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Comparisons of atmospheric mass variations derived from ECMWF reanalysis and operational fields, over 2003–2011 / E. Forootan in Journal of geodesy, vol 88 n° 5 (May 2014)
[article]
Titre : Comparisons of atmospheric mass variations derived from ECMWF reanalysis and operational fields, over 2003–2011 Type de document : Article/Communication Auteurs : E. Forootan, Auteur ; Olga Didova, Auteur ; M. Schumacher, Auteur ; J. Kusche, Auteur ; B. Elsaka, Auteur Année de publication : 2014 Article en page(s) : pp 503 - 514 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] analyse comparative
[Termes IGN] analyse diachronique
[Termes IGN] atmosphère terrestre
[Termes IGN] données GRACE
[Termes IGN] levé gravimétrique
[Termes IGN] masse d'air
[Termes IGN] variationRésumé : (Auteur) There are two spurious jumps in the atmospheric part of the Gravity Recovery and Climate Experiment-Atmosphere and Ocean De-aliasing level 1B (GRACE-AOD1B) products, which occurred in January-February of the years 2006 and 2010, as a result of the vertical level and horizontal resolution changes in the ECMWFop (European Centre for Medium-Range Weather Forecasts operational analysis). These jumps cause a systematic error in the estimation of mass changes from GRACE time-variable level 2 products, since GRACE-AOD1B mass variations are removed during the computation of GRACE level 2. In this short note, the potential impact of using an improved set of 6-hourly atmospheric de-aliasing products on the computations of linear trends as well as the amplitude of annual and semi-annual mass changes from GRACE is assessed. These improvements result from 1) employing a modified 3D integration approach (ITG3D), and 2) using long-term consistent atmospheric fields from the ECMWF reanalysis (ERA-Interim). The monthly averages of the new ITG3D-ERA-Interim de-aliasing products are then compared to the atmospheric part of GRACE-AOD1B, covering January 2003 to December 2010. These comparisons include the 33 world largest river basins along with Greenland and Antarctica ice sheets. The results indicate a considerable difference in total atmospheric mass derived from the two products over some of the mentioned regions. We suggest that future GRACE studies consider these through updating uncertainty budgets or by applying corrections to estimated trends and amplitudes/phases Numéro de notice : A2014-258 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0696-x Date de publication en ligne : 07/02/2014 En ligne : https://doi.org/10.1007/s00190-014-0696-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33161
in Journal of geodesy > vol 88 n° 5 (May 2014) . - pp 503 - 514[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2014051 SL Revue Centre de documentation Revues en salle Disponible Dynamic modeling of GNSS troposphere wet delay for estimation of precipitable water vapour / Ahmed El-Mowafy in Journal of applied geodesy, vol 8 n° 1 (April 2014)
[article]
Titre : Dynamic modeling of GNSS troposphere wet delay for estimation of precipitable water vapour Type de document : Article/Communication Auteurs : Ahmed El-Mowafy, Auteur ; Johnny Lo, Auteur Année de publication : 2014 Article en page(s) : pp 31 - 42 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] autocorrélation
[Termes IGN] humidité de l'air
[Termes IGN] modèle dynamique
[Termes IGN] positionnement par GNSS
[Termes IGN] précipitation
[Termes IGN] propagation troposphérique
[Termes IGN] signal GNSS
[Termes IGN] vapeur d'eauRésumé : (Auteur) Proper dynamic modelling of the troposphere wet delay using the Global Navigation Satellite Systems (GNSS) measurements is important in precise point positioning and in estimation of the Precipitable Water Vapour (PWV) for weather forecast. The random walk (RW) and the first-order Gauss-Markov (GM) autocorrelation models are commonly used for this purpose. However, it was found that these models consistently underestimate the temporal correlations that exist among the troposphere wet delay. Therefore, a new dynamic model is proposed. The performance of the proposed model in following the autocorrelation of actual data is demonstrated and its impact on the near-real time estimation of the wet delay was tested and compared to that of the GM and RW models. Results showed that the proposed model outperformed these models. When the computed wet delays were used to compute PWV, their estimated valueswere very close to actual PWV data measured by radiosonde with differences less than 1 mm. Numéro de notice : A2014-271 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2013-0012 2 2 total citations on Dimensions. Date de publication en ligne : 08/04/2014 En ligne : https://doi.org/10.1515/jag-2013-0012 2 2 total citations on Dimensions. Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33174
