SwePub
Sök i SwePub databas

  Extended search

Träfflista för sökning "WFRF:(Alveteg Mattias) "

Search: WFRF:(Alveteg Mattias)

  • Result 1-43 of 43
Sort/group result
   
EnumerationReferenceCoverFind
1.
  •  
2.
  • Akselsson, Cecilia, et al. (author)
  • Scaling and Mapping Regional Calculations of Soil Chemical Weathering Rates in Sweden
  • 2004
  • In: Water, Air, & Soil Pollution: Focus. - 1573-2940. ; 4:2-3, s. 671-681
  • Journal article (peer-reviewed)abstract
    • Weathering rates of base cations are crucial in critical load calculations and assessments of sustainable forestry. The weathering rate on a single site with detailed geological data can be modelled using the PROFILE model. For environmental assessments on a regional scale, the weathering rates for sites are scaled into regional maps. The step from sites to regional level requires focus on the spatial variation of weathering rates. In this paper, a method is presented by which weathering rates are calculated for 25589 Swedish sites with total elemental analysis for the soil. Based on a part of the results, a methodology for creating area covering maps by geostatistical analysis and kriging is described. A normative reconstruction model was used to transform total elemental analysis to mineralogy. Information from the Swedish Forest Inventory database and other databases were used to derive texture and other important information for the sites, e.g. climate, deposition and vegetation data. The calculated weathering rates show a regional pattern that indicates possibilities for interpolation of data in large parts of Sweden. Geostatistical analysis of an area in southern Sweden shows different properties for different base cations. Kriging was performed for potassium to demonstrate the method. It was concluded that different base cations and different regions have to be analysed separately, in order to optimise the kriging method.
  •  
3.
  • Akselsson, Cecilia, et al. (author)
  • The influence of N load and harvest intensity on the risk of P limitation in Swedish forest soils
  • 2008
  • In: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 404, s. 284-289
  • Journal article (peer-reviewed)abstract
    • Nitrogen (N) is often considered to be the major factor limiting tree growth in northern forest ecosystems. An increased N availability, however, increases the demand for other nutrients such as base cations and phosphorous (P) which in turn may change which nutrient is the limiting factor. If P or base cations become limiting, N will start to leach which means a risk of increased eutrophication of surface waters. As many studies focus on base cations, this study instead aims at estimating P budgets on a regional scale for different harvesting scenarios relevant for Swedish conditions. P budget calculations were carried out for 14,550 coniferous sites from the Swedish National Forest Inventory, as weathering+deposition–harvesting–leaching. Three scenarios with different harvest intensities were used: 1) no harvesting, 2) stem harvesting and 3) wholetree harvesting. The input data were derived from measurements and model results. The P budget estimates indicate that harvesting, especially whole-tree harvesting, result in net losses of P in large parts of Sweden. The highest losses were found in southern Sweden due to high growth rate in this area. In the whole-tree harvesting scenario the losses exceeded 1 kg ha−1 y−1 on many sites. N budget calculations on the same sites indicate that N generally accumulates in the whole country and especially in the southern parts. Consequently, the N and P budget calculations indicate that the forests in southern Sweden are in a transition phase from N-to P-limitation to growth. This transition will proceed as long as the accumulation of N continues. These results are important in a sustainable forestry context, as a basis for assessing the risk of future N leaching, and in designing recommendations for abatement strategies of N deposition and for application of wood ash recycling and N fertilization.
  •  
4.
  •  
5.
  • Alveteg, Mattias, et al. (author)
  • Developing a kinetic alternative in modeling soil aluminium.
  • 1995
  • In: Water, Air and Soil Pollution. - 1573-2932. ; 79:1-4, s. 377-389
  • Journal article (peer-reviewed)abstract
    • Soil chemistry models often use gibbsite solubility and similar equilibrium models to predict Al concentrations in soil solution. A kinetic alternative was developed with the goal of finding universal rate constants instead of the site- and depth-specific solubility constants usually associated with the equilibrium approach. The behavior of the two approaches was studied within the framework of the steady-state soil chemistry model PROFILE using data from Solling, Germany and Gårdsjön, Sweden, two sites with different mineralogy and land use history. The kinetic alternative uses a mass balance to predict Al concentrations. The sources of Al in soil water are deposition, weathering and mineralization. The sinks are leaching and the formation of an aluminosilicate precursor. The precursor slowly transforms into an ordinary clay mineral. Both formation and transformation of the precursor are treated as irreversible processes. The kinetic model introduces a new relationship between pH and Al and produces a systematic pattern of different apparent gibbsite equilibrium constants at different depths. Results show that the kinetic model systematically underestimates Al concentration in the upper horizons, which indicates that there may be additional sources of Al in the upper horizons not accounted for in the model. Predicted values of pH and Al concentrations are comparable with field observations.
  •  
6.
  •  
7.
  • Alveteg, Mattias (author)
  • Dynamics of forest soil chemistry
  • 1998
  • Doctoral thesis (other academic/artistic)abstract
    • Acidification caused by emissions of Nitrogen and Sulphur and associated adverse effects on forest ecosystems has been an issue on the political agenda for decades. Temporal aspects of soil acidification and/or recovery can be investigated using the soil chemistry model SAFE, a dynamic version of the steady-state model PROFILE used in critical loads assessment on the national level, e.g. for Sweden. In this thesis, possibilities to replace the use of apparent gibbsite solubility coefficients with a more mechanistic Al submodel are investigated and a reconstruction model, MAKEDEP, is presented which makes hindcasts and forecasts of atmospheric deposition and nutrient uptake and cycling. A regional application of SAFE/MAKEDEP based on 622 sites in Switzerland is also presented. It is concluded that the quantitative information on pools and fluxes of Al in forest ecosystems is very limited and that there currently exists no mechanistic alternative in modelling soil solution Al. MAKEDEP is a valuable and operational tool for deriving input to dynamic soil chemistry models such as SMART, MAGIC and SAFE. For multi-layer models, e.g. the SAFE model, including nutrient cycling in MAKEDEP is shown to be important. The strength of the regional assessment strategy presented in this thesis lies in its transparency and modularity. All submodules, including models, transfer functions, assumptions in the data acquisition strategy, etc., can be checked and replaced individually. As the presented assessment strategy is based on knowledge and data from a wide range of scientists and fields it is of vital importance that the research community challenge the assumptions made. The many measurable intermediate results produced by the included models will hopefully encourage scientists to challenge the models through additional measurements at the calculation sites. It is concluded that current reduction plans are not sufficient for all forest ecosystems in Switzerland to recover from acidification. Accordning to model projections, nearly 40 % of the sites will have a base cation to Al ratio below one by year 2050.
