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, University of Oulu, University of Oulu, Bioforsk, UOULU.
    Ala-Aho, Pertti
    Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, University of Oulu.
    Bertrand, Guillaume
    University of Neuchâtel.
    Ertürk, Ali
    Istanbul Technical University, IGEM.
    Gemitzi, Alexandra
    Democritus University of Thrace.
    Gönec, E.
    Moszczynska, Agnieszka
    Universita Cattolica del SacroCuore.
    Mileusnic, M.
    Kupfersberger, Hans
    Joanneum Research Forschungsgesellschaft mbH, JR.
    Kværner, J.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Haro, S Peña
    Rossi, Pekka
    Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, University of Oulu.
    Siergieiev, Dmytro
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Wachniew, Przemysław
    AGH University of Science and Technology, Mickiewicza.
    Wolak, A
    Groundwater surface water interaction in GDE2012Report (Other (popular science, discussion, etc.))
    Abstract [en]

    This report reviews and discussed the interaction of groundwaterin GDEs. The report presents and integrates past and new results.Different methods used to measure groundwater interaction withecosystems are presented. Various GENESIS case studies acrossEurope to demonstrate the variable and complex role ofgroundwater in GDEs. The basis for developing conceptual for GDEsis presented. Various methods to model GDEs are discussed.

  • 29.
    Lankreijer, Harry
    et al.
    Lunds universitet.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Grelle, Achim
    Lunds universitet.
    Lindroth, Anders
    Lunds universitet.
    Seibert, Jan
    Uppsala universitet.
    Evaporation and storage of intercepted rain analysed by comparing two models applied to a boreal forest1999In: Agricultural and Forest Meteorology, ISSN 0168-1923, E-ISSN 1873-2240, Vol. 98-99, p. 595-604Article in journal (Refereed)
    Abstract [en]

    Rainfall and throughfall were measured during the summer of 1995. Rainfall interception is often simulated by a version of the well-known Rutter-Gash analytical model. In this study this model was compared to a model based on an exponential saturation equation. The concept of the ‘minimum method' for deriving canopy storage capacity and free throughfall coefficient by the Leyton-analysis, is compared to the concept of maximum storage capacity by reversing the models. Measured evaporation rate during rain events was found to be lower than simulated by the Penman equation using different known formulations for aerodynamic resistance. The concept of a high internal canopy resistance and decoupling of the canopy from the atmosphere should be analysed further in order to explain low evaporation during rainfall.

  • 30.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Alternative assessments in civil and environmental engineering2003In: Engineering Education for a Sustainable Future: Proceedings of the 14th Annual Conference for Australasian Association for Engineering Education and 9th Australasian Women in Engineering Forum, Australasian Association for Engineering Education , 2003, p. 211-218Conference paper (Refereed)
    Abstract [en]

    Examination greatly influences course structure and student study strategies. Three courses for students in the Civil and Environmental Engineering programs at Luleå University of Technology were reconstructed with the aims of making the assessment part of the learning process and to facilitate deep learning. Several different types of assessment were tested. Assessment in the form of a large project and field- and laboratory work was shown to be successful when applied to a course in snow engineering for university students with various backgrounds. A course in hydrology and hydraulics was reconstructed with the aim of assessing increasing levels of understanding. A simple written test was designed to assess lower levels of understanding (definitions, concepts etc.). Laboratory work, fieldwork and extensive assignments (calculation tasks) were intended to assess medium levels of understanding (apply, use and combine algorithms etc). A final oral group exam that was used to assess high levels of understanding (compare/contrast, explain causes, analyse, relate) concluded the course. A course in International Sanitary Engineering was assessed with cross-group presentations and literature seminars. Teaching and assessing features known to encourage deep learning approaches were adopted. Different types of peer assessment were tested with varying degree of success. For all three courses both the students and the teachers reported increased learning with these course structures and assessment strategies than from courses with a final written exams.

