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Ajouter le résultat dans votre panier Affiner la recherche Interroger des sources externesEstimating sea floor dynamics in the southern North Sea to improve bathymetric survey planning / L. Dorst (2009)
Titre : Estimating sea floor dynamics in the southern North Sea to improve bathymetric survey planning Type de document : Thèse/HDR Auteurs : L. Dorst, Auteur Editeur : Delft : Netherlands Geodetic Commission NGC Année de publication : 2009 Collection : Netherlands Geodetic Commission Publications on Geodesy, ISSN 0165-1706 num. 69 Importance : 220 p. Format : 17 x 24 cm ISBN/ISSN/EAN : 978-90-6132-311-2 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bathymétrie
[Termes IGN] bathymétrie
[Termes IGN] covariance
[Termes IGN] déformation de la croute terrestre
[Termes IGN] fond marin
[Termes IGN] géodynamique
[Termes IGN] géostatistique
[Termes IGN] interpolation
[Termes IGN] krigeage
[Termes IGN] marée océanique
[Termes IGN] morphogenèse
[Termes IGN] nivellement indirect
[Termes IGN] Nord, mer du
[Termes IGN] océanographie dynamique
[Termes IGN] port
[Termes IGN] relèvement
[Termes IGN] Rotterdam (Pays-Bas)
[Termes IGN] sable
[Termes IGN] vagueIndex. décimale : 32.10 Bathymétrie Résumé : (Auteur) Safe nautical charts require a carefully designed bathymetric survey policy, especially in shallow sandy seas that potentially have dynamic sea floor patterns. Bathymetric resurveying at sea is a costly process with limited resources, though. A pattern on the sea floor known as tidal sand waves is clearly present in bathymetric surveys, endangering navigation in the Southern North Sea because of the potential dynamics of this pattern. An important factor in an efficient resurvey policy is the type and size of sea floor dynamics. The uncertainties of measurement and interpolation associated with the depth values enable the statistical processing of a time series of surveys, using deformation analysis. Currently, there is no procedure available that satisfies the Royal Netherlands Navy requirements. Therefore, a deformation analysis procedure is designed, implemented and tested in such a way that the procedure works on bathymetric data and satisfies the Royal Netherlands Navy requirements. Also, it is necessary to develop a procedure that translates the results into changes of the resurvey policy, taking into account their confidence intervals.
To describe the sea floor statistically, we assume the sea floor to consist of a spatial trend function (or characterization) and a residual function (or dispersion). Such a description is called a representation. The covariances between positions are expressed in a covariance function, based on the residual function. The covariance function is used by Kriging, an interpolation procedure that propagates the variances and covariances of the data points to variances of the interpolated values. This approach is used widely for spatial analyses, like the interpolation of a bathymetric data set.
The method that we propose uses Kriging to produce a time series of grids of depth values and their variances. Subsequently, it uses deformation analysis, a statistical procedure based on testing theory. Our application of deformation analysis is particularly aimed at the detection of dynamics in areas with tidal sand waves, resulting in parameter estimates for the sea floor dynamics, and their uncertainty. We apply the method to sea floor representations both with and without a sand wave pattern. A test scenario is set up, consisting of a survey of an existing area in the Southern North Sea, for which dynamics are simulated. The results show that the proposed method detects different types of sea floor dynamics well, leading to satisfactory estimates of the corresponding parameters.
We show results for the anchorage area Maas West near the Port of Rotterdam, the Netherlands first. The area is divided into 18 sub-areas. The results show that a sand wave pattern is detected for most of the sub-areas, and a shore-ward migration is detected for a majority of them. The estimated migration rates of the sand waves are up to 7.5 m/yr, with a 95% confidence interval that depends on the regularity of the pattern. The results are in confirmation with previously observed migration rates for the Southern North Sea, and with an idealized process-based model.
Thereafter, we analyze several other areas for which a time series of surveys is available in the bathymetric, archives of the Netherlands Hydrographic Service, to study the spatial variations in sea floor dynamics. We present results for several sand wave areas and a single flat area. In some of those areas, dredging takes place, to guarantee minimum depths. The results indicate sand wave migration in areas close to the coast, and bed level changes of the order of decimeters. The dominant wavelength of the sand waves varies. We compare our results to literature of the same sand wave areas, in which we find similar migration rates, and different wavelengths.
