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Diurnal cycle of the intertropical discontinuity over West Africa analysed by remote sensing and mesoscale modelling / Bernhard Pospichal in Quarterly Journal of the Royal Meteorological Society, vol 136 n° S1 (January 2010)
[article]
Titre : Diurnal cycle of the intertropical discontinuity over West Africa analysed by remote sensing and mesoscale modelling Type de document : Article/Communication Auteurs : Bernhard Pospichal, Auteur ; Diana Bou Karam, Auteur ; Susanne Crewell, Auteur ; Cyrille Flamant, Auteur ; Anja Hünerbein, Auteur ; Olivier Bock , Auteur ; Frédérique Saïd, Auteur Année de publication : 2010 Projets : AMMA & AMMA-2 / Janicot, Serge Article en page(s) : pp 92 - 106 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Afrique occidentale
[Termes IGN] Bénin
[Termes IGN] données météorologiques
[Termes IGN] humidité de l'air
[Termes IGN] image Météosat
[Termes IGN] meso échelle
[Termes IGN] mousson
[Termes IGN] température au solRésumé : (auteur) The diurnal cycle of the Intertropical discontinuity (ITD), i.e. the interface at the ground between moist monsoon air and dry Harmattan air, is an important factor in the West African monsoon system. During the whole of 2006, high‐resolution ground‐based remote‐sensing measurements were performed in the area of Djougou, Benin, which made it possible to observe the ITD and the associated sharp gradient of temperature and humidity in detail. In order to extend the point measurements to a three‐dimensional view of the ITD and to enhance the knowledge of the related processes, the mesoscale atmospheric model Meso‐NH was run for a case study (84 h period) in April 2006. In addition Meteosat infrared observations were used to determine the ITD position and its movement. From these observations a northward propagation of the moist air front (ITD) of 8–12 m s−1 was calculated. The propagation speed of the front evaluated from the satellite observations was replicated by the model and the time of the front arrival over Djougou was simulated with a maximum error of 1 hour. With respect to the ground‐based observations, the model was able to reproduce the dynamics and thermodynamics of the front as well as the diurnal cycle of the planetary boundary layer over the study area. This agreement suggests the use of the model to further describe processes in the lower atmosphere at high resolution. Numéro de notice : A2010-643 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article DOI : 10.1002/qj.435 Date de publication en ligne : 11/03/2010 En ligne : https://doi.org/10.1002/qj.435 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90735
in Quarterly Journal of the Royal Meteorological Society > vol 136 n° S1 (January 2010) . - pp 92 - 106[article]Documents numériques
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Diurnal cycle of the intertropical discontinuity ... - pdf éditeurAdobe Acrobat PDF Estimation of crustal vertical movements with GPS in a geocentric frame, within the framework of the TIGA project / Alvaro Santamaria Gomez (2010)
Titre : Estimation of crustal vertical movements with GPS in a geocentric frame, within the framework of the TIGA project Titre original : Estimation des mouvements verticaux de l'écorce terrestre par GPS dans un repère géocentrique, dans le cadre du projet TIGA Type de document : Thèse/HDR Auteurs : Alvaro Santamaria Gomez, Auteur ; Marie-Noëlle Bouin , Directeur de thèse ; Guy Wöppelmann , Directeur de thèse Editeur : Paris, Meudon et Nançay : Observatoire de Paris Année de publication : 2010 Importance : 225 p. Format : 21 x 30 cm Note générale : Bibliographie
Doctoral dissertation of the Observatoire de Paris, speciality Astronomy and Astrophysics, geodesy mention in Paris on October 11th 2010Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] déformation de la croute terrestre
[Termes IGN] géocentre
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] marégraphe
[Termes IGN] niveau moyen des mers
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement par GPS
[Termes IGN] série temporelleIndex. décimale : THESE Thèses et HDR Résumé : (Auteur) Long-term sea-level variations are provided today only by tide gauge measurements. However, these variations are contaminated by vertical long-term movements of the Earth crust. In order to obtain absolute sea-level variations, vertical movements at tide gauges can be now monitored by GPS.
