Centre de documentation
scientifique

Dynamic mechanism of blown sand hazard formation at the Jieqiong section of the Lhasa–Shigatse railway / Shengbo Xie in Geomatics, Natural Hazards and Risk, vol 12 n° 1 (2021)  

Public [article]  inGeomatics, Natural Hazards and Risk > vol 12 n° 1 (2021) . - pp 154 - 166 Titre : Dynamic mechanism of blown sand hazard formation at the Jieqiong section of the Lhasa–Shigatse railway Type de document : Article/Communication Auteurs : Shengbo Xie, Auteur ; Jianjun Qu, Auteur ; Yingjun Pang, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : pp 154 - 166 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] météorologie locale [Termes IGN] modèle dynamique [Termes IGN] prévention des risques [Termes IGN] risque naturel [Termes IGN] sable [Termes IGN] Tibet [Termes IGN] variation saisonnière [Termes IGN] vent de sable [Termes IGN] vitesse [Termes IGN] voie ferrée Résumé : (auteur) Blown sand hazards at the Jieqiong section of the Lhasa–Shigatse railway are severe, and their formation mechanism is unclear. Moreover, sand prevention and control work cannot be carried out. Therefore, the dynamic mechanism of blown sand at the Jieqiong section of the Lhasa–Shigatse Railway was investigated by field observation, laboratory analysis, and calculation. Results show that the yearly sand–moving wind at the Jieqiong section commonly originates from the SW direction. The yearly resultant drift direction and the yearly resultant angle of the maximum possible sand transport quantity are NE direction. The angle between railway trend and sand transport direction is 5°–30°. During dry season, sand materials are blown up by the wind, forming wind–sand flow and movement to the NE direction, at which they are blocked by the railway roadbed. Consequently, accumulation occurs and causes serious damage. Strong wind and dryness are synchronous within a season. The directions of sand source and prevailing wind are consistent, thereby aggravating the blown sand dynamic further. The present results provide a reference for controlling sand hazards in the locale. Numéro de notice : A2021-109 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/19475705.2020.1863268 Date de publication en ligne : 28/12/2020 En ligne : https://doi.org/10.1080/19475705.2020.1863268 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96906 [article]

Water vapour variability induced by urban/rural surface heterogeneities during convective conditions / Cédric Champollion in Quarterly Journal of the Royal Meteorological Society, vol 135 n° 642 (July 2009 Part A)  

Public [article]  inQuarterly Journal of the Royal Meteorological Society > vol 135 n° 642 (July 2009 Part A) . - pp 1266 - 1276 Titre : Water vapour variability induced by urban/rural surface heterogeneities during convective conditions Type de document : Article/Communication Auteurs : Cédric Champollion, Auteur ; Philippe Drobinski, Auteur ; M. Haeffelin, Auteur ; Olivier Bock , Auteur ; Jérôme Tarniewicz , Auteur ; Marie-Noëlle Bouin , Auteur ; R. Vautard, Auteur Année de publication : 2009 Projets : 3-projet - voir note / Article en page(s) : pp 1266 - 1276 Note générale : bibliographie This research has been funded by the Centre National de la Recherche Scientifique (CNRS), the Direction Générale de l’Armement (DGA) and the Ecole Polytechnique as well as the Institut des Sciences de l’Univers (INSU) through the Programme Atmosphère Ocean à Multiéchelle (PATOM) and Programme National de Télédétection Spatiale (PNTS) Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] coordonnées GPS [Termes IGN] météorologie locale [Termes IGN] Paris (75) [Termes IGN] teneur en vapeur d'eau [Termes IGN] teneur intégrée en vapeur d'eau [Termes IGN] zone urbaine Résumé : (auteur) Scientific interest in urban meteorology has increased because highly populated areas experience high vulnerability to pollution or heavy rain. However, compared to urban air quality or urban heat island (UHI) processes, the urban water vapour cycle is poorly understood because it has been investigated less due to the lack of upper‐air measurements and the high sensitivity of surface measurements to local heterogeneities. In this paper, surface measurements of wind, temperature, pressure and humidity, as well as integrated water vapour (IWV) from GPS and MODIS and numerical simulations, have been used to investigate the urban cycle of water vapour in May and June 2004 during the VAPIC field experiment in the Paris area. The surface data show the typical characteristics of an urban area with the absence of water vapour sources and a UHI of about 6 °C at night. The urban IWV distribution differs completely, with an urban IWV excess on average between 1600 and 0600 UTC (with a maximum of about 1.5 kg m−2 at 0600 and 1700 UTC). No IWV difference between the urban and rural areas is found in the middle of the day. The numerical simulations reproduce accurately the urban IWV anomaly. Shallow surface wind convergence associated with the UHI during nighttime provides moisture from the rural areas. Urban areas are therefore under wind convergence for most of the time. The rural water vapour sources and the depth of the convergence control the amplitude of the urban IWV excess. At about 1200 UTC, entrainment at the top of the urban boundary layer is the key process that inhibits the urban IWV excess observed at night. Numéro de notice : A2009-589 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/qj.446 Date de publication en ligne : 10/07/2009 En ligne : https://doi.org/10.1002/qj.446 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96192 [article]