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GNSS-based statistical analysis of ionospheric anomalies during typhoon landings in Taiwan/Japan / Hai Peng in IEEE Transactions on geoscience and remote sensing, vol 59 n° 6 (June 2021)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 59 n° 6 (June 2021) . - pp 5272 - 5279 Titre : GNSS-based statistical analysis of ionospheric anomalies during typhoon landings in Taiwan/Japan Type de document : Article/Communication Auteurs : Hai Peng, Auteur ; Yibin Yao, Auteur ; Jian Kong, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : pp 5272 - 5279 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] cyclone [Termes IGN] données GNSS [Termes IGN] onde de gravité [Termes IGN] perturbation ionosphérique [Termes IGN] phase [Termes IGN] propagation ionosphérique [Termes IGN] signal GNSS [Termes IGN] Taïwan [Termes IGN] teneur totale en électrons [Termes IGN] vitesse Résumé : (auteur) Using the Global Navigation Satellite System (GNSS) differenced total electron content (dTEC) series, the traveling ionosphere disturbances (TIDs) of 22 typhoons registered in Taiwan/Japan between 2013 and 2016 were studied. The horizontal speed of the first TID during a typhoon landing can be estimated by a two-station method with the ionosphere anomaly indicator in total electron count units (TECUs) (|dTEC| ≥ 0.15 TECU). The horizontal speed of the TIDs was from 155 to 210 m/s and with an average speed of 168.70 m/s. The estimated TID speeds of Typhoons Soudelor (205.93 m/s) and Megi (158.47 m/s) are not consistent with each other, even though they had very similar trajectories when cross through Taiwan Island. Moreover, the propagation velocity of the typhoon ionospheric anomaly showed a significant positive correlation ( r=0.78 , α=0.05 ) with the change rate of the typhoon central air pressure and a negative correlation ( r=−0.52 , α=0.05 ) with the central pressure before landing. Gravity waves were generated by land friction, terrain blocking, and strong wind shear transport energy into the atmosphere from the near surface to the mesosphere and thermosphere, which is the main cause of ionosphere disturbances during typhoon landing. Numéro de notice : A2021-428 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2020.3004829 date de publication en ligne : 24/08/2020 En ligne : https://doi.org/10.1109/TGRS.2020.3004829 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97784 [article]

Evaluation of crop mapping on fragmented and complex slope farmlands through random forest and object-oriented analysis using unmanned aerial vehicles / Re-Yang Lee in Geocarto international, vol 35 n° 12 ([01/09/2020])  

Public [article]  inGeocarto international > vol 35 n° 12 [01/09/2020] . - pp 1293 - 1310 Titre : Evaluation of crop mapping on fragmented and complex slope farmlands through random forest and object-oriented analysis using unmanned aerial vehicles Type de document : Article/Communication Auteurs : Re-Yang Lee, Auteur ; Kuo-Chen Chang, Auteur ; Deng-Yuan Ou, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 1293 - 1310 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] analyse d'image orientée objet [Termes IGN] carte de la végétation [Termes IGN] classification par forêts aléatoires [Termes IGN] image captée par drone [Termes IGN] interprétation automatique [Termes IGN] pente [Termes IGN] Taïwan Résumé : (auteur) Conducting field research in Taiwan can be challenging because of the abundance of steep slopes. This study aimed to establish an automatic interpretation procedure applicable to exploring images of large-scale slope land taken using UAVs. The proposed method was compared with traditional field surveying and manual image interpretation techniques to determine the advantages and disadvantages of the proposed procedure in terms of efficiency. The object-based image analysis (OBIA) and texture features were first combined and the random forest (RF) classifier was then employed to interpret crop types. This study selected three sites of slope land and plains for experimentation. The obtained results indicated that the overall accuracy of the proposed classification method exceeded 91%, and the Kappa value was approximately 0.9 for all sites. In addition, interpretation of the proposed method was more efficient than that of the two traditional methods. Numéro de notice : A2020-479 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2018.1559886 date de publication en ligne : 04/06/2019 En ligne : https://doi.org/10.1080/10106049.2018.1559886 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95628 [article]

