Reachable Futures, Structural Change, and the Practical Credibility of Environmental Simulation Models

Reachable Futures, Structural Change, and the Practical Credibility of Environmental Simulation Models PDF

Author: Olufemi O. Osidele

Publisher: Universal-Publishers

Published: 2002-03

Total Pages: 219

ISBN-13: 1581121474

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Simulation modeling is arguably the most versatile scientific tool for predicting the future environment. However, the reliability of model-based predictions is limited to the behavior domain defined by the historical data employed for conceptualizing and calibrating the model. Future changes in external inputs and internal structure tend to produce system behavior significantly different from prior predictions. To abate this seeming lack of credibility, it is now customary to qualify model predictions with uncertainty estimates. This dissertation explores the complementary approach of back-casting future scenarios. Centered on the analysis of uncertainty, a methodological framework is developed for the computational evaluation of environmental futures, driven by stakeholder participation as a means for establishing credibility in the model. The analysis reveals possible structural change between the observed past and speculated future scenarios by comparing the ranking of key sources of uncertainty in model outputs. Three sampling-based methods are employed: Regionalized Sensitivity Analysis (RSA), Tree-Structured Density Estimation (TSDE), and Uniform Covering by Probabilistic Rejection (UCPR). RSA and TSDE are tested for identifying and ranking the key factors that influence ecological behavior in Lake Oglethorpe, Georgia, and UCPR, for recovering parameters of a rainfall-runoff model of an experimental watershed near Loch Ard, Scotland. The framework is applied to an integrated assessment of ecological behavior in Lake Lanier, Georgia. Stakeholders' fears and desires for the future state of the reservoir are elicited and encoded for analysis. The results indicate: (i) that the desired future is more reachable, and accompanied by more significant structural change, than the feared future, and (ii) that sediment-water-nutrient interactions, secondary production, and microbial processes play a critical role in the future ecological behavior of the reservoir. Thus, it is possible to: (i) confirm or refute stakeholder concerns for the future environment, (ii) inform priorities for future environmental policy actions, (iii) identify critical gaps in current knowledge, in order to prioritize future scientific research, and (iv) promote adaptive community learning, through the continual mutual feedback between scenario-generation and systematic analysis. By bridging the gap between stakeholder imagination and scientific theory, through computational analysis, the framework provides a promising direction for integrated environmental assessment.

Sensitivity Analysis in Practice

Sensitivity Analysis in Practice PDF

Author: Andrea Saltelli

Publisher: John Wiley & Sons

Published: 2004-07-16

Total Pages: 232

ISBN-13: 047087094X

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Sensitivity analysis should be considered a pre-requisite for statistical model building in any scientific discipline where modelling takes place. For a non-expert, choosing the method of analysis for their model is complex, and depends on a number of factors. This book guides the non-expert through their problem in order to enable them to choose and apply the most appropriate method. It offers a review of the state-of-the-art in sensitivity analysis, and is suitable for a wide range of practitioners. It is focussed on the use of SIMLAB – a widely distributed freely-available sensitivity analysis software package developed by the authors – for solving problems in sensitivity analysis of statistical models. Other key features: Provides an accessible overview of the current most widely used methods for sensitivity analysis. Opens with a detailed worked example to explain the motivation behind the book. Includes a range of examples to help illustrate the concepts discussed. Focuses on implementation of the methods in the software SIMLAB - a freely-available sensitivity analysis software package developed by the authors. Contains a large number of references to sources for further reading. Authored by the leading authorities on sensitivity analysis.

Environmental Foresight and Models

Environmental Foresight and Models PDF

Author: M.B. Beck

Publisher: Elsevier

Published: 2002-03-20

Total Pages: 490

ISBN-13: 0080531067

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Policy-makers and the public, it has famously been said, are more interested in the possibility of non-linear dislocations and surprises in the behaviour of the environment than in smooth extrapolations of current trends. The International Task Force in Forecasting Environmental Change (1993-1998) dedicated its work to developing procedures of model building capable of addressing our palpable concerns for substantial change in the future. This volume discusses the immense challenges that such structural change presents - that the behaviour of the environment may become radically different from that observed in the past - and investigates the potentially profound implications for model development. Drawing upon case histories from the Great Lakes, acidic atmospheric deposition and, among others, the urban ozone problem, this discourse responds to a new agenda of questions. For example: "What system of 'radar' might we design to detect threats to the environment lying just beyond the 'horizon'?" and "Are the seeds of structural change identifiable within the record of the recent past?" Meticulously researched by leading environmental modellers, this milestone volume engages vigorously with its subject and offers an animated account of how models can begin to take into consideration the significant threats and uncertainties posed by structural change.