  •  
8.
  •  
9.
  • Alveteg, Mattias, et al. (author)
  • Egen formulering, plagiat eller kopia. Hur höjer vi ribban för vad studenten anser vara fusk?
  • 2004
  • In: Andra Pedagogiska Inspirationskonferensen. ; , s. 43-45
  • Conference paper (peer-reviewed)abstract
    • Fusk och plagiat är något av en ödesfråga för den högre utbildningen. Om studenter klarar sig igenom kurser på grund av fusk hotas allmänhetens och arbetsgivarnas förtroende för den högre utbildningen. Tyvärr råder det idag en avsevärd oenighet om var gränsen för fusk går. Vi anser det därför vara hög tid att vi som lärare tar vårt ansvar och diskuterar dessa frågor ingående samt ger tips till varandra om hur fusk kan undvikas och upptäckas.
  •  
10.
  • Alveteg, Mattias, et al. (author)
  • Evaluating simplifications used in regional applications of the SAFE and MAKEDEP models
  • 1998
  • In: Ecological Modelling. - 0304-3800. ; 107:2-3, s. 265-277
  • Journal article (peer-reviewed)abstract
    • The importance of different additional simplifications used when moving from single site applications to regional applications of the SAFE and MAKEDEP models was studied. The SAFE model is a dynamic soil chemistry model, which apart from physical and chemical soil parameters also needs the historic evolution of atmospheric deposition and nutrient uptake to simulate the effects of acidic deposition on the chemical status of forest soils. The historic evolution of atmospheric deposition and nutrient uptake are reconstructed by the MAKEDEP model, using information on current deposition and nutrients status together with general deposition trends. Additional simplifica- tions are enforced by limitations in available regional data sets and the costs involved in completing regional data sets. The simplifications studied here are the same as those used in an actual regional application to Scania, southern Sweden: (1) Use of default values for certain soil parameters such as dissolved organic carbon (DOC) and soil bulk density; (2) Use of general depth trends to extrapolate soil parameters, such as mineralogy and surface area, measured for one soil layer to the other three soil layers considered in the SAFE model application; (3) Use of a simplified version of MAKEDEP, where some of the key feedbacks, such as the effects of a growing canopy on dry deposition rates have been removed in order to limit the input data needed to run the MAKEDEP model. The models where applied to two well documented sites, Solling, Germany and Rothamsted, UK. Model results using the above simplifications and subsets thereof were compared with soil chemistry measurements and model results based on previously published single-site applications for the two sites. The study shows that the trends and the present day values of pH and base cation concentration are reproduced fairly well even when all of the simplifications are used. In order to increase the reliability of the regional applications, however, the non-simplified version of MAKEDEP should be used rather than the simplified version. Regional data sets of standing biomass and nutrient contents are therefore needed.
  •  
11.
  • Alveteg, Mattias, et al. (author)
  • Incorporating nutrient content elasticity in the MAKEDEP model
  • 2002
  • In: Sustainable Forestry inTemperate Regions - Proceedings from the SUFOR International Workshop, April 7-9, 2002 (Reports in Ecology and Environmental Engineering ). - 1104-2877. ; 2002:1, s. 52-67
  • Conference paper (peer-reviewed)abstract
    • The MAKEDEP model is designed to produce the time series of atmospheric deposition and nutrient uptake and cycling needed by dynamic soil chemistry models such as SAFE. A range of new features were implemented in the MAKEDEP model including separate treatment of several tree compartments (e.g. root, stem, bark, branch, canopy) and variable nutrient content in the different compartments. The model is designed to produce output that can easily be used as input to the multi-layer soil chemistry model SAFE. The introduction of variable nutrient content calls for a separate treatment of biomass and stored nutrients and also affects the calibration procedure used in the MAKEDEP model
  •  
12.
  • Alveteg, Mattias, et al. (author)
  • Integrated assessment of soil chemical status. 1. Integration of existing models and derivation of a regional database for Switzerland
  • 1998
  • In: Water, Air and Soil Pollution. - 1573-2932. ; 105:1-2, s. 1-9
  • Journal article (peer-reviewed)abstract
    • A regional soil acidification model was developed by integration and adaptation of existing models. The regional model consists of the dynamic multi-layer soil chemistry model SAFE, its steady-state version INITSAFE, the atmospheric deposition and nutrient uptake reconstruction model MAKEDEP, and a routine with empirical relations concerning depth-dependent parameters. A scheme for the extraction of input to the regional model from available information of different geographical detail also was developed. Basic data sources considered were: 1) national surveys such as the National Forest Inventory, covering site specific information, 2) available point measurements of parameter values, and 3) literature sources. Not all parameters were available on a regional scale with sufficient resolution. Input required for the model calculations therefore was derived from the available data sources by means of transfer algorithms including spatial interpolation. Interpolation was done allocating parameter values determined at reference sites to conventionally mapped entities such as geological units, soil type, and other kinds of geographical information. The exercise resulted in a data base of the required 68 site-specific parameter values covering climatic, deposition and land use parameters, as well as stand characteristics and soil properties.
