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Recurrent-based regression of Sentinel time series for continuous vegetation monitoring / Anatol Garioud in Remote sensing of environment, vol 263 (15 September 2021)  

Public [article]  inRemote sensing of environment > vol 263 (15 September 2021) . - n° 112419 Titre : Recurrent-based regression of Sentinel time series for continuous vegetation monitoring Type de document : Article/Communication Auteurs : Anatol Garioud , Auteur ; Silvia Valero, Auteur ; Sébastien Giordano , Auteur ; Clément Mallet , Auteur Année de publication : 2021 Projets : 3-projet - voir note / Article en page(s) : n° 112419 Note générale : bibliographie This work is funded by the Agence de la transition écologique (ADEME) and the Centre National d'Études Spatiales (CNES). Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] classification par réseau neuronal [Termes IGN] classification par réseau neuronal récurrent [Termes IGN] fusion d'images [Termes IGN] image Sentinel-MSI [Termes IGN] image Sentinel-SAR [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] régression [Termes IGN] série temporelle [Termes IGN] surveillance de la végétation Résumé : (auteur) Dense time series of optical satellite imagery describing vegetation activity provide essential information for the efficient and regular monitoring of vegetation. Nevertheless, the temporal resolution of optical sensors is strongly affected by cloud cover, resulting in significant missing information. The use of complementary acquisitions, such as Synthetic Aperture Radar (SAR) data, opens the door to the development of new multi-sensor methodologies aiming at the reconstruction of missing information. However, the joint exploitation of new radar and optical missions, such as the Sentinel, raises new challenges given the different nature and response of the two data sources. In this work, the SenRVM methodology is proposed as a new multi-sensor approach to regress SAR time series towards Normalized Difference Vegetation Index (NDVI). A deep Recurrent Neural Network architecture which integrates SAR acquisitions and ancillary data is adopted. The regression task permits a continuous optical temporal resolution of 6 days. Multiple experiments are carried out to assess the SenRVM framework by studying two large-scale areas in France. Through an extensive interpretation of the results, SenRVM is evaluated on three main vegetation types (grasslands, crops, and forests). High accurate results (R2 > 0.83 and MAE Numéro de notice : A2021-499 Affiliation des auteurs : UGE-LaSTIG+Ext (2020- ) Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1016/j.rse.2021.112419 date de publication en ligne : 25/06/2021 En ligne : https://doi.org/10.1016/j.rse.2021.112419 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98004 [article]

Fiducial reference systems for time and coordinates in satellite altimetry / Stelios Mertikas in Advances in space research, vol 68 n° 2 (15 July 2021)  

Public [article]  inAdvances in space research > vol 68 n° 2 (15 July 2021) . - pp 1140 - 1160 Titre : Fiducial reference systems for time and coordinates in satellite altimetry Type de document : Article/Communication Auteurs : Stelios Mertikas, Auteur ; Craig Donlon, Auteur ; Demetrios Matsakis, Auteur ; Constantin Mavrocordatos, Auteur ; Zuheir Altamimi , Auteur ; Costas Kokolakis, Auteur ; Achilles Tripolitsiotis, Auteur Année de publication : 2021 Projets : 3-projet - voir note / Article en page(s) : pp 1140 - 1160 Note générale : bibliographie Part of this work has been produced with the financial assistance of the European Union and the European Space Agency under the project FRM4S6 (Fiducial Reference Systems For Sentinel-6, No. 4000129892/20/NL/FF/ab) Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] altimétrie satellitaire par radar [Termes IGN] coordonnées cartésiennes géocentriques [Termes IGN] système de référence altimétrique Résumé : (auteur) Time is the fundamental measurement in satellite altimetry and the key parameter in building and keeping up a long-term, consistent, and reliable record for monitoring changes in sea level. Over the years, different time scales, although interconnected, have been used in altimetry and also in satellite positioning. This sometimes leads to inexplicit descriptions and ambiguous use of time and orbit coordinates as well as of their transformations between various reference and measuring systems. Altimetry satellites, like Sentinel-3, CryoSat-2, Jason-3, HY-2A/-2B, IceSat-2, etc., observe and practically realize ranges by measuring time differences between the transmission and reception of an electromagnetic wave (either radar or laser at present). Similar principles apply for global navigation satellite systems and for their terrestrial reference systems upon which altimetry is linked and tied together. Yet, the “meter” of any terrestrial reference systems is also defined by time. This work seeks to establish a standard reference system for “time” and “coordinates” in an effort to reach uniform and absolute standardization for satellite altimetry. It describes various errors generated from differences, discontinuities and interactions in time, frequency, range, time tagging, and reference coordinate frames. A new approach, called “fiducial reference measurements for altimetry”, is here given to examine ways to connect errors with metrology standards in order to improve the estimation of uncertainty budgets in ocean and water level observation by altimetry. Finally, the geocentric inertial reference system and the international atomic time are proposed in this paper for satellite altimetry observations and products. Numéro de notice : A2021-601 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2020.05.014 En ligne : https://doi.org/10.1016/j.asr.2020.05.014 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98240 [article]

