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Auteur Thierry Koleck |
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Affiner la recherche Interroger des sources externesNear-real-time identification of the drivers of deforestation in French Guiana / Marie Ballère (2021)
Titre : Near-real-time identification of the drivers of deforestation in French Guiana Type de document : Article/Communication Auteurs : Marie Ballère Editeur : Munich [Allemagne] : European Geosciences Union EGU Année de publication : 2021 Conférence : EGU 2021, General Assembly 19/04/2021 30/04/2021 en ligne OA Abstracts only Format : 21 x 30 cm Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] déboisement
[Termes IGN] exploitation forestière
[Termes IGN] forêt tropicale
[Termes IGN] Guyane (département français)
[Termes IGN] image radar moirée
[Termes IGN] image Sentinel-SAR
[Termes IGN] mine d'or
[Termes IGN] surveillance forestière
[Termes IGN] urbanisationNuméro de notice : C2021-004 Affiliation des auteurs : UGE-LASTIG+Ext (2020- ) Thématique : BIODIVERSITE/FORET/IMAGERIE Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : sans En ligne : https://doi.org/10.5194/egusphere-egu21-16015 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97598
Titre : SAR data for tropical forest disturbance alerts in French Guiana: Benefit over optical imagery Type de document : Article/Communication Auteurs : Marie Ballère Année de publication : 2021 Projets : 1-Pas de projet / Article en page(s) : n° 112159 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] forêt tropicale
[Termes IGN] Guyane (département français)
[Termes IGN] image radar moirée
[Termes IGN] image Sentinel-SAR
[Termes IGN] surveillance forestière
[Termes IGN] temps réelRésumé : (auteur) French Guiana forests cover 8 million hectares. With 98% of emerged land covered by forests, French Guiana is the area with the highest proportion of forest cover in the world. These forests are home to an exceptionally rich and diverse wealth of biodiversity that is both vulnerable and under threat due to high levels of pressure from human activity. As part of the French territory, French Guiana benefits from determined and continuous national efforts in the preservation of biodiversity and the environmental functionalities of ecosystems. The loss and fragmentation of forest cover caused by gold mining (legal and illegal), smallholder agriculture and forest exploitation, are considered as small-scale disturbances, although representing strong effects to vulnerable natural habitats, landscapes, and local populations. To monitor forest management programs and combat illegal deforestation and forest opening near-real time alerts system based on remote sensing data are required. For this large territory under frequent cloud cover, Synthetic-Aperture Radar (SAR) data appear to be the best adapted. In this paper, a method for forest alerts in a near-real time context based on Sentinel-1 data over the whole of French Guiana (83,534 km2) was developed and evaluated. The assessment was conducted for 2 years between 2016 and 2018 and includes comparisons with reference data provided by French Guiana forest organizations and comparisons with the existing University of Maryland Global Land Analysis and Discovery Forest Alerts datasets based on Landsat data. The reference datasets include 1,867 plots covering 2,124.5 ha of gold mining, smallholder agriculture and forest exploitation. The validation results showed high user accuracies (96.2%) and producer accuracies (81.5%) for forest loss detection, with the latter much higher than for optical forest alerts (36.4%). The forest alerts maps were also compared in terms of detection timing, showing systematic temporal delays of up to one year in the optical method compared to the SAR method. These results highlight the benefits of SAR over optical imagery for forest alerts detection in French Guiana. Finally, the potential of the SAR method applied to tropical forests is discussed. The SAR-based map of this study is available on http://cesbiomass.net/. Numéro de notice : A2021-066 Affiliation des auteurs : UGE-LASTIG+Ext (2020- ) Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2020.112159 Date de publication en ligne : 05/11/2020 En ligne : https://doi.org/10.1016/j.rse.2020.112159 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96937
in Remote sensing of environment > Vol 252 (January 2021) . - n° 112159[article]
Titre : Potential of Sentinel-1 data for monitoring temperate mixed forest phenology Type de document : Article/Communication Auteurs : Pierre-Louis Frison Année de publication : 2018 Projets : 3-projet - voir note / Article en page(s) : n° 2049 Note générale : bibliographie
This research was funding by the Centre National d’Etudes Spatiales (CNES), grant number DCT/SI/TR/2016-01532Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse diachronique
[Termes IGN] arbre caducifolié
[Termes IGN] coefficient de rétrodiffusion
[Termes IGN] cohérence des données
[Termes IGN] données polarimétriques
[Termes IGN] Fontainebleau, forêt de (Seine-et-Marne)
[Termes IGN] forêt tempérée
[Termes IGN] image radar moirée
[Termes IGN] image Sentinel-SAR
[Termes IGN] phénologie
[Termes IGN] signature spectrale
