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Accuracy of ionospheric models used in GNSS and SBAS: methodology and analysis / Adria Rovira-Garcia in Journal of geodesy, vol 90 n° 3 (March 2016)
[article]
Titre : Accuracy of ionospheric models used in GNSS and SBAS: methodology and analysis Type de document : Article/Communication Auteurs : Adria Rovira-Garcia, Auteur ; José Miguel Juan, Auteur ; Jaume Sanz, Auteur ; Guillermo Gonzalez-Casado, Auteur ; D. Ibáñez, Auteur Année de publication : 2016 Article en page(s) : pp 229 - 240 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] caractérisation
[Termes IGN] données GNSS
[Termes IGN] modèle ionosphérique
[Termes IGN] phase GNSSRésumé : (auteur) The characterization of the accuracy of ionospheric models currently used in global navigation satellite systems (GNSSs) is a long-standing issue. The characterization remains a challenging problem owing to the lack of sufficiently accurate slant ionospheric determinations to be used as a reference. The present study proposes a methodology based on the comparison of the predictions of any ionospheric model with actual unambiguous carrier-phase measurements from a global distribution of permanent receivers. The differences are separated as hardware delays (a receiver constant plus a satellite constant) per day. The present study was conducted for the entire year of 2014, i.e. during the last solar cycle maximum. The ionospheric models assessed are the operational models broadcast by the global positioning system (GPS) and Galileo constellations, the satellite-based augmentation system (SBAS) (i.e. European Geostationary Navigation Overlay System (EGNOS) and wide area augmentation system (WAAS)), a number of post-process global ionospheric maps (GIMs) from different International GNSS Service (IGS) analysis centres (ACs) and, finally, a more sophisticated GIM computed by the research group of Astronomy and GEomatics (gAGE). Ionospheric models based on GNSS data and represented on a grid (IGS GIMs or SBAS) correct about 85 % of the total slant ionospheric delay, whereas the models broadcasted in the navigation messages of GPS and Galileo only account for about 70 %. Our gAGE GIM is shown to correct 95 % of the delay. The proposed methodology appears to be a useful tool to improve current ionospheric models. Numéro de notice : A2016-248 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0868-3 Date de publication en ligne : 29/10/2015 En ligne : https://doi.org/10.1007/s00190-015-0868-3 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80755
in Journal of geodesy > vol 90 n° 3 (March 2016) . - pp 229 - 240[article]An evolutionary ecology perspective to address forest pathology challenges of today and tomorrow / Marie-Laure Desprez-Loustau in Annals of Forest Science, vol 73 n° 1 (March 2016)
[article]
Titre : An evolutionary ecology perspective to address forest pathology challenges of today and tomorrow Type de document : Article/Communication Auteurs : Marie-Laure Desprez-Loustau, Auteur ; Jaime Aguayo, Auteur ; Cyril Dutech, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 45 - 67 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] biologie
[Termes IGN] changement climatique
[Termes IGN] étude d'impact
[Termes IGN] gestion durable
[Termes IGN] plantation forestière
[Termes IGN] risque naturel
[Termes IGN] sylviculture
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) Key message : Increasing human impacts on forests, including unintentional movement of pathogens, climate change, and large-scale intensive plantations, are associated with an unprecedented rate of new diseases. An evolutionary ecology perspective can help address these challenges and provide direction for sustainable forest management.
Context : Forest pathology has historically relied on an ecological approach to understand and address the practical management of forest diseases. A widening of this perspective to include evolutionary considerations has been increasingly developed in response to the rising rates of genetic change in both pathogen populations and tree populations due to human activities.
Aims : Here, five topics for which the evolutionary perspective is especially relevant are highlighted.
Results : The first relates to the evolutionary diversity of fungi and fungal-like organisms, with issues linked to the identification of species and their ecological niches. The second theme deals with the evolutionary processes that allow forest pathogens to adapt to new hosts after introductions or to become more virulent in homogeneous plantations. The third theme presents issues linked to disease resistance in tree breeding programs (e.g., growth-defense trade-offs) and proposes new criteria and methods for more durable resistance. The last two themes are dedicated to the biotic environment of the tree–pathogen system, namely, hyperparasites and tree microbiota, as possible solutions for health management.
