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Author Hjelkrem, A.-G.R.; Höglind, M.; van Oijen, M.; Schellberg, J.; Gaiser, T.; Ewert, F.
Title Sensitivity analysis and Bayesian calibration for testing robustness of the BASGRA model in different environments Type Journal Article
Year 2017 Publication Ecological Modelling Abbreviated Journal Ecol. Model.
Volume 359 Issue Pages 80-91
Keywords Metropolis-hasting; Morris method; Reducing complexity; Robustness
Abstract Highlights • The parameters to be fixed were consistent across sites. • Model calibration must be performed separately for each specific case. • Possible to reduce model parameters from 66 to 45. • Strong model reductions must be avoided. • The error term for the training data were characterised by timing (phase shift). Abstract Proper parameterisation and quantification of model uncertainty are two essential tasks in improvement and assessment of model performance. Bayesian calibration is a method that combines both tasks by quantifying probability distributions for model parameters and outputs. However, the method is rarely applied to complex models because of its high computational demand when used with high-dimensional parameter spaces. We therefore combined Bayesian calibration with sensitivity analysis, using the screening method by Morris (1991), in order to reduce model complexity by fixing parameters to which model output was only weakly sensitive to a nominal value. Further, the robustness of the model with respect to reduction in the number of free parameters were examined according to model discrepancy and output uncertainty. The process-based grassland model BASGRA was examined in the present study on two sites in Norway and in Germany, for two grass species (Phleum pratense and Arrhenatherum elatius). According to this study, a reduction of free model parameters from 66 to 45 was possible. The sensitivity analysis showed that the parameters to be fixed were consistent across sites (which differed in climate and soil conditions), while model calibration had to be performed separately for each combination of site and species. The output uncertainty decreased slightly, but still covered the field observations of aboveground biomass. Considering the training data, the mean square error for both the 66 and the 45 parameter model was dominated by errors in timing (phase shift), whereas no general pattern was found in errors when using the validation data. Stronger model reduction should be avoided, as the error term increased and output uncertainty was underestimated.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3800 ISBN Medium
Area (down) Expedition Conference
Notes CropM, LiveM, ft_macsur Approved no
Call Number MA @ admin @ Serial 5010
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Author Mitter, H.; Schmid, E.; Sinabell, F.
Title Integrated modelling of protein crop production responses to climate change and agricultural policy scenarios in Austria Type Journal Article
Year 2015 Publication Climate Research Abbreviated Journal Clim. Res.
Volume 65 Issue Pages 205-220
Keywords Climate change impact; Adaptation; Soybean; EPIC; Common Agricultural Policy; Land use
Abstract Climate and policy changes are likely to affect protein crop production and thus trade balances in Europe, which is highly dependent on imports. Exemplified for Austrian cropland, we developed an integrated modelling framework to analyze climate change and policy scenario impacts on protein crop production and environmental outcomes. The integrated modelling framework consists of a statistical climate change model, a crop rotation model, the bio-physical process model EPIC, and the economic bottom-up land use optimization model BiomAT. EPIC is applied to simulate annual dry matter crop yields for different crop management practices including crop rotations, fertilization intensities, and irrigation, as well as for 3 regional climate change scenarios until 2040 at a 1 km grid resolution. BiomAT maximizes total gross margins by optimizing land use choices and crop management practices subject to spatially explicit cropland endowments. The model results indicate that changes in agricultural policy conditions, cropland use, and higher flexibility in crop management practices may reduce protein import dependence under changing climatic conditions. Expanding protein crop production is most attractive in south-eastern Austria with its Central European continental climate where maize is most often replaced in crop rotations. However, the acreage of protein crops is limited by agronomically suitable cropland. An intended side effect is the reduction of nitrogen fertilizer inputs by about 0.1% if total protein crop production increases by 1%.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0936-577x ISBN Medium
Area (down) Expedition Conference
Notes TradeM, ft_macsur Approved no
Call Number MA @ admin @ Serial 5012
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Author Mitter, H.; Schönhart, M.; Meyer, I.; Mechtler, K.; Schmid, E.; Sinabell, F.; Bachner, G.
Title Agriculture Type Book Chapter
Year 2015 Publication Abbreviated Journal
Volume Issue Pages 121-144
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Publisher Place of Publication Vienna Editor Steininger, K.; König, M.; Bednar-Friedl, B.; Kranzl, L.; Loibl, W.; Prettenthaler, F.
Language Summary Language Original Title
Series Editor Series Title Economic Evaluation of Climate Change Impacts. Development of a Cross-Sectoral Framework and Results for Austria Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area (down) Expedition Conference
Notes TradeM, ftnotmacsur Approved no
Call Number MA @ admin @ Serial 5014
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Author Sinabell, F.; Sommer, M.; Kappert, R.; Kaul, H.P.
Title Ist Mais unentbehrlich? Type Magazine Article
Year 2015 Publication Der Pflanzenarzt Abbreviated Journal
Volume 68 Issue Pages 19-21
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Notes TradeM, ft_macsur Approved no
Call Number MA @ admin @ Serial 5015
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Author Sinabell, F.; Kappert, R.; Kaul, H.-P.; Kratena, K.; Sommer, M.
Title Maisanbau in Österreich. Ökonomische Bedeutung und pflanzenbauliche Herausforderungen Type Report
Year 2015 Publication Studie des Österreichischen Instituts für Wirtschaftsforschung im Auftrag des Ökosozialen Forums Abbreviated Journal
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Language Summary Language Original Title
Series Editor Österreichisches Institut für Wirtschaftsforschung Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area (down) Expedition Conference
Notes TradeM Approved no
Call Number MA @ admin @ Serial 5018
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