Descripteur
Documents disponibles dans cette catégorie (329)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
Time-lapse photogrammetry of distributed snow depth during snowmelt / Simon Filhol in Water resources research, vol 55 n° 9 (September 2019)
[article]
Titre : Time-lapse photogrammetry of distributed snow depth during snowmelt Type de document : Article/Communication Auteurs : Simon Filhol, Auteur ; Alexis Perret , Auteur ; Luc Girod , Auteur ; Guillaume Sutter, Auteur ; Thomas V. Schuler, Auteur ; John F. Burkhart, Auteur Année de publication : 2019 Projets : 3-projet - voir note / Note générale : bibliographie
This work was supported by the Norwegian Research Council—Enhancing Snow Competency of Models and Operators(ESCYMO) project (NFR 244024), the University of Oslo eInfrastructure Competence Hub Geohive, and the European Research Council under the European Union's Seventh FrameworkProgram (FP/2007-2013)/ERC GrantAgreement 320816. This work forms a contribution to LATICE, which is a strategic research initiative funded by the Faculty of Mathematics and Natural Sciences at the University of Oslo. The source code of the software is available at this site (https://github.com/ArcticSnow/photo4D). Data are freely available from Zenodo.org (Filhol et al., 2018).FILHOL ET AL.7925Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] chaîne de traitement
[Termes IGN] code source libre
[Termes IGN] eau de fonte
[Termes IGN] manteau neigeux
[Termes IGN] Norvège
[Termes IGN] profondeur
[Termes IGN] semis de pointsRésumé : (auteur) Characterizing snowmelt both spatially and temporally from in situ observation remains a challenge. Available sensors (i.e., sonic ranger, lidar, airborne photogrammetry) provide either time series of local point measurements or sporadic surveys covering larger areas. We propose a methodology to recover from a minimum of three synchronized time-lapse cameras changes in snow depth and snow cover extent over area smaller or equivalent to 0.12 km2. Our method uses photogrammetry to compute point clouds from a set of three or more images and automatically repeat this task for the entire time series. The challenges were (1) finding an optimal experimental setup deployable in the field, (2) estimating the error associated with this technique, and (3) being able to minimize the input of manual work in the data processing pipeline. Developed and tested in the field in Finse, Norway, over 1 month during the 2018 melt season, we estimated a median melt of 2.12 ± 0.48 m derived from three cameras 1.2 km away from the region of interest. The closest weather station recorded 1.94 m of melt. Other parameters like snow cover extent and duration could be estimated over a 300 × 400m region. The software is open source and applicable to a broader range of geomorphologic processes like glacier dynamic, snow accumulation, or any other processes of surface deformation, with the conditions of (1) having fixed visible points within the area of interest and (2) resolving sufficient surface textures in the photographs. Numéro de notice : A2019-663 Affiliation des auteurs : ENSG+Ext (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2018WR024530 Date de publication en ligne : 19/08/2019 En ligne : https://doi.org/10.1029/2018WR024530 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99691
in Water resources research > vol 55 n° 9 (September 2019)[article]Integration of corner reflectors for the monitoring of mountain glacier areas with Sentinel-1 time series / Matthias Jauvin in Remote sensing, vol 11 n° 8 (August 2019)
[article]
Titre : Integration of corner reflectors for the monitoring of mountain glacier areas with Sentinel-1 time series Type de document : Article/Communication Auteurs : Matthias Jauvin, Auteur ; Yajing Yan, Auteur ; Emmanuel Trouvé, Auteur ; Bénédicte Fruneau , Auteur ; Michel Gay, Auteur ; Blaise Girard, Auteur Année de publication : 2019 Projets : 3-projet - voir note / Article en page(s) : n° 988 Note générale : bibliographie
