Andreas Fischlin


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Fischlin

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Andreas

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0000-0002-6385-9045

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Publications 1 - 10 of 33
  • ModelWorks - An interactive simulation environment for workstations
    Item type: Report
    Fischlin, Andreas; Roth, Olivier; Gyalistras, Dimitrios; et al. (1990)
    Systems Ecology Report
    ModelWorks is a modeling and simulation environment in Modula-2 specifically designed to be run interactively on modern personal computers and workstations. It supports modular modeling by featuring a coupling mechanism between submodels and unrestricted number of state variables, model parameters etc. up to the limits of the computer resources. It allows for the formulation of continuous time, discrete time as well as continuous and discrete time mixed models. Finally ModelWorks offers in its interactive simulation environment a handy user interface featuring efficient alterations of model and simulation run parameters.
  • ModelWorks 2.2: An interactive simulation environment for personal computers and workstations
    Item type: Report
    Fischlin, Andreas; Gyalistras, Dimitrios; Roth, Olivier; et al. (1994)
    Systems Ecology Report
    ModelWorks is a modelling and simulation environment in Modula-2 specifically designed to be run interactively on modern personal computers and workstations. It supports modular modelling by featuring a coupling mechanism between submodels and an unrestricted number of state variables, model parameters etc. up to the limits of the computer resources. It allows for the formulation of continuous time, discrete time, discrete event models, as well as the free mixing of all these formalisms. Not only does ModelWorks offer the simulationist a handy user interface to experiment interactively with model systems, but also allows the modeller to use ModelWorks' functions via a client interface in any other programming context.
  • Calculating temperature dependence over long time periods: derivation of methods
    Item type: Report
    Lischke, Heike; Löffler, Thomas J.; Fischlin, Andreas (1996)
    Systems Ecology Report
    Rates of ecological processes are usually influenced by temperature. For simplicity and efficiency of ecosystem models it is often necessary to summarise information about temperature dependence from short, e.g. hourly, time intervals over longer, e.g. monthly, time periods, i.e. to calculate long term expected values of dependence functions. This aim can seldom be achieved by applying the temperature function to the mean temperature, because temperature dependencies are in many cases nonlinear. Therefore, we derived newly seven methods for such a temporal aggregation of temperature dependence. The methods determine the expected value interpreting either hourly temperature, daily temperature mean, or daily temperature mean and amplitude as random variables. The dependence function hereby is approximated by a piecewise linear function, the daily temperature course by a triangle and the density function of the normal distribution by a parabola. The resulting methods cover a range of temperature input data resolutions: monthly mean or standard deviation or both of either hourly temperatures, daily temperature extrema, daily temperature means and amplitudes, or only daily tempuature means. The methods can be applied to all types of dependence functions, in particular to nonlinear ones.
  • The response of the carbon cycle in undisturbed forest ecosystems to climate change: A review of plant-soil models
    Item type: Report
    Perruchoud, Daniel; Fischlin, Andreas (1994)
    Systems Ecology Report
    We compared 6 plantsoil models from the literature which describe the Cdynamics in forests and include climatic forcing explicitly. Our selection included the two physiological models FORESTBGC and TCX, the ecosystem/population model FORCLIM, two ecosystem/tissue models viz. MBLGEM and CENTURY Forest and the global model TEM. The review revealed a multitude of differences with respect to the model structure, the incorporation of particular processes and the coupling with the abiotic environment. We gave an assessment to what kind of questions the models can be best applied and how well they are suited for studying the response of the Ccycle under climate change. In this context organic C in litter and humus play a keyrole. The number of compartments and the pathways of Cflows influence both the transient phase and equilibrium of the system, a fact that has been recognized before (Harvey, 1989), but has not been investigated systematically for any of the models. Hence, the multitude of aggregation levels used to represent detritus and the variety of decomposition formulations used in the models may result in inconsistencies of the simulation results. Similarly, the control of ecoprocesses via abiotic factors differs among the models. They use distinct abiotic quantities and different mathematical parametrizations, hereby affecting the systems response in a changing environment substantially, even if this is not the case for present conditions. Given the differences in experimental frames of published simulations it was not possible to trace back behavior deviations to particular model formulations. In order to make consistent projections of the Ccycle s response in forests in a changing climate there remains an urgent need to analyze the models from a structural point of view based on quantitative model comparisons under welldefined conditions.