The research work carried out was centered around the methodological study to improve the estimation of vertical velocities of a global GPS network co-located with tide gauges. We devised an optimal distribution of GPS stations which greatly improved the processing performance. This original procedure also allowed us to extend the analyzed data period. We obtained and exported station positions, satellite orbits, Earth orientation parameters, and apparent geocenter motion estimates to be combined by the International GNSS Service (IGS). The coupled effect of periodic signals and discontinuities on the estimated velocities was highlighted, showing the need to estimate both parameters in a consistent and rigorous way. The realistic velocity uncertainties were analyzed in depth taking into account the time-correlated noise content in the data. The noise content analysis led to the confirmation that temporal correlation of homogeneously reprocessed time series is dependent on data epoch. This way, we demonstrated that noise content in long GPS time series is mainly driven by the noise level of older data. However, to get the smallest formal velocity uncertainty, we still needed to use all the data available. The estimated velocity uncertainty was shown to agree with velocity differences with respect to the incoming new terrestrial reference frame, the ITRF2008.Note de contenu : Introduction
PART I. CONTEXT
1. Coastal sea level change and vertical land movements
1.1. Sea level observations
1.2. Long-term sea level rise estimation
1.3. Vertical movements at tide gauges
2. International efforts to monitor tide gauge benchmarks
2.1. First steps
2.2. The TIGA Pilot Project.
2.3. The University of La Rochelle TIGA Analysis Center
PART II. METHODOLOGY
3. GPS processing strategy definition
3.1. Testing the antenna modeling impact.
3.2. Tropospheric modeling test
3.3. Sub-network distribution
3.4. Other changes
3.5. Summary
4. Combination and products.
4.1. ULR3 combination procedure
4.2. ULR4 combination procedure
4.3. Comparison between ULR3 and ULR4 combination procedures
4.4. Summary
5. Vertical velocity field estimation.
5.1. Offsets, discontinuities and outliers
5.2. Seasonal signals
5.3. Datum selection
5.4. Summary
6. Vertical velocity field uncertainty
6.1. Noise effect on velocity uncertainties
6.2. Noise analysis methodology
6.3. Noise analysis procedure
6.4. Stochastic noise model selection
6.5. Reference frame uncertainty
6.6. Summary
PART III. RESULTS
7. ULR4 products
7.1. Frame transformation parameters
7.2. Terrestrial frame
7.3. Earth orientation parameters
7.4. Orbits
7.5. Summary
8. Vertical velocity field.
8.1. Selection of the stations in the ULR4 velocity field
8.2. Comparison of ULR3 and ULR4 vertical velocity fields
8.3. Comparison with multi-technique vertical velocity fields
8.4. Comparison with the ITRF2008 vertical velocity field
8.5. Sea level application
8.6. Summary
Conclusion and perspectivesNuméro de notice : 10447 Affiliation des auteurs : LAREG (1991-2011) Thématique : POSITIONNEMENT Nature : Thèse française Note de thèse : Thèse de doctorat : Astronomie et astrophysique. Géodésie : Observatoire de Paris : 2010 Organisme de stage : LAREG (IGN) nature-HAL : Thèse DOI : sans En ligne : https://hal.science/tel-00686823 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=45140 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 10447-01 THESE Livre Centre de documentation Thèses Disponible 10447-02 THESE Livre Centre de documentation Thèses Disponible Identification and modelling of sea level change contributors on GRACE satellite gravity data and their applications to climate monitoring / Bert Wouters (2010)
Titre : Identification and modelling of sea level change contributors on GRACE satellite gravity data and their applications to climate monitoring Type de document : Rapport Auteurs : Bert Wouters, Auteur Editeur : Delft : Netherlands Geodetic Commission NGC Année de publication : 2010 Collection : Netherlands Geodetic Commission Publications on Geodesy, ISSN 0165-1706 num. 73 Importance : 182 p. Format : 17 x 24 cm ISBN/ISSN/EAN : 978-90-6132-316-7 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] changement climatique
[Termes IGN] GRACE
[Termes IGN] Groenland
[Termes IGN] niveau moyen des mers
[Termes IGN] surveillance météorologiqueIndex. décimale : 30.83 Applications océanographiques de géodésie spatiale Résumé : (Auteur) Recently, the Intergovernmental Panel on Climate Change named sea level rise as one of the major challenges of the 21st century. Given the high population density of coastal regions, a small rise of the sea level will have a substantial impact on human society. However, the Earth's climate system is a complex matter arid model predictions of the sea level changes likely to be expected in the coming century currently show a wide spread. Clearly, a thorough understanding of present-day climate variability is imperative narrow this uncertainty band, which on its turn depends on the availability of accurate and detailed observations of our climate.
