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A spatially explicit database of wind disturbances in European forests over the period 2000–2018 / Giovanni Forzieri in Earth System Science Data, vol 12 n° 1 (January 2020)  

Public [article]  inEarth System Science Data > vol 12 n° 1 (January 2020) . - pp 257 - 276 Titre : A spatially explicit database of wind disturbances in European forests over the period 2000–2018 Type de document : Article/Communication Auteurs : Giovanni Forzieri, Auteur ; Matteo Pecchi, Auteur ; Marco Girardello, Auteur ; Achille Mauri, Auteur ; Marcus Klaus, Auteur ; Christo Nikolov, Auteur ; Marius Rüetschi, Auteur ; Barry Gardiner, Auteur ; Julian Tomaštík, Auteur ; David Small, Auteur ; Constantin Nistor, Auteur ; Donatas Jonikavičius, Auteur ; Jonathan Spinoni, Auteur ; Luc Feyen, Auteur ; Francesca Giannetti, Auteur ; Rinaldo Comino, Auteur ; Alessandro Wolynski, Auteur ; Francesco Pirotti, Auteur ; Fabio Maistrelli, Auteur ; Ionut Savulescu, Auteur ; Stéphanie Wurpillot , Auteur ; et al., Auteur Année de publication : 2020 Projets : 3-projet - voir note / Article en page(s) : pp 257 - 276 Note générale : bibliographie This research has been supported by the European Commission, Joint Research Centre (project FOREST@RISK). Langues : Anglais (eng) Descripteur : [Termes IGN] base de données localisées [Termes IGN] capital sur pied [Termes IGN] données vectorielles [Termes IGN] écosystème forestier [Termes IGN] Europe (géographie politique) [Termes IGN] forêt [Termes IGN] inventaire forestier étranger (données) [Termes IGN] inventaire forestier national (données France) [Termes IGN] perturbation écologique [Termes IGN] tempête [Termes IGN] tempête Klaus de 2009 [Termes IGN] tempête Lothar de 1999 [Termes IGN] tempête Xynthia de 2010 [Termes IGN] vent [Termes IGN] vingt-et-unième siècle [Vedettes matières IGN] Foresterie Mots-clés libres : FORWIND Résumé : (auteur) Strong winds may uproot and break trees and represent a major natural disturbance for European forests. Wind disturbances have intensified over the last decades globally and are expected to further rise in view of the effects of climate change. Despite the importance of such natural disturbances, there are currently no spatially explicit databases of wind-related impact at a pan-European scale. Here, we present a new database of wind disturbances in European forests (FORWIND). FORWIND is comprised of more than 80 000 spatially delineated areas in Europe that were disturbed by wind in the period 2000–2018 and describes them in a harmonized and consistent geographical vector format. The database includes all major windstorms that occurred over the observational period (e.g. Gudrun, Kyrill, Klaus, Xynthia and Vaia) and represents approximately 30 % of the reported damaging wind events in Europe. Correlation analyses between the areas in FORWIND and land cover changes retrieved from the Landsat-based Global Forest Change dataset and the MODIS Global Disturbance Index corroborate the robustness of FORWIND. Spearman rank coefficients range between 0.27 and 0.48 (p value  Numéro de notice : A2020-874 Affiliation des auteurs : IGN+Ext (2012-2019) Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/essd-12-257-2020 Date de publication en ligne : 10/02/2020 En ligne : https://doi.org/10.5194/essd-12-257-2020 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99655 [article]

High-precision positioning of radar scatterers / Prabu Dheenathayalan in Journal of geodesy, vol 90 n° 5 (May 2016)  

Public [article]  inJournal of geodesy > vol 90 n° 5 (May 2016) . - pp 403 – 422 Titre : High-precision positioning of radar scatterers Type de document : Article/Communication Auteurs : Prabu Dheenathayalan, Auteur ; David Small, Auteur ; Adrian Schubert, Auteur ; Ramon F. Hanssen, Auteur Année de publication : 2016 Article en page(s) : pp 403 – 422 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] diffusomètre [Termes IGN] données localisées 3D [Termes IGN] ellipsoïde (géodésie) [Termes IGN] image TerraSAR-X [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] matrice de covariance [Termes IGN] précision du positionnement [Termes IGN] série temporelle [Termes IGN] télédétection spatiale Résumé : (auteur) Remote sensing radar satellites cover wide areas and provide spatially dense measurements, with millions of scatterers. Knowledge of the precise position of each radar scatterer is essential to identify the corresponding object and interpret the estimated deformation. The absolute position accuracy of synthetic aperture radar (SAR) scatterers in a 2D radar coordinate system, after compensating for atmosphere and tidal effects, is in the order of centimeters for TerraSAR-X (TSX) spotlight images. However, the absolute positioning in 3D and its quality description are not well known. Here, we exploit time-series interferometric SAR to enhance the positioning capability in three dimensions. The 3D positioning precision is parameterized by a variance–covariance matrix and visualized as an error ellipsoid centered at the estimated position. The intersection of the error ellipsoid with objects in the field is exploited to link radar scatterers to real-world objects. We demonstrate the estimation of scatterer position and its quality using 20 months of TSX stripmap acquisitions over Delft, the Netherlands. Using trihedral corner reflectors (CR) for validation, the accuracy of absolute positioning in 2D is about 7 cm. In 3D, an absolute accuracy of up to ∼66 cm is realized, with a cigar-shaped error ellipsoid having centimeter precision in azimuth and range dimensions, and elongated in cross-range dimension with a precision in the order of meters (the ratio of the ellipsoid axis lengths is 1/3/213, respectively). The CR absolute 3D position, along with the associated error ellipsoid, is found to be accurate and agree with the ground truth position at a 99% confidence level. For other non-CR coherent scatterers, the error ellipsoid concept is validated using 3D building models. In both cases, the error ellipsoid not only serves as a quality descriptor, but can also help to associate radar scatterers to real-world objects. Numéro de notice : A2016-268 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0883-4 En ligne : https://doi.org/10.1007/s00190-015-0883-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80808 [article]