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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)
[article]
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]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]Correction of humidity bias for Vaïsala RS80 sondes during AMMA 2006 Observing Period / Mathieu Nuret in Journal of Atmospheric and Oceanic Technology, vol 25 n° 11 (November 2008)
[article]
Titre : Correction of humidity bias for Vaïsala RS80 sondes during AMMA 2006 Observing Period Type de document : Article/Communication Auteurs : Mathieu Nuret, Auteur ; Jean-Philippe Lafore, Auteur ; Françoise Guichard, Auteur ; Jean-Luc Redelsperger, Auteur ; Olivier Bock , Auteur ; Anna Agusti-Panareda, Auteur ; Jean-Blaise N’Gamini, Auteur Année de publication : 2008 Article en page(s) : pp 2152 - 2158 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Afrique occidentale
[Termes IGN] données GPS
[Termes IGN] données météorologiques
[Termes IGN] erreur systématique
[Termes IGN] humidité de l'air
[Termes IGN] mousson
[Termes IGN] radiosondageRésumé : (autuer) During the African Monsoon Multidisciplinary Analyses (AMMA) program, which included a special observing period that took place over West Africa in 2006, a major effort was devoted to monitor the atmosphere and its water cycle. The radiosonde network was upgraded and enhanced, and GPS receivers deployed. Among all sondes released in the atmosphere, a significant number were Vaisala RS80-A sondes, which revealed a significant dry bias relative to Vaisala RS92 (a maximum of 14% in the lower atmosphere, reaching 20% in the upper levels). This paper makes use of a simple but robust statistical approach to correct the bias. Comparisons against independent GPS data show that the bias is almost removed at night, whereas for daytime conditions, a weak dry bias (5%) still remains. The correction enhances CAPE by a factor of about 4 and, thus, becomes much more in line with expected values over the region. Numéro de notice : A2008-570 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1175/2008JTECHA1103.1 Date de publication en ligne : 01/11/2008 En ligne : https://doi.org/10.1175/2008JTECHA1103.1 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103427
in Journal of Atmospheric and Oceanic Technology > vol 25 n° 11 (November 2008) . - pp 2152 - 2158[article]Cloud-top pressure retrieval using the oxygen a-band in the IRS-3 MOS instrument / R. Preusker in International Journal of Remote Sensing IJRS, vol 28 n° 9 (May 2007)
[article]
Titre : Cloud-top pressure retrieval using the oxygen a-band in the IRS-3 MOS instrument Type de document : Article/Communication Auteurs : R. Preusker, Auteur ; J. Fischer, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 1957 - 1967 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] image IRS-MOS
[Termes IGN] nuage
[Termes IGN] pression atmosphérique
[Termes IGN] radiance
[Termes IGN] radiosondageRésumé : (Auteur) Backscattered solar radiation as measured by MOS (Modular Optoelectronical Scanner) on the IRS3 (Indian Remote sensing Satellite 3) has been used in an algorithm to retrieve cloud top pressure. The algorithm uses a radiance ratio between absorbing channels in the Oxygen-A absorption band at 761 nm and a window channel at 750 nm. The ratios are directly related to the average photon path length, which is mainly determined by the cloud top pressure. This paper presents the principles of the retrieval scheme, results of a sensitivity study and a first validation using radiosondes. Copyright Taylor & Francis Numéro de notice : A2007-278 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160600641632 En ligne : https://doi.org/10.1080/01431160600641632 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28641
in International Journal of Remote Sensing IJRS > vol 28 n° 9 (May 2007) . - pp 1957 - 1967[article]Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 080-07051 RAB Revue Centre de documentation En réserve L003 Exclu du prêt An Improved mean-gravity model for GPS hydrostatic delay calibration / Pierre Bosser in IEEE Geoscience and Remote Sensing Letters, vol 4 n° 1 (2007)
[article]
Titre : An Improved mean-gravity model for GPS hydrostatic delay calibration Type de document : Article/Communication Auteurs : Pierre Bosser , Auteur ; Olivier Bock , Auteur ; Jacques Pelon, Auteur ; Christian Thom , Auteur Année de publication : 2007 Article en page(s) : pp 3 - 7 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] étalonnage des données
[Termes IGN] hauteur ellipsoïdale
[Termes IGN] incertitude géométrique
[Termes IGN] modèle atmosphérique
[Termes IGN] précision submillimétrique
[Termes IGN] radiosondage
[Termes IGN] retard troposphérique
[Termes IGN] retard troposphérique zénithal
[Termes IGN] variabilité
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) The determination of global positioning system (GPS) heights with submillimeter accuracy needs proper correction of tropospheric delay. In this letter, the modeling of zenith hydrostatic delay (ZHD) was addressed, considering that wet delay must be treated separately. ZHD is traditionally estimated from Saastamoinen's formula using a mean-gravity model and surface pressure observations. The uncertainty in ZHD associated with the mean-gravity model is about 0.3 mm. An improved parametric model is derived here, which yields an uncertainty in the ZHD less than 0.1 mm when the surface altitude lies in the range of 0-9 km. A second parametric model is derived for higher altitudes (such as above radiosonde observations or atmospheric models). Both parametric models depend on latitude, height, and time variables. This dependence is due to the link between the mean gravity and temperature profiles between the surface and ~80-km altitude. The uncertainty in the parametric models due to short-term temporal variability of the temperature profiles is shown to produce an uncertainty in ZHD smaller than 0.1 mm. Numéro de notice : A2007-668 Affiliation des auteurs : LOEMI+Ext (1985-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/LGRS.2006.881725 Date de publication en ligne : 15/01/2007 En ligne : http://doi.org/10.1109/LGRS.2006.881725 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84147
in IEEE Geoscience and Remote Sensing Letters > vol 4 n° 1 (2007) . - pp 3 - 7[article]GPS water vapor project associated to the ESCOMPTE programme: description and first results of the field experiment / Olivier Bock in Physics and chemistry of the Earth (A/B/C), vol 29 n° 2-3 ([01/03/2004])PermalinkEstimation of tropical forest canopy temperatures, thermal response numbers, and evapotranspiration using an aircraft-based thermal sensor / J.C. Luvall in Photogrammetric Engineering & Remote Sensing, PERS, vol 56 n° 10 (october 1990)PermalinkAtmospheric water vapour over oceans from SSM-I measurements / P. Schluessel in International Journal of Remote Sensing IJRS, vol 11 n° 5 (May 1990)PermalinkA theoretical estimate of tropospheric water vapour attenuation at 94GhZ from radiosonde data / Asok K. Sen in International Journal of Remote Sensing IJRS, vol 9 n° 7 (July 1988)Permalink