A valuable contribution to the expanding array of satellites dedicated to observations of the Earth System, are the Gravity Recovery and Climate Experiment (GRACE) satellites, launched in March 2002. This mission is dedicated to observing changes of the Earth's gravity field at (sub-)monthly intervals. At time-scales of a few years, these changes are mostly related to the redistribution of water on the Earth's surface. For example, a thinning of the Greenland ice sheet will manifest itself as a local negative anomaly in the gravity field, whereas the water that is added to the ocean will show up as a predominantly positive anomaly. The main objective of this dissertation is to study how the GRACE observations can be used to improve our knowledge of changes in the Earth's climate systems, and how the data should be processed in order to optimize quality and spatial resolution.
The GRACE data provided by the science teams consist of spherical harmonic coefficients. They show particular correlations between coefficients of identical order and even and odd degree, respectively, due to the mission's architecture and deficiencies in the background models used throughout the processing of the satellite measurements. These noise artifacts show up as striping patterns along the north-south direction in the monthly maps of surface mass changes, hampering the interpretation of the observations. In this dissertation, it is shown that empirical orthogonal function (EOF) analysis is an effective method to reduce the noise in the GRACE data. This statistical tool separates a data set into a number of characteristic (eigen) modes of variance, in combination with an index describing the amplitude of the mode in time, i.e. the principal components. The EOF analysis can be applied to the maps of surface mass changes, in which case the first few modes are related to the annual and long-term trend components. The fourth mode appears to be related to the El Nino/Southern Oscillation. The noise signals arc absorbed by the higher modes, which makes the leading modes largely stripe-free up to a resolution of approximately 400 kilometers.
A further reduction of the noise can be obtained by applying the EOF de-composition directly to the spherical harmonic coefficients, after grouping them following order. The principal components arc compared to a random process and, if the two arc statistically sufficiently alike, not used in the further data processing. A series of tests shows that this approach reduces the noise by 60-80 %, compared the non-filtered case. An important feature of this filter is that it does not alter the shape of the signal and causes less reduction its power, compared to other commonly used filter methods based on the approach of Swenson and Walir (2006).
Using the filtered data, changes in the mass content of the ocean have been studied. The GRACE satellites are capable of capturing seasonal changes in the ocean mass content accurately on a global scale. In combination with sea surface height observations made by satellite altimeter, the steric sea level component (related to changes in the heat and salinity content of the ocean) can be separated as well. A comparison with reference data sets shows that locally a coherent signal can be obtained at a (Gaussian) resolution of approximately 500 km over the oceans. These steric changes dominate the sea level in most of the oceans, but strong ocean bottom pressure fluctuations are observed in several areas, e.g., the Gulf of Carpentaria and the Gulf of Thailand. Estimates of long-term changes in the ocean mass and heat content arc a more challenging problem, and require a longer observation period and a better modeling of mass redistribution in the solid earth and the position of the center of mass of the Earth, two components to which the GRACE observations arc particularly sensitive.
It is found that the global spherical harmonic coefficients contain more information than previously acknowledged. This is demonstrated by using the GRACE data to obtain a picture of the mass balance of the Greenland ice sheet at a regional scale. From the research in this dissertations, it shows that Greenland lost 179 Gigaton each year on average between 2003 and 2008, causing a global mean rise of sea level by 0.5 mm/yr. Comparing the trend in the first few to that in the last few years shows a speed-up of the thinning, which corroborates the picture of an increasingly negative mass balance of the ice sheet since the mid 1990's as indicated by, for example, regional climate models and radar altimetry observations. The majority of the losses occur in the coastal regions in the southeastern sector. The northwestern coastal zones were approximately in balance up to the summer of 2005, but show strong negative trends since. Large year-to-year differences in the mass balance of the ice sheet are observed, with a record loss in the warm summer of 2007. A strong correlation between the GRACE observations in summer and satellite measurements of surface melt area extent is demonstrated. Also, good agreement is found with regional climate modeling data, highlighting the potential of the GRACE observations to validate and improve the numerical models.