  • 31.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Combination of a conceptual model and an autoregressive error model for improving short time forecasting1982In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 13, no 4, p. 233-246Article in journal (Refereed)
    Abstract [en]

    An autoregressive error model has been tested on the residuals of the conceptual HBV-model for the Eman catchment. The autoregressive model gives considerable improvements for real shorttime forecasting, but for long range (10 days or more) forecasting no improvement is achieved compared to the conceptual model

  • 32.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Combination of a conceptual model and an autoregressive error model for improving short time forecasting1983Report (Other academic)
  • 33.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Evaporation of intercepted snow: measurement techniques and governing factors1993Licentiate thesis, comprehensive summary (Other academic)
  • 34.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Evaporation of intercepted snow: review of existing and new measurement methods1993In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 151, no 2-4, p. 267-290Article in journal (Refereed)
    Abstract [en]

    Knowledge of the annual water balance within a catchment is still hampered by an insufficient understanding of winter conditions. The least known term of the winter water balance is evaporation - particularly that from intercepted snow. Methods to measure interception and evaporation are reviewed. Undisturbed meteorological conditions, high time resolution and continuous measurements of intercepted mass were taken as criteria for an ideal method. The ideal method should work during periods of melt and sublimation and above rough forest surfaces. None of the existing methods fulfils all the criteria. Most traditional hydrological methods to estimate winter-time evaporation, such as runoff and snow-course studies, non-weighing lysimeters, and precipitation and throughfall measurements, produce too little information to distinguish the causes of the observed changes. Among micrometeorological methods, only the eddy-correlation technique is suitable, and should be used in combination with interception measurements. Of the methods primarily designed to quantify interception, i.e. collection of intercepted snow, visual or photographic observations, displacement transducers, weighing of branches and trees and gamma-ray attenuation, only the last two yield continuous interception records. In combination with continuous measurements of throughfall and drip, these methods can be used to study the evaporation process. The gamma-ray method can be used to measure whole-canopy losses, whereas the other two methods deal only with losses from a branch or a single tree. The weighing-lysimeter technique produces the same information as the method of weighing a cut tree but employs a more complex set-up. The weighing-tree method combined with measurement of drip is one of the current methods that is most suitable for process studies. A new device for this purpose is presented, which differs from earlier designs by allowing a continuous weighing of drip in a tray of 2m width placed around the tree. The tray was fastened to the tree with wires and was automatically raised and lowered, thus allowing continuous measurements of both intercepted mass (with the tray raised) and evaported mass (with the tray lowered). A maximum evaporation rate of 0.3 mm h-1 was recorded with this device on 22-23 March 1990 at a site close to Luleå in northern Sweden. This maximum value was measured when wet snow was present, and confirmed earlier reports of high evaporation rates. The maximum evaporated mass during 24 h was 3.3 mm.

  • 35.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    How to recruit the next generation of snow researchers and encourage them to apply deep learning approaches2005In: Proceedings of the 15 northern research basins international symposium and workshop, Lund: Department of Water Resources Engineering, Lund University , 2005, p. 111-120Conference paper (Refereed)
    Abstract [en]

    Assessment in the form of a large project and field- and laboratory work was shown to be successful when applied to a course in snow engineering for university students with various backgrounds. The course was interdisciplinary, with teachers representing three different engineering disciplines. The project work was assessed by a report, a short oral presentation and an optional presentation such as a home page, a poster or a physical model. The students experienced that they had learned more with this assessment strategy than from courses with a final written exam. Peer evaluation of the relative contributions to the project work was applied and was appreciated by the students. The experiences of practical engineering tasks during the project work were also appreciated.

  • 36.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Interception evaporation: processes and measurement techniques1996Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In temperate regions, evaporation of water intercepted by the vegetation represents an important part of the evapotranspiration. A review of interception evaporation studies showed that knowledge about interception evaporation processes is limited and progress is hampered by technical difficulties. Existing snow and rain interception measurement methods were reviewed and evaluated with criteria that were established for the ideal method for interception evaporation process studies. No existing methods fulfil all criteria. Two new load-cell based devices for process studies are tested, one weighing-cut-tree technique for snow interception and a technique based on weighing of both net and gross precipitation (with new type of wind-shield) for rain interception. By comparing measured (weighed) and calculated (combination method with different ways to calculate the aerodynamic resistance) evaporation rates for wet intercepted snow it was shown that the most important factors for calculating the evaporation were the relative humidity, the aerodynamic resistance, the wind speed and the intercepted mass. Calculations of evaporation of intercepted snow with a water budget method showed an average evaporation of 0.24 mm/hour and a maximum evaporation of 3.9 mm/7 hours when snow canopy storage was measured with a gamma-ray attenuation system and throughfall with plastic-sheet net-rainfall gauges. Total snow interception evaporation was estimated to be of the order 200 mm/year in Scotland. Comparison with evaporation determined with a combination method (Penman) and two different aerodynamic resistances, the "standard" rain aerodynamic resistance ...