  •  
13.
  • Alveteg, Mattias, et al. (author)
  • On the Calculation and Interpretation of Target Load Functions
  • 2007
  • In: Water, Air, & Soil Pollution: Focus. - : Springer Science and Business Media LLC. - 1573-2940 .- 1567-7230. ; 7:1-3, s. 385-390
  • Journal article (peer-reviewed)abstract
    • In this study critical load functions and target load functions of nitrogen and sulphur deposition with respect to acidity and minimum base cation to aluminium ratio were calculated with the SAFE model using three different averaging strategies: (1) averaging based on current forest generation, (2) averaging based on next generation and (3) averaging based on the entire simulation period. From the results it is evident that although target load calculation and indeed critical load calculation is straight forward, there is a problem in translating a predicted recovery according to the target load calculation back to a site-specific condition. We conclude that a policy strategy for emission reductions that ensures recovery, according to calculated target load functions, is likely to be beneficial from an ecosystem point of view. However, such a strategy may not be sufficient to achieve actual non-violation of the chemical criteria throughout the seasonal or rotational variations. To address this issue we propose a method for calculating dynamic critical loads which ensures that the chosen criteria is not violated.
  •  
14.
  •  
15.
  • Alveteg, Mattias (author)
  • Projecting Regional Patterns of Future Soil Chemistry Status in Swedish Forests using SAFE
  • 2004
  • In: Water, Air, & Soil Pollution: Focus. - 1573-2940. ; 4:2-3, s. 49-59
  • Journal article (peer-reviewed)abstract
    • As part of the Abatement Strategies for Transboundary Air Pollution (ASTA) research program, the dynamic soil chemistry model SAFE was used to make hindcasts and future projections of soil solution chemistry for 645 Swedish forest soils between 1800 and 2100. The data needed were derived from different databases of different spatial resolution ranging from site-specific measurements of soil and stand characteristics from the Swedish Forest Inventory to species-specific nutrient content ranges based on literature surveys. The time-series of nutrient uptake and atmospheric deposition needed were created using the MAKEDEP model and the future scenarios were based on the 1999 Gothenburg protocol. The version of MAKEDEP used included nutrient content elasticity, and the modelled biomass nutrient content thus varies between regions as well as over time. The results were analysed by dividing the sites into three different regions (southwest, central and north) as well as nationally. It was shown that acidification remains a severe environmental problem in the southwest region even after implementation of the 1999 Gothenburg protocol, whereas in the north the problem is far less pronounced.
  •  
16.
  • Alveteg, Mattias, et al. (author)
  • Reconstructing historic atmospheric deposition and nutrient uptake from present day values using MAKEDEP.
  • 1998
  • In: Water, Air and Soil Pollution. - 1573-2932. ; 104:3-4, s. 269-283
  • Journal article (peer-reviewed)abstract
    • A model, MAKEDEP, was developed for reconstructing historic atmospheric deposition and nutrient uptake for forests using present day values. Deposition is reconstructed by separation of wet deposition and throughfall into five different categories. Dry deposition is assumed to depend linearly on needle biomass. Non-marine deposition is scaled using general European emission and deposition trends for sulphur, nitrate and ammonia. Historic nutrient uptake is reconstructed using current biomass and nutrient content, a logistic forest growth curve and information on historic land use.
  •  
17.
  • Alveteg, Mattias, et al. (author)
  • Regional assessment of the temporal trends in soil acidification in Southern Sweden, using the safe model
  • 1995
  • In: Water, Air and Soil Pollution. - 1573-2932. ; 85:4, s. 2509-2514
  • Journal article (peer-reviewed)abstract
    • The dynamic soil acidification model SAFE was applied to 44 forested sites in Skåne, southern Sweden, using available Swedish databases on present soil status, vegetation and deposition. Time series of deposition were derived for each site from present deposition in a generalized fashion by dividing deposition into different classes and scaling with deposition trends from the literature. This study connects the current status of the soil and the soil development with critical load maps calculated with the steady-state model PROFILE. The model was calibrated against measurements of present base saturation from the Swedish Forest Inventory. Model output was compared with available measurements of soil water chemistry. Model output was used to assess the time delay between changes in acidic input and system response in terms of exchangeable base cations and pH. The model was also used for scenario analysis, applying the reductions agreed in the Oslo Protocol to assess the environmental benefits of the agreement.
  •  
18.
  • Alveteg, Mattias, et al. (author)
  • Taking pedagogic responsibility for the difference between plagiarism and cheating
  • 2009
  • In: NU2008 Proceedings : Lärande i en ny tid - samtal om undervisning i högre utbildning.. - 9789197797412 ; , s. 261-264
  • Conference paper (peer-reviewed)abstract
    • The Swedish Higher Education Ordinance states1 in Chapter 8, section 1 (Svensk Förfat- tningssamling [SFS] 1993:100) that disciplinary action can be taken against a student who “at- tempt to deceive during examinations or when academic work is otherwise assessed”. Suspicion of such behaviour is to be reported to the disciplinary board, which in turn has to establish the students intent. The main focus of the teacher, however, is to uphold the quality of the educa- tion and thus the teacher typically cares less about intent and more about scientific quality and progression. Contrary to popular belief the Swedish Higher Education Ordinance does not force teachers to report every suspicion of plagiarism to the disciplinary board. The ordinance forces teachers to report well-grounded suspicions of cheating (SFS 1993:100, Chapter 8, section 9). Once the pedagogical challenges of teaching academic conduct are recognised, suspicions of plagiarism may well take another turn: The differentiation between obvious deficiencies in the ability to formulate oneself independently and suspected attempts to cheat require pedagogic insights and actions.