A mass redistribution on land will cause a change in the shape of the global geoid. Sea level, when not acted upon by any other forcings, will adjust to this equipotential surface. Therefore, when water is exchanged between ocean and continents (and changes due to ocean dynamics are disregarded), sea level will not rise or fall uniformly, which is known as the so-called self-gravitation effect. Due to their global coverage, the GRACE observations of continental mass distribution are an excellent input to model this phenomenon. Strongest deviations from a uniform distribution are found off the coast of Alaska and in the Bay of Bengal, where differences of more than 100% are found on seasonal time-scales. In these regions, inclusion of the self-gravitation effect into numerical ocean model would result in a better agreement between modeled and observational data.
From the work presented in this dissertation, it shows that the GRACE satellites are an invaluable tool for the monitoring of our climate system. Statistically filtering of the data reveals a wealth of information. In combination with altimetry observations, the GRACE data allows the separation of mass and steric components in sea level on seasonal time scales. Given a longer observational period and an improved understanding of the processes in the solid earth, expected to come available soon thanks to ESA's GOCE missions, long-term trends in these components will be identifiable. Furthermore, the GRACE mission allows us to put a constraint on the contribution of the Greenland ice sheet to present-day sea level rise. The technique to recover these changes can easily be expanded to other regions, such as the Antarctic or the Alaskan glacier fields. The synergy between GRACE data, future missions such as Cryosat-2, which will map height variations of the cryosphere with an unprecedented accuracy, and regional climate models, uncovering the physical processes behind the observed changes, promises a leap forward in our understanding of the mass balance of the ice sheets. Finally, com-paring the modeled deviations from uniform sea level changes with in-situ data such as from tide-gauges, may lead to a direct validation of the aforementioned self-gravitation theory with present-day data.Numéro de notice : 10335 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport de recherche DOI : sans En ligne : https://www.ncgeo.nl/downloads/73Wouters.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62396 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 10335-01 30.83 Livre Centre de documentation Géodésie Disponible Méthodologie GPS, mesure des déformations verticales et humidité atmosphérique / Marie-Noëlle Bouin (2010)
Titre : Méthodologie GPS, mesure des déformations verticales et humidité atmosphérique Type de document : Thèse/HDR Auteurs : Marie-Noëlle Bouin , Auteur ; C. Delacourt, Directeur de thèse Editeur : Brest : Université de Bretagne Occidentale Année de publication : 2010 Importance : 67 p. Format : 21 x 30 cm Note générale : Bibliographie
Mémoire d'habilitation à diriger les recherchesLangues : Français (fre) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] champ de vitesse
[Termes IGN] déformation verticale de la croute terrestre
[Termes IGN] erreur systématique
[Termes IGN] fond marin
[Termes IGN] hauteur ellipsoïdale
[Termes IGN] humidité de l'air
[Termes IGN] mousson
[Termes IGN] niveau moyen des mers
[Termes IGN] positionnement par GPS
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] traitement de données GNSSRésumé : (Auteur) Pendant 10 ans, j'ai travaillé au LAREG (Laboratoire de Recherche en Géodésie de l'IGN) sur la méthodologie du traitement GPS pour le positionnement vertical précis, avec plusieurs applications à des domaines variés des sciences de la Terre. J'ai cherché : 1) à mettre en évidence et quantifier les sources d'incertitudes, qu'elles viennent d'effets physiques (traversée de l'atmosphère par les signaux GPS en particulier) ou géodésiques (effets géométriques ou de systèmes de référence..) ; 2) à obtenir les résultats les plus précis, voire les plus exacts possible, en développant une méthodologie adaptée. Les domaines d'application où j'ai obtenu des résultats novateurs sont :
