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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)
[article]
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 urbaineRésumé : (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
in Quarterly Journal of the Royal Meteorological Society > vol 135 n° 642 (July 2009 Part A) . - pp 1266 - 1276[article]Mesoscale GPS tomography applied to the 12 June 2002 convective initiation event of IHOP_2002 / Cédric Champollion in Quarterly Journal of the Royal Meteorological Society, vol 135 n° 640 (April 2009 part A)
[article]
Titre : Mesoscale GPS tomography applied to the 12 June 2002 convective initiation event of IHOP_2002 Type de document : Article/Communication Auteurs : Cédric Champollion, Auteur ; Cyrille Flamant, Auteur ; Olivier Bock , Auteur ; Florian Masson, Auteur ; David D. Turner, Auteur ; T. Weckwerth, Auteur Année de publication : 2009 Projets : 3-projet - voir note / Article en page(s) : pp 645 - 662 Note générale : bibliographie
This work was partially supported by the PATOM of the CNRS and via grant DE-FG02-08ER64538 from the U.S. Department of Energy as part of the ARM program.Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] coordonnées GPS
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] tomographie par GPSRésumé : (auteur) The time‐varying three‐dimensional water vapour field derived from mesoscale Global Positioning System (GPS) tomography data is used to describe the water vapour variability in relation to the dynamics of the atmosphere during convective initiation (CI). The paper presents the theoretical framework of GPS tomography at the mesoscale, including aspects related to the assimilation of independent data (e.g. water vapour profiles issued from meteorological balloon soundings). GPS tomography‐derived water vapour density retrievals are validated against lidar, the Atmospheric Emitted Radiance Interferometer and radiosonde data, even if the short three‐day period of the study prevents conclusions about the real accuracy of the GPS tomography technique.
GPS tomography products are used, in synergy with surface and sounding‐derived meteorological variable measurements, satellite imagery and reflectivity composites from the WSR‐88D network and S‐POL radar, to study environmental conditions leading to the 12 June 2002 CI event during the International H2O Project. On this day, CI was triggered simultaneously, shortly after 2100 UTC, in two locations along an old outflow boundary lying east‐west in the vicinity of the Oklahoma–Kansas border. The study focuses on CI to the east, which was triggered at the intersection of the outflow boundary with a distinct southwest–northeast‐oriented moisture convergence line. The latter formed as the result of a cross‐dryline circulation leading to the penetration of dry air meeting with the moister air mass associated with the southerly low‐level flow east of the dryline. These intersecting boundaries appeared to have provided the necessary triggering mechanism for getting moist surface air parcels up to the level of free convection. Tomography‐derived water vapour fields provided observational evidence of the vertical transport of water vapour above the lifting condensation level and the level of free convection to the south of and along the intersecting boundaries.Numéro de notice : A2009-573 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/qj.386 Date de publication en ligne : 25/03/2009 En ligne : https://doi.org/10.1002/qj.386 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96188
in Quarterly Journal of the Royal Meteorological Society > vol 135 n° 640 (April 2009 part A) . - pp 645 - 662[article]Radiosonde 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)
[article]
Titre : Radiosonde humidity bias correction over the West African region for the special AMMA reanalysis at ECMWF Type de document : Article/Communication Auteurs : Anna Agustí‐Panareda, Auteur ; Drasko Vasiljevic, Auteur ; Anton Beljaars, Auteur ; Olivier Bock , Auteur ; Françoise Guichard, Auteur ; et al., Auteur Année de publication : 2009 Projets : AMMA & AMMA-2 / Janicot, Serge Article en page(s) : pp 595 - 617 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Afrique (géographie physique)
[Termes IGN] erreur systématique
[Termes IGN] mousson
[Termes IGN] radiosondage
[Termes IGN] teneur en vapeur d'eauRésumé : (auteur) During the African Monsoon Multidisciplinary Analysis (AMMA) field experiment in 2006 there was a large increase in the number of radiosonde data over West Africa. This has the potential of improving the numerical weather prediction (NWP) analysis/forecast and the water budget studies over that region. However, it is well known that the humidity from radiosondes can have some errors depending on sonde type, relative humidity (RH), temperature and the age of the sensor and can give rise to dry biases that are typically between 5% and 30% for RH. Three main sonde types were used in the AMMA field experiment: Vaisala RS80A, Vaisala RS92 and MODEM. In this article, a new empirical method is presented by using the operational European Centre for Medium‐Range Weather Forecasts (ECMWF) short‐range forecast as an intermediary dataset for computing biases. The validation of the correction method using global positioning system (GPS) total columnar water vapour (TCWV) confirms that the method is able to correct for a large part of the dry biases associated with the different sonde types. Results from analysis experiments show how the correction of humidity is particularly important in the West African region due to its impact on the development of convection in NWP models. The proposed radiosonde humidity bias correction has been applied to the special AMMA reanalysis experiment performed at ECMWF for the 2006 West African wet monsoon season. This is expected to benefit a wide number of AMMA‐related studies that make use of the reanalysis, in particular those focusing on the water cycle. Numéro de notice : A2009-574 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/qj.396 Date de publication en ligne : 23/03/2009 En ligne : https://doi.org/10.1002/qj.396 Format de la ressource électronique : URL bulletin Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96190