The authors would like to thank Antoine Rabatel (Univ. Grenoble Alpes, I.G.E.) for having provided DSM LiDAR-based, acquired as part of the project European Facility for Airborne Research Transnational Access (EUFAR TA, EU FP7 Integrating Activity)—project ISOTHERM (Ice, SnOw vegeTation HypERspectral Measurements) that he has led. The authors would also like to thank the French National Geographic Institute (IGN) for providing the DEM.Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] Alpes
[Termes IGN] chambre anéchoïque
[Termes IGN] coin réflecteur
[Termes IGN] erreur de phase
[Termes IGN] faille géologique
[Termes IGN] glacier d'Argentière
[Termes IGN] image radar moirée
[Termes IGN] image Sentinel-SAR
[Termes IGN] interféromètrie par radar à antenne synthétique
[Termes IGN] moraine
[Termes IGN] pente
[Termes IGN] prévention des risques
[Termes IGN] rétrodiffusion
[Termes IGN] surface équivalente radar
[Termes IGN] tectoniqueRésumé : (auteur) Glacier flow and slope instabilities in Alpine mountain areas represent a hazard issue. Sentinel-1 satellites provide regular Synthetic Aperture Radar (SAR) acquisitions that are potentially useful to monitor these areas, but they can be affected by temporal decorrelation due to rapid changes in the surface. The application of interferometric synthetic aperture radar (InSAR) therefore seems difficult due to loss of coherence. On the other hand, Corner Reflectors (CR) can be used as coherent targets in SAR images for accurate displacement measurement thanks to their strong backscattering property and temporal stability. The use of CRs in multi-temporal InSAR analysis in Alpine mountain areas can thus be beneficial. In this study, we present a comparison between triangular and rectangular CRs, based on Radar Cross Section (RCS) measurements in an anechoic chamber and on long-term experiments over the Argentière glacier and the surrounding slopes and moraine. The visibility in both summer and winter of 10 CRs installed on the test site was investigated. As this area is exposed to heavy precipitation including snow falls, two perforated CRs were tested. The amplitude stability and the phase error of each CR were estimated. A precise tracking of two CRs installed at the glacier surface was also able to measure the displacement of the Argentière glacier, giving results close to previous GPS measurements. Furthermore, a Persistent Scatterer Interferometry (PSI) study was conducted, using the most stable CR as reference point to estimate slope instabilities, which led to the identification of an area corresponding to a tectonic fault called “Faille de l’angle”. The precise absolute locations of the CRs were successfully estimated and PS heights were compared with a LiDAR-based (Light Detection And Ranging) digital elevation model (DEM) and GPS measurements. Numéro de notice : A2019-627 Affiliation des auteurs : UPEM-LASTIG+Ext (2016-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/rs11080988 Date de publication en ligne : 25/04/2019 En ligne : https://doi.org/10.3390/rs11080988 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95363
in Remote sensing > vol 11 n° 8 (August 2019) . - n° 988[article]Classification of glacial lakes using integrated approach of DFPS technique and gradient analysis using Sentinel 2A data / Prateek Verma in Geocarto international, vol 34 n° 10 ([15/07/2019])
[article]
Titre : Classification of glacial lakes using integrated approach of DFPS technique and gradient analysis using Sentinel 2A data Type de document : Article/Communication Auteurs : Prateek Verma, Auteur ; Sanjay Kumar Ghosh, Auteur Année de publication : 2019 Article en page(s) : pp 1075 - 1088 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] changement climatique
[Termes IGN] glacier
[Termes IGN] Himalaya
[Termes IGN] image Sentinel-MSI
[Termes IGN] lac glaciaire
[Termes IGN] Normalized Difference Water Index
[Termes IGN] seuillage d'image