- la déformation d'une zone de subduction rapide, l'arc des Vanuatu. Sur cette zone bien instrumentée par l'IRD depuis plus de 15 ans, nous avons obtenu un champ de vitesses 3D précis grâce à un traitement adapté et cohérent. On met ainsi en évidence l'effet de la Ride d'Entrecasteaux, relief sous marin qui s'engage dans la subduction, sur les vitesses verticales proches de la fosse et très probablement sur le cycle sismique. - l'étude des variations à long terme du niveau de la mer. La mise en place d'un centre d'analyse GPS des données des stations colocalisées avec les marégraphes d'un réseau mondial permet, avec près de 10 ans de données continues traitées de 1) proposer un champ de vitesses verticales homogènes sur plus de 220 stations, validé par des estimations géophysiques indépendantes ; 2) en utilisant ces vitesses, réévaluer la vitesse long terme de variation du niveau de la mer dans un référentiel absolu (donc comparable aux variations données par l'altimétrie sur 15 ans). - l'étude de l'humidité atmosphérique dans le cycle de mousson en Afrique de l'Ouest. Durant la campagne AMMA, qui s'est déroulée principalement de 2005 à 2007 en Afrique de l'Ouest, nous avons mis en place un réseau de 6 stations GPS permanentes et un centre d'analyse de leurs données pour la production de Contenus Intégrés en Vapeur d'Eau atmosphérique. Des traitements automatiques en temps peu différé ont fourni, pendant toute la durée de la campagne, des indicateurs d'aide à la décision, avec des CIVE comparables aux prévisions et aux analyses. Le traitement scientifique, à l'état de l'art, met en évidence des biais importants des mesures « classiques » de radio sondages en Afrique, qui se répercutent ensuite sur les analyses. Il apporte des informations nouvelles sur les différentes étapes de la mousson (que l'on caractérise bien par l'évolution de la vapeur d'eau atmosphérique) et sur le cycle diurne et son évolution au cours du cycle de mousson. - la géodésie de fond de mer. Les résultats ne concernent pour l'instant que la composante verticale. Sur une zone calme au Vanuatu, des tests sur un réseau de répétition montrent que la répétabilité sur la hauteur ellipsoïdale d'un repère installé par 16 m de fond est sub centimétrique. Le facteur limitant est la précision que l'on peut obtenir sur la mesure de hauteur par GPS en surface, évaluée grâce à une étude méthodologique à 10 à 15 cm sur la zone d'intérêt (fosse de subduction). On a obtenu, sur cette zone, une cartographie GPS de la surface moyenne océanique à même précision, qui met en évidence des biais importants dans les surfaces altimétriques et alti-gravimétriques au Vanuatu.Note de contenu : PREMIERE PARTIE : RAPPORT SCIENTIFIQUE
1 Introduction
2 Géodynamique et composante verticale
2-1 Zone de déformation rapide et composante verticale
2-2 Variation à long terme du niveau de la mer
2-3 Mesure de la surcharge océanique
3 GPS et vapeur d'eau atmosphérique
3-1 Méthodologie : du produit dérivé à l'outil innovant
3-2 GPS et mousson africaine
4 Evolution thématique : positionnement sous-marin et surface de la mer
4-1 Du GPS a la géodésie sous-marine
4-2 Le GPS comme complément à l'altimétrie
5 Conclusion et perspectives
SECONDE PARTIE : INFORMATIONS BIOGRAPHIQUESNuméro de notice : 10857 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : HDR Note de thèse : Habilitation à diriger les recherches : : UBO : 2010 nature-HAL : HDR DOI : sans En ligne : https://theses.hal.science/tel-00519369/ Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=45150 Sea surface topography and marine geoid by airborne laser altimetry and shipborne ultrasound altimetry / Philippe Limpach (2010)