  • 37.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Interception loss wintertime1990In: Nordisk hydrologisk konferens 1990: Kalmar, Sverige 29 juli - 1 augusti 1990 / [ed] Gun Sigurdsson, Norrköping: Nordisk hydrologisk förening , 1990, p. 21-30Conference paper (Refereed)
  • 38.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Laboratory calibration of TDR-probes for snow wetness measurements1997In: Cold Regions Science and Technology, ISSN 0165-232X, E-ISSN 1872-7441, Vol. 25, no 3, p. 197-205Article in journal (Refereed)
    Abstract [en]

    In situ registration of snow liquid water content for avalanche protection and snow-melt prognosis is much needed. The Time Domain Reflectometry (TDR) method is a possible method to meet this need. Laboratory comparison of the TDR-method with the dilution method shows that the TDR-method has the potential to register variations in snow liquid water content down to 1-2 vol.%. It should be possible to achieve continuous registration of snow-pack wetness with a spatial resolution down to approximately 5 cm with several sets of TDR-probes (mounted with 3 cm vertical and 5 cm horizontal distance) combined with a multiplexer and a storage unit. For application when changes in snow density are great (as with newly fallen snow) the method has to be combined with separate density determinations. The dielectric constant of night-time refrozen snow can be used for density determination.

  • 39.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Measuring snow interception and loss from a tree by weighing1990In: Eighth International Northern Research Basins Symposium and Workshop: 26-30 March 1990, Abisko, Sweden., Luleå tekniska universitet, 1990Conference paper (Refereed)
  • 40.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Mine tailings: waterbudget and frost conditions1986In: Nordic Hydrological Conference: Reykjavík, August 11-13, 1986 : preprints of papers, Nordisk hydrologisk förening , 1986, p. 595-604Conference paper (Refereed)
  • 41. Lundberg, Angela
    Halldin, M. (Producer)
    Kellner, E. (Producer)
    Seibert, J. (Producer)
    Rainfall-interception dynamics in a pine-spruce forest stand: agricultural and forest meteorology1999Other (Other academic)
  • 42.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Snösmältning i en punkt: rapport från mätningarna i Bensbyn1979Report (Other academic)
  • 43.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Student and teacher experiences of assessing different levels of understanding2004In: Assessment & Evaluation in Higher Education, ISSN 0260-2938, E-ISSN 1469-297X, Vol. 29, no 3, p. 323-333Article in journal (Refereed)
    Abstract [en]

    Examinations greatly influence course structures and student study strategies. A course for students in the civil and environmental engineering programme at Luleå University of Technology was reconstructed with the aim of increasing levels of understanding. A simple written test was designed to assess low levels of understanding (definitions, concepts, etc.). Laboratory work, fieldwork and extensive assignments (calculation tasks) were intended to assess medium levels of understanding (apply, use and combine algorithms, etc.). A final oral group exam that was used to assess high levels of understanding (compare/contrast, explain causes, analyse, relate) concluded the course. Peer assessment of laboratory work and assignments was also applied. The students ranked the entire course at 5 on a 6 grade scale and appreciated the extensive assignments and the assessment approach.

  • 44.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Vassar College liberal art education from a Swedish engineering perspective2007Report (Other (popular science, discussion, etc.))
  • 45.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Vattenomsättningsstudie i Bensbyområdet 1976-1979: speciellt snösmältningsperioden1979Report (Other academic)
  • 46.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Water budget analysis: a tool to minimize leachate production1998In: Hydrology in the humid tropic environment / [ed] A. Ivan Johnson; Carlos A. Fernandez-Jauregui, IAHS Press, 1998, p. 15-25Conference paper (Refereed)
    Abstract [en]

    Uncontrolled leakage of polluted leachate from landfills is the largest long-term hazard of environment disturbance from landfills. Large efforts should be made to control the leakage. Depending on the type of waste, different water transport regimes are desirable. For municipal waste with a large fraction of organic matter, high water transport through the landfill is advantageous during landfill operation time. Large water transport benefits biological decomposition and the attendance time can be reduced. For coal and peat ashes that produce leachate where we lack practical applicable methods today to reduce the environmentally hazardous concentrations, the water flux through the deposit has to be small to minimize leachate production from such deposits. For tailings with a large sulphide content, oxidation (producing acid) can be reduced by using a saturated cover-layer. Actions undertaken must be of such sustainability that the landfills then can be left without supervision. Water budget analysis is a useful tool when tailoring water flow through landfills. Effects of location (recharge/discharge area), bottom and top liners, surface drains, capillary barrier and vegetation covers are discussed.

