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Amazon forest spectral seasonality is consistent across sensor resolutions and driven by leaf demography / Nathan B. Gonçalves in ISPRS Journal of photogrammetry and remote sensing, vol 196 (February 2023)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 196 (February 2023) . - pp 93 - 104 Titre : Amazon forest spectral seasonality is consistent across sensor resolutions and driven by leaf demography Type de document : Article/Communication Auteurs : Nathan B. Gonçalves, Auteur ; Ricardo Dalagnol, Auteur ; Jin Wu, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : pp 93 - 104 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] Amazonie [Termes IGN] distribution du coefficient de réflexion bidirectionnelle BRDF [Termes IGN] forêt tropicale [Termes IGN] image Landsat-8 [Termes IGN] image Landsat-OLI [Termes IGN] image proche infrarouge [Termes IGN] image Terra-MODIS [Termes IGN] indice de végétation [Termes IGN] Leaf Area Index [Termes IGN] réflectance spectrale [Termes IGN] sécheresse [Termes IGN] variation saisonnière Résumé : (Auteur) Controversy surrounds the reported dry season greening of the Central Amazon forests based on the Enhanced Vegetation Index (EVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS). As the solar zenith angle decreases during the dry season, it affects the sub-pixel shade content and artificially increases Near-infrared (NIR) reflectance and EVI. MODIS' coarse resolution also creates a challenge for cloud and terrain filtering. To reduce these artifacts and then validate MODIS seasonal spectral patterns we use 16 years of 1 km resolution MODIS-MAIAC (Multi-Angle Implementation of Atmospheric Correction) images, corrected to a nadir view and 45° solar zenith angle, together with an improved cloud filter. Then we show that the 30 m Landsat-8 Operational Land Imager (OLI) surface reflectance over two Landsat scenes provides independent evidence supporting the MODIS-MAIAC seasonality for EVI, NIR, and GCC (an additional important vegetation index, green chromatic coordinate). Our empirical method for controlling for sun-sensor geometry effects in Landsat scenes encompasses the use of seasonally distinct images that have similar solar zenith angles and cloud-free pixels on flat uplands having the same phase angle. We extended this validation to nine Amazon sub-basins comprising ∼546 Landsat-8 images. Our study shows that the dry-season green-up pattern observed by MODIS is corroborated by Landsat-8, and is independent of satellite data artifacts. To investigate the mechanisms driving these seasonal changes we further used Central Amazon tower-mounted RGB cameras providing a 4-year record at the Amazon Tall Tower (ATTO, 2°8′36″S, 59°0′2″W) and a 7-year record at the Manaus k34 tower (2°36′33″ S, 60°12′33″W) to obtain monthly upper canopy green leaf cover (a proxy for Leaf Area Index - LAI) and monthly leaf age class abundances (based on the age since leaf flushing, by crown). These were compared to seasonal patterns of GCC and EVI in small MODIS-MAIAC windows centered on each tower. MODIS-MAIAC GCC was positively correlated with newly flushed leaves (R2 = 0.76 and 0.44 at ATTO and k34, respectively). EVI correlated strongly with the abundance of mature leaves (R2 = 0.82 and 0.80) but was poorly correlated with LAI (R2 = 0.20 and 0.41, respectively). Therefore, seasonal spectral patterns in the Central Amazon are likely controlled by leaf age variation, not quantity of leaf area. Numéro de notice : A2023-065 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2022.12.001 Date de publication en ligne : 04/01/2023 En ligne : https://doi.org/10.1016/j.isprsjprs.2022.12.001 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102423 [article]

Forêt amazonienne : de nouveau sous contrôle ? / Laurent Polidori in Géomètre, n° 2208 (décembre 2022)

Public [article]  inGéomètre > n° 2208 (décembre 2022) . - pp 24 - 24 Titre : Forêt amazonienne : de nouveau sous contrôle ? Type de document : Article/Communication Auteurs : Laurent Polidori, Auteur Année de publication : 2022 Article en page(s) : pp 24 - 24 Langues : Français (fre) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] Amazonie [Termes IGN] déboisement [Termes IGN] forêt [Termes IGN] incendie de forêt [Termes IGN] télédétection spatiale Résumé : (Auteur) La forêt amazonienne s’est encore trouvée au centre de toutes les attentions lors de la COP27 qui vient de se tenir en Egypte, compte tenu de son rôle essentiel dans l’évolution du climat mondial. Mais 2022 était une année atypique. Numéro de notice : A2022-806 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtSansCL DOI : sans Date de publication en ligne : 01/12/2022 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102191 [article]