Titre : Sea surface topography and marine geoid by airborne laser altimetry and shipborne ultrasound altimetry Type de document : Thèse/HDR Auteurs : Philippe Limpach, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2010 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 80 Importance : 208 p. Format : 20 x 30 cm ISBN/ISSN/EAN : 978-3-908440-24-6 Note générale : Bibliographie
Doctoral thesisLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] anomalie de pesanteur
[Termes IGN] bathymétrie acoustique
[Termes IGN] Crète (île)
[Termes IGN] données Jason
[Termes IGN] Egée, mer
[Termes IGN] géoïde altimétrique
[Termes IGN] géoïde local
[Termes IGN] geoïde marin
[Termes IGN] géoréférencement direct
[Termes IGN] GPS en mode cinématique
[Termes IGN] GPS en mode différentiel
[Termes IGN] océanographie dynamique
[Termes IGN] relief de la surface de la mer
[Termes IGN] sondage acoustique
[Termes IGN] surface de la mer
[Termes IGN] télémétrie laser aéroporté
[Termes IGN] validation des donnéesIndex. décimale : 30.83 Applications océanographiques de géodésie spatiale Résumé : (Auteur) The aim of this project was to contribute to the improvement of sea level monitoring and to provide local-scale information on the short-wavelength structure of the marine gravity field, by developing enhanced methods for offshore sea surface height observations. The methods include airborne laser altimetry, shipborne ultrasound altimetry and GPS-equipped buoys. In a first step, instrumental aspects of sea surface height observations by airborne and shipborne altimetry were analyzed. Precise position and attitude of the range sensor are crucial for an accurate sea surface height computation. For this purpose, the survey aircraft and boat were equipped with a multi-antenna GPS array and inertial systems. Sea surface heights were computed from the range data by direct georeferencing. Important aspects are the influences of errors in the differential kinematic GPS positioning and in the attitude determination, as well as the calibration of boresight misalignments. In a second step, the obtained sea surface heights were reduced to mean sea surface by applying corrections for geophysical effects, including waves, tides, atmospheric pressure and wind forcing.
In the framework of this work, several regional campaigns for sea surface height surveys based on airborne and shipborne altimetry were carried out in the Eastern Mediterranean Sea. Dedicated surveys, including deployments of GPS buoys, were performed along Jason-1 radar altimetry ground tracks. Airborne laser altimetry data was acquired along densely spaced flight tracks covering an area of 200 by 200km around the western part of the island of Crete, Greece, in the vicinity of the Hellenic Trench. The objective was the determination of a detailed regional geoid and sea surface topography model in the framework of the GAVDOS project, funded by the European Union. Furthermore, several shipborne campaigns for sea surface height observations were carried out in the North Aegean Sea, in the vicinity of the North Aegean Trough.
Based on the airborne and shipborne altimetry data, a high-resolution sea surface topography of the survey areas was computed, with an accuracy of better than 10 cm. Geoid undulations were derived from the sea surface heights by subtracting the mean dynamic ocean topography induced by oceanic currents. Around western Crete, the geoid obtained from airborne laser altimetry is characterized by very large gradients, with an average height difference of 20m along a distance of only 200km and maximum local gradients of 22 cm/km. These gradients are a clear indication for significant gravity effects caused by the bathymetry and the geodynamic system of the Hellenic Trench. In the survey area in the North Aegean Sea, the geoid obtained from shipborne altimetry shows a distinct depression of 1.5 m, indicating a connection with the bathymetry and the geodynamic features of the North Aegean Trough.
