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Verification of NWP model analyses and radiosonde humidity data with GPS precipitable water vapor estimates during AMMA / Olivier Bock in Weather and Forecasting, vol 24 n° 4 (August 2009)
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Titre : Verification of NWP model analyses and radiosonde humidity data with GPS precipitable water vapor estimates during AMMA Type de document : Article/Communication Auteurs : Olivier Bock , Auteur ; Mathieu Nuret, Auteur
Année de publication : 2009 Projets : AMMA & AMMA-2 / Janicot, Serge Article en page(s) : pp 1085 - 1101 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] erreur systématique
[Termes IGN] mousson
[Termes IGN] précipitation
[Termes IGN] prédiction
[Termes IGN] prévision météorologique
[Termes IGN] radiosondage
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] variation diurneRésumé : (auteur) This paper assesses the performance of the European Centre for Medium-Range Weather Forecasts-Integrated Forecast System (ECMWF-IFS) operational analysis and NCEP–NCAR reanalyses I and II over West Africa, using precipitable water vapor (PWV) retrievals from a network of ground-based GPS receivers operated during the African Monsoon Multidisciplinary Analysis (AMMA). The model analyses show reasonable agreement with GPS PWV from 5-daily to monthly means. Errors increase at shorter time scales, indicating that these global NWP models have difficulty in handling the diurnal cycle and moist processes at the synoptic scale. The ECMWF-IFS analysis shows better agreement with GPS PWV than do the NCEP–NCAR reanalyses (the RMS error is smaller by a factor of 2). The model changes in ECMWF-IFS were not clearly reflected in the PWV error over the period of study (2005–08). Radiosonde humidity biases are diagnosed compared to GPS PWV. The impacts of these biases are evidenced in all three model analyses at the level of the diurnal cycle. The results point to a dry bias in the ECMWF analysis in 2006 when Vaisala RS80-A soundings were assimilated, and a diurnally varying bias when Vaisala RS92 or Modem M2K2 soundings were assimilated: dry during day and wet during night. The overall bias is offset to wetter values in NCEP–NCAR reanalysis II, but the diurnal variation of the bias is observed too. Radiosonde bias correction is necessary to reduce NWP model analysis humidity biases and improve precipitation forecast skill. The study points to a wet bias in the Vaisala RS92 data at nighttime and suggests that caution be used when establishing a bias correction scheme. Numéro de notice : A2009-576 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1175/2009WAF2222239.1 Date de publication en ligne : 01/08/2009 En ligne : https://doi.org/10.1175/2009WAF2222239.1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102424
in Weather and Forecasting > vol 24 n° 4 (August 2009) . - pp 1085 - 1101[article]Street hierarchies: a minority of streets account for a majority of traffic flow / Bin Jiang in International journal of geographical information science IJGIS, vol 23 n° 7-8 (july 2009)
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Titre : Street hierarchies: a minority of streets account for a majority of traffic flow Type de document : Article/Communication Auteurs : Bin Jiang, Auteur Année de publication : 2009 Article en page(s) : pp 1033 - 1048 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] approche hiérarchique
[Termes IGN] distribution de Pareto
[Termes IGN] mobilité urbaine
[Termes IGN] réseau routier
[Termes IGN] trafic routier
[Termes IGN] trafic urbainRésumé : (Auteur) Urban streets are hierarchically organized in the sense that a majority of streets are trivial, while a minority of streets is vital. This hierarchy can be simply, but elegantly, characterized by the 80/20 principle, i.e. 80% of streets are less connected (below the average), while 20% of streets are well connected (above the average); out of the 20%, there is 1% of streets that are extremely well connected. This paper, using a European city as an example, examined, at a much more detailed level, such street hierarchies from the perspective of geometric and topological properties. Based on an empirical study, we further proved a previous conjecture that a minority of streets accounts for a majority of traffic flow; more accurately, the 20% of top streets accommodate 80% of traffic flow (20/80), and the 1% of top streets account for more than 20% of traffic flow (1/20). Our study provides new evidence as to how a city is (self-)organized, contributing to the understanding of cities and their evolution using increasingly available mobility geographic information. Copyright Taylor & Francis Numéro de notice : A2009-345 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810802004648 En ligne : https://doi.org/10.1080/13658810802004648 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29975
in International journal of geographical information science IJGIS > vol 23 n° 7-8 (july 2009) . - pp 1033 - 1048[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 079-09051 RAB Revue Centre de documentation En réserve L003 Disponible 079-09052 RAB Revue Centre de documentation En réserve L003 Disponible Use Markov random fields for automatic cloud-shadow detection on high resolution / Sylvie Le Hégarat-Mascle in ISPRS Journal of photogrammetry and remote sensing, vol 64 n° 4 (July - August 2009)
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Titre : Use Markov random fields for automatic cloud-shadow detection on high resolution Type de document : Article/Communication Auteurs : Sylvie Le Hégarat-Mascle, Auteur ; Cyrille André, Auteur Année de publication : 2009 Article en page(s) : pp 351 - 366 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] champ aléatoire de Markov
[Termes IGN] connexité (graphes)
[Termes IGN] détection automatique
[Termes IGN] graphe
[Termes IGN] image optique
[Termes IGN] nuage
[Termes IGN] ombre
[Termes IGN] pixel
[Termes IGN] processus ponctuel marquéRésumé : (Auteur) In this study, we propose an automatic detection algorithm for cloud/shadow on remote sensing optical images. It is based on physical properties of clouds and shadows, namely for a cloud and its associated shadow: both are connex objects of similar shape and area, and they are related by their relative locations. We show that these properties can be formalized using Markov Random Field (MRF) framework at two levels: one MRF over the pixel graph for connexity modelling, and one MRF over the graph of objects (clouds and shadows) for their relationship modelling. Then, we show that, practically, having performed an image pre-processing step (channel inter-calibration) specific to cloud detection, the local optimization of the proposed MRF models leads to a rather simple image processing algorithm involving only six parameters. Using a 39 image database, performance is shown and discussed, in particular in comparison with the Marked Point Process approach. Numéro de notice : A2009-294 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2008.12.007 En ligne : https://doi.org/10.1016/j.isprsjprs.2008.12.007 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29924
