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Homogenizing GPS integrated water vapor time series: Benchmarking break detection methods on synthetic data sets / Roeland Van Malderen in Earth and space science, vol 7 n° 5 (May 2020)  

Public [article]  inEarth and space science > vol 7 n° 5 (May 2020) . - n° e2020EA001121 Titre : Homogenizing GPS integrated water vapor time series: Benchmarking break detection methods on synthetic data sets Type de document : Article/Communication Auteurs : Roeland Van Malderen, Auteur ; Eric Pottiaux, Auteur ; Anna Klos, Auteur ; P. Domonkos, Auteur ; Michal Elias, Auteur ; Tong Ning, Auteur ; Olivier Bock , Auteur ; J. Guijarro, Auteur ; F. Alshawaf, Auteur ; M. Hoseini, Auteur ; Annarosa Quarello , Auteur ; et al., Auteur Année de publication : 2020 Projets : GNSS4SWEC / Article en page(s) : n° e2020EA001121 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] coordonnées GNSS [Termes IGN] données hétérogènes [Termes IGN] homogénéisation [Termes IGN] jeu de données [Termes IGN] prévision météorologique [Termes IGN] série temporelle [Termes IGN] station permanente [Termes IGN] teneur intégrée en vapeur d'eau Résumé : (auteur) We assess the performance of different break detection methods on three sets of benchmark data sets, each consisting of 120 daily time series of integrated water vapor differences. These differences are generated from the Global Positioning System (GPS) measurements at 120 sites worldwide, and the numerical weather prediction reanalysis (ERA‐Interim) integrated water vapor output, which serves as the reference series here. The benchmark includes homogeneous and inhomogeneous sections with added nonclimatic shifts (breaks) in the latter. Three different variants of the benchmark time series are produced, with increasing complexity, by adding autoregressive noise of the first order to the white noise model and the periodic behavior and consecutively by adding gaps and allowing nonclimatic trends. The purpose of this “complex experiment” is to examine the performance of break detection methods in a more realistic case when the reference series are not homogeneous. We evaluate the performance of break detection methods with skill scores, centered root mean square errors (CRMSE), and trend differences relative to the trends of the homogeneous series. We found that most methods underestimate the number of breaks and have a significant number of false detections. Despite this, the degree of CRMSE reduction is significant (roughly between 40% and 80%) in the easy to moderate experiments, with the ratio of trend bias reduction is even exceeding the 90% of the raw data error. For the complex experiment, the improvement ranges between 15% and 35% with respect to the raw data, both in terms of RMSE and trend estimations. Numéro de notice : A2020-335 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : MATHEMATIQUE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2020EA001121 Date de publication en ligne : 20/04/2020 En ligne : https://doi.org/10.1029/2020EA001121 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96837 [article]

A two-stage tropospheric correction model combining data from GNSS and numerical weather model / Jan Douša in GPS solutions, vol 22 n° 3 (July 2018)  

Public [article]  inGPS solutions > vol 22 n° 3 (July 2018) Titre : A two-stage tropospheric correction model combining data from GNSS and numerical weather model Type de document : Article/Communication Auteurs : Jan Douša, Auteur ; Michal Elias, Auteur ; Pavel Vaclavovic, Auteur ; Krystof Eben, Auteur ; Pavel Krč, Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] correction troposphérique [Termes IGN] données GNSS [Termes IGN] données météorologiques [Termes IGN] gradient de troposphère [Termes IGN] modèle météorologique [Termes IGN] retard hydrostatique [Termes IGN] retard troposphérique zénithal [Termes IGN] station permanente Résumé : (Auteur) We have developed a new concept for providing tropospheric augmentation corrections. The two-stage correction model combines data from a Numerical Weather Model (NWM) and precise ZTDs estimated from Global Navigation Satellite System (GNSS) permanent stations in regional networks. The first-stage correction is generated using the background NWM forecast only. The second-stage correction results from an optimal combination of the background model data and GNSS (near) real-time tropospheric products. The optimum correction is achieved when using NWM for the hydrostatic delay modeling and for vertical scaling, while GNSS products are used for correcting the non-hydrostatic delay. The method is assessed in several variants including study of the combination of NWM and GNSS data, spatial densification of the original NWM grid, and GNSS ZTD densification using tropospheric linear horizontal gradients. The first-stage correction can be characterized by overall accuracy of about 10 mm for ZTD (1-sigma). The second-stage correction supported with GNSS tropospheric products improved the first-stage correction by a factor of 2–4 in terms of the ZTD accuracy and by a factor of 2.5 in terms of its spatio-temporal stability. Numéro de notice : A2018-373 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-018-0742-x Date de publication en ligne : 29/05/2018 En ligne : https://doi.org/10.1007/s10291-018-0742-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90767 [article]

Homogeneizing GPS integrated water vapour time series: methodology and benchmarking the algorithms on synthetic datasets / Roeland Van Malderen (2017)    

Public Titre : Homogeneizing GPS integrated water vapour time series: methodology and benchmarking the algorithms on synthetic datasets Type de document : Article/Communication Auteurs : Roeland Van Malderen, Auteur ; Eric Pottiaux, Auteur ; Anna Klos, Auteur ; Olivier Bock , Auteur ; Janusz Bogusz, Auteur ; Barbara Chimani, Auteur ; Michal Elias, Auteur ; et al., Auteur Editeur : Genève : Organisation Météorologique Mondiale OMM / World Meteorological Organization WMO Année de publication : 2017 Collection : WCDMP series num. 85 Conférence : HQCD & SITCM 2017, 9th seminar for Homogenization and Quality control in Climatological Databases and 4th Conference on Spatial Interpolation Techniques in Climatology and Meteorology 03/04/2017 07/04/2017 Budapest Bulgarie Importance : pp 102 - 114 Format : 21 x 30 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] données hétérogènes [Termes IGN] homogénéisation [Termes IGN] jeu de données [Termes IGN] jeu de données localisées [Termes IGN] surveillance météorologique [Termes IGN] teneur intégrée en vapeur d'eau Résumé : (auteur) [motivation] Within the COST Action ES1206 “Advanced Global Navigation Satellite Systems tropospheric products for monitoring severe weather events and climate” (GNSS4SWEC), there was a clear interest and need to homogenize Integrated Water Vapour (IWV) datasets retrieved from Global Navigation Satellite System (GNSS) observations, by correcting (artificial) breakpoints due to e.g. instrumental changes. Based on the results of an inquiry, a homogenization activity was started within Working Group 3 (”Use of GNSS tropospheric products for climate monitoring”), targeting the following objectives: (i) select one or two long-term reference datasets, (ii) apply different homogenization algorithms on these reference datasets, and build up a list of commonly identified inhomogeneities based on statistical detection and metadata information, and (iii) come up with an homogenized version of the reference dataset that can be re-used to study climate trends and time variability by the entire community. Numéro de notice : C2017-047 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : sans En ligne : https://repositorio.aemet.es/bitstream/20.500.11765/8393/1/Homogenizing_Guijarro [...] Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91941

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