Climate warming predispose sessile oak forests to drought-induced tree mortality regardless of management legacies / Any Mary Petritan in Forest ecology and management, vol 491 (1st July 2021)  

Public [article]  inForest ecology and management > vol 491 (1st July 2021) . - n° 119097 Titre : Climate warming predispose sessile oak forests to drought-induced tree mortality regardless of management legacies Type de document : Article/Communication Auteurs : Any Mary Petritan, Auteur ; Ion Catalin Petritan, Auteur ; Andrea Hevia, Auteur ; Helge Walentowski, Auteur ; Olivier Bouriaud , Auteur ; Raul Sánchez-Salguero, Auteur Année de publication : 2021 Projets : 3-projet - voir note / Article en page(s) : n° 119097 Note générale : bibliographie This work was supported by NEMKLIM project: Nemoral Forests under Climate Extremes (NEMKLIM Project, grant number 3517861300), financed by the German Federal Agency for Nature Conservation (Bundesamt für Naturschutz, BfN) and the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, Germany and by project PN 19070506 financed by Romanian National Authority from Scientific Research and Innovation. Langues : Anglais (eng) Descripteur : [Termes IGN] chênaie [Termes IGN] croissance des arbres [Termes IGN] Europe centrale [Termes IGN] forêt tempérée [Termes IGN] mortalité [Termes IGN] précipitation [Termes IGN] Quercus sessiliflora [Termes IGN] Roumanie [Termes IGN] sécheresse [Termes IGN] structure d'un peuplement forestier [Termes IGN] température de l'air [Termes IGN] vulnérabilité [Vedettes matières IGN] Végétation et changement climatique Résumé : (auteur) Climate warming-related drought could become a major driver of large-scale forest dieback. However, little is known about how past management legacies modulate the climate-growth responses during recent dieback episodes in central European oak forests. Here, we examine the role played by past management –unmanaged old-growth vs. managed forests– in recent tree mortality events occurring in Quercus petraea (Matt.) Liebl. stands across large areas of western Romania. We analyze how stand structure (tree size, competition) and climatic factors (drought, temperature and precipitation) drive tree radial growth patterns in neighboring standing dead and living trees. We analyzed basal area increments (BAI) trends, past management legacies and climate- and drought-growth relationships during the 20th century to distinguish the roles and interactions on recent warming-induced dieback. We observed that temperature rises and changes in atmospheric water demand during growing season let to increasing drought stress during the late 20th century affecting both managed and unmanaged forests. Dead trees from old-growth and managed forests showed lower growth than living trees after dieback onset. In both forests, dead and living trees displayed divergent growth patterns after dry 1980s, indicating that dieback was triggered by severe extreme conditions. Dead trees from managed stands experienced significant stronger growth reductions after 1980s though they experienced less tree-to-tree competition than dead trees in old-growth forest. High stand density negatively drove growth and enhanced climate sensitivity in old-growth stands. Competition acted synergistically with climate warming and drought causing tree mortality regardless of the management legacies in of Q. petraea forests. Our retrospective assessment of growth rates in relation with climate and structure changes offers valuable information for further forest conservation and management decisions of Q. petraea forests. These findings highlight the importance of past uses legacies driving recent forest dieback in temperate oak forests, making them more vulnerable under forecasted climate-warming related droughts in central Europe. Numéro de notice : A2021-496 Affiliation des auteurs : LIF+Ext (2020- ) Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.foreco.2021.119097 date de publication en ligne : 07/04/2021 En ligne : https://doi.org/10.1016/j.foreco.2021.119097 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97973 [article]