  •  
19.
  • Alveteg, Mattias, et al. (author)
  • Time for a more inclusive definition of plagiarism?
  • 2010
  • In: Improving Student Learning. ; 17:For the Twenty-First Century Learner, s. 194-200
  • Conference paper (peer-reviewed)abstract
    • Commonly used definitions of plagiarism are misleading in that they seem to indicate that 1) plagiarism is associated with either intent or ignorance and that 2) the requirements for claiming ownership can be uniquely defined. However, the differences between coexisting socio-cultural contexts are large enough that a clear case of plagiarism in one context might even be considered as good practice in another. At the same time, being accused of plagiarism is one of the most serious allegations that can be made in academia and is not surprisingly often associated with strong emotions. Thus, accepting and trying to understand the differences between different contexts might feel threatening to a scientist as such an endeavour might result in questioning the integrity of ones own work. In an attempt to address these problems I propose the use of definitions of plagiarism that are more inclusive and that explicitly address the socio-cultural perspective.
  •  
20.
  • Alveteg, Mattias, et al. (author)
  • Vad räknas som belägg för studenters måluppfyllelse?
  • 2018
  • In: 10:e Pedagogiska Inspirationskonferensen 2018. - 2003-3761 .- 2003-377X. ; 10
  • Conference paper (peer-reviewed)abstract
    • Universitetskanslerämbetet (UKÄ) ställer numera krav på svenska lärosäten att vi ska utvärdera oss själva. Vi på LTH bör då gemensamt försöka hitta sätt att uppfylla UKÄs krav som även ger de verktyg vi själva behöver för att förbättra våra utbildningars kvalitét.Hur tar vi reda på våra utbildningars styrkor och svagheter och vad vi kan göra för att förbättra dem ytterligare? Ett sätt är att undersöka hur väl studenterna uppfyller examensmålen. Vad som ska räknas som belägg för studenters måluppfyllelse är dock svårt, av flera olika skäl. Vår rekommendation blir att triangulera olika typer av belägg samt att tydligt involvera institutionerna i arbetet.
  •  
21.
  • Barkman, Andreas, et al. (author)
  • Effects of data uncertainty in Swedish critical load assessment for forest soils.
  • 2001
  • In: Water, Air and Soil Pollution. - 1573-2932. ; 125:1-4, s. 133-156
  • Journal article (peer-reviewed)abstract
    • The effects of input data uncertainty on the critical loads and exceedance estimates for Swedish forest soils was assessed using Monte Carlo simulations of the PROFILE model. The study focuses on the effects of data uncertainty on the 5%-ile critical load at 150 × 150 km resolution and the 95%-ile exceedance at 150 × 150 km and 50 × 50 km resolution. The results indicate that data uncertainty limits the possibility to differentiate grid cells on 150 × 150 km resolution. The confidence interval for a given percentile can generally be reduced if the uncertainties in calculated critical loads are addressed simultaneously for all sites in a grid cell. The resulting best estimates of the 5%-ile critical load were found to be lowered, thereby advocating larger deposition reductions to comply with a given gap closure of exceedance. The results further indicate that the number of sites within the grid cells is important for the range of the confidence interval for a given percentile. Re-aggregation of exceedance estimate in 50 × 50 km grid cells showed that differentiation may be improved as compared to 150 × 150 km resolution. For 70% of the grid cells on 50 × 50 km resolution, the confidence interval for calculated exceedance covers both negative and positive values.
  •  
22.
  • Barkman, Andreas, et al. (author)
  • Identifying potentials for reducing uncertainty in critical load calculations using the PROFILE model
  • 2001
  • In: Water, Air and Soil Pollution. - 1573-2932. ; 125:1-4, s. 35-54
  • Journal article (peer-reviewed)abstract
    • A sensitivity analysis was performed testingweathering rates, critical loads andexceedances for Swedish forest soils using Monte Carlosimulations of the PROFILE model. Different subsetsof input data were investigated with respect to theirpotential to reduce data uncertainty at site level butalso for modified estimates of the 5%-ile critical load andthe 95%-ile exceedance on 150×150 kmresolution. Physical soil properties were of dominantimportance for all sites and yield up to 62%reduction of the output standard deviation in weathering rate.The study showed that the critical ratio ofbase cations to inorganic aluminium (Bc/Al ratio) in the soilsolution was of major importance for reducingdata uncertainty in critical loads and exceedance estimates.The critical Bc/Al ratio was found to beimportant for reducing data uncertainties in modifiedestimates of the 5%-ile critical load and the95%-ile exceedance, in particular in the northern part ofSweden. Atmospheric deposition, uptake andlitterfall were more important for reducing data uncertaintyin the southern part. Physical soil propertiesand especially mineral content were found to be less importantfor reducing data uncertainties in criticalloads and exceedance estimates. The greatest scope forreducing data uncertainties in an applied perspectiveis to improve estimates of atmospheric deposition of anionsand cations as well as uptake and litterfall ofbase cations and nitrogen.
  •  
23.
  •  
24.
  • Borell, Jonas, et al. (author)
  • Vad kan vi lära oss efter fem år med CEQ?
  • 2008
  • In: Proceedings från 5:e pedagogiska inspirationskonferensen.