in Quarterly Journal of the Royal Meteorological Society > vol 135 n° 640 (April 2009 part A) . - pp 595 - 617[article]Etude du cycle de l’eau à partir de modèles numériques de prévision météorologique et d’observations sur l’Afrique du Nord / Maïté Lacarra (2009)
Titre : Etude du cycle de l’eau à partir de modèles numériques de prévision météorologique et d’observations sur l’Afrique du Nord Type de document : Mémoire Auteurs : Maïté Lacarra, Auteur Editeur : Paris : Université de Paris 6 Pierre et Marie Curie Année de publication : 2009 Importance : 42 p. Format : 21 x 30 cm Note générale : bibliographie
Rapport de Master 2 Recherche Méthodes Physiques en TélédétectionLangues : Français (fre) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] données DORIS
[Termes IGN] données GPS
[Termes IGN] interpolation
[Termes IGN] modèle météorologique
[Termes IGN] retard troposphérique zénithal
[Termes IGN] teneur en vapeur d'eauIndex. décimale : MPT Mémoires de fin d'études du Master Méthodes physiques en télédétection Résumé : (auteur) [introduction] Ce stage s’inscrit dans l’étude du cycle de l’eau en Afrique (AMMA) et des échanges entre sous-régions, en particulier l’Afrique de l’Ouest, la région saharienne et la région méditerranéenne. Une des questions scientifiques sous-jacente est notamment de comprendre le rôle des advections de l’humidité depuis la Méditerranée vers l’Afrique de l’Ouest sur la mousson africaine et les mécanismes d’interaction associés (Rowell, 2003 ; Jung et al., 2006 ; Vizy and Cook, 2008). Pour aborder ces questions, le recours aux modèles et aux données d’observation est indispensable. Il est donc important de se créer d’abord une base de données d’observations. Dans un premier temps, il est nécessaire de connaître précisément les produits utilisés et les méthodes de traitement de données appliquées afin de sélectionner des jeux de données pertinents. Nous avons utilisé des produits troposphériques GPS et DORIS, qu’il a fallu valider en faisant des inter-comparaisons. Ensuite, nous avons extrait des données de plusieurs modèles de prévision numérique tel que la ré-analyse ERA-Interim ainsi que des analyses produites en mode recherche au centre européen ECMWF en collaboration avec Peter Bauer (ECMWF) et Fatima Karbou (Météo-France). Nous avons alors pu évaluer les différentes analyses à l’échelle globale et régionale au niveau de l’Afrique. Ce travail nous a permis d’avoir une idée de la qualité de la représentation de l’humidité atmosphérique dans ces modèles. Note de contenu : 1. Introduction
2. Méthodes et données
2.1. GPS
2.2. DORIS
2.3. Modèle
2.4. Transformation des ZTD en IWV
3. Validation des ZTD de la solution IGS trop new
3.1. Comparaison des ZTD du traitement IGS trop new avec le traitement GPS c4.2
3.2. Comparaison des ZTD du produit IGS trop new avec le traitement IGS (IGS old)
3.3. Comparaison des ZTD du produit IGS trop new avec celui de DORIS
3.4. Conclusion sur les comparaisons de ZTD
4. Validation des modèles de prévision numérique
4.1. Sources d’erreurs de la transformation ZTD en IWV
4.2. Correction verticale et interpolation des IWV
4.3. Validation des modèles météorologiques
5. ConclusionNuméro de notice : 14912 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Mémoire masters divers Organisme de stage : LAREG (IGN) Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76812
Titre : High-resolution GPS tomography in view of hydrological hazard assessment Type de document : Thèse/HDR Auteurs : Simon Lutz, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2009 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 76 Importance : 200 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-20-8 Note générale : Bibliographie
Doctoral thesisLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] aérosol
[Termes IGN] atmosphère terrestre
[Termes IGN] Bernese
[Termes IGN] campagne d'expérimentation
[Termes IGN] collocation
[Termes IGN] distribution spatiale
[Termes IGN] double différence
[Termes IGN] interpolation spatiale
[Termes IGN] météorologie
[Termes IGN] méthode des moindres carrés
[Termes IGN] modèle atmosphérique
[Termes IGN] prévision météorologique
[Termes IGN] propagation troposphérique
[Termes IGN] réfraction atmosphérique
[Termes IGN] risque naturel
[Termes IGN] temps réel
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] tomographie
[Termes IGN] traitement de données GNSS
[Termes IGN] Valais (Suisse)
[Termes IGN] vapeur d'eau
[Termes IGN] voxelIndex. décimale : 30.83 Applications océanographiques de géodésie spatiale Résumé : (Auteur) In the last few years, the use of propagation delays of GNSS radio signals due to the atmospheric effect has gained considerable importance as a valuable contribution to numerical weather forecasting. GPS-based tomography is a dedicated method to resolve the temporal variation and spatial distribution of the most important constituent of the atmosphere, the tropospheric water vapor. The four-dimensional tomographic approach, however, has not yet been completely established. Investigations on the small-scale high-resolution configuration will now help to determine and model water vapor distribution and variation over local, mountainous catchment areas. Especially, the development towards near real-time analysis with a high update rate of less than one hour will reveal the potential in the field of short and medium range forecasts.
