Descripteur
Documents disponibles dans cette catégorie (412)
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
Post-1980 shifts in the sensitivity of boreal tree growth to North Atlantic Ocean dynamics and seasonal climate / Clémentine Ols in Global and Planetary Change, vol 165 (June 2018)
[article]
Titre : Post-1980 shifts in the sensitivity of boreal tree growth to North Atlantic Ocean dynamics and seasonal climate Type de document : Article/Communication Auteurs : Clémentine Ols , Auteur ; Valérie Trouet, Auteur ; Martin P. Girardin, Auteur ; Annika Hofgaard, Auteur ; Yves Bergeron, Auteur ; Igor Drobyshev, Auteur Année de publication : 2018 Projets : 3-projet - voir note / Article en page(s) : pp 1 - 12 Note générale : bibliographie
This study was financed by the Natural Sciences and Engineering Research Council of Canada (NSERC) through the project ‘Naturaldisturbances, forest resilience and forest management: the study case of the northern limit for timber allocation in Quebec in a climate change context’(STPGP 413444-11).Langues : Anglais (eng) Descripteur : [Termes IGN] analyse de sensibilité
[Termes IGN] Atlantique Nord
[Termes IGN] cerne
[Termes IGN] circulation océanique
[Termes IGN] climat froid
[Termes IGN] croissance des arbres
[Termes IGN] dendrochronologie
[Termes IGN] forêt boréale
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] océanographie dynamique
[Termes IGN] Picea abies
[Termes IGN] Picea mariana
[Termes IGN] puits de carbone
[Termes IGN] Québec (Canada)
[Termes IGN] Suède
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) The mid-20th century changes in North Atlantic Ocean dynamics, e.g. slow-down of the Atlantic meridional overturning thermohaline circulation (AMOC), have been considered as early signs of tipping points in the Earth climate system. We hypothesized that these changes have significantly altered boreal forest growth dynamics in northeastern North America (NA) and northern Europe (NE), two areas geographically adjacent to the North Atlantic Ocean. To test our hypothesis, we investigated tree growth responses to seasonal large-scale oceanic and atmospheric indices (the AMOC, North Atlantic Oscillation (NAO), and Arctic Oscillation (AO)) and climate (temperature and precipitation) from 1950 onwards, both at the regional and local levels. We developed a network of 6876 black spruce (NA) and 14437 Norway spruce (NE) tree-ring width series, extracted from forest inventory databases. Analyses revealed post-1980 shifts from insignificant to significant tree growth responses to summer oceanic and atmospheric dynamics both in NA (negative responses to NAO and AO indices) and NE (positive response to NAO and AMOC indices). The strength and sign of these responses varied, however, through space with stronger responses in western and central boreal Quebec and in central and northern boreal Sweden, and across scales with stronger responses at the regional level than at the local level. Emerging post-1980 associations with North Atlantic Ocean dynamics synchronized with stronger tree growth responses to local seasonal climate, particularly to winter temperatures. Our results suggest that ongoing and future anomalies in oceanic and atmospheric dynamics may impact forest growth and carbon sequestration to a greater extent than previously thought. Cross-scale differences in responses to North Atlantic Ocean dynamics highlight complex interplays in the effects of local climate and ocean-atmosphere dynamics on tree growth processes and advocate for the use of different spatial scales in climate-growth research to better understand factors controlling tree growth. Numéro de notice : A2018-662 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.gloplacha.2018.03.006 Date de publication en ligne : 18/03/2018 En ligne : https://doi.org/10.1016/j.gloplacha.2018.03.006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93844
in Global and Planetary Change > vol 165 (June 2018) . - pp 1 - 12[article]LiDAR, a technology to assist with smart cities and climate change resilience: a case study in an urban metropolis / Ryan Garnett in ISPRS International journal of geo-information, vol 7 n° 5 (May 2018)
[article]
Titre : LiDAR, a technology to assist with smart cities and climate change resilience: a case study in an urban metropolis Type de document : Article/Communication Auteurs : Ryan Garnett, Auteur ; Matthew D. Adams, Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] bassin hydrographique
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] eau pluviale
[Termes IGN] énergie solaire
[Termes IGN] métropole
[Termes IGN] modèle numérique de terrain
[Termes IGN] secours d'urgence
