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Geographic-dependent variational parameter estimation: A case study with a 2D ocean temperature model / Zhenyang Du in Journal of Marine Systems, vol 237 (January 2023)  

Public [article]  inJournal of Marine Systems > vol 237 (January 2023) Titre : Geographic-dependent variational parameter estimation: A case study with a 2D ocean temperature model Type de document : Article/Communication Auteurs : Zhenyang Du, Auteur ; Xuefeng Zhang, Auteur ; et al., Auteur Année de publication : 2023 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] assimilation des données [Termes IGN] estimation statistique [Termes IGN] modèle océanographique [Termes IGN] océanographie spatiale [Termes IGN] température de surface de la mer [Termes IGN] teneur en chaleur de l'océan Résumé : (auteur) Using observational information to tune uncertain physical parameters in an ocean model via a robust data assimilation method has great potential to reduce model bias and improve the quality of sea temperature analysis and prediction. However, how observational information should be used to optimize geographic-dependent parameters through four-dimensional variational (4DVAR) data assimilation, which is one of the most prevailing assimilation methods, has not been fully studied. In this study, a two-step 4DVAR method is proposed to enhance parameter correction when the assimilation model contains biased geographic-dependent parameters within a biased model framework. Here, the biased parameters are set to an oceanic eddy diffusion coefficient, Kv, that plays an important role in modulating synoptic, seasonal and long-term changes in ocean heat content. Within a twin assimilation experiment framework, the temperature “observations” generated from sampling a “truth” model are assimilated into a biased model to investigate to what extent Kv can be estimated using the 4DVAR method when Kv remains geographic-dependent. The results show that the geographic-dependent Kv distribution can be optimally estimated to further improve the sea temperature analysis performance compared with the state estimation only method. In addition, the model prediction performance is also discussed with optimally estimated parameters under various conditions of noisy and/or sparse ocean observations. These results provide some insights for the prediction of ocean temperature mixing and stratification in a 3D primitive ocean numerical model using 4DVAR data assimilation. Numéro de notice : A2023-080 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1016/j.jmarsys.2022.103824 En ligne : https://doi.org/10.1016/j.jmarsys.2022.103824 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102716 [article]

Evaluation of global ocean tide models based on tidal gravity observations in China / Hongbo Tan in Geodesy and Geodynamics, vol 12 n° 6 (November 2021)  

Public [article]  inGeodesy and Geodynamics > vol 12 n° 6 (November 2021) . - pp 451 - 458 Titre : Evaluation of global ocean tide models based on tidal gravity observations in China Type de document : Article/Communication Auteurs : Hongbo Tan, Auteur ; Olivier Francis, Auteur ; Guiju Wu, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : pp 451 - 458 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] Chine [Termes IGN] effet de charge [Termes IGN] marée océanique [Termes IGN] modèle océanographique [Termes IGN] surcharge océanique Résumé : (auteur) Previous studies show that the calculated loading effects from global ocean tide models do not match actual measurements of gravity attraction and loading effects in Southeast Asia. In this paper, taking advantage of a unique network of gravity tidal stations all over the Chinese mainland, we compare the observed and modeled tidal loading effects on the basis of the most recent global ocean tide models. The results show that the average efficiencies of the ocean tidal loading correction for O1, K1, M2 are 77%, 73% and 59%, respectively. The loading correction efficiencies using recent ocean tidal models are better than the 40 years old Schwiderskis model at coastal stations, but relative worse at stations far from ocean. Numéro de notice : A2021-885 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1016/j.geog.2021.08.001 Date de publication en ligne : 13/08/2021 En ligne : https://doi.org/10.1016/j.geog.2021.08.001 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99208 [article]

Assessment of mass-induced sea level variability in the Tropical Indian Ocean based on GRACE and altimeter observations / Shiva Shankar Manche in Journal of geodesy, vol 95 n° 2 (February 2021)  