in ISPRS Journal of photogrammetry and remote sensing > vol 64 n° 4 (July - August 2009) . - pp 351 - 366[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-09041 SL Revue Centre de documentation Revues en salle Disponible Classification through consultation: public views of the geography of the e-society / Paul A. Longley in International journal of geographical information science IJGIS, vol 23 n° 6 (june 2009)
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Titre : Classification through consultation: public views of the geography of the e-society Type de document : Article/Communication Auteurs : Paul A. Longley, Auteur ; A. Singleton, Auteur Année de publication : 2009 Article en page(s) : pp 737 - 763 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique
[Termes IGN] classification
[Termes IGN] données démographiques
[Termes IGN] erreur systématique
[Termes IGN] géomatique web
[Termes IGN] participation du public
[Termes IGN] société de l'information
[Termes IGN] technologies de l'information et de la communicationRésumé : (Auteur) Although viewed by business and commerce as successful solutions, geodemographic profiling of neighbourhoods has attracted wide-ranging criticism in the academic literature. This paper addresses some specific concerns that arise because the derivation of classifications is rarely transparent and open to scrutiny or challenge. The substantive focus of the research reported in this paper is a nationwide geodemographic classification of how people engage with new information and communication technologies (ICTs). In response to the critique of geodemographics as a 'black box' technology, we describe how the classification was opened up to public scrutiny and how we conducted a major consultation exercise into the reliability of its results. We assess the message of the 50,000+ searches and 3952 responses collected during the consultation exercise, in terms of possible systematic errors in the shape and detail of the classification. Unusually for Internet-based surveys, we also investigate the likely reliability of the response information received and identify ways in which the outcome of consultation might be used to improve the classification. We believe that this is the first-ever large-scale consultation survey of the validity and remit of a geodemographic classification and that it may have wider implications for the creation of geodemographic classifications. Copyright Taylor & Francis Numéro de notice : A2009-316 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810701704652 En ligne : https://doi.org/10.1080/13658810701704652 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29946
in International journal of geographical information science IJGIS > vol 23 n° 6 (june 2009) . - pp 737 - 763[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 079-09041 RAB Revue Centre de documentation En réserve L003 Disponible 079-09042 RAB Revue Centre de documentation En réserve L003 Disponible A closer look at the Tau Criterion as a method of blunder detection within a differential leveling network least squares adjustment / J. Gabor in SaLIS Surveying and land information science, vol 69 n° 2 (Summer 2009)
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Titre : A closer look at the Tau Criterion as a method of blunder detection within a differential leveling network least squares adjustment Type de document : Article/Communication Auteurs : J. Gabor, Auteur Année de publication : 2009 Article en page(s) : pp 67 - 73 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Nivellement
[Termes IGN] application informatique
[Termes IGN] compensation par moindres carrés
[Termes IGN] détection d'erreur
[Termes IGN] Fortran
[Termes IGN] réseau de nivellementRésumé : (auteur) (Auteur) Data collection is a very tedious and repetitive process. No matter how carefully the data are collected, mistakes are a part of life during field collections. Even during the most careful data collecting processes, it is easy to overlook something or make a simple mistake, which can introduce a blunder in the data. This paper analyzes blunder detection using the Tau criterion and researches its use to isolate and eliminate blunders from the data. A software program that was previously written to perform a least squares adjustment on a differential leveling network has been enhanced to incorporate the Tau criterion as a method for the detection of blunders within the data. Copyright SaLIS Numéro de notice : A2009-330 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83708
in SaLIS Surveying and land information science > vol 69 n° 2 (Summer 2009) . - pp 67 - 73[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 121-09021 RAB Revue Centre de documentation En réserve L003 Disponible Testing the stereoscopic precision of a large-format digital camera / Benjamin Arias in Photogrammetric record, vol 24 n° 126 (June - August 2009)
PermalinkRadiosonde humidity bias correction over the West African region for the special AMMA reanalysis at ECMWF / Anna Agustí‐Panareda in Quarterly Journal of the Royal Meteorological Society, vol 135 n° 640 (April 2009 part A)
PermalinkPermalinkAutomatic estimation of fine terrain models from multiple high-resolution satellite images / Nicolas Champion (2009)
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PermalinkAutonomous integrity: an error isotropy-based approach for multiple fault conditions / M. Azaola-Saenz in Inside GNSS, Vol 4 n° 1 (January-Fabruary 2009)
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PermalinkCalibrage de quelques modèles de géoide dans la zone des collines Albanes (Rome) / Valerio Baiocchi in Géomatique expert, n° 66 (01/01/2009)
PermalinkA kernel density estimation method for networks, its computational method and a GIS-based tool / Atsuyuki Okabe in International journal of geographical information science IJGIS, vol 23 n° 1-2 (january 2009)
PermalinkPrecise point positioning with GPS: A new approach for positioning, atmospheric studies, and signal analysis / Rodrigo Figueiredo Leandro (2009)
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