[Termes IGN] TorontoRésumé : (Auteur) In this paper, we demonstrate three unique use cases of LiDAR data and processing, which can be implemented in an urban metropolis to determine the challenges that are associated with climate change. LiDAR data for the City of Toronto were collected in April 2015 with a density of 10 points/m2. We utilized both a digital terrain model and a bare earth digital elevation model in this work. The first case study estimated storm water, in which we compared flow accumulation values and catchment areas generated with a 20-m DEM and a 1-m LiDAR DEM. The finer resolution DEM demonstrated that the urban street features play a significant role in flow accumulation by directing flows. Urban catchment areas were found to occur on spatial scales that were smaller than the 20-m DEM cell size. For the second case study, the solar potential in the City of Toronto was calculated based on the slope and aspect of each land parcel. According to area, 56% of the city was found to have high solar potential, with 33% and 11% having medium and low solar potential. For the third case study, we calculated the building heights for 16,715 high-rise buildings in Toronto, which were combined with ambulance and fire emergency response times required to reach the base of the building. All buildings that had more than 17 stories were within a 5-min response time for both fire and ambulance services. Only 79% and 88% of these buildings were within a 3-min response time for ambulance and fire emergencies, respectively. LiDAR data provides a highly detailed record of the built urban environment and can provide support in the planning and assessment of climate change resilience activities. Numéro de notice : A2018-343 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/ijgi7050161 Date de publication en ligne : 24/04/2018 En ligne : https://doi.org/10.10.3390/ijgi7050161 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90565
in ISPRS International journal of geo-information > vol 7 n° 5 (May 2018)[article]3D building model-assisted snapshot positioning algorithm / Rakesh Kumar in GPS solutions, vol 21 n° 4 (October 2017)
[article]
Titre : 3D building model-assisted snapshot positioning algorithm Type de document : Article/Communication Auteurs : Rakesh Kumar, Auteur ; Mark G. Petovello, Auteur Année de publication : 2017 Article en page(s) : pp 1923 - 1935 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] Calgary
[Termes IGN] compensation par moindres carrés
[Termes IGN] corrélateur
[Termes IGN] lancer de rayons
[Termes IGN] milieu urbain
[Termes IGN] modèle 3D de l'espace urbain
[Termes IGN] positionnement par GNSS
[Termes IGN] récepteur GNSS
[Termes IGN] résidu
[Termes IGN] trajet multipleRésumé : (Auteur) A method for constructively using non-line-of-sight GNSS signals from a snapshot of signal samples for positioning of users in urban areas is presented here. Using a 3D building model and a ray-tracing algorithm, the number of reception paths and the corresponding path delays of reflected signals are predicted, across a rid of candidate positions. These predictions are then used to compute a least squares fit to the GNSS receiver’s correlator outputs, and the position with smallest residuals is selected as the position estimate. Using data collected along 3.5 km of road in downtown Calgary, Canada, where buildings reach heights of over 200 m, the root-mean-square position error is below 10 m in the along-track and across-track directions. Compared to two pseudorange-based receivers, the proposed method yields RMS error improvements of at least 31% in the along-track direction, 63% in the across-track direction, and 53% in the horizontal plane. Numéro de notice : A2017-621 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-017-0661-2 En ligne : https://doi.org/10.1007/s10291-017-0661-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86931
in GPS solutions > vol 21 n° 4 (October 2017) . - pp 1923 - 1935[article]Tree size thresholds produce biased estimates of forest biomass dynamics / Eric B. Searle in Forest ecology and management, vol 400 (15 September 2017)
[article]
Titre : Tree size thresholds produce biased estimates of forest biomass dynamics Type de document : Article/Communication Auteurs : Eric B. Searle, Auteur ; Han Y.H. Chen, Auteur Année de publication : 2017 Article en page(s) : pp 468 - 474 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] biomasse aérienne
[Termes IGN] changement climatique
[Termes IGN] diamètre des arbres
[Termes IGN] échantillonnage
[Termes IGN] erreur systématique
[Termes IGN] estimation statistique
[Termes IGN] forêt boréale
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] Manitoba (Canada)
[Termes IGN] placette d'échantillonnage
[Termes IGN] seuillage
