Détail de l'auteur
Auteur Patrick Chazette |
Documents disponibles écrits par cet auteur



Multi‐scale observations of atmospheric moisture variability in relation to heavy precipitating systems in the northwestern Mediterranean during HyMeX IOP12 / Samiro Khodayar in Quarterly Journal of the Royal Meteorological Society, vol 144 n° 717 (October 2018 Part B)
![]()
[article]
Titre : Multi‐scale observations of atmospheric moisture variability in relation to heavy precipitating systems in the northwestern Mediterranean during HyMeX IOP12 Type de document : Article/Communication Auteurs : Samiro Khodayar, Auteur ; Beata Czajka, Auteur ; Alberto Caldas-Álvarez, Auteur ; Sebastian Helgert, Auteur ; Cyrille Flamant, Auteur ; Olivier Bock , Auteur ; Patrick Chazette, Auteur
Année de publication : 2018 Projets : HyMeX / Article en page(s) : pp 2761 - 2780 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes descripteurs IGN] convection
[Termes descripteurs IGN] coordonnées GPS
[Termes descripteurs IGN] couche atmosphérique
[Termes descripteurs IGN] distribution spatiale
[Termes descripteurs IGN] données météorologiques
[Termes descripteurs IGN] humidité de l'air
[Termes descripteurs IGN] image Cosmo-Skymed
[Termes descripteurs IGN] Méditerranée, mer
[Termes descripteurs IGN] teneur intégrée en vapeur d'eau
[Termes descripteurs IGN] troposphèreRésumé : (auteur) The deployment of special instrumentation for the Hydrological Cycle in the Mediterranean Experiment (HyMeX) provides a valuable opportunity to investigate the spatio‐temporal variability of atmospheric water vapour across scales in relationship with the occurrence of Heavy Precipitation Systems (HPSs) in the north Western Mediterranean (WMed) during the Intensive Observation Period (IOP12), which is the focus of this investigation. High‐resolution convection‐permitting COSMO simulations complement the observational network and allow the calculation of on‐line trajectories. In addition to the presence of a favourable large‐scale situation and low‐level convergence, atmospheric moisture changes resulting in conditionally unstable air are identified as responsible for convective initiation (CI). All HPSs within the north‐WMed form in periods/areas of maximum integrated water vapour (IWV; 35–45 kg/m2) after an increase of about 10–20 kg/m2. The most intense events receive moisture from different sources simultaneously and show a sudden increase of about 10 kg/m2 between 6 and 12 h prior to the event, whereas in the less intense events the increase is larger, about 20 kg/m2, over a period of at least 24–36 h. Changes in the lower (∼900 hPa) and mid‐troposphere (∼700 hPa) control the evolution of the atmospheric moisture and the instability increase prior to CI. Spatial inhomogeneities in the lower boundary layer determine the timing and location of deep convection, whereas enhanced moisture in the mid‐troposphere favours intensification. Moister and deeper boundary layers, with updraughts reaching up to 2 km are identified in those pre‐convective environments leading to HPS, whereas dry, shallow boundary layers are found everywhere else. The build‐up time and vertical distribution of the moisture changes are found to be crucial for the evolution and severity of the HPSs rather than the amount of total column atmospheric moisture. Numéro de notice : A2018-550 Affiliation des auteurs : LaSTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/qj.3402 date de publication en ligne : 09/09/2018 En ligne : https://doi.org/10.1002/qj.3402 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91637
in Quarterly Journal of the Royal Meteorological Society > vol 144 n° 717 (October 2018 Part B) . - pp 2761 - 2780[article]A multi-instrument and multi-model assessment of atmospheric moisture variability over the Western Mediterranean during HyMeX / Patrick Chazette in Quarterly Journal of the Royal Meteorological Society, vol 142 n° S1 (August 2016)
![]()
[article]
Titre : A multi-instrument and multi-model assessment of atmospheric moisture variability over the Western Mediterranean during HyMeX Type de document : Article/Communication Auteurs : Patrick Chazette, Auteur ; Cyrille Flamant, Auteur ; Xiaoxia Shang, Auteur ; Julien Totems, Auteur ; Jean-Christophe Raut, Auteur ; Alexis Doerenbecher, Auteur ; Véronique Ducrocq, Auteur ; Nadia Fourrié, Auteur ; Olivier Bock , Auteur ; Sophie Cloché, Auteur
