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Monitoring and prediction of precipitable water vapor using GPS data in Turkey / Kutubuddin Ansari in Journal of applied geodesy, vol 10 n° 4 (December 2016)
[article]
Titre : Monitoring and prediction of precipitable water vapor using GPS data in Turkey Type de document : Article/Communication Auteurs : Kutubuddin Ansari, Auteur ; Omar F. Althuwaynee, Auteur ; Ozsen Corumluoglu, Auteur Année de publication : 2016 Article en page(s) : pp 233 – 245 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] analyse diachronique
[Termes IGN] données météorologiques
[Termes IGN] effet atmosphérique
[Termes IGN] précipitation
[Termes IGN] réfraction atmosphérique
[Termes IGN] réseau géodésique permanent
[Termes IGN] signal GPS
[Termes IGN] température
[Termes IGN] Turquie
[Termes IGN] vapeur d'eauRésumé : (auteur) Although Global Positioning System (GPS) primarily provide accurate estimates of position, velocity and time of the receiver, as the signals pass through the atmoshphere carrying its signatures, thus offers opportunities for atmoshpheric applications. Precipitable water vapor (PWV) is a vital component of the atmosphere and significantly influences atmospheric processes like rainfall and atmospheric temperature. The developing networks of continuously operating GPS can be used to efficiently estimate PWV. The Turkish Permanent GPS Network (TPGN) is employed to monitor PWV information in Turkey. This work primarily aims to derive long-term data of PWV by using atmospheric path delays observed through continuously operating TPGN from November 2014 to October 2015. A least square mathematical approach was then applied to establish the relation of the observed PWV to rainfall and temperature. The modeled PWV was correlated with PWV estimated from GPS data, with an average correlation of 67.10 %–88.60 %. The estimated root mean square error (RMSE) varied from 2.840 to 6.380, with an average of 4.697. Finally, data of TPGN, rainfall, and temperature were obtained for less than 2 months (November 2015 to December 2015) and assessed to validate the mathematical model. This study provides a basis for determining PWV by using rainfall and temperature data. Numéro de notice : A206-973 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2016-0037 En ligne : https://doi.org/10.1515/jag-2016-0037 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83680
in Journal of applied geodesy > vol 10 n° 4 (December 2016) . - pp 233 – 245[article]An approach for estimating time-variable rates from geodetic time series / Olga Didova in Journal of geodesy, vol 90 n° 11 (November 2016)
[article]
Titre : An approach for estimating time-variable rates from geodetic time series Type de document : Article/Communication Auteurs : Olga Didova, Auteur ; Brian Gunter, Auteur ; Riccardo Riva, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 1207 - 1221 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Antarctique
[Termes IGN] calotte glaciaire
[Termes IGN] compensation par moindres carrés
[Termes IGN] données GRACE
[Termes IGN] filtre de Kalman
[Termes IGN] Global Ocean Observing System
[Termes IGN] montée du niveau de la mer
[Termes IGN] niveau moyen des mers
[Termes IGN] optimisation (mathématiques)
[Termes IGN] positionnement par GPS
[Termes IGN] série temporelleRésumé : (Auteur) There has been considerable research in the literature focused on computing and forecasting sea-level changes in terms of constant trends or rates. The Antarctic ice sheet is one of the main contributors to sea-level change with highly uncertain rates of glacial thinning and accumulation. Geodetic observing systems such as the Gravity Recovery and Climate Experiment (GRACE) and the Global Positioning System (GPS) are routinely used to estimate these trends. In an effort to improve the accuracy and reliability of these trends, this study investigates a technique that allows the estimated rates, along with co-estimated seasonal components, to vary in time. For this, state space models are defined and then solved by a Kalman filter (KF). The reliable estimation of noise parameters is one of the