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) Studies that examine forest biomass dynamics often rely on long-term, spatially extensive, repeatedly measured permanent sample plots. Due to the intensive cost of sampling all trees within these plots, an arbitrary size threshold is typically imposed, which leads to only larger trees being sampled. However, it remains unclear whether the sampling of only large trees is representative of the entirety of stands of diverse sizes; the sampling of only large trees may produce biased estimates of biomass dynamics (growth, ingrowth, and mortality). Using a network of 141 permanent sample plots from Manitoba, Canada, with all trees of >1.3 m in height repeatedly measured, we constructed three distinct data sets, with 10 cm, 5 cm, and no diameter at breast height threshold, to illustrate that total productivity and mortality are increasingly underestimated with increasingly larger diameter at breast height thresholds. This effect is particularly significant in young stands, where productivity estimates peak at least 20 years earlier than the determined estimates under large thresholds. We highlight the need to account for smaller trees in long-term observational studies to ensure unbiased estimates of stand level aboveground biomass productivity and loss. Numéro de notice : A2017-807 Affiliation des auteurs : non IGN Thématique : FORET/MATHEMATIQUE Nature : Article DOI : 10.1016/j.foreco.2017.06.042 En ligne : https://doi.org/10.1016/j.foreco.2017.06.042 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89245
in Forest ecology and management > vol 400 (15 September 2017) . - pp 468 - 474[article]Northern conifer forest species classification using multispectral data acquired from an unmanned aerial vehicle / Steven E. Franklin in Photogrammetric Engineering & Remote Sensing, PERS, vol 83 n° 7 (July 2017)
[article]
Titre : Northern conifer forest species classification using multispectral data acquired from an unmanned aerial vehicle Type de document : Article/Communication Auteurs : Steven E. Franklin, Auteur ; Oumer S. Ahmed, Auteur ; Griffin Williams, Auteur Année de publication : 2017 Article en page(s) : pp 501 - 507 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse d'image orientée objet
[Termes IGN] Canada
[Termes IGN] classification automatique
[Termes IGN] drone
[Termes IGN] espèce végétale
[Termes IGN] image aérienne
[Termes IGN] image multibande
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] Ontario (Canada)
[Termes IGN] Pinophyta
[Termes IGN] semis de pointsRésumé : (auteur) Object-based image analysis and machine learning classification procedures, after field calibration and photogrammetric processing of consumer-grade unmanned aerial vehicle (UAV) digital camera data, were implemented to classify tree species in a conifer forest in the Great Lakes/St Lawrence Lowlands Ecoregion, Ontario, Canada. A red-green-blue (RGB) digital camera yielded approximately 72 percent classification accuracy for three commercial tree species and one conifer shrub. Accuracy improved approximately 15 percent, to 87 percent overall, with higher radiometric quality data acquired separately using a digital camera that included near infrared observations (at a lower spatial resolution). Interpretation of the point cloud, spectral, texture and object (tree crown) classification Variable Importance (VI) selected by a machine learning algorithm suggested a good correspondence with the traditional aerial photointerpretation cues used in the development of well-established large-scale photography northern conifer elimination keys, which use three-dimensional crown shape, spectral response (tone), texture derivatives to quantify branching characteristics, and crown size, development and outline features. These results suggest that commonly available consumer-grade UAV-based digital cameras can be used with object-based image analysis to obtain acceptable conifer species classification accuracy to support operational forest inventory applications. Numéro de notice : A2017-434 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.14358/PERS.83.7.501 En ligne : https://doi.org/10.14358/PERS.83.7.501 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86338
in Photogrammetric Engineering & Remote Sensing, PERS > vol 83 n° 7 (July 2017) . - pp 501 - 507[article]Code Grey : mapping healthcare service deserts in Hamilton, Ontario and the impact on senior populations / Kristin M. Dosen in Cartographica, vol 52 n° 2 (Summer 2017)PermalinkGPS coordinate time series measurements in Ontario and Quebec, Canada / Hadis Samadi Alinia in Journal of geodesy, vol 91 n° 6 (June 2017)PermalinkNRC Remote clock secure dissemination of traceable time / Marina Gertsvolf in Inside GNSS, vol 12 n° 3 (May - June 2017)PermalinkPan-sharpening of Landsat-8 images and its application in calculating vegetation greenness and canopy water contents / Khan Rubayet Rahaman in ISPRS International journal of geo-information, vol 6 n° 6 (June 2017)PermalinkEstimating benefits to Canada and the world : the canadian spatial reference system precise point positioning service / Calvin Klatt in Geomatica, vol 71 n° 1 (March 2017)PermalinkPermalinkPermalinkPermalinkSVM et réseaux neuronaux convolutifs pour la classification de scènes urbaines / Amaury Zarzelli (2017)PermalinkDEM Fusion of elevation REST API data in support of rapid flood modelling / Heather McGrath in Geomatica, vol 70 n° 4 (December 2016)Permalink