  • Conference paper (peer-reviewed)abstract
    • LTH:s policy för kvalitetsarbete kring grund- utbildningen placerar studenternas lärande i fokus, och anger att den pedagogiska utvecklingen ska bygga på en väl- informerad dialogprocess. Enkäten CEQ används sedan hösten 2003 i stor omfattning som dataunderlag i kvalitetsarbetet. Under de första fem åren har stora mängder data samlats in, men inte särskilt många undersökningar gjorts på materialet. Vi har med hjälp av CEQ-data tittat på ett par olika övergripande frågor om den pedagogiska praktiken och om kvalitetsarbetet vid LTH. Vi redovisar följande: a) Tecken på en svag, övergripande utveckling av återkoppling till studenterna, b) En nedgång av svarsfrekvenser och en ökning av längden på fritextkommentarer vid övergång från pappersenkäter till webbenkäter, c) Mycket stor spridning av snittlängden på slutrapportskommentarer av programledare och studieråd mellan olika program, d) En liten minskning av LTH-studenternas upplevda arbetsbelastning. Sammantaget ser vi stora möjligheter för LTH och dess lärare att basera utvecklingsarbete på information från kursutvärderings- systemets datamängder.
  •  
25.
  • Forsius, Martin, et al. (author)
  • MAGIC, SAFE and SMART model applications at integrated monitoring sites: Effects of emission reduction scenarios
  • 1998
  • In: Water, Air and Soil Pollution. - 1573-2932. ; 105:1-2, s. 21-30
  • Journal article (peer-reviewed)abstract
    • Three well-known dynamic acidification models (MAGIC, SAFE, SMART) were applied to data sets from five Integrated Monitoring sites in Europe. The calibrated models were used in a policy-oriented framework to predict the long-term soil acidification of these background forest sites, given different scenarios of future deposition of S and N. Emphasis was put on deriving realistic site-specific scenarios for the model applications. The deposition was calculated with EMEP transfer matrices and official emissions for the target years 2000, 2005 and 2010. The alternatives for S deposition were current reduction plans and maximum feasible reductions. For N, the NOx and NHy depositions were frozen at the present level. For NOx, a reduction scenario of flat 30% reduction from present deposition also was utilized to demonstrate the possible effects of such a measure. The three models yielded generally consistent results. The Best prediction-scenario (including the effects of the second UN/ECE protocol for reductions of SO2 emissions and present level for NOx-emissions), resulted in many cases in a stabilization of soil acidification, although significant improvements were not always shown. With the exception of one site, the Maximum Feasible Reductions scenario always resulted in significant improvements. Dynamic models are needed as a complement to steady-state techniques for estimating critical loads and assessing emission reduction policies, where adequate data are available.
  •  
26.
  • Fransson, Liisa, et al. (author)
  • A regional perspective on present and future soil chemistry at 16 Swedish forest sites
  • 2005
  • In: Water, Air and Soil Pollution. - : Springer Science and Business Media LLC. - 1573-2932 .- 0049-6979. ; 162:1-4, s. 89-105
  • Journal article (peer-reviewed)abstract
    • Assessing the timescales of recovery, by the use of dynamic models, will be used as input to the policy process to abate acidification. In this study the multilayer dynamic soil chemistry model SAFE was applied to 16 forest sites in Sweden, covering a sulfur deposition gradient of 1.2-11 kg S/ha/yr. Soil samples were collected at all sites and the pH and sulfate concentration dependent isotherm, used for modeling sulfate adsorption in SAFE, was parameterized for every site. A new way of implementing the nutrient uptake distribution in SAFE was developed, which allows the uptake distribution between layers in the rooting zone to vary with time, depending on the availability of base cations in the individual layers. Model output was compared to measurements of base cation concentration, total inorganic Al, pH and Bc/Al both site-by-site and cumulatively for all sites, and the usefulness of these comparisons is discussed from a policy viewpoint. Future projections of recovery show that the overall recovery, expressed as minimum Bc/Al ratio > 1 in the rooting zone, is slow. Assuming full implementation of the UNECE LRTAP Gothenburg Protocol and no further emission reductions thereafter, 44% of the modeled sites still have a Bc/Al ratio below 1 in 2100 in some soil layer within the rooting zone.
  •  
27.
  • Fransson, Liisa, et al. (author)
  • Parameterization and evaluation of sulfate adsorption in a dynamic soil chemistry model.
  • 2003
  • In: Environmental Pollution. - 0269-7491. ; 124:1, s. 119-125
  • Journal article (peer-reviewed)abstract
    • Sulfate adsorption was implemented in the dynamic, multi-layer soil chemistry model SAFE. The process is modeled by an isotherm in which sulfate adsorption is considered to be fully reversible and dependent on sulfate concentration as well as pH in soil solution. The isotherm was parameterized by a site-specific series of simple batch experiments at different pH (3.8–5.0) and sulfate concentration (10–260 mol l−1) levels. Application of the model to the Lake Gårdsjön roof covered site shows that including sulfate adsorption improves the dynamic behavior of the model and sulfate adsorption and desorption delay acidification and recovery of the soil. The modeled adsorbed pool of sulfate at the site reached a maximum level of 700 mmol/m2 in the late 1980s, well in line with experimental data.
  •  
28.
  • Fransson, Liisa, et al. (author)
  • The effect of changes in natural and anthropogenic deposition on modelling recovery from acidification.
  • 2003
  • In: Hydrology and Earth System Sciences. - 1607-7938. ; 7:5, s. 766-776
  • Journal article (peer-reviewed)abstract
    • The mufti-layer dynamic soil chemistry SAFE model was used to study the dynamics of recovery in the F1 catchment at Lake Gardsjon, Sweden. The influence of (F) sulphate adsorption, and (2) changes in marine deposition, oil model predictions of recovery was studied. Sulphate adsorption/desorption in SAFE is modeled by all isotherm in which sulphate adsorption is dependent oil both the sulphate concentration and the pH in the soil solution. This isotherm was parameterised for the B-horizon of F1 for the sulphate concentration range 10-260 mumol(-1) and the pH range 3.8-5.0. Sulphate adsorption/desorption as the only soil process involving sulphate is adequate to predict sulphate in run-off at F1. Adding the process caused time-delays in sulphate concentration in run-off of only 1-2 years. which was Much shorter than previously seen in the adjacent G1 catchment. The location of Lake Gardsjon. approximately 15 km inland from the Swedish west coast, ensures that the marine deposition to the area is high. Model Output showed that the temporal variation in marine deposition has a considerable impact oil the run-off-chemistry. Such changes in marine deposition are difficult to foresee and their influence on modelled run-off-chemistry, can be large when soils start to recover as the previously high concentrations of anthropogenic sulphate in the soil solution decrease.