main problems encountered when using a KF approach, which is solved by numerically optimizing likelihood. Since the optimization problem is non-convex, it is challenging to find an optimal solution. To address this issue, we limited the parameter search space using classical least-squares adjustment (LSA). In this context, we also tested the usage of inequality constraints by directly verifying whether they are supported by the data. The suggested technique for time-series analysis is expanded to classify and handle time-correlated observational noise within the state space framework. The performance of the method is demonstrated using GRACE and GPS data at the CAS1 station located in East Antarctica and compared to commonly used LSA. The results suggest that the outlined technique allows for more reliable trend estimates, as well as for more physically valuable interpretations, while validating independent observing systems. Numéro de notice : A2016-798 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0918-5 En ligne : http://dx.doi.org/ 10.1007/s00190-016-0918-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82575
in Journal of geodesy > vol 90 n° 11 (November 2016) . - pp 1207 - 1221[article]A phase-altimetric simulator : studying the sensitivity of Earth-reflected GNSS signals to ocean topography / Aaron Maximilian Semmling in IEEE Transactions on geoscience and remote sensing, vol 54 n° 11 (November 2016)
[article]
Titre : A phase-altimetric simulator : studying the sensitivity of Earth-reflected GNSS signals to ocean topography Type de document : Article/Communication Auteurs : Aaron Maximilian Semmling, Auteur ; Vera Leister, Auteur ; Jan Saynisch, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 6791 - 6802 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] altimétrie
[Termes IGN] analyse de sensibilité
[Termes IGN] océanographie spatiale
[Termes IGN] positionnement par GNSS
[Termes IGN] réflectométrie par GNSS
[Termes IGN] signal GNSS
[Termes IGN] surface de la merRésumé : (Auteur) This paper presents a simulation study on Global Navigation Satellite System (GNSS) reflections focusing on a phase altimetric method for ocean topography retrieval. It examines carrier phase residuals of Earth-reflected GNSS signals in preparation for the GNSS Reflectometry Radio Occultation and Scatterometry experiment aboard the International Space Station (GEROS-ISS). The residuals' sensitivity to ocean topography (maximum of 2-m amplitude variation of global sea level) is shown. A trigonometric approach to determine the specular reflection point is proposed. Reflection events are simulated assuming different low Earth orbit receivers and GNSS-type transmitters. Suitable events for phase altimetry are assumed between 5° and 30° elevation lasting between 10 and 15 min with ground tracks length of > 3000 km. Typical along-track footprints (1 s integration time) have a length of about 5 km. Within the assumed elevation range the coherent footprint ellipse has a major axis between 1 and 6 km. A Master-Slave sampling is proposed to approximate large-scale delay and Doppler variations of the reflected signal (Slave channel) relative to the direct signal (Master channel). Slave residuals of an example event are simulated to retrieve a small-scale phase delay for ocean topography inversion. The signal-to-noise ratio restricts the quality of the topography results. Height precision on sub-decimeter level for 30-dB SNR is degraded up to a meter level for 20-dB SNR. Ionosphere-free linear combination allows keeping the precision level. Troposphere refraction degrades precision particularly at the low elevation limit. Precision improves toward higher elevations. The tolerance to ocean roughness decreases in the same way. Numéro de notice : A2016-918 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2016.2591065 En ligne : http://dx.doi.org/10.1109/TGRS.2016.2591065 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83147
in IEEE Transactions on geoscience and remote sensing > vol 54 n° 11 (November 2016) . - pp 6791 - 6802[article]Review of the state of the art and future prospects of the ground-based GNSS meteorology in Europe / Guergana Guerova in Atmospheric measurement techniques, vol 9 n° 11 (November 2016)