Conclusion : We conclude by highlighting three major conceptual advances brought by evolutionary biology, i.e., that (i) “not everything is everywhere”, (ii) evolution of pathogen populations can occur on short time scales, and (iii) the tree is a multitrophic community. We further translate these into a framework for immediate policy recommendations and future directions for research.Numéro de notice : A2016-186 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-015-0487-4 Date de publication en ligne : 01/03/2016 En ligne : https://doi.org/10.1007/s13595-015-0487-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80612
in Annals of Forest Science > vol 73 n° 1 (March 2016) . - pp 45 - 67[article]Comparison of Satellite-Only Gravity Field Models Constructed with All and Parts of the GOCE Gravity Gradient Dataset / Sean L. Bruinsma in Marine geodesy, vol 39 n° 3-4 (March - June 2016)
[article]
Titre : Comparison of Satellite-Only Gravity Field Models Constructed with All and Parts of the GOCE Gravity Gradient Dataset Type de document : Article/Communication Auteurs : Sean L. Bruinsma, Auteur ; Christoph Förste, Auteur ; Sandrine Mulet, Auteur ; Marie-Hélène Rio, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 238 - 255 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] circulation géostrophique
[Termes IGN] données GOCE
[Termes IGN] données Lageos
[Termes IGN] gradient de gravitation
[Termes IGN] modèle de géopotentielRésumé : (auteur) The impact of GOCE Satellite Gravity Gradiometer data on gravity field models was tested. All models were constructed with the same Laser Geodynamics Satellite (LAGEOS) and Gravity Recovery and Climate Experiment (GRACE) data, which were combined with one or two of the diagonal gravity gradient components for the entire GOCE mission (November 2009 to October 2013). The Stokes coefficients were estimated by solving large normal equation (NE) systems (i.e., the direct numerical approach). The models were evaluated through comparisons with the European Space Agency's (ESA) gravity field model DIR-R5, by GPS/Leveling, GOCE orbit determination, and geostrophic current evaluations. Among the single gradient models, only the model constructed with the vertical ZZ gradients gave good results that were in agreement with the formal errors. The model based only on XX gradients is the least accurate. The orbit results for all models are very close and confirm this finding. All models constructed with two diagonal gradient components are more accurate than the ZZ-only model due to doubling the amount of data and having two complementary observation directions. This translates also to a slower increase of model errors with spatial resolution. The different evaluation methods cannot unambiguously identify the most accurate two-component model. They do not always agree, emphasizing the importance of evaluating models using many different methods. The XZ gravity gradient gives a small positive contribution to model accuracy. Numéro de notice : A2016-965 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/01490419.2016.1182090 En ligne : http://dx.doi.org/10.1080/01490419.2016.1182090 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83616
in Marine geodesy > vol 39 n° 3-4 (March - June 2016) . - pp 238 - 255[article]Determination of differential code biases with multi-GNSS observations / Ningbo Wang in Journal of geodesy, vol 90 n° 3 (March 2016)
[article]
Titre : Determination of differential code biases with multi-GNSS observations Type de document : Article/Communication Auteurs : Ningbo Wang, Auteur ; Yunbin Yuan, Auteur ; Zishen Li, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 209 - 228 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] code GNSS
[Termes IGN] erreur systématique
[Termes IGN] estimation de précision
[Termes IGN] retard ionosphèrique
[Termes IGN] teneur totale en électrons
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) In order to better understand the differential code biases (DCBs) of global navigation satellite system, the IGGDCB method is extended to estimate the intra- and inter-frequency biases of the global positioning system (GPS), GLONASS, BeiDou navigation satellite system (BDS), and Galileo based on observations collected by the multi-GNSS experiment (MGEX) of the international GNSS service (IGS). In the approach of IGGDCB, the local ionospheric total electronic content is modeled with generalized triangular series (GTS) function rather than using a global ionosphere model or a priori ionospheric information. The DCB estimated by the IGGDCB method is compared with the DCB products from the Center for Orbit Determination in Europe (CODE) and German Aerospace Center (DLR), as well as the broadcast timing group