Apports de la télédétection au calcul d’indicateurs agri-environnementaux au service de la PAC, des agriculteurs et porteurs d’enjeu / Christian Bockstaller in Innovations Agronomiques, vol 83 (Mars 2021)  

Public [article]  inInnovations Agronomiques > vol 83 (Mars 2021) . - pp 43 - 59 Titre : Apports de la télédétection au calcul d’indicateurs agri-environnementaux au service de la PAC, des agriculteurs et porteurs d’enjeu Titre original : Contribution of remote sensing to the calculation of agri-environmental indicators for the CAP, farmers and stakeholders Type de document : Article/Communication Auteurs : Christian Bockstaller, Auteur ; Clélia Sirami, Auteur ; David Sheeren , Auteur ; Olivier Keichinger, Auteur ; Ludovic Arnaud, Auteur ; Arthur Favreau, Auteur ; F. Angevin, Auteur ; Dominique Laurent , Auteur ; Guillaume Marchand , Auteur ; Emmanuel de Laroche, Auteur ; Eric Ceschia, Auteur Année de publication : 2021 Projets : 3-projet - voir note / Conférence : Colloque 2020 Le spatial au service de la transition agro-écologique 16/12/2020 16/12/2020 en ligne France Article en page(s) : pp 43 - 59 Note générale : bibliographie projet NIVA Langues : Français (fre) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] biodiversité [Termes IGN] image Sentinel [Termes IGN] indicateur environnemental [Termes IGN] nitrate [Termes IGN] teneur en carbone Résumé : (auteur) Le développement de méthodes d’évaluation multicritère est une des étapes pour accompagner et soutenir la transition agroécologique en cours. La mise en œuvre d’indicateurs agri-environnementaux au niveau territorial se heurte à un obstacle opérationnel qui est la phase d’acquisition des données sur les pratiques, la description des sols, la végétation voire des données climatiques et ceci que ce soit à des résolutions fines (parcelles, exploitation) ou sur de grandes étendues (département, région ou pays). Le recours à des données satellitaires constitue une piste majeure pour lever ce verrou, notamment avec l’arrivée à partir de 2014 d’une nouvelle génération de satellites à haute résolution d’observation de la terre : les Sentinel. Après un bref état de l’art des possibilités offertes par ces nouveaux satellites, l’article présente les avancées sur le développement d’indicateurs agri-environnementaux calculables au moyen de la télédétection. Un focus est mis sur trois indicateurs dans le cadre du projet H2020 NIVA: bilan carbone, risque de lixiviation des nitrates et biodiversité. Numéro de notice : A2021-486 Affiliation des auteurs : IGN+Ext (2020- ) Thématique : BIODIVERSITE/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueNat DOI : 10.15454/ns4w-a314 En ligne : https://doi.org/10.15454/ns4w-a314 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97470 [article]

Turgor – a limiting factor for radial growth in mature conifers along an elevational gradient / Richard L. Peters in New phytologist, vol 229 n° 1 (January 2021)  