Public [article]  inJournal of geodesy > vol 95 n° 2 (February 2021) . - n° 19 Titre : Assessment of mass-induced sea level variability in the Tropical Indian Ocean based on GRACE and altimeter observations Type de document : Article/Communication Auteurs : Shiva Shankar Manche, Auteur ; Rabindra K. Nayak, Auteur ; Prakash Chandra Mohanty, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : n° 19 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] analyse harmonique [Termes IGN] changement climatique [Termes IGN] données altimétriques [Termes IGN] données GRACE [Termes IGN] Indien (océan) [Termes IGN] masse d'eau [Termes IGN] modèle océanographique [Termes IGN] niveau de la mer [Termes IGN] surcharge océanique [Termes IGN] variabilité [Termes IGN] variation saisonnière Résumé : (auteur) Assessment of mass-induced sea level (MISL) variability in the Tropical Indian Ocean (TIO) was studied using observations from the Gravity Recovery and Climate Experiment (GRACE) during 2003–2017 in conjunction with the steric effects in the sea level anomaly as measured by satellite altimeters. Two steric sea levels were estimated from the ocean model analysis and Argo gridded temperature and salinity fields. These datasets were consistent with each other and to the altimeter measured sea level records. They exhibited a coherent seasonal cycle with unique spatial patterns of amplitude maxima associated with annual and semi-annual harmonics. Steric component remained as a major contributor to the sea level variability at all the time scales. Addition of the GRACE measured MISL to the steric sea level improved the estimation of sea level (as measured by satellite altimeter) over most part of the TIO except over the northern part of the Arabian Sea. It was observed that the MISL had a significant contribution to the sea level variability at intra-seasonal and seasonal time scales and a minor contribution to the sea level inter-annual variability. During all the El Niño years, sea level underwent a large fluctuation coherent to the steric component. A linear barotropic vortex conservation model driven by ocean surface winds explained a major part of the observed MISL high-frequency variability in the Equatorial and southern TIO, and overestimated the observation in the northern TIO. Numéro de notice : A2021-137 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-021-01471-2 Date de publication en ligne : 31/01/2021 En ligne : https://doi.org/10.1007/s00190-021-01471-2 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97010 [article]

Optimal lowest astronomical tide estimation using maximum likelihood estimator with multiple ocean models hybridization / Mohammed El-Diasty in ISPRS International journal of geo-information, vol 9 n° 5 (May 2020)  

Public [article]  inISPRS International journal of geo-information > vol 9 n° 5 (May 2020) . - 11 p. Titre : Optimal lowest astronomical tide estimation using maximum likelihood estimator with multiple ocean models hybridization Type de document : Article/Communication Auteurs : Mohammed El-Diasty, Auteur Année de publication : 2020 Article en page(s) : 11 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Océanographie [Termes IGN] carte marine [Termes IGN] données hydrographiques [Termes IGN] incertitude des données [Termes IGN] levé hydrographique [Termes IGN] marée océanique [Termes IGN] marégraphe [Termes IGN] méthode du maximum de vraisemblance (estimation) [Termes IGN] modèle océanographique [Termes IGN] navigation maritime [Termes IGN] niveau de la mer [Termes IGN] océanographie dynamique [Termes IGN] Rouge, mer Résumé : (auteur) Developing an accurate Lowest Astronomical Tide (LAT) in a continuous form is essential for many maritime applications as it can be employed to develop an accurate continuous vertical control datum for hydrographic surveys applications and to produce accurate dynamic electronic navigation charts for safe maritime navigation by mariners. The LAT can be developed in a continuous (surface) using an estimated LAT surface model from the hydrodynamic ocean model along with coastal discrete LAT point values derived from tide gauges data sets to provide the corrected LAT surface model. In this paper, an accurate LAT surface model was developed for the Red Sea case study using a Maximum Likelihood Estimator (MLE) with multiple hydrodynamic ocean models hybridization, namely, WebTide, FES2014, DTU10, and EOT11a models. It was found that the developed optimal hybrid LAT model using MLE with multiple hydrodynamic ocean models hybridization ranges from 0.1 m to 1.63 m, associated with about 2.4 cm of uncertainty at a 95% confidence level in the Red Sea case study area. To validate the accuracy of the developed model, the comparison was made between the optimal hybrid LAT model developed from multiple hydrodynamic ocean models hybridization using the MLE method with the individual LAT models estimated from individual WebTide, FES2014, DTU10, or EOT11a ocean models based on the associated uncertainties estimated at a 95% confidence level. It was found that the optimal hybrid LAT model accuracy is superior to the individual LAT models estimated from individual ocean models with an improvement of about 50% in average, based on the estimated uncertainties. The importance of developing optimal LAT surface model using the MLE method with multiple hydrodynamic ocean models hybridization in this paper with few centimeters level of uncertainty can lead to accurate continuous vertical datum estimation that is essential for many maritime applications. Numéro de notice : A2020-301 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/ijgi9050327 Date de publication en ligne : 17/05/2020 En ligne : https://doi.org/10.3390/ijgi9050327 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95141 [article]

Estuaries and coastal zones / Jiayi Pan (2020)  