[Termes IGN] Uttarakhand (Inde ; état)Résumé : (auteur) It is important to identify and locate glacial lakes for assessing any potential hazard. This study presents a combination of semi-automatic method Double-Window Flexible Pace Search (DFPS) and edge detection technique to identify glacial lakes using Sentinel 2A satellite data. Initially, Normalized Difference Water Index (NDWI) has been used to identify water and non-water areas, while DFPS and Edge detection technique has been used to identify an optimum threshold value to distinguish between water and shadow areas. The optimal threshold from DFPS process is 0.21, while threshold value of gradient magnitude using edge detection process is 0.318. The number of glacial lakes identified using the above algorithm is in close agreement with previously published results on glacial lakes in Gangotri glacier using different techniques. Thus, a combination of DFPS and edge detection process has successfully segregated glacial lakes from other features present in Gangotri glacier. Numéro de notice : A2019-300 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2018.1469677 Date de publication en ligne : 15/05/2018 En ligne : https://doi.org/10.1080/10106049.2018.1469677 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93220
in Geocarto international > vol 34 n° 10 [15/07/2019] . - pp 1075 - 1088[article]Improved algorithms for the measurement of total precipitable water and cloud liquid water from SARAL microwave radiometer observations / Rajput Neha Mangalsinh in Marine geodesy, vol 42 n° 4 (July 2019)
[article]
Titre : Improved algorithms for the measurement of total precipitable water and cloud liquid water from SARAL microwave radiometer observations Type de document : Article/Communication Auteurs : Rajput Neha Mangalsinh, Auteur ; Atul Kumar Varma, Auteur Année de publication : 2019 Article en page(s) : pp 367 - 381 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] cryosphère
[Termes IGN] données altimétriques
[Termes IGN] hauteurs de mer
[Termes IGN] image GPM
[Termes IGN] image SSMIS
[Termes IGN] image TRMM-MI
[Termes IGN] nuage
[Termes IGN] précipitation
[Termes IGN] radiomètre à hyperfréquence
[Termes IGN] température de luminance
[Termes IGN] vapeur d'eauRésumé : (auteur) SARAL carried onboard a radar altimeter that provides very precise measurements of the sea surface height (SSH). Like other altimetric missions, SARAL carries a passive microwave radiometer (PMR) for wet tropospheric correction to SSH. In the present study, new algorithms are developed for the retrieval of cloud liquid water (CLW) and total precipitable water vapor (TPW) over the global oceans from PMR measurements of the brightness temperatures. A radiative transfer and genetic algorithm based retrieval scheme is proposed for the estimation of CLW and TPW from SARAL PMR. The comparisons of CLW from PMR with independent measurements from GPM-GMI and SSMIS within and outside ±40° latitudes show correlation (R) of 0.86 and 0.83, bias of 0.7 and −3.61 mg/cm2, and root mean square error (RMSE) of 8.42 and 8.07 mg/cm2, respectively. Similarly, TPW from PMR with GPM-GMI and SSMIS show R of 0.99 and 0.98, bias of −0.04 and −0.03 g/cm2 and RMSE of 0.17 and 0.17 g/cm2, respectively. The retrieval accuracy of CLW and TPW from the new algorithms is compared with these parameters provided in the SARAL geophysical data records as finished products, which showed substantial improvement in the quality of the parameters from the new algorithm. Numéro de notice : A2019-282 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01490419.2019.1624662 Date de publication en ligne : 12/06/2019 En ligne : https://doi.org/10.1080/01490419.2019.1624662 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93116
in Marine geodesy > vol 42 n° 4 (July 2019) . - pp 367 - 381[article]Real-time sea-level monitoring using Kalman filtering of GNSS-R data / Joakim Strandberg in GPS solutions, vol 23 n° 3 (July 2019)
[article]
Titre : Real-time sea-level monitoring using Kalman filtering of GNSS-R data Type de document : Article/Communication Auteurs : Joakim Strandberg, Auteur ; Thomas Hobiger, Auteur ; Rüdiger Haas, Auteur Année de publication : 2019 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] B-Spline
[Termes IGN] déformation de la croute terrestre
[Termes IGN] filtre de Kalman
[Termes IGN] glace de mer
[Termes IGN] marée terrestre
[Termes IGN] niveau de la mer
[Termes IGN] rapport signal sur bruit
[Termes IGN] réflectométrie par GNSS
[Termes IGN] surface de la mer
[Termes IGN] temps réel