Fast local adaptive multiscale image matching algorithm for remote sensing image correlation / Niccolò Dematteis in Computers & geosciences, vol 159 (February 2022)  

Public [article]  inComputers & geosciences > vol 159 (February 2022) . - n° 104988 Titre : Fast local adaptive multiscale image matching algorithm for remote sensing image correlation Type de document : Article/Communication Auteurs : Niccolò Dematteis, Auteur ; Daniele Giordan, Auteur ; Bruno Crippa, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 104988 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] appariement automatique [Termes IGN] appariement d'images [Termes IGN] données multiéchelles [Termes IGN] fonte des glaces [Termes IGN] glacier [Termes IGN] image Sentinel-MSI [Termes IGN] implémentation (informatique) [Termes IGN] Matlab [Termes IGN] Patagonie Résumé : (auteur) Various studies have shown that image correlation calculated in the space domain outperforms frequency-based methods. However, such an approach usually requires great computational efforts, making it challenging to adopt for surveying fast moving processes like glaciers, particularly over wide areas. We present a local adaptive multiscale image matching algorithm (LAMMA), which repeatedly applies image correlation on grids of increasing spatial resolution and adapts the size of the interrogation area according to the local range of displacements. LAMMA allows reducing the number of calculi of several orders of magnitude and limits the occurrence of displacement outliers. We show an example of LAMMA application on Sentinel-2 images to measure glaciers flow of the Southern Patagonian Icefield, where LAMMA's runtime was comparable to that of frequency-based correlation. LAMMA's Matlab code is freely available on GitHub. Numéro de notice : A2022-094 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1016/j.cageo.2021.104988 Date de publication en ligne : 19/11/2021 En ligne : https://doi.org/10.1016/j.cageo.2021.104988 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99528 [article]

Maps, volunteered geographic information (VGI) and the spatio-discursive construction of nature / Juan Astaburuaga in Digital Geography and Society, vol 3 (2022)  

Public [article]  inDigital Geography and Society > vol 3 (2022) . - n° 100029 Titre : Maps, volunteered geographic information (VGI) and the spatio-discursive construction of nature Type de document : Article/Communication Auteurs : Juan Astaburuaga, Auteur ; Michael E. Martin, Auteur ; Agnieszka Leszczynski, Auteur ; JC Gaillard, Auteur Année de publication : 2022 Article en page(s) : n° 100029 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse du discours [Termes IGN] cartographie collaborative [Termes IGN] données localisées des bénévoles [Termes IGN] gestion de la vie sauvage [Termes IGN] milieu naturel [Termes IGN] Patagonie [Termes IGN] représentation mentale [Vedettes matières IGN] Cartologie Résumé : (auteur) This paper interrogates the role that spatial media such as maps and Volunteered Geographic Information (VGI) play in the construction and mobilisation of representations of nature. Drawing on poststructural political ecology, critical cartography, and GIScience, this article engages maps and VGI as discursive mechanisms that solidify and convey meanings and representations of nature tied to broader strategies of commodification. Particularly, we explore how spatial media reproduces and legitimises discursive strategies that rationalise the reconciliation of economic development and conservation through nature-based tourism by producing new ways of nature commodification. Drawing on evidence from Patagonia-Aysén, Chile, this paper examines the intersections between the discourse of nature encoded within institutional tourist maps and advertisements, and within the VGI platform for travellers, TripAdvisor. This illustrative case shows, firstly, how tourist maps and advertisements have contributed to normalising a discursive construction of nature as pristine, grandiose, sublime and wild that has not only secured aesthetics as ontological qualities of nature, but also as embedded values that protect ‘nature’ as a commodity to consume. Secondly, our findings evidence that TripAdvisor emerges out of this context as content that mobilises individual perceptions of and narratives about Patagonian nature that is already mediated by this dominant discourse. This dynamic suggests that VGI constitutes a new form of discursive power that digitally reproduces and mobilises a dominant discourse of nature, (re)producing what we term ‘discursive digital nature’. Numéro de notice : A2022-140 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1016/j.diggeo.2022.100029 Date de publication en ligne : 22/01/2022 En ligne : https://doi.org/10.1016/j.diggeo.2022.100029 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99772 [article]