in Journal of applied geodesy > vol 8 n° 1 (April 2014) . - pp 31 - 42[article]Hyperspectral-based adaptive matched filter detector error as a function of atmospheric water vapor estimation / Allan W. Yarbrough in IEEE Transactions on geoscience and remote sensing, vol 52 n° 4 (April 2014)
[article]
Titre : Hyperspectral-based adaptive matched filter detector error as a function of atmospheric water vapor estimation Type de document : Article/Communication Auteurs : Allan W. Yarbrough, Auteur ; Michael J. Mendenhall, Auteur ; Richard K. Martin, Auteur ; Steven T. Fiorino, Auteur Année de publication : 2014 Article en page(s) : pp 2029 - 2039 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] détection d'erreur
[Termes IGN] données météorologiques
[Termes IGN] erreur de classification
[Termes IGN] estimation statistique
[Termes IGN] filtrage numérique d'image
[Termes IGN] filtre spectral
[Termes IGN] humidité de l'air
[Termes IGN] image hyperspectrale
[Termes IGN] transfert radiatif
[Termes IGN] vapeur d'eauRésumé : (Auteur) Accurate target detection and classification in hyperspectral imagery require that the spectral measurements by the imager match as closely as possible the known “true” target as collected under controlled conditions and stored in a target database. Therefore, the effect of the radiation source and the atmosphere must be factored out of the result before detection is attempted. Our objective is to evaluate detection error due to the error in estimating the atmospherics. We apply a range of atmospheric water vapor profiles, corresponding to different relative humidities, to a model-based prediction of the radiative transfer to examine the effect of water vapor on simulated hyperspectral imagery. These profiles are taken from known distribution percentiles as obtained from historic meteorological measurements close to the sites being simulated. We quantify the expected detection error for the adaptive matched filter, as measured by the receiver operating characteristic (ROC) and the area under the ROC curve, given the range of atmospheric conditions in the historic profile. We discover that, depending on the target, and given the uncertainty as to the true atmospheric conditions, detection rates improve on average across the historic range when we assume the atmospheric profile is at the 35th percentile of atmospheric relative humidity instead of the 50th percentile. Numéro de notice : A2014-269 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2013.2257797 En ligne : https://doi.org/10.1109/TGRS.2013.2257797 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33172
in IEEE Transactions on geoscience and remote sensing > vol 52 n° 4 (April 2014) . - pp 2029 - 2039[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-2014041 RAB Revue Centre de documentation En réserve L003 Disponible An improved dark object method to retrieve 500 m-resolution AOT (Aerosol Optical Thickness) image from MODIS data: A case study in the Pearl River Delta area, China / Lili Li in ISPRS Journal of photogrammetry and remote sensing, vol 89 (March 2014)
[article]
Titre : An improved dark object method to retrieve 500 m-resolution AOT (Aerosol Optical Thickness) image from MODIS data: A case study in the Pearl River Delta area, China Type de document : Article/Communication Auteurs : Lili Li, Auteur ; Jingxue Yang, Auteur ; Yupeng Wang, Auteur Année de publication : 2014 Article en page(s) : pp 1 - 12 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] aérosol
[Termes IGN] bande spectrale
[Termes IGN] delta
[Termes IGN] delta de la rivière des perles
[Termes IGN] densité de la végétation
[Termes IGN] flore locale
[Termes IGN] image à moyenne résolution
[Termes IGN] image Aqua-MODIS
[Termes IGN] Kouangtoung (Chine)
[Termes IGN] réflectance de surfaceRésumé : (Auteur) This paper presents an improved Dark Dense Vegetation (DDV) method for retrieving 500 m-resolution aerosol optical depth (AOT) based on MOD04-C005 arithmetic with the Moderate Resolution Imaging Spectroradiometer (MODIS) from the National Aeronautics and Space Administration (NASA). The improvements include change of the movement pattern of retrieval window, selection of a more suitable aerosol type, and storage of the look-up table. The method is then applied to obtain the AOT over the Pearl River Delta region (PRD). By comparing the results with the co-temporal ground sunphotometer observations in 2010, the correlation coefficient is found to be 0.794 with RMSE 0.139 and their variations remain consistent. Contrasts between model values in 2008 and MODIS AOT products in the same date also reveal a high accuracy of the improved DDV method. We also performed sensitivity tests to analyze the impacts of several parameters on apparent reflectance at different bands, and the results show that apparent reflectance is much more sensitive to surface reflectance and AOT than to elevation. Numéro de notice : A2014-120 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2013.12.008 En ligne : https://doi.org/10.1016/j.isprsjprs.2013.12.008 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33025