  • Implementation and parameter adaptation of a potato crop simulation model combined with a soil water subsystem
    Item type: Report
    Roth, Olivier; Derron, Jacques; Fischlin, Andreas; et al. (1992)
    Systems Ecology Report
    For the study of virus epidemics in Swiss seed potatoes a simple, yet useful crop growth model was needed. It had to provide information on tuber yield, leaf area, leaf age (for age resistance) and responses to water excess or deficit. The model of JOHNSON et al. (1986) satisfied most of these criteria. However this model does not compute the water stress factor from easily available weather data. Therefore we built a submodel for the soil water balance based on published models (VAN KEULEN & WOLF, 1986) and combined it with a new implementation of the JOHNSON model. For this purpose the simulation environment “ModelWorks” with its open system architecture and numerous interactive features e.g. for parameter settings and graphing, proved to be most useful. The model’s parameters were identified by graphical examination and automatic iterative minimization of the squared differences of the simulated and the given crop calibration data sets. For most situations the simulated results showed satisfactory agreement with the measured data. The simulated qulitative and quantitative behavior fitted the observations similarly for the calibration and their equivalent validation data sets, both for potential and drought conditions. The exception is the leaf area index, which is usually due to the considerably simple model structure simulated with less accuracy than the tubers or other plant parts. The coupled soil water balance model contains more details and fits the validation data in most cases very well. For the purpose of our study we consider the overall model output to be satisfactory.
  • Unterrichtsprogramm «Weltmodell 2»
    Item type: Report
    Fischlin, Andreas; Blanke, T.; Gyalistras, Dimitrios; et al. (2010)
    Systems Ecology Report
  • Leben im und mit dem Klimawandel Lebensgrundlagen in Gefahr?
    Item type: Report
    Fischlin, Andreas (2010)
    Systems Ecology Report
  • Introducing RASS - the RAMSES simulation server
    Item type: Report
    Thöny, J.; Fischlin, Andreas; Gyalistras, Dimitrios (1995)
    Systems Ecology Report
    RASS forms a new component of the RAMSES (Research Aids for the Modelling and Simulation of Environmental Systems) modelling and simulation concept. It allows to automatically translate interactive RAMSES model definition programs and to execute them in a batch mode on a high performance computer.
  • Comparing the behaviour of mountainous forest succession models in a changing climate
    Item type: Report
    Fischlin, Andreas; Bugmann, Harald (1993)
    Systems Ecology Report
    The temporal behaviour of three forest gap models built to simulate species succession in central Europe is compared in the current as well as future climates. The first model, FORECE, represents a conventional forest gap model, the second, FORCLIM 1.1, is an ecologically simplified descendant of the first, and the third model, FORCLIM 1.3, was derived from the second by avoiding any implicit climate dependencies. The species compositions produced by the three models were studied along an altitudinal gradient in the European Alps while manipulating climatic parameters. First, the equilibrium states of the models were calculated for the present climate. Second, starting from the equilibrium states, the step responses of the models were explored by imposing an instantaneous climatic change based on regional projections, which have been statistically downscaled from transient GCM simulations for the next century. According to similarity coefficients all three models produce similar equilibrium species compositions in the present climate. In a changed climate the results suggest that central European forests at high altitudes are more susceptible to temperature changes and that lower forests are more susceptible to precipitation changes. However, some models produce a markedly differing behaviour in a changed climate. Hence, contrary to wide-held expectations, this type of models needs to be thoroughly revised before forest gap models may be applied to assess in details the impacts of climatic change impacts on forests.
Publications 1 - 10 of 33