delay (TGD) parameters over a 2-year span (2013 and 2014). The results indicate that GPS and GLONASS intra-frequency biases obtained in this work show the same precision levels as those estimated by DLR (about 0.1 and 0.2–0.4 ns for the two constellations, respectively, with respect to the products of CODE). The precision levels of IGGDCB-based inter-frequency biases estimated over the 24-month period are about 0.29 ns for GPS, 0.56 ns for GLONASS, 0.36 ns for BDS, and 0.24 ns for Galileo, respectively. Here, the accuracies of GPS and GLONASS biases are assessed relative to the products of CODE, while those of BDS and Galileo are compared with the estimates of DLR. In addition, the monthly stability indices of IGGDCB-based DCBs are 0.11 (GPS), 0.18 (GLONASS), 0.17 (BDS), and 0.14 (Galileo) ns for the individual constellation. Numéro de notice : A2016-246 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0867-4 Date de publication en ligne : 11/11/2015 En ligne : https://doi.org/10.1007/s00190-015-0867-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80752
in Journal of geodesy > vol 90 n° 3 (March 2016) . - pp 209 - 228[article]Effect of tree location on mitigating parking lot insolation / Ivana Bajsanski in Computers, Environment and Urban Systems, vol 56 (March 2016)
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Titre : Effect of tree location on mitigating parking lot insolation Type de document : Article/Communication Auteurs : Ivana Bajsanski, Auteur ; Vesna Stojakovic, Auteur ; Marko Jovanovic, Auteur Année de publication : 2016 Article en page(s) : pp 59 - 67 Note générale : bibloiographie Langues : Anglais (eng) Descripteur : [Termes IGN] changement climatique
[Termes IGN] effet d'ombre
[Termes IGN] ensoleillement
[Termes IGN] optimisation (mathématiques)
[Termes IGN] parking
[Termes IGN] urbanisme
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) Urban land used for parking lots can contribute to the effect of overheating, whereas vegetation, especially high growth vegetation (trees), can mitigate this effect. Accordingly, in this paper we propose an algorithm, the inputs to which consist of predetermined parameters of a parking lot's geometry, trees and surrounding buildings, where the shadows help to mitigate the heat. The algorithm optimizes tree locations, aiming to provide maximum overshadowing of the parking lots, while leaving the useable parking area and the parking lot shape intact. The paper focuses on parameterization of elements that are important for this analysis process as well as combinatory calculations. These combinatory calculations are based on solar simulations, which are carried out, and take into account climate and geographical data. The algorithm is applied to several cases, depicting real world examples, as well as those based on design and greening instruction manuals. The results indicate that the tree locations estimated by the algorithm increase parking lot overshadowing, indicating that the algorithm efficiently decreases the negative influence of urban overheating. Numéro de notice : A2016-393 Affiliation des auteurs : non IGN Thématique : FORET/GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.compenvurbsys.2015.11.006 Date de publication en ligne : 01/12/2015 En ligne : http://dx.doi.org/10.1016/j.compenvurbsys.2015.11.006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81210
in Computers, Environment and Urban Systems > vol 56 (March 2016) . - pp 59 - 67[article]Extreme events and climate change: the post-disaster dynamics of forest fires and forest storms in Sweden / Rolf Lidskog in Scandinavian journal of forest research, vol 31 n° 2 (March 2016)PermalinkUn modèle global d'anticipation des mouvements de terrain / Anonyme in GEOrama, le journal d'Information du BRGM, n° 32 (mars 2016)PermalinkThin cloud removal based on signal transmission principles and spectral mixture analysis / Meng Xu in IEEE Transactions on geoscience and remote sensing, vol 54 n° 3 (March 2016)PermalinkMangrove forest characterization in Southeast Côte d’Ivoire / Isimemen Osemwegie in Open journal of forestry, vol 6 n° 3 (February 2016)PermalinkChiffres clés du climat France et Monde, édition 2016 / CGDD Commissariat Général au Développement Durable (2016)PermalinkA comprehensive cartographic approach to evacuation map creation for Hurricane Ike in Galveston County, Texas / Yin-Hsuen Chen in Cartography and Geographic Information Science, Vol 43 n° 1 (January 2016)PermalinkCorrection troposphérique des interférogrammes issus d’images radar par mesures GNSS et modèle global d’atmosphère / Vincent Dubreuil (2016)PermalinkPermalinkLa maîtrise du foncier prête main-forte à la Cop 21 / Olivier Razemon in Géomètre, n° 2132 (janvier 2016)PermalinkPermalink