Année de publication : 2016 Article en page(s) : pp 7 - 22 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes descripteurs IGN] données météorologiques
[Termes descripteurs IGN] lidar Raman
[Termes descripteurs IGN] littoral méditerranéen
[Termes descripteurs IGN] modèle de simulation
[Termes descripteurs IGN] modèle météorologique
[Termes descripteurs IGN] positionnement par GPS
[Termes descripteurs IGN] prévision météorologique
[Termes descripteurs IGN] récepteur GPS
[Termes descripteurs IGN] teneur en vapeur d'eauMots-clés libres : water vapour lidars Numerical Weather Prediction Models Weather Research and Forecasting model Mediterranean HyMeX cross-validation Résumé : (auteur) The Hydrological cycle in the Mediterranean eXperiment (HyMeX) was held in autumn 2012 during which part of the observational effort was established on Menorca Island to characterize the upwind marine low-level flow. The ground-based Water-vapour Raman Lidar (WALI), the airborne water-vapour lidar LEANDRE 2 and boundary-layer pressurized balloons were implemented during the first Special Observing Period and contributed to characterize water vapour variability in the vicinity of the Balearic Islands, together with the existing network of Global Positioning System receivers. Furthermore, analyses from regional and global numerical weather prediction (NWP) models (AROME-WMED, the ECMWF/IFS NWP system and the Weather Research and Forecasting (WRF) model) were also available over large domains encompassing part of or the entire western Mediterranean basin. We assess the consistency of water vapour mixing ratio (WVMR) profiles and integrated water vapour contents (IWVC) derived from the different datasets by comparing them to a common reference, the ground-based lidar WALI. We use consistency indicators such as root-mean-square errors, biases and correlations. Comparison between WVMR profiles from ground-based and airborne lidars (ground-based lidar and boundary-layer pressurized balloons) leads to a root-mean-square error lower than 1.6 g kg−1 (1.3 g kg−1) when the closest possible air masses are sampled. We observed a good agreement between the vertical WVMR profiles derived from WALI and the numerical models with correlations higher than 0.7 and root-mean-square errors lower than 2 g kg−1. Regarding IWVCs, the models exhibit biases less than 2 kg m−2, root-mean-square errors lower than 2.3 g kg−1 and correlations higher than 0.86 when compared to WALI. Finally, AROME-WMED 48 h forecasts were compared with WALI data composited over eleven 48 h periods. The quality of the forecast does not visibly degrade within the 48 h period from the initial analyses. Numéro de notice : A2016-936 Affiliation des auteurs : IGN+Ext (2012-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/qj.2671 date de publication en ligne : 18/09/2015 En ligne : http://dx.doi.org/10.1002/qj.2671 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83164
in Quarterly Journal of the Royal Meteorological Society > vol 142 n° S1 (August 2016) . - pp 7 - 22[article]Offshore deep convection initiation and maintenance during the HyMeX IOP 16a heavy precipitation event / F. Duffourg in Quarterly Journal of the Royal Meteorological Society, vol 142 n° S1 (August 2016)
![]()
[article]
Titre : Offshore deep convection initiation and maintenance during the HyMeX IOP 16a heavy precipitation event Type de document : Article/Communication Auteurs : F. Duffourg, Auteur ; O. Nuissier, Auteur ; Véronique Ducrocq, Auteur ; Cyrille Flamant, Auteur ; Patrick Chazette, Auteur ; J. Delanoë, Auteur ; Alexis Doerenbecher, Auteur ; Nadia Fourrié, Auteur ; Paolo Di Girolamo, Auteur ; C. Lac, Auteur ; Dominique Legain, Auteur ; M. Martinet, Auteur ; Frédérique Saïd, Auteur ; Olivier Bock , Auteur