[article]
Titre : Review of the state of the art and future prospects of the ground-based GNSS meteorology in Europe Type de document : Article/Communication Auteurs : Guergana Guerova, Auteur ; Jonathan Jones, Auteur ; Jan Douša, Auteur ; Galina Dick, Auteur ; Siebren de Haan, Auteur ; Eric Pottiaux, Auteur ; Olivier Bock , Auteur ; et al., Auteur Année de publication : 2016 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] données GNSS
[Termes IGN] données météorologiques
[Termes IGN] état de l'art
[Termes IGN] Europe (géographie politique)
[Termes IGN] modèle météorologique
[Termes IGN] propagation troposphériqueRésumé : (auteur) Global navigation satellite systems (GNSSs) have revolutionised positioning, navigation, and timing, becoming a common part of our everyday life. Aside from these well-known civilian and commercial applications, GNSS is now an established atmospheric observing system, which can accurately sense water vapour, the most abundant greenhouse gas, accounting for 60–70% of atmospheric warming. In Europe, the application of GNSS in meteorology started roughly two decades ago, and today it is a well-established field in both research and operation. This review covers the state of the art in GNSS meteorology in Europe. The advances in GNSS processing for derivation of tropospheric products, application of GNSS tropospheric products in operational weather prediction and application of GNSS tropospheric products for climate monitoring are discussed. The GNSS processing techniques and tropospheric products are reviewed. A summary of the use of the products for validation and impact studies with operational numerical weather prediction (NWP) models as well as very short weather prediction (nowcasting) case studies is given. Climate research with GNSSs is an emerging field of research, but the studies so far have been limited to comparison with climate models and derivation of trends. More than 15 years of GNSS meteorology in Europe has already achieved outstanding cooperation between the atmospheric and geodetic communities. It is now feasible to develop next-generation GNSS tropospheric products and applications that can enhance the quality of weather forecasts and climate monitoring. This work is carried out within COST Action ES1206 advanced global navigation satellite systems tropospheric products for monitoring severe weather events and climate (GNSS4SWEC, http://gnss4swec.knmi.nl). Numéro de notice : A2016--181 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/amt-9-5385-2016 Date de publication en ligne : 08/11/2016 En ligne : http://dx.doi.org/10.5194/amt-9-5385-2016 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91814
in Atmospheric measurement techniques > vol 9 n° 11 (November 2016)[article]Direct measurement of evapotranspiration from a forest using a superconducting gravimeter / Michel Van Camp in Geophysical research letters, vol 43 n° 19 (15 October 2016)
[article]
Titre : Direct measurement of evapotranspiration from a forest using a superconducting gravimeter Type de document : Article/Communication Auteurs : Michel Van Camp, Auteur ; Olivier de Viron, Auteur ; Gwendoline Pajot-Métivier , Auteur ; Fabien Casenave , Auteur ; Arnaud Watlet, Auteur ; Alain Dassargues, Auteur ; Marnik Vanclooster, Auteur Année de publication : 2016 Article en page(s) : pp 10225 - 10231 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Belgique
[Termes IGN] évapotranspiration
[Termes IGN] feuillu
[Termes IGN] forêt tempérée
[Termes IGN] gravimètre supraconducteur
[Termes IGN] humidité du sol
[Termes IGN] levé gravimétrique
[Termes IGN] variation diurneRésumé : (auteur) Evapotranspiration (ET) controls the flux between the land surface and the atmosphere. Assessing the ET ecosystems remains a key challenge in hydrology. We have found that the ET water mass loss can be directly inferred from continuous gravity measurements: as water evaporates and transpires from terrestrial ecosystems, the mass distribution of water decreases, changing the gravity field.