Environmental Modelling

Environmental Modelling PDF

Author: Keith Beven

Publisher: CRC Press

Published: 2018-09-03

Total Pages: 329

ISBN-13: 1482288575

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Uncertainty in the predictions of science when applied to the environment is an issue of great current relevance in relation to the impacts of climate change, protecting against natural and man-made disasters, pollutant transport and sustainable resource management. However, it is often ignored both by scientists and decision makers, or interpreted as a conflict or disagreement between scientists. This is not necessarily the case, the scientists might well agree, but their predictions would still be uncertain and knowledge of that uncertainty might be important in decision making. Environmental Modelling: An Uncertain Future? introduces students, scientists and decision makers to: the different concepts and techniques of uncertainty estimation in environmental prediction the philosophical background to different concepts of uncertainty the constraint of uncertainties by the collection of observations and data assimilation in real-time forecasting techniques for decision making under uncertainty. This book will be relevant to environmental modellers, practitioners and decision makers in hydrology, hydraulics, ecology, meteorology and oceanography, geomorphology, geochemistry, soil science, pollutant transport and climate change. A companion website for the book can be found at www.uncertain-future.org.uk

Advancing Land Change Modeling

Advancing Land Change Modeling PDF

Author: National Research Council

Publisher: National Academies Press

Published: 2014-03-31

Total Pages: 267

ISBN-13: 0309288363

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People are constantly changing the land surface through construction, agriculture, energy production, and other activities. Changes both in how land is used by people (land use) and in the vegetation, rock, buildings, and other physical material that cover the Earth's surface (land cover) can be described and future land change can be projected using land-change models (LCMs). LCMs are a key means for understanding how humans are reshaping the Earth's surface in the past and present, for forecasting future landscape conditions, and for developing policies to manage our use of resources and the environment at scales ranging from an individual parcel of land in a city to vast expanses of forests around the world. Advancing Land Change Modeling: Opportunities and Research Requirements describes various LCM approaches, suggests guidance for their appropriate application, and makes recommendations to improve the integration of observation strategies into the models. This report provides a summary and evaluation of several modeling approaches, and their theoretical and empirical underpinnings, relative to complex land-change dynamics and processes, and identifies several opportunities for further advancing the science, data, and cyberinfrastructure involved in the LCM enterprise. Because of the numerous models available, the report focuses on describing the categories of approaches used along with selected examples, rather than providing a review of specific models. Additionally, because all modeling approaches have relative strengths and weaknesses, the report compares these relative to different purposes. Advancing Land Change Modeling's recommendations for assessment of future data and research needs will enable model outputs to better assist the science, policy, and decisionsupport communities.

Biomedical Image Synthesis and Simulation

Biomedical Image Synthesis and Simulation PDF

Author: Ninon Burgos

Publisher: Academic Press

Published: 2022-06-18

Total Pages: 676

ISBN-13: 0128243503

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Biomedical Image Synthesis and Simulation: Methods and Applications presents the basic concepts and applications in image-based simulation and synthesis used in medical and biomedical imaging. The first part of the book introduces and describes the simulation and synthesis methods that were developed and successfully used within the last twenty years, from parametric to deep generative models. The second part gives examples of successful applications of these methods. Both parts together form a book that gives the reader insight into the technical background of image synthesis and how it is used, in the particular disciplines of medical and biomedical imaging. The book ends with several perspectives on the best practices to adopt when validating image synthesis approaches, the crucial role that uncertainty quantification plays in medical image synthesis, and research directions that should be worth exploring in the future. Gives state-of-the-art methods in (bio)medical image synthesis Explains the principles (background) of image synthesis methods Presents the main applications of biomedical image synthesis methods

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