Public [article]  inNew phytologist > vol 229 n° 1 (January 2021) . - pp 213 - 229 Titre : Turgor – a limiting factor for radial growth in mature conifers along an elevational gradient Type de document : Article/Communication Auteurs : Richard L. Peters, Auteur ; Kathy Steppe, Auteur ; Henri E. Cuny , Auteur ; Dirk J.W. de Pauw, Auteur ; David Frank, Auteur ; Marcus Schaub, Auteur ; Cyrille B.K. Rathgeber, Auteur ; Antoine Cabon, Auteur ; Patrick Fonti, Auteur Année de publication : 2021 Projets : 3-projet - voir note / Article en page(s) : pp 213 - 229 Note générale : bibliographie Funding information : COST Action network. Grant Number: STReESS/FP1106 -&- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung. Grant Numbers: CLIMWOOD/160077, Early Postdoc.Mobility/P2BSP3_184475, LOTFOR/150205 Langues : Anglais (eng) Descripteur : [Termes IGN] cerne [Termes IGN] changement climatique [Termes IGN] croissance des arbres [Termes IGN] gradient [Termes IGN] gradient de pente [Termes IGN] Larix decidua [Termes IGN] modèle de croissance végétale [Termes IGN] modèle de simulation [Termes IGN] Picea abies [Termes IGN] Pinophyta [Termes IGN] puits de carbone [Termes IGN] sécheresse [Vedettes matières IGN] Végétation et changement climatique Résumé : (auteur) A valid representation of intra‐annual wood formation processes in global vegetation models is vital for assessing climate change impacts on the forest carbon stock. Yet, wood formation is generally modelled with photosynthesis, despite mounting evidence that cambial activity is rather directly constrained by limiting environmental factors. Here, we apply a state‐of‐the‐art turgor‐driven growth model to simulate 4 yr of hourly stem radial increment from Picea abies (L.) Karst. and Larix decidua Mill. growing along an elevational gradient. For the first time, wood formation observations were used to validate weekly to annual stem radial increment simulations, while environmental measurements were used to assess the climatic constraints on turgor‐driven growth. Model simulations matched the observed timing and dynamics of wood formation. Using the detailed model outputs, we identified a strict environmental regulation on stem growth (air temperature > 2°C and soil water potential > −0.6 MPa). Warmer and drier summers reduced the growth rate as a result of turgor limitation despite warmer temperatures being favourable for cambial activity. These findings suggest that turgor is a central driver of the forest carbon sink and should be considered in next‐generation vegetation models, particularly in the context of global warming and increasing frequency of droughts. Numéro de notice : A2021-177 Affiliation des auteurs : IGN+Ext (2020- ) Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/nph.16872 date de publication en ligne : 07/12/2020 En ligne : https://doi.org/10.1111/nph.16872 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96863 [article]

Monitoring of wheat crops using the backscattering coefficient and the interferometric coherence derived from Sentinel-1 in semi-arid areas / Nadia Ouaadi in Remote sensing of environment, Vol 251 (15 December 2020)  

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Cartographie des cultures dans le périmètre du Loukkos (Maroc) : apport de la télédétection radar et optique / Siham Acharki in Revue Française de Photogrammétrie et de Télédétection, n° 222 (novembre 2020)  

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Good things take time : Diversity effects on tree growth shift from negative to positive during stand development in boreal forests / Tommaso Jucker in Journal of ecology, vol 108 n° 6 (November 2020)  

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Modalflow: cross-origin flow data visualization for urban mobility / Ignacio Pérez-Messina in Algorithms, vol 13 n° 11 (November 2020)  

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From space to lithosphere: inversion of the GOCE gravity gradients. Supply to the Earth’s interior study / Matthieu Plasman in Geophysical journal international, vol 223 n° 1 (October 2020)  

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GipsyX/RTGx, a new tool set for space geodetic operations and research / Willy I. Bertiger in Advances in space research, vol 66 n° 3 (1 August 2020)  

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Toward a standardized encoding of remote sensing geo-positioning sensor models / Meng Jin in Remote sensing, vol 12 n° 9 (May 2020)  

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Assessment of geocenter motion estimates from the IGS second reprocessing / Yifang Ma in GPS solutions, vol 24 n° 2 (April 2020)  

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Comparative analysis of different atmospheric surface pressure models and their impacts on daily ITRF2014 GNSS residual time series / Zhao Li in Journal of geodesy, vol 94 n°4 (April 2020)  

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Species richness influences the spatial distribution of trees in European forests / Cristina Bastias in Oikos, vol 129 n° 3 (March 2020)  

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