  • 47.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Winter forest processes: measurements and modeling2006In: EOS: Transactions, ISSN 0096-3941, E-ISSN 2324-9250, Vol. 87, no 52Article in journal (Other academic)
    Abstract [en]

    Winter-forest processes affect global and local climates. Weather-forecast, climate and hydrological modelers incorporate increasingly realistic surface schemes into their models, and algorithms describing snow accumulation and snow-interception sublimation are now finding their way into these schemes. Both point and spatially variable data for calibration and verification of wintertime dynamics are therefore needed for such modeling schemes. Snow forest atmosphere interaction studies at Luleå University of Technology (in co-operation with researchers in Sweden, Finland, UK and Japan) show that seasonal sublimation fraction of snow precipitation in confined coniferous forests range about 0.35 and single events with sublimation rates of up to 3.9 mm in 7 h were observed. The most important factors for calculating the sublimation were: the relative humidity, the aerodynamic resistance, the wind speed and the intercepted mass. The techniques used to study processes and rates were weighing cut tree and weighing througfall (in Sweden) γ-ray attenuation and tree weighing systems, combined with plastic sheet net rainfall gauges for throughfall (in UK) and snow course measurements in combination with forest density measurements (in Finland) and with sky view fraction (SVF) measurements (fish eyed camera)(in Japan). For the last study forest snow accumulation (SF) could be estimated from snowfall in open fields (SO) and from SVF according to: SF = SO (0.56 + 0.6 × SVF) for SVF < 0.72 and SF = SO for SVF > 0.72 (R2 = 0.86) as well as from leaf area index (LAI). For observation plots exceeding 1 ha the SVF was correlated to the normalized difference snow index (NDSI) using a Landsat-TM image and SF was related to SO and NDSI according to SF = SO (0.81 - 0.37 × NDSI). Plot-size limitations allowed inclusion of only one sparse forest observation so the relationship.

  • 48.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Översyn av och förslag till organisation av pedagogiskt förnyelsearbete vid Luleå tekniska universitet2009In: Strategisk pedagogisk utveckling: proceedings / [ed] Katarina Mårtensson, Lund: Lunds universitet, Centre for Educational Development, CED , 2009, p. 53-Conference paper (Other academic)
  • 49.
    Lundberg, Angela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Översyn av organisation för pedagogiskt förbättringsarbete vid LTU2006Report (Other (popular science, discussion, etc.))
  • 50.
    Lundberg, Angela
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ala-Aho, Pertti
    Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, University of Oulu.
    Eklo, Ole-Martin
    Bioforsk, Norwegian Institute for Agricultural and Environmental Research, Ås.
    Kløve, Bjørn
    Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, University of Oulu, University of Oulu, Bioforsk, UOULU.
    Kværner, Jens
    Bioforsk, Norwegian Institute for Agricultural and Environmental Research, Ås.
    Stumpp, Christine
    Helmholtz Zentrum München, German Research Center for Environmental Health – Institute of Groundwater Ecology.
    Snow and frost: implications for spatiotemporal infiltration patterns - a review2016In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 30, no 8, p. 1230-1250Article in journal (Refereed)
    Abstract [sv]

    Vast regions of the northern hemisphere are exposed to snowfall and seasonal frost. This has large effects on spatiotemporal distribution of infiltration and groundwater recharge processes as well as on the fate of pollutants. Therefore, snow and frost need to be central inherent elements of risk assessment and management schemes. However, snow and frost are often neglected or treated summarily or in a simplistic way by groundwater modellers. Snow deposition is uneven, and the snow is likely to sublimate, be redistributed and partly melt during the winter influencing the mass and spatial distribution of snow storage available for infiltration, the presence of ice layers within and under the snowpack and, therefore, also the spatial distribution of depths and permeability of the soil frost. In steep terrain, snowmelt may travel downhill tens of metres in hours along snow layers. The permeability of frozen soil is mainly influenced by soil type, its water and organic matter content, and the timing of the first snow in relation to the timing of sub-zero temperatures. The aim with this paper is to review the literature on snow and frost processes, modelling approaches with the purpose to visualize and emphasize the need to include these processes when modelling, managing and predicting groundwater recharge for areas exposed to seasonal snow and frost

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