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Big scanning on a small scale / Stephen Richardson in GEO: Geoconnexion international, vol 13 n° 6 (june 2014)
[article]
Titre : Big scanning on a small scale Type de document : Article/Communication Auteurs : Stephen Richardson, Auteur Année de publication : 2014 Article en page(s) : pp 26 - 28 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] balayage laser
[Termes IGN] courant marin
[Termes IGN] érosion hydrique
[Termes IGN] littoral
[Termes IGN] petite échelle
[Termes IGN] vagueRésumé : (Auteur) Understanding the way that waves, currents and sediments interact with coastal structures, and the potential impact they can have, is far from simple. Stephen Richardson explains how 3D laser scanners are helping to improve the design of these structures and how use of this technology on a small scale can deliver big benefits. Numéro de notice : A2014-305 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33208
in GEO: Geoconnexion international > vol 13 n° 6 (june 2014) . - pp 26 - 28[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 062-2014061 SL Revue Centre de documentation Revues en salle Disponible Comparison of grid averaged altimeter and buoy significant wave heights in the Northern Indian Ocean / L. Sabique in Marine geodesy, vol 36 n° 1 (January - March 2013)
[article]
Titre : Comparison of grid averaged altimeter and buoy significant wave heights in the Northern Indian Ocean Type de document : Article/Communication Auteurs : L. Sabique, Auteur ; T. Balakrishnan Nair, Auteur ; K. Srinivas, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 72 - 85 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] altimétrie satellitaire par radar
[Termes IGN] analyse diachronique
[Termes IGN] AVISO
[Termes IGN] bouée
[Termes IGN] bouée dérivante
[Termes IGN] cyclone
[Termes IGN] hauteurs de mer
[Termes IGN] Indien (océan)
[Termes IGN] série temporelle
[Termes IGN] vagueRésumé : (Auteur) A quantitative comparison of the collocated inter-annual significant wave height (SWH) data collected between 2006 and 2009 from buoys and altimeters at nine buoy locations (total n = 2241) in the Northern Indian Ocean is attempted for assessing the validity of daily averaged gridded altimeter significant wave height (ASWH) provided by AVISO for operational use. ASWH is underestimated by 0.20 m, the root-mean-square error (RMSE) is less than 0.30 m, the Scatter Index is less than 20%, and the correlation coefficient is greater than 0.90. Further, at three locations, the examination of the above statistics showed that the bias and RMSE is high during the southwest monsoon season compared with the Northeast monsoon. Scatter Index showed only slight variation (14–18%) for different ranges of SWH. The response of the daily average gridded ASWH data during extreme conditions (cyclones) in the vicinity of the buoy locations is poor at all compared buoy locations. The gridded ASWH from different satellite missions provided by AVISO can be used for basin scale validation experiments of the wave model and for climatological studies in the Indian Ocean, except during cyclone conditions. Numéro de notice : A2013-246 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/01490419.2012.743493 Date de publication en ligne : 13/03/2013 En ligne : https://doi.org/10.1080/01490419.2012.743493 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32384
in Marine geodesy > vol 36 n° 1 (January - March 2013) . - pp 72 - 85[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 230-2013011 RAB Revue Centre de documentation En réserve L003 Disponible Estimating 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 française DOI : sans En ligne : https://www.ncgeo.nl/index.php/en/publicatiesgb/publications-on-geodesy/item/258 [...] Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62737 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 15495-01 32.10 Livre Centre de documentation Topographie Disponible Mapping of river surface currents with GNSS / J. Bancroft in Geomatica, vol 62 n° 3 (September 2008)
[article]
Titre : Mapping of river surface currents with GNSS Type de document : Article/Communication Auteurs : J. Bancroft, Auteur ; S. Kwakkel, Auteur ; B. Troyer, Auteur ; Gérard Lachapelle, Auteur Année de publication : 2008 Article en page(s) : pp 267 - 276 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Alberta (Canada)
[Termes IGN] courant fluvial
[Termes IGN] cours d'eau
[Termes IGN] double différence
[Termes IGN] GPS en mode différentiel
[Termes IGN] hydrodynamique
[Termes IGN] mesurage de phase
[Termes IGN] phase GPS
[Termes IGN] positionnement par GNSS
[Termes IGN] précision centimétrique
[Termes IGN] rivière
[Termes IGN] vague