Three main objectives were defined for this research project: The first objective was the study of the feasibility of GPS tomography in a small-scale and Alpine area. Furthermore, the processing of campaign-type measurements had to be considered specifically. The second aim was the determination of the four-dimensional distribution of atmospheric water vapor over a local region using GPS tomography in view of hydrological hazard assessment. Thirdly, aspects of real-time determination had to be investigated. In this context, it had to be accounted for that, instead of precise GNSS satellite orbits, predicted ones like broadcast ephemerides or ultra-rapid orbits had to be used. Also, it had to be addressed that the processing time is a critical issue in real-time computation. As a consequence, the parameters of the complete GPS processing were refined and adapted to near real-time applications. Furthermore, new algorithms in the tomographic software were to be designed and evaluated.
The tomographic software package AWATOS (Atmospheric Water Vapor Tomography Software), developed at the Geodesy and Geodynamics Laboratory, ETH Zurich, was used for the assimilation of double-differenced GPS observations and interpolated meteorological data sets. The spatial distribution of water vapor can be determined by least-squares inversion with a high temporal resolution.
The work was carried out in five steps: Simulations helped to design an optimal GPS network for the tomographic purpose. Based on these findings, two dedicated field campaigns were performed to study the feasibility of the method for a non-permanent densification network in an Alpine region in Switzerland. Secondly, GPS derived zenith total delays (ZTD) as well as double-differenced residuals were estimated using a high performance and high accuracy post-processing software package (Bernese GPS Software Version 5.0). The results were validated by comparison with independent methods. With the software package COMEDIE, meteorological data was collocated and interpolated for the separation of the total delays into a wet and a dry part. In the third step, this set of data was processed with the GPS tomography software package AWATOS to obtain spatially and temporally highly-resolved wet refractivity fields. An automatic generation of tomographic voxel models was developed in the forth step. This tool allows high flexibility in tomographic processing and forms a fundamental part of an adaptive method of choosing voxel models at a particular spatial resolution. In the fifth step, the aspects of near real-time processing were investigated.
Measurements from a solar spectrometer and data from the current numerical weather model COSMO-7 of MeteoSwiss were available for comparison purposes. During the campaigns, radiosondes were launched to measure vertical profiles of the tropospheric meteorological components in situ and to validate the tomographic results.
The success of the tomographic method was revealed by the statistical analyses. The wet refractivity profiles from the GPS tomography software package AWATOS in the high-resolution mode match the profiles derived from corresponding radiosonde measurements within 10 ppm (refractivity units). The AWATOS profiles represent the characteristics of the different tropospheric layers in most cases with high significance.
The accuracy of GPS tomography in near real-time was assessed based on dedicated case studies with real-time orbits. The error budget of the near real-time calculations was compared to the best postprocessing solutions available. Due to large variations in the time series of the Up component of the GPS coordinate estimation, the broadcast ephemerides are not recommended for GPS meteorological applications. But ultra-rapid orbits, which are also available in real-time, yield satisfying results regarding tropospheric parameter estimation (ZTD) and the high-resolution GPS tomographic analysis.Note de contenu : 1 Introduction