[Termes IGN] surveillance forestièreRésumé : (auteur) In this study, the potential of Sentinel-1 data to seasonally monitor temperate forests was investigated by analyzing radar signatures observed from plots in the Fontainebleau Forest of the Ile de France region, France, for the period extending from March 2015 to January 2016. Radar backscattering coefficients, σ0 and the amplitude of temporal interferometric coherence profiles in relation to environmental variables are shown, such as in situ precipitation and air temperature. The high temporal frequency of Sentinel-1 acquisitions (i.e., twelve days, or six, if both Sentinel-1A and B are combined over Europe) and the dual polarization configuration (VV and VH over most land surfaces) made a significant contribution. In particular, the radar backscattering coefficient ratio of VV to VH polarization, σ0VV/σ0VH , showed a well-pronounced seasonality that was correlated with vegetation phenology, as confirmed in comparison to NDVI profiles derived from Landsat-8 (r = 0.77) over stands of deciduous trees. These results illustrate the high potential of Sentinel-1 data for monitoring vegetation, and as these data are not sensitive to the atmosphere, the phenology could be estimated with more accuracy than optical data. These observations will be quantitatively analyzed with the use of electromagnetic models in the near future. Numéro de notice : A2018-669 Affiliation des auteurs : UPEM-LASTIG+Ext (2016-2019) Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/rs10122049 Date de publication en ligne : 17/12/2018 En ligne : https://doi.org/10.3390/rs10122049 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94271
in Remote sensing > vol 10 n° 12 (December 2018) . - n° 2049[article]
Titre : Cartographier le relief sous les forêts, et le substrat sous les déserts de sable : les attentes de la mission radar Biomass Type de document : Article/Communication Auteurs : Laurent Polidori, Auteur ; Thierry Koleck, Auteur ; Ludovic Villard, Auteur ; Mhamad El Hage, Auteur ; Philippe Paillou, Auteur ; Thuy Le Toan, Auteur Année de publication : 2018 Article en page(s) : pp 56 - 61 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Missions spatiales
[Termes IGN] bande P
[Termes IGN] Biomass
[Termes IGN] désert
[Termes IGN] forêt
[Termes IGN] interféromètrie par radar à antenne synthétique
[Termes IGN] modèle numérique de terrain
[Termes IGN] polarimétrie radar
[Termes IGN] radar à antenne synthétique
[Termes IGN] tomographie radarRésumé : (Auteur) La mission spatiale Biomass sera lancée par l'Agence spatiale européenne en 2021 avec un radar à synthèse d'ouverture en bande P dans le but de cartographier la biomasse forestière à l'échelle planétaire, ainsi que la hauteur et les dégradations du couvert forestier. Plusieurs produits secondaires sont aussi envisagés, notamment la cartographie 30 du relief sous les forêts et du substrat sous les déserts de sable, qui devraient bénéficier du pouvoir de pénétration des ondes radar en bande P et de l'aptitude de la tomographie à séparer les contributions des différentes couches dans un profil vertical de rétrodiffusion. Ces possibilités ayant été démontrées lors de campagnes aéroportées, la qualité des modèles 3D attendus de la mission Biomass reste à évaluer. Numéro de notice : A2018-090 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89464
in XYZ > n° 154 (mars - mai 2018) . - pp 56 - 61[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 112-2018011 RAB Revue Centre de documentation En réserve L003 Disponible
Titre : Potential of Sentinel-1 data for vegetation monitoring Type de document : Article/Communication Auteurs : Pierre-Louis Frison Editeur : Valence [Espagne] : Universidad de Valencia Année de publication : 2017 Conférence : RAQRS 2017, 5th international symposium on Recent Advance in Quantitative Remote Sensing 18/09/2017 22/09/2017 Valence Espagne open access proceedings Langues : Anglais (eng) Résumé : (auteur) The monitoring of seasonal variations of Earth Surfaces needs acquisitions realized with high temporal frequencies. Radar remote sensing data have shown its potential for surface parameters monitoring (biomass and soil moisture). For example, the high temporal frequency of acquisitions (about 1-5 days depending of the latitude) realized par radar spaceborne scatterometers, such as those onboard ERS or METOP satellites allowed the quantitative estimation of yearly biomass and soil moisture estimations over semi-arid areas, such as the Sahelian region. The associated coarse spatial resolution (20 – 50 km) makes these data dedicated applications at regional and global scales. The Sentinel-1 mission allows to acquire of radar data every 12 days from the period extending from March 2015 to August 2016, when only Sentinel-1A operated alone. This period is reduced to 6 days since September 2016 by the combination of Sentinel-1B acquisitions. Consequently, it allows for the first time to assess the potential of radar data acquired with this revisiting time associated to a spatial resolution of about 20 m. In addition to the radar intensity, data acquired by the CSAR (C-band Synthetic Aperture Radar) onboard Sentinel-1 allow to access to he phase information. Consequently, interferometric products between two consecutive aquisitions can be generated, such as the interferometric coherence ρ. In this talk we analyze temporal profiles of radar backscattering coefficient σ0 as well as coherence |ρ| over vegetated areas. Two different sites are considered, both located in France: a temperate forest near Fontainebleau, in the region of Ile de France, and an agricultural area located near Toulouse. Primary results show that on the contrary to existing SAR missions, characterized by a temporal repetitivity of about one month, the 12 days temporal period, combined to the dual polarization (both VV and VH polarizations are acquired in the Interferometric Wide Swath mode over land surfaces) allow to observe a seasonal cycle in the σ0 temporal profile. This temporal behaviour, which appears to be time coincident with the leaves activity period over the Fontainebleau Forest, is particularly emphasis with the polarization ration, i.e.: σ0VV⁄σ0VH. The coherence behaviour appears to be low (≈ 0.2) and constant most of the year over the forest. It appears that the highest seasonal variations are observed over agricultural fields where both σ0 and |ρ| temporal profiles show complementary behaviour. Numéro de notice : C2017-050 Affiliation des auteurs : UPEM-LASTIG+Ext (2016-2019) Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91948