[Termes IGN] vitesseRésumé : (Auteur) L'information sur les canaux à surface libre, comme les rivières et les autres voies navigables, devient déplus en plus intéressante avec l'adoption de technologies qui donnent des données plus fiables, précises et complètes, tout en augmentant les conditions de sécurité dans lesquelles les données sur les rivières sont recueillies. Les systèmes mondiaux de navigation par satellite peuvent offrir une exactitude de l'ordre du centimètre et peuvent être utilisés dans une variété de scénarios pour canaux ouverts. Deux rivières du sud de l'Alberta ont fait l'objet de levés à l'aide de mesures des doubles différences de phase de la porteuse pour déterminer les courants de surface ainsi que les dynamiques de la trajectoire et du débit. Les formes des vagues ont été mesurées à mieux qu'un centimètre près et les vélocités ont été mesurées avec une précision de quelques centimètres par seconde. Les données sont traitées en précision d'une interprétation d'utilisateur non technique afin d'optimiser l'utilité des données et de fournir un modèle avec lequel les gestionnaires des rivières peuvent travailler. Copyright Geomatica Numéro de notice : A2008-447 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.5623/geomat-2008-0031 En ligne : https://cdnsciencepub.com/doi/abs/10.5623/geomat-2008-0031 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29516
in Geomatica > vol 62 n° 3 (September 2008) . - pp 267 - 276[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 035-08031 RAB Revue Centre de documentation En réserve L003 Disponible GIS modeling of wave exposure at the seabed: a depth-attenuated wave exposure model / T. Bekkby in Marine geodesy, vol 31 n° 2 (June - September 2008)
[article]
Titre : GIS modeling of wave exposure at the seabed: a depth-attenuated wave exposure model Type de document : Article/Communication Auteurs : T. Bekkby, Auteur ; E. Isachsen, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : pp 117 - 127 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG
[Termes IGN] eaux côtières
[Termes IGN] faune aquatique
[Termes IGN] modèle océanographique
[Termes IGN] océanographie spatiale
[Termes IGN] profondeur
[Termes IGN] relief sous-marin
[Termes IGN] Stockholm (Suède)
[Termes IGN] substrat
[Termes IGN] système d'information géographique
[Termes IGN] vagueRésumé : (Auteur) Several studies have documented relationships between wave exposure and distribution, density, and size of marine species. Hence, this factor is at a high level in the hierarchical habitat classification system EUNIS and is one of the Water Framework Directive water typology criteria of coastal waters. Isaeligus (2004) has developed a continuous simplified wave model (SWM) that has been applied to several Nordic countries. Here we refine this model by introducing depth-attenuation, giving us the advantage of a model for wave exposure as it will actually work at the seabed. The values of the depth-attenuated model SWM(d) are approximately similar to the SWM model in shallow areas but noticeably lower in deep areas. The two models were compared in an analysis of the distribution of seabed substrate in the Stockholm archipelago. Using the depth-attenuated wave exposure instead of the SWM model as predictor in substrate modeling improved these models considerably. Copyright Taylor & Francis Numéro de notice : A2008-497 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/01490410802053674 En ligne : https://doi.org/10.1080/01490410802053674 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29566
in Marine geodesy > vol 31 n° 2 (June - September 2008) . - pp 117 - 127[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 230-08021 RAB Revue Centre de documentation En réserve L003 Disponible Estimation of storm surge in the bay of Bengal / John Fiske (2008)PermalinkA wavelet-based algorithm to estimate ocean wave parameters from radar images / A. Niedermeier in IEEE Transactions on geoscience and remote sensing, vol 43 n° 2 (February 2005)PermalinkGlobal structure of marine wind speed variability derived from Topex altimeter data / G. Chen in International Journal of Remote Sensing IJRS, vol 24 n° 24 (December 2003)PermalinkWind-directional effects on the hydrodynamic modulation of microwave radar images of ocean waves / F.J. Ocampo-Torres in International Journal of Remote Sensing IJRS, vol 10 n° 8 (August 1989)PermalinkIGARSS'88 remote sensing: Moving towards the 21st century: International Geosciences and remote sensing Symposium, Edinburgh (U.K.), 12-16 September 1988, 1. Volume 1 / T.D. Guyenne (1988)PermalinkRemote sensing of wave patterns with oceanographic implications / D. Sheres in International Journal of Remote Sensing IJRS, vol 8 n° 11 (November 1987)PermalinkContribution à l'étude des interactions entre hyperfréquences et champs d'ondes de surface / A. Lifermann (1987)PermalinkErrors in depth determination caused by waves in through-water photogrammetry / J.G. Fryer in Photogrammetric record, vol 11 n° 66 (October 1985 - March 1986)PermalinkTélédétection des vagues par radar HF / Philippe Forget (1983)PermalinkContribution expérimentale à l'interprétation des images de radar latéral en mer ; utilisation des données de scattermomètre sur plate-forme / D. De Staerke (1981)Permalink