1.1 Trends in GPS meteorology
1.2 Research review of atmospheric water vapor profiling
1.3 Significance of high-resolution GPS tomography
1.3.1 For the research community
1.3.2 For practical applications
1.4 Objectives
1.5 Structure
2 Theoretical background of GPS meteorology
2.1 Atmospheric water vapor
2.2 Radio wave refractivity
2.3 Refraction and path delay modeling
2.3.1 Definition
2.3.2 The Saastamoinen formula
2.3.3 Integrating tropospheric refractivity
2.3.4 Path delay interpolation with COITROPA
2.4 The Global Positioning System (GPS)
2.4.1 Introduction to GPS
2.4.2 The GPS observation equations
2.4.3 Mapping functions and standard models
2.4.4 Troposphere modeling in the Bernese GPS Software
2.5 The software package COMEDIE
2.5.1 4-D refractivity field from meteorological data
2.5.2 Estimation of tropospheric path delays
3 Ground-based GPS tomography of the neutral atmosphere
3.1 Models, methods and algorithms
3.1.1 The tomographic voxel model
3.1.2 The apriori model .
3.1.3 Inter-voxel constraints
3.1.4 Separation of the total path delay
3.2 The software package AWATOS
3.2.1 Double-difference GPS tomography
3.2.2 The tomographic equation system
3.2.3 Ray tracing and the design matrix
3.2.4 (Pscudo-) Observations and the weight matrix
3.2.5 Error budget
3.3 Network analysis tool
4 Outline of the two field campaigns
4.1 Introduction
4.2 The project area in the canton of Valais (Switzerland)
4.3 The July 2005 field campaign
4.3.1 GPS network
4.3.2 Meteorological ground measurement network
4.3.3 Radiosondes
4.4 The October 2005 field campaign
4.4.1 GPS Network
4.4.2 Meteorological ground measurement network
4.4.3 Radiosondes
4.4.4 Solar Spectrometry for comparison purpose
5 Data preprocessing
5.1 Introduction
5.2 GPS data processing
5.2.1 Overview
5.2.2 Criteria for fix station selection
5.2.3 Parameter settings in the Bernese GPS Software
5.2.4 Network solutions
5.2.5 Section summary
5.3 Meteorological data processing
5.4 Path delay comparison
6 The numerical weather model COSMO-7
6.1 Model description
6.2 Distribution of the available data
6.3 Data processing workflow
6.4 Data analysis
6.4.1 Comparison with balloon sounding profiles
6.4.2 Time series of integrated path delays
6.4.3 Comparison with time series of hourly GPS-ZTD
6.4.4 ZTD comparison with rainfall data
7 Enhancements of AWATOS
7.1 Introduction
7.2 New models and algorithms
7.2.1 Designing the voxel model
7.2.2 Obtaining a priori information
7.2.3 Allocation of meteorological data
7.2.4 Selection of beneficial stations
7.3 Further analysis tools
7.4 Notes on near real-tirnc analysis and predictive algorithms
7.5 Accuracy and reliability assessment
8 Results and discussion
8.1 Towards high spatial resolution
8.1.1 Impact of vertical spacing
8.1.2 Vertical resolution and cutoff elevation angle
8.1.3 Impact of horizontal spacing
8.1.4 Summary on the July 2005 campaign data
8.1.5 Summary on the October 2005 campaign data
8.1.6 Impact of a reduced network in October 2005
8.1.7 Discussion on spatial resolution
8.2 Correlation analysis with meteorological surface data
8.2.1 Comparison with air temperature
8.2.2 Wet refractivity variation and sunshine duration
8.2.3 Dew point temperature and atmospheric water vapor
8.3 Aspects of changing temporal resolution
8.4 Investigations in near real-time analysis
8.4.1 Processing real-time GPS orbits
8.4.2 Examination of time correlation strategies
9 ConclusionsNuméro de notice : 15512 Affiliation des auteurs : non IGN Autre URL associée : URL ETH Zurich Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : 10.3929/ethz-a-005648120 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-76.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62745 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 15512-01 30.83 Livre Centre de documentation Géodésie Disponible Développement et validation d'une méthode de calcul GPS intégrant des mesures de profils de vapeur d'eau en visée multi-angulaire pour l'altimétrie de haute précision / Pierre Bosser (2008)PermalinkStudy of the statistics of water vapor mixing ratio determined from Raman lidar measurements / Pierre Bosser in Applied Optics, vol 46 n° 3 ([20/11/2007])PermalinkPotentiel de la mesure GPS sol pour l’étude des pluies intenses méditerranéennes / Hugues Brenot (2006)PermalinkEtude d’une méthode de sondage de la vapeur d’eau dans la troposphère appliquée à la correction de mesures GPS pour l’altimétrie de haute précision / Jérôme Tarniewicz (2005)PermalinkPermalinkQuantification de la vapeur d'eau troposphérique par GPS (modèles 2D et tomographies 3D) - Application aux précipitations intenses / Cédric Champollion (2005)PermalinkSatellite constellation with direct radio measurements for atmospheric studies : WATS mission case / G. Alberti in International Journal of Remote Sensing IJRS, vol 25 n° 18 (September 2004)PermalinkGPS based determination of the integrated and spatially distributed water vapor in the troposphere / Marc Troller (2004)PermalinkGPS Tomography and Remote Sensing Techniques for Water Vapor Determination in the ESCOMPTE Campaign / Beat Bürki (2004)PermalinkRemote sensing of atmospheric water vapor with the Global Positioning System / John Joseph Braun (2004)Permalink