Public Titre : Estuaries and coastal zones : dynamics and response to environmental changes Type de document : Monographie Auteurs : Jiayi Pan, Éditeur scientifique ; Adam Devlin, Éditeur scientifique Editeur : London [UK] : IntechOpen Année de publication : 2020 Importance : 268 p. ISBN/ISSN/EAN : 978-1-78985-579-1 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Océanographie [Termes IGN] altimétrie satellitaire par radar [Termes IGN] correction atmosphérique [Termes IGN] données Jason [Termes IGN] données localisées [Termes IGN] données ouvertes [Termes IGN] eaux côtières [Termes IGN] écosystème [Termes IGN] ERS-1 [Termes IGN] estuaire [Termes IGN] géodésie spatiale [Termes IGN] Hong-Kong [Termes IGN] image Envisat [Termes IGN] marée océanique [Termes IGN] modèle océanographique [Termes IGN] océanographie spatiale [Termes IGN] rayonnement électromagnétique [Termes IGN] zone humide Résumé : (Editeur) Estuaries and their surrounding wetland regions are among the most productive ecosystems in the world, with more than half of humanity inhabiting their shores. Anthropogenic factors make estuaries highly susceptible to ecosystem degradation. Coastal waters are closely connected with human activity, and their dynamic processes may greatly affect coastal environments. This book provides a compendium of studies on estuarine dynamics, river plumes, and coastal water dynamics, studies that have investigated the changes in estuarine and coastal zones in response to sea-level rise and other environmental factors, and policy and management strategies to ensure the health and economy of coastal zones. This book aims to display novel frontiers in these fields and may help to inspire in-depth studies in the future. Note de contenu : 1. A 30-Year History of the Tides and Currents in Elkhorn Slough, California / William W. Broenkow and Laurence C. Breaker 2. Tidal Evolution Related to Changing Sea Level; Worldwide and Regional Surveys, and the Impact to Estuaries and Other Coastal Zones / Adam Thomas Devlin and Jiayi Pan 3. Linear and Nonlinear Responses to Northeasters Coupled with Sea Level Rise: A Tale of Two Bays / Stephen Moore, Huijie Xue, Neal R. Pettigrew and John Cannon 4. Coastal Altimetry: A Promising Technology for the Coastal Oceanography Community / Xi-Yu Xu, Ke Xu, Ying Xu and Ling-Wei Shi 5. Structure and Dynamics of Plumes Generated by Small Rivers / Alexander Osadchiev and Peter Zavialov 6. Circulations in the Pearl River Estuary: Observation and Modeling / Jiayi Pan, Wenfeng Lai and Adam Thomas Devlin 7. Phytoplankton Biomass and Environmental Descriptors of Water Quality of an Urban Lagoon / Marco V.J. Cutrim, Francinara S. Ferreira, Lisana F. Cavalcanti, Ana K.D.S. Sá, Andrea Christina Gomes de Azevedo-Cutrim and Ricardo Luvizotto Santos 8. Variations of the Absorption of Chromophoric Dissolved Organic Matter in the Pearl River Estuary / Xia Lei, Jiayi Pan and Adam Thomas Devlin 9. Response of Coastal Upwelling East of Hainan Island in the South China Sea to Sudden Impact and Long-Term Variability of Atmospheric Forcing / Lingling Xie and Mingming Li 10. Strengthening Democracy in Indonesian Marine Spatial Planning through Open Spatial Data / Adipandang Yudono and Permana Yudiarso 11. Environmental Problems and Coastal Mitigation in South America: Examples from Northeast Brazil and Northern Colombia / Vanda Claudino-Sales, Ping Wang, Fábio Perdigão Vasconcelos and Adely Pereira Silveira Numéro de notice : 26785 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Recueil / ouvrage collectif DOI : 10.5772/intechopen.77837 Date de publication en ligne : 25/03/2020 En ligne : https://doi.org/10.5772/intechopen.77837 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99910

On the assimilation of absolute geodetic dynamic topography in a global ocean model: impact on the deep ocean state / Alexey Androsov in Journal of geodesy, vol 93 n° 2 (February 2019)  

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Geoid, sea level and vertical datum of the Arctic improved by ICESAT and GRACE / Henriette Skourup in Geomatica, vol 62 n° 2 (June 2008)  

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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)  

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Estimation of storm surge in the bay of Bengal / John Fiske (2008)

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Tsunami en Asie : le raz-de-marée des images satellites / Françoise de Blomac in SIG la lettre, n° 64 (février 2005)

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