[Vedettes matières IGN] AltimétrieRésumé : (auteur) Current GNSS-R (GNSS reflectometry) techniques for sea surface measurements require data collection over longer periods, limiting their usability for real-time applications. In this work, we present a new, alternative GNSS-R approach based on the unscented Kalman filter and the so-called inverse modeling approach. The new method makes use of a mathematical description that relates SNR (signal-to-noise ratio) variations to multipath effects and uses a B-spline formalism to obtain time series of reflector height. The presented algorithm can provide results in real time with a precision that is significantly better than spectral inversion methods and almost comparable to results from inverse modeling in post-processing mode. To verify the performance, the method has been tested at station GTGU at the Onsala Space Observatory, Sweden, and at the station SPBY in Spring Bay, Australia. The RMS (root mean square) error with respect to nearby tide gauge data was found to be 2.0 cm at GTGU and 4.8 cm at SPBY when evaluating the output corresponding to real-time analysis. The method can also be applied in post-processing, resulting in RMS errors of 1.5 cm and 3.3 cm for GTGU and SPBY, respectively. Finally, based on SNR data from GTGU, it is also shown that the Kalman filter approach is able to detect the presence of sea ice with a higher temporal resolution than the previous methods and traditional remote sensing techniques which monitor ice in coastal regions. Numéro de notice : A2019-198 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-019-0851-1 En ligne : https://doi.org/10.1007/s10291-019-0851-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92653
in GPS solutions > vol 23 n° 3 (July 2019)[article]Classification du type et de la concentration de la banquise, à partir d’images Sentinel-1 SAR, grâce à des réseaux de neurones convolutifs / Hugo Boulze (2019)PermalinkMicrowave indices from active and passive sensors for remote sensing applications / Emanuele Santi (2019)PermalinkPermalinkRelevé de la grotte glacée de Cenote Abyss dans les Dolomites / Farouk Kadded in XYZ, n° 157 (décembre 2018 - février 2019)PermalinkA data model for moving regions of fixed shape in databases / Florian Heinz in International journal of geographical information science IJGIS, vol 32 n° 9-10 (September - October 2018)PermalinkContribution actuelle de la calotte Antarctique à la variation du niveau marin / Clémence Chupin (2018)PermalinkGenerating terrestrial glacier views from historic airphotos for comparison with contemporary ground photographs / Marion Holst (2018)PermalinkPotential and limits of Sentinel-1 data for small alpine glaciers monitoring / Matthias Jauvin (2018)PermalinkGPS coordinate time series measurements in Ontario and Quebec, Canada / Hadis Samadi Alinia in Journal of geodesy, vol 91 n° 6 (June 2017)PermalinkPushing the sensitivity limits of RTS-based continuous deformation monitoring of an alpine valley / Mariusz Frukacz in Applied geomatics, vol 9 n° 2 (June 2017)PermalinkBaltic sea ice concentration estimation using SENTINEL-1 SAR and AMSR2 microwave radiometer data / Juha Karvonen in IEEE Transactions on geoscience and remote sensing, vol 55 n° 5 (May 2017)PermalinkEvaluation of multisource data for glacier terrain mapping : a neural net approach / Aparna Shukla in Geocarto international, vol 32 n° 5 (May 2017)PermalinkInverting Glacial Isostatic Adjustment signal using Bayesian framework and two linearly relaxing rheologies / Lambert Caron in Geophysical journal international, vol 209 n° 2 (May 2017)PermalinkDevelopment of a sampling protocol for monitoring snow melt using photogrammetry / Guillaume Sutter (2017)PermalinkPermalinkPermalinkTélédétection pour l'observation des surfaces continentales, Volume 4. Observation des surfaces continentales par télédétection 2 / Nicolas Baghdadi (2017)PermalinkAn approach for estimating time-variable rates from geodetic time series / Olga Didova in Journal of geodesy, vol 90 n° 11 (November 2016)PermalinkSMAP L-Band microwave radiometer: RFI mitigation prelaunch analysis and first year on-orbit observations / Priscilla N. Mohammed in IEEE Transactions on geoscience and remote sensing, vol 54 n° 10 (October 2016)PermalinkTopographic gravitational potential up to second-order derivatives: an examination of approximation errors caused by rock-equivalent topography (RET) / Michael Kuhns in Journal of geodesy, vol 90 n° 9 (September 2016)Permalink