| 1. |
- Larson, Magnus, et al.
(författare)
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Analysis and modeling of field data on coastal morphological evolution over yearly and decadal time scales. Part 1: Background and linear techniques
- 2003
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Ingår i: Journal of Coastal Research. - 0749-0208. ; 19:4, s. 760-775
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Tidskriftsartikel (refereegranskat)abstract
- A number of statistical techniques to analyze and model coastal morphological evolution over yearly and decadal (i.e., long-term) time scales based on field data are presented. After a general introduction to long-term morphological modeling, mainly linear methods are discussed, whereas nonlinear methods are treated in a companion paper (SOUTHGATE et al., 2001). The theoretical background to the methods introduced is summarized and examples of field applications are given to illustrate each method. High-quality field data sets from different sites in the world, including Germany, The Netherlands, and United States, were employed in these examples. The analysis and modeling techniques used encompassed bulk statistics (mean, standard deviation, correlation etc), random sine functions, empirical orthogonal functions, canonical correlation analysis, and principal oscillation pattern analysis. Besides an evaluation of how suitable respective technique is for analyzing and modeling long-term morphological evolution, some general observations are presented regarding scales of morphological response as derived from the field applications. Data describing the evolution of both natural and anthropogenically affected coastal systems were studied. All methods investigated proved their usefulness for extracting characteristics of long-term morphological evolution, as well as for modeling this evolution, when applied under the right circumstances. However, more sophisticated techniques rely on more data in time and space, which is typically the limiting factor in the application of statistical methods as those presented here.
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| 2. |
- Capobianco, M, et al.
(författare)
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Nourishment design and evaluation: applicability of model concepts
- 2002
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Ingår i: Coastal Engineering. - 0378-3839. ; 47:2, s. 113-135
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Tidskriftsartikel (refereegranskat)abstract
- Models can play a fundamental role while moving from nourishment projects to nourishment plans, i.e., when nourishment becomes an integral component of a coastal management strategy. Planning nourishment in the context of a multi-years management strategy requires more significant prediction skills than available in the past and an awareness of dealing with uncertainty. The present paper introduces model classes and modelling situations and describes those elements that are the main sources of such uncertainty. Equilibrium Profile (EP) and Depth of Closure (DoC) are discussed with their time-scale related aspects; granulometry changes are discussed with their effects on the dynamics of a nourished coast; estimation of erosion rate is introduced with its implications on the definition of the "basic state" or the "basic trend" of the coastal system; lateral spreading and beach fill transition are discussed with their economic implications; and calibration and verification are introduced with the additional degrees of freedom that might be added to model development and with reference to risk issues in decision-making. These sources of uncertainty are examined in relation with implications for nourishment and modelling. The main conclusion is that, while there have been significant advances in modelling morphodynamics and morphodynamics applied to nourishment design, advances in defining procedures for quality control of the modelling activity are now required. (C) 2002 Published by Elsevier Science B.V.
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| 3. |
- Hanson, Hans, et al.
(författare)
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Modelling of coastal evolution on yearly to decadal time scales
- 2003
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Ingår i: Journal of Coastal Research. - 0749-0208. ; 19:4, s. 790-811
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Tidskriftsartikel (refereegranskat)abstract
- There is still no universal model for analysing and predicting coastal evolution and its governing processes on yearly to decadal time scales. Instead, depending on the nature of the problem and project objectives, there is a wide range of models available, each focusing on the problem complex from a specific standpoint. The present paper gives an overview of available numerical model types. A differentiation is made between equilibrium and non-equilibrium model types as well as between longshore uniform and non-longshore uniform model types. These models are discussed in terms of their general assumptions, approaches, and applicability. Most of the model descriptions are supplemented by an illustrative example. In addition, generic issues, such as level of knowledge on different scales, selection of model type on the basis of the nature of the application, the concept of equilibrium, model validation and utilisation are discussed.
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| 4. |
- Stive, MJF, et al.
(författare)
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Variability of shore and shoreline evolution
- 2002
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Ingår i: Coastal Engineering. - 0378-3839. ; 47:2, s. 211-235
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Tidskriftsartikel (refereegranskat)abstract
- Shore and shoreline evolution both due to natural and human-induced causes or factors can be variable over a wide range of different temporal and/or spatial scales. Our capability to understand and especially predict this variability is still limited. This can lead to misinterpretation of coastal change information, which hampers informed decision making and the subsequent design and implementation of (soft) engineering interventions. Collecting and describing example observations of shore and shoreline variability is one way to support and improve such human intervention. This paper describes causes and factors for the variability and the resulting possible evolutions of wave-dominated shores and shorelines, which are illustrated by a number of case studies. The new element of this work is that the variability is described in terms of a range of different time and space scales, which helps to structure such analysis. However, it is difficult to generalise the results for arbitrary situations, especially on decadal time scales. Scientific and engineering improvements require more quantitative insight into the physical mechanisms behind the free and forced shore behaviour responsible for the variability. (C) 2002 Elsevier Science B.V All rights reserved.
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