Année de publication : 2016 Article en page(s) : pp 259 - 274 Note générale : bibliographie Langues : Anglais (eng) Résumé : (auteur) During the first special observation period of the HyMeX program dedicated to heavy precipitation over the western Mediterranean, several Mesoscale Convective Systems (MCSs) formed over the sea and produced heavy precipitation over the coastal regions, as for example during IOP (Intensive Operation Period) 16a. On 26 October 2012, back‐building MCSs formed and renewed over the northwestern Mediterranean Sea while producing heavy rain over the French coastal urbanized regions. This paper analyses the storm evolution along with the ambient flow and the initiation and maintenance mechanisms of the offshore deep convection observed during IOP16a. The suites of water vapour lidars, wind profilers, radiosoundings and boundary‐layer drifting balloons over and along the coast of the northwestern Mediterranean offer a unique framework for validating the convective processes over the sea investigated using kilometre‐scale analyses and simulation. The high‐resolution simulation shows clearly that the convective system is fed during its evolution over the sea by moist and conditionally unstable air carried by a southwesterly to southeasterly low‐level jet. The low‐level wind convergence in this southeasterly to southwesterly flow over the sea is the main triggering mechanism acting to continually initiate and maintain the renewal of convective cells contributing to the back‐building system. The convergence line appears when a secondary pressure low forms in the lee of the Iberian mountains. A sensitivity test turning off the evaporative cooling within the microphysical parametrization shows that the exact location of the main convergence area focusing the heaviest precipitation is determined by small‐scale feedback mechanisms of the convection to the environment. Numéro de notice : A2016--182 Affiliation des auteurs : LAREG+Ext (1991-2011) Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/qj.2725 date de publication en ligne : 18/12/2015 En ligne : https://doi.org/10.1002/qj.2725 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91816
in Quarterly Journal of the Royal Meteorological Society > vol 142 n° S1 (August 2016) . - pp 259 - 274[article]Water vapor measurements by mobile Raman lidar over the Mediterranean Sea in the framework of HyMeX: application to multi-platform validation of moisture profiles / Julien Totems in EPJ Web of Conferences, vol 119 (2016)
![]()
[article]
Titre : Water vapor measurements by mobile Raman lidar over the Mediterranean Sea in the framework of HyMeX: application to multi-platform validation of moisture profiles Type de document : Article/Communication Auteurs : Julien Totems, Auteur ; Patrick Chazette, Auteur ; Xiaoxia Shang, Auteur ; Cyrille Flamant, Auteur ; Jean-Christophe Raut, Auteur ; Alexis Doerenbecher, Auteur ; Véronique Ducrocq, Auteur ; Olivier Bock , Auteur ; Fabien Marnas, Auteur
Année de publication : 2016 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes descripteurs IGN] Baléares, îles
[Termes descripteurs IGN] données météorologiques
[Termes descripteurs IGN] humidité de l'air
[Termes descripteurs IGN] image MetOp-IASI
[Termes descripteurs IGN] lidar Raman
[Termes descripteurs IGN] Méditerranée, mer
[Termes descripteurs IGN] teneur en vapeur d'eauRésumé : (auteur) The Water Aerosol Lidar (WALI) system, deployed for 14 weeks during 2012 & 2013 on the island of Menorca, provided the Hydrological cycle in the Mediterranean eXperiment (HyMeX) with an opportunity to perform a multi-platform comparison on moisture retrievals at the timescales relevant for extreme precipitation events in the West Mediterranean basin. After calibration, the WALI lidar yields nighttime profiles of water vapor with ~7% accuracy from the ground up to 7 km, and daytime coverage of the lower layers, alongside common aerosol retrievals. It is used to characterize the water vapor profile product given by the IASI instrument on-board MetOp-B, and the fields simulated by the Météo-France AROME-WMED model and the open-source WRF model. IASI is found to be reliable above 1 km altitude, and the two models obtain similar high scores in the middle troposphere; WRF beneficiates from a more accurate modelling of the planetary boundary layer. Numéro de notice : A2016--187 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1051/epjconf/201611926006 date de publication en ligne : 07/06/2016 En ligne : https://doi.org/10.1051/epjconf/201611926006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91826