  •  
29.
  • Fransson, Liisa, et al. (author)
  • The importance of including the pH dependence of sulfate adsorption in a dynamic soil chemistry model
  • 2004
  • In: Water, Air and Soil Pollution. - 1573-2932. ; 154:1-4, s. 349-356
  • Journal article (peer-reviewed)abstract
    • Sulfate adsorption is an important process when modeling the dynamics of recovery from acidification. In the dynamic soil chemistry model SAFE sulfate adsorption is modeled by a pH and sulfate concentration dependent isotherm. This isotherm has been parameterized by fitting it to data from batch experiments on soil samples using multiple linear regression. The soil samples were from the B-horizon from three sites, two from the Lake Gardsjon area in south-west Sweden and one from southern Poland. The pH dependency of sulfate adsorption is important. The batch experiments show that the adsorbed amount, at a specific sulfate concentration, increases considerably with decreasing pH. This implies that the adsorbed pool of anthropogenic sulfate in soils may remain fairly high during the recovery phase. Although a decrease of sulfate concentration is commonly seen, the modeled pH increase is often slow, and thus delays in the modeled desorption of anthropogenic sulfate can be expected.
  •  
30.
  • Grennfelt, Peringe, et al. (author)
  • Critical loads - is there a need for a new concept?
  • 2001
  • In: Water, Air, & Soil Pollution: Focus. - 1573-2940. ; 1:1-2, s. 21-27
  • Journal article (peer-reviewed)abstract
    • The concept of critical loads has been an important and successful tool for the development of control strategies for transboundary air pollution in Europe. The use of the concept has led us to a situation where very few areas in Europe will have an exceedance of critical loads for acidification in 2010, indicating that the benefits of further control acidifying substances will be less useful. The critical loads concept does not, however, take into account the large benefits of further control in damaged systems but where critical loads are no longer exceeded. In this paper we discuss the importance of widening the critical loads concept to include these benefits and we propose an additional effect-related measure, Dynamic Impact Analysis, to be included in further control strategies and assessments. With such a concept the actual situation and its further development will be included in assessments and control strategies.
  •  
31.
  • Johansson, Matti, et al. (author)
  • Integrated Assessment Modeling of Air Pollution in Four European Countries.
  • 2001
  • In: Water, Air and Soil Pollution. - 1573-2932. ; 130:1-4, s. 175-186
  • Journal article (peer-reviewed)abstract
    • The integrated assessment modeling on acid rain has incorporated several related effects and pollutants into a multi-pollutant/multi-effect approach, resulting in complex integrated models and policy assessments. The development and implementation of effects-oriented cost-effective emission reduction strategies in Europe are based on integrated assessment models. The project on national integrated assessment modeling in Finland, Denmark, Spain and Sweden aimed to support the national evaluation of European emission reduction strategies. The tasks covered the comparison of inventories and projections for emissions of sulfur, nitrogen oxides, ammonia and volatile organic compounds, assessment of control techniques and related costs, concentration and deposition scenarios to estimate environmental effects of acidification, eutrophication and ground-level ozone and their temporal aspects, uncertainty analyses on both individual modules and whole integrated models, and dissemination of results to stakeholders. The integrated assessment modeling provided a consistent framework for the harmonization of input data and in-depth scientific research tasks on emissions, pollutant loading and impacts including comprehensive uncertainty analyses, and facilitated the dissemination of knowledge to policy-makers.
  •  
32.
  • Kurz, Daniel, et al. (author)
  • Integrated assessment of soil chemical status. 2. Application of a regionalised model to 622 forested sites in Switzerland.
  • 1998
  • In: Water, Air and Soil Pollution. - 1573-2932. ; 105:1-2, s. 11-20
  • Journal article (peer-reviewed)abstract
    • A model, MAKEDEP, was developed for reconstructing historic atmospheric deposition and nutrient uptake for forests using present day values. Deposition is reconstructed by separation of wet deposition and throughfall into five different categories. Dry deposition is assumed to depend linearly on needle biomass. Non-marine deposition is scaled using general European emission and deposition trends for sulphur, nitrate and ammonia. Historic nutrient uptake is reconstructed using current biomass and nutrient content, a logistic forest growth curve and information on historic land use.
  •  
33.
  • Kurz, Daniel, et al. (author)
  • Steady-State and Dynamic Assessment of Forest Soil Acidification in Switzerland.
  • 2001
  • In: Water, Air and Soil Pollution. - 1573-2932. ; 130:1-4, s. 1217-1222
  • Journal article (peer-reviewed)abstract
    • The European steady-state Simple Mass Balance (SMB) model and the dynamic soil acidification model SAFE were used to assess the risk of future forest soil acidification in Switzerland. 2010 deposition forecasts on a 150x150 km grid resolution as well as corresponding ecosystem protection levels were obtained from RAINS model runs based on the 1999 Gothenburg Protocol obligations under the UN/ECE LRTAP Convention. Deposition values for 2010 on the national resolution were derived by scaling down present 1x1 km deposition values according to the deposition trends at the 150x150 km grid resolution. Meeting the Protocol obligations will reduce the percentage of Swiss forest ecosystems not protected against acidification between 1990 and 2010 from 41 to 4% according to the RAINS assessment and from 63 to 16% according to the assessment with the SMB at the 1x1 km resolution. The dynamic approach indicates, however, that soil conditions may not improve as much as these steady-state models suggest. By 2010, 39% of the sites considered will still have soil solution Bc/Al molar ratios below 1 at least in one soil layer. Nevertheless, deposition reductions obtained from the implementation of the new protocol will prevent the major part of Swiss forest soils from further acidification. Aiming at recovery of the more sensitive forest ecosystems would require emission reductions beyond the Protocol's obligations.