in ISPRS Journal of photogrammetry and remote sensing > vol 89 (March 2014) . - pp 1 - 12[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2014031 RAB Revue Centre de documentation En réserve L003 Disponible Climatological study of ionospheric irregularities over the European mid-latitude sector with GPS / Gilles Wautelet in Journal of geodesy, vol 88 n° 3 (March 2014)
[article]
Titre : Climatological study of ionospheric irregularities over the European mid-latitude sector with GPS Type de document : Article/Communication Auteurs : Gilles Wautelet, Auteur ; René Warnant, Auteur Année de publication : 2014 Article en page(s) : pp 223 - 240 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] analyse diachronique
[Termes IGN] Belgique
[Termes IGN] données GPS
[Termes IGN] Europe (géographie politique)
[Termes IGN] perturbation ionosphérique
[Termes IGN] teneur totale en électrons
[Termes IGN] variation
[Termes IGN] variation temporelleRésumé : (Auteur) High-frequency variability of the ionosphere, or irregularities, constitutes the main threat for real-time precise positioning techniques based on Global Navigation Satellite Systems (GNSS) measurements. Indeed, during periods of enhanced ionospheric variability, GNSS users in the field—who cannot verify the integrity of their measurements—will experience positioning errors that can reach several decimeters, while the nominal accuracy of the technique is cm-level. In the frame of this paper, a climatological analysis of irregularities over the European mid-latitude region is presented. Based on a 10 years GPS dataset over Belgium, the work analyzes the occurrence rate (as a function of the solar cycle, season and local time) as well as the amplitude of ionospheric irregularities observed at a single GPS station. The study covers irregularities either due to space weather events (solar origin) or of terrestrial origin. If space weather irregularities are responsible for the largest effects in terms of ionospheric error, their occurrence rate highly depends on solar activity. Indeed, the occurrence rate of ionospheric irregularities is about 9 % during solar maximum, whereas it drops to about 0 % during medium or low solar activity periods. Medium-scale ionospheric disturbances (MSTIDs) occurring during daytime in autumn/winter are the most recurrent pattern of the time series, with yearly proportions slightly varying with the solar cycle and an amplitude of about 10 % of the TEC background. Another recurrent irregularity type, though less frequent than MSTIDs, is the noise-like variability in TEC observed during summer nighttime, under quiet geomagnetic conditions. These summer nighttime irregularities exhibit amplitudes ranging between 8 and 15 % of the TEC background. Numéro de notice : A2014-133 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0678-4 Date de publication en ligne : 11/12/2013 En ligne : https://doi.org/10.1007/s00190-013-0678-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33038
in Journal of geodesy > vol 88 n° 3 (March 2014) . - pp 223 - 240[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2014031 SL Revue Centre de documentation Revues en salle Disponible Improved one/multi-parameter models that consider seasonal and geographic variations for estimating weighted mean temperature in ground-based GPS meteorology / Yi Bin Yao in Journal of geodesy, vol 88 n° 3 (March 2014)PermalinkWater vapor probabilistic retrieval using GNSS signals / Andrea Antonini in IEEE Transactions on geoscience and remote sensing, vol 52 n° 3 (March 2014)PermalinkGNSS ambiguity resolution with controllable failure rate for long baseline network RTK / Bofeng Li in Journal of geodesy, vol 88 n° 2 (February 2014)PermalinkIonospheric modeling using GPS: Greater fidelity using a 3D approach / Wei Zhang in GPS world, vol 25 n° 2 (February 2014)PermalinkModeling and sensing the vertical structure of the atmospheric path delay by microwave radiometry to correct SAR interferograms / Patrizia Basili in IEEE Transactions on geoscience and remote sensing, vol 52 n° 2 (February 2014)PermalinkStatistical data fusion of multi-sensor AOD over the Continental United States / Sweta Jinnagara Puttaswamy in Geocarto international, vol 29 n° 1 - 2 (February - April 2014)PermalinkAtmospheric water vapour sensing by means of differential absorption spectrometry using solar and lunar radiation / Stefan Walter Münch (2014)PermalinkDORIS tropospheric estimation at IGN : Current strategies, GPS intercomparisons and perspectives / Pascal Willis (2014)PermalinkPermalinkModélisation de la propagation troposphérique des signaux de positionnement par satellites : un tour d'horizon / Camille Desjardins (2014)Permalink