Using continuous superconducting gravity measurements, we were able to identify daily gravity changes at the level of, or smaller than 10-9 nm.s-2 (or 10-10 g) per day. This corresponds to 1.7 mm of water over an area of 50 ha. The strength of this method is its ability to enable a direct, traceable and continuous monitoring of actual ET for years at the mesoscale with a high accuracy.Numéro de notice : A2016-684 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/2016GL070534 Date de publication en ligne : 07/10/2016 En ligne : http://dx.doi.org/10.1002/2016GL070534 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81973
in Geophysical research letters > vol 43 n° 19 (15 October 2016) . - pp 10225 - 10231[article]Documents numériques
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Direct measurement of evapotranspiration ... - pdf éditeurAdobe Acrobat PDF An advanced GNSS code multipath detection and estimation algorithm / Negin Sokhandan in GPS solutions, vol 20 n° 4 (October 2016)PermalinkGenerating GPS satellite fractional cycle bias for ambiguity-fixed precise point positioning / Pan Li in GPS solutions, vol 20 n° 4 (October 2016)PermalinkIonospheric tomography using GNSS: multiplicative algebraic reconstruction technique applied to the area of Brazil / Fabricio Dos Santos Prol in GPS solutions, vol 20 n° 4 (October 2016)PermalinkLong-term soil moisture dynamics derived from GNSS interferometric reflectometry: a case study for Sutherland, South Africa / Sibylle Vey in GPS solutions, vol 20 n° 4 (October 2016)PermalinkUsing a regional numerical weather prediction model for GNSS positioning over Brazil / Daniele Barroca Marra Alves in GPS solutions, vol 20 n° 4 (October 2016)PermalinkEvaluation d'une solution de positionnement ponctuel précis temps réel / Pierre Bosser in XYZ, n° 148 (septembre - novembre 2016)PermalinkHigh rate 30 seconds vs clock interpolation in precise point positioning (PPP) / Sorin Nistor in Geodetski vestnik, vol 60 n° 3 (September - November 2016)PermalinkPPP-RTK and inter-system biases: the ISB look-up table as a means to support multi-system PPP-RTK / Amir Khodabandeh in Journal of geodesy, vol 90 n° 9 (September 2016)PermalinkAutomatic extraction of road networks from GPS traces / Jia Qiu in Photogrammetric Engineering & Remote Sensing, PERS, vol 82 n° 8 (August 2016)PermalinkBimodal pattern of seismicity detected at the ocean margin of an Antarctic ice shelf / Denis Lombardi in Geophysical journal international, vol 206 n° 2 (August 2016)PermalinkDiagnostic study of a high‐precipitation event in the Western Mediterranean: adequacy of current operational networks / Samiro Khodayar in Quarterly Journal of the Royal Meteorological Society, vol 142 n° S1 (August 2016)PermalinkA geometry-free and ionosphere-free multipath mitigation method for BDS three-frequency ambiguity resolution / Dezhong Chen in Journal of geodesy, vol 90 n° 8 (August 2016)PermalinkA high-quality reprocessed ground-based GPS dataset for atmospheric process studies, radiosonde and model evaluation, and reanalysis of HyMeX Special Observing Period / Olivier Bock in Quarterly Journal of the Royal Meteorological Society, vol 142 n° S1 (August 2016)PermalinkA multi-instrument and multi-model assessment of atmospheric moisture variability over the Western Mediterranean during HyMeX / Patrick Chazette in Quarterly Journal of the Royal Meteorological Society, vol 142 n° S1 (August 2016)PermalinkA new computerized ionosphere tomography model using the mapping function and an application to the study of seismic-ionosphere disturbance / Jian Kong in Journal of geodesy, vol 90 n° 8 (August 2016)PermalinkA seamless weather–climate multi‐model intercomparison on the representation of a high impact weather event in the western Mediterranean: HyMeX IOP12 / Samiro Khodayar in Quarterly Journal of the Royal Meteorological Society, vol 142 n° S1 (August 2016)PermalinkThe study of key issues about integration of GNSS and strong-motion records for real-time earthquake monitoring / Rui Tu in Advances in space research, vol 58 n° 3 (August 2016)PermalinkThe variability of water vapour and pre-convective conditions over the mountainous island of Corsica / Bianca Adler in Quarterly Journal of the Royal Meteorological Society, vol 142 n° S1 (August 2016)PermalinkApplication of satellite navigation system for emergency warning and alerting / Suelynn Choy in Computers, Environment and Urban Systems, vol 58 (July 2016)PermalinkModeling of ionosphere time series using wavelet neural networks (case study: N-W of Iran) / Mir Reza Ghaffari Razin in Advances in space research, vol 58 n° 1 (July 2016)Permalink