Relationships between species richness and ecosystem services in Amazonian forests strongly influenced by biogeographical strata and forest types / Gijs Steur in Scientific reports, vol 12 (2022)  

Public [article]  inScientific reports > vol 12 (2022) . - n° 5960 Titre : Relationships between species richness and ecosystem services in Amazonian forests strongly influenced by biogeographical strata and forest types Type de document : Article/Communication Auteurs : Gijs Steur, Auteur ; Hans Ter Steege, Auteur ; René W. Verburg, Auteur ; Daniel Sabatier, Auteur ; Jean-François Molino, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 5960 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Amazonie [Termes IGN] forêt tropicale [Termes IGN] produit forestier non ligneux [Termes IGN] puits de carbone [Termes IGN] richesse floristique [Termes IGN] service écosystémique [Termes IGN] strate végétale [Termes IGN] volume en bois [Vedettes matières IGN] Ecologie forestière Résumé : (auteur) Despite increasing attention for relationships between species richness and ecosystem services, for tropical forests such relationships are still under discussion. Contradicting relationships have been reported concerning carbon stock, while little is known about relationships concerning timber stock and the abundance of non-timber forest product producing plant species (NTFP abundance). Using 151 1-ha plots, we related tree and arborescent palm species richness to carbon stock, timber stock and NTFP abundance across the Guiana Shield, and using 283 1-ha plots, to carbon stock across all of Amazonia. We analysed how environmental heterogeneity influenced these relationships, assessing differences across and within multiple forest types, biogeographic regions and subregions. Species richness showed significant relationships with all three ecosystem services, but relationships differed between forest types and among biogeographical strata. We found that species richness was positively associated to carbon stock in all biogeographical strata. This association became obscured by variation across biogeographical regions at the scale of Amazonia, resembling a Simpson’s paradox. By contrast, species richness was weakly or not significantly related to timber stock and NTFP abundance, suggesting that species richness is not a good predictor for these ecosystem services. Our findings illustrate the importance of environmental stratification in analysing biodiversity-ecosystem services relationships. Numéro de notice : A2022-308 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET Nature : Article DOI : 10.1038/s41598-022-09786-6 Date de publication en ligne : 08/04/2022 En ligne : http://dx.doi.org/10.1038/s41598-022-09786-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100403 [article]

Impacts of drought on biomass and carbon fluxes in the Amazon rainforest / Yitong Yao (2022)  

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Establishing vertical separation models for vulnerable coastlines in developing territories / Cassandra Nanlal in Marine geodesy, vol 44 n° 5 (September 2021)  

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Les impacts spatiaux du changement climatique / Denis Mercier (2021)

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Remote Sensing / Andrew Hammond (2021)  

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Wide-area near-real-time monitoring of tropical forest degradation and deforestation using Sentinel-1 / Dirk Hoekman in Remote sensing, vol 12 n° 19 (October-1 2020)  

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Clinal variation along precipitation gradients in Patagonian temperate forests: unravelling demographic and selection signatures in three Nothofagus spp. / Carolina Soliani in Annals of Forest Science, Vol 77 n° 1 (March 2020)  

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Analyse des surcharges hydrologiques observées par géodésie spatiale avec l’outil Multi Singular Spectrum Analysis / Louis Bonhomme (2020)  

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Détermination conjointe des inondations et du type d’eau au moyen de l’imagerie multi-spectrale / Sabrine Amzil (2020)  

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Deep learning for multi-modal classification of cloud, shadow and land cover scenes in PlanetScope and Sentinel-2 imagery / Yuri Shendryk in ISPRS Journal of photogrammetry and remote sensing, vol 157 (November 2019)  

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Un été brûlant sous l’oeil des satellites / Laurent Polidori in Géomètre, n° 2173 (octobre 2019)

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