Détail de l'auteur
Auteur C.K. Shum |
Documents disponibles écrits par cet auteur (4)
Ajouter le résultat dans votre panier Affiner la recherche Interroger des sources externes
The ambiguous sea level rise at Brest’s 212 yearlong record elucidated / Huseyin Baki Iz in Journal of geodetic science, vol 11 n° 1 (January 2021)
[article]
Titre : The ambiguous sea level rise at Brest’s 212 yearlong record elucidated Type de document : Article/Communication Auteurs : Huseyin Baki Iz, Auteur ; C.K. Shum, Auteur Année de publication : 2021 Article en page(s) : pp 95 - 101 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse diachronique
[Termes IGN] Brest
[Termes IGN] changement climatique
[Termes IGN] données marégraphiques
[Termes IGN] marégraphe
[Termes IGN] montée du niveau de la mer
[Termes IGN] série temporelleRésumé : (auteur) The tide gauge record at Brest, France, along Eastern part of Atlantic coast is one of the longest records in Europe spanning 212 years (1807–2019). Analyzing these records has important ramifications in assessing anthropogenic impact of climate change at local and regional scales during this period. All the previous studies that analyzed Brest’s tide gauge record have used vaguely defined quadratics models and did not incorporate the effect of sea level variations at various frequencies, which confounded the presence or absence of a plausible uniform acceleration. Here, we entertained two competing kinematic models; one with a uniform acceleration representing 212 years of monthly averaged tide gauge data, the other is a two-phase trend model (Phase I is 93 years long and Phase II is 119 years long). Both models include statistically significant (α= 0.05) common periodic effects, and sub and super harmonics of luni-solar origin for representing monthly averaged sea level anomalies observed at Brest. The least squares statistics for both models’ solutions cannot distinguish one model over the other, like earlier studies. However, the assessment of Phase I segment of the records disclosed the absence of a statistically significant trend and a uniform acceleration during this period. This outcome eliminates conclusively the occurrence of a uniform acceleration during the entire 212-year data span of the tide gauge record at Brest, favoring the two-phase trend model as a sound alternative. Numéro de notice : A2021-981 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jogs-2020-0124 Date de publication en ligne : 20/09/2021 En ligne : https://doi.org/10.1515/jogs-2020-0124 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100978
in Journal of geodetic science > vol 11 n° 1 (January 2021) . - pp 95 - 101[article]The certitude of a global sea level acceleration during the satellite altimeter era / Huseyin Baki Iz in Journal of geodetic science, vol 10 n° 1 (January 2020)
[article]
Titre : The certitude of a global sea level acceleration during the satellite altimeter era Type de document : Article/Communication Auteurs : Huseyin Baki Iz, Auteur ; C.K. Shum, Auteur Année de publication : 2020 Article en page(s) : pp 29 - 40 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Océanographie
[Termes IGN] données altimétriques
[Termes IGN] matrice de covariance
[Termes IGN] montée du niveau de la mer
[Termes IGN] niveau moyen des mers
[Termes IGN] positionnement cinématique
[Termes IGN] série temporelleRésumé : (auteur) Recent studies reported a uniform global sea level acceleration during the satellite altimetry era (1993–2017) by analyzing globally averaged satellite altimetry measurements. Here, we discuss potential omission errors that were not thoroughly addressed in detecting and estimating the reported global sea level acceleration in these studies. Our analyses results demonstrate that the declared acceleration in recent studies can also be explained equally well by alternative kinematic models based on previously well-established multi-decadal global mean sea level variations of various origins, which suggests prudence before declaring the presence of an accelerating global mean sea level with confidence during the satellite altimetry era. Numéro de notice : A2020-422 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jogs-2020-0101 Date de publication en ligne : 29/05/2020 En ligne : https://doi.org/10.1515/jogs-2020-0101 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95483
in Journal of geodetic science > vol 10 n° 1 (January 2020) . - pp 29 - 40[article]Triangulated spherical splines for geopotential reconstruction / M.J. Lai in Journal of geodesy, vol 83 n° 8 (August 2009)
[article]
Titre : Triangulated spherical splines for geopotential reconstruction Type de document : Article/Communication Auteurs : M.J. Lai, Auteur ; C.K. Shum, Auteur ; V. Baramidze, Auteur ; P. Wenston, Auteur Année de publication : 2009 Article en page(s) : pp 695 - 708 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur local
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] Earth Gravity Model 1996
[Termes IGN] équation de Laplace
[Termes IGN] fonction spline
[Termes IGN] fonction spline d'interpolation
[Termes IGN] modèle de géopotentiel
[Termes IGN] potentiel de pesanteur terrestreRésumé : (Auteur) We present an alternate mathematical technique than contemporary spherical harmonics to approximate the geopotential based on triangulated spherical spline functions, which are smooth piecewise spherical harmonic polynomials over spherical triangulations. The new method is capable of multi-spatial resolution modeling and could thus enhance spatial resolutions for regional gravity field inversion using data from space gravimetry missions such as CHAMP, GRACE or GOCE. First, we propose to use the minimal energy spherical spline interpolation to find a good approximation of the geopotential at the orbital altitude of the satellite. Then we explain how to solve Laplace’s equation on the Earth’s exterior to compute a spherical spline to approximate the geopotential at the Earth’s surface. We propose a domain decomposition technique, which can compute an approximation of the minimal energy spherical spline interpolation on the orbital altitude and a multiple star technique to compute the spherical spline approximation by the collocation method. We prove that the spherical spline constructed by means