in EPJ Web of Conferences > vol 119 (2016)[article]Potential of an ultraviolet, medium-footprint lidar prototype for retrieving forest structure / Tristan Allouis in ISPRS Journal of photogrammetry and remote sensing, vol 66 n° 6 supplement (December 2011)
![]()
[article]
Titre : Potential of an ultraviolet, medium-footprint lidar prototype for retrieving forest structure Type de document : Article/Communication Auteurs : Tristan Allouis, Auteur ; Sylvie Durrieu, Auteur ; Patrick Chazette, Auteur ; J. Bailly, Auteur ; et al., Auteur ; Cédric Vega , Auteur
Année de publication : 2011 Article en page(s) : pp 92 - 102 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes descripteurs IGN] Aquitaine
[Termes descripteurs IGN] atténuation du signal
[Termes descripteurs IGN] correction du signal
[Termes descripteurs IGN] données lidar
[Termes descripteurs IGN] empreinte
[Termes descripteurs IGN] forêt tempérée
[Termes descripteurs IGN] géostatistique
[Termes descripteurs IGN] hauteur des arbres
[Termes descripteurs IGN] instrument aéroporté
[Termes descripteurs IGN] Landes (40)
[Termes descripteurs IGN] pinophyta
[Termes descripteurs IGN] rayonnement ultraviolet
[Termes descripteurs IGN] surveillance forestièreRésumé : (Auteur) The aim of the paper is to carry on methodological development for retrieving forest parameters from medium-footprint lidar signals and for assessing the performance of different sampling strategies. The 2.4 m footprint lidar prototype (a profiler instrument using an ultraviolet laser) was flown above two different maritime pine stands: a young plantation (10 years old) and a mature, semi-natural stand (55 years old), both in the Landes forest, France. The vertical distribution of lidar measurements was studied for retrieving forest height parameters (mean total height, mean crown height and top height). The processing algorithm was based on an aggregation of successive signals followed by the correction of the signal attenuation along the travel through the vegetation. The performance of different sampling strategies was assessed by comparing the results for the full dataset (several fight lines over the stands) and for only a data subset (one flight line). In addition, the horizontal distribution of height measurements was studied for identifying the planting pattern of the stands and assessing the tree spacing of the semi-natural parcel, using geostatistics. We obtained a submetric estimation error (lidar – reference) of 0.2 m on the mean total height in the young stand (-0.7 m in the mature stand), a bias of -0.3 m (-0.3 m) on the mean crown height measurement and of 0.6 m (-1.0 m) on the top height. The planting pattern was also successfully identified, and the distance between trees was assessed in agreement with ground measurements. Having demonstrated its ability to assess forest structure, even with a unique flight line, the lidar prototype seems to be a valuable sensor for performing fast forest inventory at regional scale. In addition, this sensor opens the way to the development of bi-functional lidar for both atmosphere and vegetation remote sensing. Numéro de notice : A2011-522 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern En ligne : http://www.sciencedirect.com/science/article/pii/S0924271611000967 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31416
in ISPRS Journal of photogrammetry and remote sensing > vol 66 n° 6 supplement (December 2011) . - pp 92 - 102[article]Réservation
Réserver ce documentExemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 081-2011071 SL Revue Centre de documentation Revues en salle Disponible La canopée forestière vue par un Lidar ultra-violet aéroporté de nouvelle génération / J. Cuesta in Revue Française de Photogrammétrie et de Télédétection, n° 191 (Mai 2010)
PermalinkMapping the aerodynamic roughness length of desert surfaces from the POLDER/ADEOS bi-directional reflectance product / Béatrice Marticorena in International Journal of Remote Sensing IJRS, vol 25 n° 3 (February 2004)
Permalink