By formulating four indicators, recommendations are made for the resurvey policy on the Belgian and Netherlands Continental Shelf. These indicators follow from the estimates for sea floor dynamics. We present a concept for the shallowest likely depth surface, on which we base two of the indicators. The other two indicators act as a warning: they quantify the potentially missed dynamics, which makes the procedure more robust in case of complicated morphology. We show clear differences in recommended resurvey frequency between the five analyzed regions.
We conclude that the designed method is able to use a time series of bathy-metric surveys for the estimation of sea floor dynamics in a satisfactory way. Those dynamics may be present on the scale of the sea floor, it may be a local effect, or it may be due to a tidal sand wave pattern. Also, the results are successfully reduced to a set of four indicators, used to improve a resurvey policy. Based on these conclusions, we formulate recommendations on the extrapolation of the results in space and time, on potential adaptations to the designed procedure, and on implementation of the procedure.Note de contenu : Preface
1 Introduction
1.1 Nautical charting
1.2 Survey plan design
1.3 Detection of sea floor dynamics
1.4 Tidal sand waves
1.5 The uncertainty of depth measurements
1.6 Problem formulation
1.7 Research question and subquestions
1.8 Research strategy and outline
2 Bathymetric applications of Geostatistics
2.1 Introduction
2.2 Depth as a trend and its residuals
2.3 Covariance functions
2.4 Kriging
2.5 Conclusion
3 Estimating sea floor dynamics
3.1 Introduction
3.2 The method for the estimation of sea floor dynamics
3.3 Specification of a test scenario
3.4 Analysis results of a dynamic sea floor
3.5 Discussion
3.6 Conclusion
3.A Error characteristics
3.B Transformation of the sand wave parameters
3.C The application of statistical estimation and testing
4 The analysis of migrating tidal sand waves
4.1 Introduction
4.2 The application of deformation analysis
4.3 Results of the deformation analysis
4.4 Discussion of results
4.5 Conclusion
4.A Overview of used surveys
4.B Quantification of measurement errors
4.B.1 Covariance function of the error
4.B.2 Variances of the SEES surveys
4.B.3 Variances of the MBES survey
5 Spatial variations in sea floor dynamics
5.1 Introduction
5.2 Deformation analysis
5.3 The Selected Track region: little dynamics
5.4 The Noordhinder region: comparison with other methods
5.5 The region West of IJmuiden: sand wave migration
5.6 The region North of Terschelling: a flat sea floor
5.7 Discussion
5.8 Conclusion
5.A Overview of used surveys
6 Application to the resurvey policy
6.1 Introduction
6.2 Background: Hydrographic practice
6.3 Method: indicators of sea floor dynamicsNuméro de notice : 15495 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : sans Accessibilité hors numérique : Non accessible via le SUDOC En ligne : https://www.ncgeo.nl/downloads/69Dorst.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62737 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 15495-01 32.10 Livre Centre de documentation Topographie Disponible
Titre : Levés bathymétriques Type de document : Guide/Manuel Auteurs : Service de la photogrammetrie, Auteur Editeur : Paris : Institut Géographique National - IGN (1940-2007) Année de publication : 1984 Importance : 15 p. Format : 21 x 30 cm Langues : Français (fre) Descripteur : [Vedettes matières IGN] Bathymétrie
[Termes IGN] lever bathymétrique
[Termes IGN] profil bathymétriqueIndex. décimale : 32.10 Bathymétrie Numéro de notice : 55450 Affiliation des auteurs : IGN (1940-2011) Thématique : POSITIONNEMENT Nature : Manuel Accessibilité hors numérique : Non accessible via le SUDOC Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=52015
Titre : Seetiefenmessung mit einem LIDAR-System. Möglichkeiten und Grenzen, Dargestellt an verschiedenen Modellfällen Titre original : [Sondage de mer avec un système lidar : Possibilités et limites, représentation de différents pièges de modèles] Type de document : Thèse/HDR Auteurs : T. Lange, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1972 Collection : DGK - C Sous-collection : Dissertationen num. 179 Importance : 115 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Bathymétrie
[Termes IGN] bathymétrie laserIndex. décimale : 32.10 Bathymétrie Numéro de notice : 48492 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Accessibilité hors numérique : Non accessible via le SUDOC Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=64001 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 48492-01 32.10 Livre Centre de documentation Topographie Disponible