  •  
34.
  • Malmgren, Charlotte, et al. (author)
  • PBL för 100 studenter. Problem och möjligheter
  • 2004
  • In: [Host publication title missing].
  • Conference paper (peer-reviewed)abstract
    • Abstract in Undetermined Särskilt när en kurs läses av många studenter är en fungerande kommunikation mellan studenter och lärare väsentlig. PBL-metoden är i sig ett sätt att etablera en tvåvägskommunikation genom att låta studenterna komma till tals. Vi diskuterar några av de problem vi mött när en kurs har utvecklats från valfri med relativ få studenter till obligatorisk kurs för ett hundratal, samt hur vi har försökt tackla dem. Bland annat används operativ utvärdering i olika former för att underlätta kommunikationen med studenterna.
  •  
35.
  • Munthe, John, et al. (author)
  • New concepts and methods for effect-based strategies on transboundary air pollution. Synthesis Report, April 2002
  • 2002
  • Reports (other academic/artistic)abstract
    • This report was prepared in connection with the scientific evaluation of the ASTA programme in May, 2002. It consists of a comprehensive summary of the approaches and results from the different ASTA sub programmes. ASTA is presently in its fourth and last year of the first phase. The report is not intended to give a full description of all relevant aspects of the problem of transboundary air pollution but rather discuss some crucial problems and their possible scientific solutions. After the preparation and submission of this report, ASTA has been positively evaluated and will continue into its second phase. The evaluation reports as well as a letter of intent for the second phase of the ASTA programme are available on the ASTA web page (http://asta.ivl.se). Further information of the programme is also available at the web page. For those who wish to receive more information of the programme, there is a list of contact persons at the end of the report. Many of the ASTA phase 1 activities are currently in a state of intense evaluation and reporting and additional scientific results as well as synthesises and assessments will be prepared during the remainder of 2002.
  •  
36.
  •  
37.
  • Roxå, Torgny, et al. (author)
  • Understanding and influencing teaching and learning cultures at university - A network approach
  • 2011
  • In: Higher Education. - : Springer Science and Business Media LLC. - 1573-174X .- 0018-1560. ; 62:1, s. 99-111
  • Journal article (peer-reviewed)abstract
    • Academic cultures might be perceived as conservative, at least in terms of development of teaching and learning. Through a lens of network theory this conceptual article analyses the pattern of pathways in which culture is constructed through negotiation of meaning. The perspective contributes to an understanding of culture construction and maintenance with a potential to aid academic developers and others in the endeavour to influence teaching and learning cultures in academia. Throughout the discussion the importance of supporting the weak links between clusters of individuals stands out as a feature to focus upon. We propose that the sheer complexity of culture construction and maintenance in academic organisations is likely to cause any single, isolated attempt for change to fail Instead, we argue that a multitude of inter-related initiatives over a long period of time is likely to distinguish strategies that are successful in influencing academic teaching and learning cultures.
  •  
38.
  •  
39.
  • Sverdrup, Harald, et al. (author)
  • Modeling recovery of Swedish ecosystems from acidification
  • 2005
  • In: Ambio: a Journal of Human Environment. - 0044-7447. ; 34:1, s. 25-31
  • Journal article (peer-reviewed)abstract
    • Dynamic models complement existing time series of observations and static critical load calculations by simulating past and future development of chemistry in forest and lake ecosystems. They are used for dynamic assessment of the acidification and to produce target load functions, that describe what combinations of nitrogen and sulfur emission reductions are needed to achieve a chemical or biological criterion in a given target year. The Swedish approach has been to apply the dynamic acidification models MAGIC, to 133 lakes unaffected by agriculture and SAFE, to 645 productive forest sites. While the long-term goal is to protect 95% of the area, implementation of the Gothenburg protocol will protect approximately 75% of forest soils in the long term. After 2030, recovery will be very slow and involve only a limited geographical area. If there had been no emission reductions after 1980, 87% of the forest area would have unwanted soil status in the long term. In 1990, approximately 17% of all Swedish lakes unaffected by agriculture received an acidifying deposition above critical load. This fraction will decrease to 10% in 2010 after implementation of the Gothenburg protocol. The acidified lakes of Sweden will recover faster than the soils. According to the MAGIC model the median pre-industrial ANC of 107 mueq L-1 in acid sensitive lakes decreased to about 60 mueq L-1 at the peak of the acidification (1975-1990) and increases to 80 mueq L-1 by 2010. Further increases were small, only 2 mueq L-1 between 2010 and 2040. Protecting 95% of the lakes will require further emission reductions below the Gothenburg protocol levels. More than 7000 lakes are limed regularly in Sweden and it is unlikely that this practice can be discontinued in the near future without adverse effects on lake chemistry and biology.
  •  
40.