of the domain decomposition technique converges to the minimal energy spline interpolation. We also prove that the modeled spline geopotential is continuous from the satellite altitude down to the Earth’s surface. We have implemented the two computational algorithms and applied them in a numerical experiment using simulated CHAMP geopotential observations computed at satellite altitude (450 km) assuming EGM96 (n max = 90) is the truth model. We then validate our approach by comparing the computed geopotential values using the resulting spherical spline model down to the Earth’s surface, with the truth EGM96 values over several study regions. Our numerical evidence demonstrates that the algorithms produce a viable alternative of regional gravity field solution potentially exploiting the full accuracy of data from space gravimetry missions. The major advantage of our method is that it allows us to compute the geopotential over the regions of interest as well as enhancing the spatial resolution commensurable with the characteristics of satellite coverage, which could not be done using a global spherical harmonic representation. Copyright Springer Numéro de notice : A2009-323 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-008-0283-0 En ligne : https://doi.org/10.1007/s00190-008-0283-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29953
in Journal of geodesy > vol 83 n° 8 (August 2009) . - pp 695 - 708[article]Réservation
Réserver ce documentExemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 266-09071 SL Revue Centre de documentation Revues en salle Disponible
Titre : Satellite Altimetry for geodesy, geophysics and oceanography : Proceedings of the International Workshop on satellite altimetry, a joint workshop of IAG section 3 Special study group SSG3.186 and IAG section 2, September 8-13, 2002, Wuhan, China Type de document : Actes de congrès Auteurs : C. Hwang, Éditeur scientifique ; C.K. Shum, Éditeur scientifique ; J. Li, Éditeur scientifique Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2004 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 126 Conférence : IAG 2002, International Workshop on satellite altimetry, a joint workshop of IAG section 3 Special study group SSG3.186 and IAG section 2, Satellite Altimetry for geodesy, geophysics and oceanography 13/08/2002 Wuhan Chine Importance : 280 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 3-540-420211-0 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] altimétrie satellitaire par radar
[Termes IGN] circulation océanique
[Termes IGN] géodésie spatiale
[Termes IGN] géophysique
[Termes IGN] océanographie spatialeRésumé : (Editeur) This volume covers a broad range of altimetry applications, including marine gravity and geoïd, sea level change, ocean tide modeling, ocean circulations, marine plate tectonics, mesoscale eddies and bathymetry predictions. Virtually all disciplines of earth sciences are touched upon through the technique of satellite altimetry. Readers will find useful data processing techniques and movel applications of satellite altimetry, which otherwise are scattered in journals and special books. Note de contenu : KEYNOTE SPEECHES
Geodetic Applications of Satellite Altimetry
Present-day Sea Level Rise : from Satellite and in Situ Observations to Physical Causes
Advances in Large-scale Ocean Dynamics from a Decade of Satellite Altimetric Measurement of Ocean Surface Topography
GEODETIC APPLICATIONS
Calibration Results of GFO
Determination of 30'x 30'Marine Gravity Anomalies from Multisatellite Altimetry
Recovering Deflections of Vertical from Tangent Plane of Gridded Geoidal Heights from Altimetry
Marine Gravity Anomaly from Satellite Altimetry: a Comparison of Methods over Shallow Waters
Enhanced Free6air Gravity Anomalies by Satellite Radar Altimetry
Topex Altimetric Mean Sea Level and Gravimetric Geoid in the North of Algeria
A Modified Method for Recovering Bathymetry from Altimeter Data
Absolute Calibration of the ERS-2 Altimeter using UK Tide Gauges
An Intercomparison of Parametric Models of Sea State Bias for the TOPEX,Poseidon and Jason- I Altimeters
Determination of Global Mean Sea Surface Using Multi-satellite Altimetric Data
Pseudo-Harmonic Representation of Gravity Field over South China Sea
GEOPHYSICAL AND OCEANOGRAPHIC APPLICATIONS
Investigation of Hydrological and Atmospheric Loading by Space Geodetic Techniques
Joint Application of Altimeter Data and EGM96 to Submarine Tectonic and Geodynamic Study in West Pacific
Bathymetry and Crustal Thickness Variations from Gravity Inversion and Flexural Isostasy.
Comparisons of Three Inversion Approaches for Recovering Gravity Anomalies From Altimeter Data
Accuracy Assessment of Gravity Field Models by Independent Satellite Crossover Altimetry
Low Frequency Change of Sea Level in the North Atlantic Ocean as Observed with Satellite Altimetry
Application of Satellite Remote Sensing on the Tuna Fishery of Eastern - Tropical Pacific
The Kinematics of Mesoscale Eddies from TOPEX/POSEIDON Altimetry over the Subtropical Counter Current
OCEANOGRAPHIC APPLICATIONS
Oceanography with GPS
Geostrophic Uncertainty and Anomalous Current Structure in Association.with Mesoscale Eddies Delineated by Altimeter Observations East of Taiwan
Current Variability over the Scotian Slope in the 1990s
Determination of Sea Level Height Variation by Dynamics Crossover Adjustment
Extreme Southern Ocean Tide Modeling
The M4 Shallow Water Tidal Constituent From Altimetry and Tide Gauges
Harmonic Tidal Analysis Along T/P Tracks in China Seas and Vicinity
Analysis of Temporal Sea Level Variation in the Barents and the White Seas from Altimetry, Tide Gauges and Hydrodynamic Simulation
The Envisat Radar Altimeter System
Absolute Comparison of Satellite Altimetry and Tide Gauge Registrations in Venezuela
Sea Level Changes Detected by Using Satellite Altimeter Data and Comparing with Tide Gauge Records in China SeaNuméro de notice : 18912 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Actes DOI : 10.1007/978-3-642-18861-9 En ligne : https://doi.org/10.1007/978-3-642-18861-9 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=34884 Réservation
Réserver ce documentExemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 18912-01 CG2002 Livre Centre de documentation Congrès Disponible