The high resolution and accuracy of the sea surface and geoid heights obtained were verified by comparisons with mean sea surface models from multi-mission satellite radar altimetry, as well as with global and regional geoid models. The reduction of the geoid heights for modeled mass effects of topography, bathymetry, marine sedimentary deposits and crust-mantle boundary revealed pronounced gravity anomalies related to the geodynamic processes in the survey areas.Note de contenu : 1 Introduction
1.1 Motivation and Goals
1.2 Geophysical Characteristics of the Eastern Mediterranean
1.3 Former Work by the GGL in Related Fields of Research
1.4 Research Tasks and Project Outline
2 Geoid, Sea Surface and Dynamic Ocean Topography
2.1 Introduction
2.2 Geoid
2.3 Mean Sea Surface
2.4 Sea Level Anomaly
2.5 Dynamic Ocean Topography
2.6 Permanent Tide
3 Geophysical Effects on Sea Surface Heights
3.1 Introduction
3.2 Ocean Waves
3.3 Tides
3.4 Atmospheric Pressure and Wind Forcing
4 Airborne Laser Altimetry
4.1 Introduction
4.2 Instumental Setup
4.3 Laser Ranging
4.4 Laser Backscatter from Sea Surface
5 Shipborne Ultrasound Altimetry
5.1 Introduction
5.2 Instrumental Setup
5.3 Ultrasound Ranging
5.4 Sensor Synchronization
6 Direct Georeferencing
6.1 Introduction
6.2 Basic Principle
6.3 Kinematic GPS Positioning
6.4 Multi-Antenna GPS Attitude Determination
6.5 Boresight Misalignment Calibration in Airborne Altimetry
7 Sea Surface Heights by Airborne Laser Altimetry around Western Crete
7.1 GAVDOS Airborne Laser Altimetry Campaign
7.2 Instantaneous Sea Surface Height Profiles
7.3 Sea Surface Height Corrections
7.4 Repeatability Analysis
7.5 Time-Independent Sea Surface Topography
8 Sea Surface Heights by Shipborne Ultrasound Altimetry in the North Aegean Sea
8.1 Shipborne Ultrasound Altimetry Campaigns
8.2 Instantaneous Sea Surface Height Profiles
8.3 Sea Surface Height Corrections
8.4 Repeatability Analysis
8.5 Time-Independent Sea Surface Topography
9 Validation of Satellite Radar Altimetry Data
9.1 Introduction
9.2 Validation of Jason-1 Data with Airborne Laser Altimetry
9.3 Validation of Mean Sea Surface from Radar Altimetry
10 Geoscientific Exploitation of Airborne Altimetry Data around Western Crete
10.1 Marine Geoid, Gravity Anomalies and Deflections of the Vertical from Sea Surface Heights
10.2 Local Altimetric Geoid vs. Existing Models
10.3 Mean Dynamic Topography Estimation
10.4 Modeled Mass Effects on Geoid Heights and Gravity
10.5 Mass Reduction of Local Altimetric Geoid
11 Geoscientific Exploitation of Shipborne Altimetry Data in the North Aegean Sea
11.1 Marine Geoid, Gravity Anomalies and Deflections of the Vertical from Sea Surface Heights
11.2 Local Altimetric Geoid vs. Existing Models
11.3 Mean Dynamic Topography Estimation
11.4 Modeled Mass Effects on Geoid Heights and Gravity
11.5 Mass Reduction of Local Altimetric Geoid
12 Summary and ConclusionsNuméro de notice : 10369 Affiliation des auteurs : non IGN Autre URL associée : URL ETH Zurich Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : 10.3929/ethz-a-005876550 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-80.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62408 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 10369-01 30.83 Livre Centre de documentation Géodésie Disponible Understanding sea-level rise and variability, ch 9. Geodetic observations and global reference frame contributions to understanding sea-level rise and variability / Geoffrey Blewitt (2010)PermalinkA kinematic GPS methodology for sea surface mapping, Vanuatu / Marie-Noëlle Bouin in Journal of geodesy, vol 83 n° 12 (December 2009)PermalinkThe GHYRAF (Gravity and Hydrology in Africa) experiment: Description and first results / Jacques Hinderer in Journal of geodynamics, vol 48 n° 3-5 (December 2009)PermalinkVers une nouvelle représentation des déformations horizontales de la croûte terrestre et de leurs erreurs avec un champ régulier de tenseurs / Leila Eissa in XYZ, n° 121 (décembre 2009 - février 2010)Permalinkvol 4 n° 6 - November - December 2009 (Bulletin de Inside GNSS)PermalinkImproving resolution and accuracy of mean sea surface from kinematic GPS, Vanuatu subduction zone / Marie-Noëlle Bouin in Journal of geodesy, vol 83 n° 11 (November 2009)PermalinkMonumentation of geodetic permanent GPS stations: processing of data download in the first year of observation / A. Cavinato in Geoinformatics, vol 12 n° 7 (01/10/2009)PermalinkTechnologie & plus = Technology & more (Bulletin de Technology & more) / TrimblePermalinkThe impacts of AMMA radiosonde data on the French global assimilation and forecast system / C. Faccani in Weather and Forecasting, vol 24 n° 5 (October 2009)PermalinkGNSS-R [GNSS-Reflectometry]: a space asset for non-space applications / A. Egido in Geoinformatics, vol 12 n° 6 (01/09/2009)Permalink