  • Tominaga, Koji, et al. (author)
  • Predicting Acidification Recovery at the Hubbard Brook Experimental Forest, New Hampshire: Evaluation of Four Models
  • 2010
  • In: Environmental Science & Technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; 44:23, s. 9003-9009
  • Journal article (peer-reviewed)abstract
    • The performance and prediction uncertainty (owing to parameter and structural uncertainties) of four dynamic watershed acidification models (MAGIC, PnET-BGC, SAFE, and VSD) were assessed by systematically applying them to data from the Hubbard Brook Experimental Forest (HBEF), New Hampshire, where long-term records of precipitation and stream chemistry were available. In order to facilitate systematic evaluation, Monte Carlo simulation was used to randomly generate common model input data sets (n ) 10 000) from parameter distributions; input data were subsequently translated among models to retain consistency. The model simulations were objectively calibrated against observed data (streamwater: 1963-2004, soil: 1983). The ensemble of calibrated models was used to assess future response of soil and stream chemistry to reduced sulfur deposition at the HBEF. Although both hindcast (1850-1962) and forecast (2005-2100) predictions were qualitatively similar across the four models, the temporal pattern of key indicators of acidification recovery (stream acid neutralizing capacity and soil base saturation) differed substantially. The range in predictions resulted from differences in model structure and their associated posterior parameter distributions. These differences can be accommodated by employing multiple models (ensemble analysis) but have implications for individual model applications.
  •  
41.
  • Tominaga, Koji, et al. (author)
  • Voyage without constellation: evaluating the performance of three uncalibrated process-oriented models
  • 2009
  • In: Hydrology Research. - : IWA Publishing. - 1998-9563 .- 0029-1277 .- 2224-7955. ; 40:2-3, s. 261-272
  • Journal article (peer-reviewed)abstract
    • Three process-oriented dynamic acidification models were applied to a long-term monitoring site without calibration to evaluate the influence of model structural differences on simulation. The models were simplified to share as many commonalities as possible so that the main structural differences could be investigated. The models differed in sub-models for cation exchange, organic acids and acid anion speciation. All models were populated with ‘equivalent’ parameters by systematic input mapping. The influence of input variability was addressed through Monte Carlo parameter sampling. The three models behaved exactly the same for tracers (e.g. sulphate and chloride), indicating successful cross-parameterization of the models. Differences in model structure had an impact on some of the simulated chemical parameters. In particular, models using Gapon cation exchange simulated higher base saturation levels in the long run than their Gaines-Thomas counterparts, but simulated lower base cation concentration and acid neutralizing capacity in soil solution when acid deposition levels were high. Multiple-model evaluation frameworks as presented here allow for greater certainty in model predictions; ultimately, this type of framework should be employed when evaluating the impacts of future climate and environmental changes on soil and surface water hydrogeochemistry.
  •  
42.
  • Wallman, Patrik, et al. (author)
  • Integrated modelling
  • 2002
  • In: Developing Principles and Models for Sustainable Forestry in Swede.
  • Book chapter (other academic/artistic)
  •  
43.
  • Warfvinge, Per, et al. (author)
  • Modelling geochemistry and Lake pH since glaciation at Lake Gårdsjön
  • 1995
  • In: Water, Air and Soil Pollution. - 1573-2932. ; 85:2, s. 713-718
  • Journal article (peer-reviewed)abstract
    • The soil acidification model SAFE was modified to calculate historical changes in geochemistry and runoff since the last glaciation ended at the Lake Gårdsjön F1 catchment 12 000 B.P. Changes in runoff pH and ANC, soil weathering rate, soil mineralogy, soil texture and base saturation was also calculated. The changes in mineralogy compared favorable to data. Modeled historic weathering rates were slightly higher than data suggest, while present weathering rate was somewhat to low, 37 mmolc m–2 yr–1. The weathering rate was very high immediately after the last glaciation, and decreased as the smaller particles were consumed by weathering. The calculated runoff pH follows the pattern of the paleo-inferred pH. SAFE suggests a natural depletion of base cations in the C-layer.
  •  
Skapa referenser, mejla, bekava och länka
  • Result 1-43 of 43
Type of publication
journal article (26)
conference paper (13)
book chapter (2)
reports (1)
doctoral thesis (1)
Type of content
peer-reviewed (39)
other academic/artistic (4)
Author/Editor
Alveteg, Mattias (43)
Sverdrup, Harald (15)
Warfvinge, Per (9)
Fransson, Liisa (6)
Kurz, Daniel (4)
Leire, Eva (4)
show more...
Sonesson, Anders (3)
Roxå, Torgny (3)
Malmgren, Charlotte (3)
Walse, Charlotta (3)
Moldan, Filip (3)
Munthe, John (2)
Ahlberg, Anders (2)
Mårtensson, Katarina (2)
Akselsson, Cecilia (2)
Grennfelt, Peringe (2)
Olsson, Thomas (1)
Larsson, Rolf (1)
Ståhl, Lars-Henrik (1)
Bishop, Kevin (1)
Hillbom, Ellen (1)
Hansson, Hans-Christ ... (1)
Svensson, Mats (1)
Stjernquist, Ingrid (1)
Näsholm, Torgny (1)
Svensson, Ingrid (1)
Andersson, Roy (1)
Amnér, Gunilla (1)
Pleijel, Håkan (1)
Josefsson, Jonas (1)
Kronnäs, Veronika (1)
Karlsson, Per Erik (1)
Westling, Olle (1)
Olle, Westling (1)
Holmqvist, Johan (1)
Thelin, Gunnar (1)
Fransson, Ann-Mari (1)
Sofie, Hellsten (1)
Wingren, Christer (1)
Becker, Rolf (1)
Björk, Lena (1)
Kurz, D (1)
Hedberg, Maria (1)
Rust, Chris (1)
Malm, Jan-Olle (1)
Mauritsson, Johan (1)
Nilsson, Sandra (1)
Nordbeck, Patrik (1)
Andersson, Karim (1)
Schlyter, Peter (1)
show less...
University
Lund University (42)
Linnaeus University (1)
IVL Swedish Environmental Research Institute (1)
Language
English (39)
Swedish (4)
Research subject (UKÄ/SCB)
Engineering and Technology (36)
Social Sciences (9)
Natural sciences (1)
Medical and Health Sciences (1)
Agricultural Sciences (1)

Year

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Close

Copy and save the link in order to return to this view