Evaluation of single-frequency receivers for studying crustal deformation at the longitudinal Valley fault, eastern Taiwan / Horng-Yue Chen in Survey review, vol 52 n° 374 (August 2020)  

Public [article]  inSurvey review > vol 52 n° 374 (August 2020) . - pp 454 - 462 Titre : Evaluation of single-frequency receivers for studying crustal deformation at the longitudinal Valley fault, eastern Taiwan Type de document : Article/Communication Auteurs : Horng-Yue Chen, Auteur ; Hsin Tung, Auteur ; Ya-Ju Hsu, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 454 - 462 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] correction ionosphérique [Termes IGN] déformation de la croute terrestre [Termes IGN] distance [Termes IGN] faille géologique [Termes IGN] récepteur bifréquence [Termes IGN] récepteur GPS [Termes IGN] récepteur monofréquence [Termes IGN] retard ionosphèrique [Termes IGN] station GPS [Termes IGN] surveillance géologique [Termes IGN] Taïwan Résumé : (auteur) Applications of low-cost single-frequency continuous GPS receivers for monitoring volcano and landslide activities as well as to complement dual-frequency receivers have been demonstrated to produce stable and accurate positioning. In studies of crustal deformation, the relative distance between monitoring stations may vary from several kilometers to tens of kilometers, hence the differential single-frequency observations cannot model the ionospheric delay or other distance dependent errors. The 55 low-cost single-frequency continuous stations have been deployed together with 52 continuous dual-frequency stations in southeastern Taiwan since 2008. All of the single-frequency stations have applied corrections using dual-frequency stations to eliminate the distance dependent errors. Comparing velocity estimates from 8 co-located, the differences in horizontal and vertical components are less than 3 mm/yr and 6 mm/yr, respectively. Our study shows that the combination of single- and dual-frequency GPS data can provide robust results to study the fault slip behavior on the Longitudinal Valley fault. Numéro de notice : A2020-519 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2019.1634340 date de publication en ligne : 01/07/2019 En ligne : https://doi.org/10.1080/00396265.2019.1634340 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95680 [article]

Dynamic floating stations model for emergency medical services with a consideration of traffic data / Chih-Hong Sun in ISPRS International journal of geo-information, vol 9 n° 5 (May 2020)  

Public [article]  inISPRS International journal of geo-information > vol 9 n° 5 (May 2020) . - 15 p. Titre : Dynamic floating stations model for emergency medical services with a consideration of traffic data Type de document : Article/Communication Auteurs : Chih-Hong Sun, Auteur ; Chen-Yang Cheng, Auteur ; Cheng-Hui Wang, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : 15 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse des besoins [Termes IGN] distance kilométrique [Termes IGN] durée de déplacement [Termes IGN] géolocalisation [Termes IGN] gestion urbaine [Termes IGN] migration pendulaire [Termes IGN] planification urbaine [Termes IGN] secours d'urgence [Termes IGN] système d'information géographique [Termes IGN] Taipei (Taïwan) [Termes IGN] temps de trajet [Termes IGN] trafic routier Résumé : (auteur) To equally distribute the workload and minimize the travel distance for fire departments, we developed a new dynamic floating stations model (DFSM) to target traffic-related emergency medical services (EMS) during peak hours. This study revealed that traffic-related EMS incidents have different characteristics to other EMS incidents. The number of floating stations was determined by the number of available ambulances at a given time. The optimum floating station location was identified by using the given capacity to establish the smallest service radius. In DFSM simulations using floating stations with a capacity of 100 and 150 EMS incidents, the result shows significant improvements in comparison to the current situation. Numéro de notice : A2020-296 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/ijgi9050336 date de publication en ligne : 20/05/2020 En ligne : https://doi.org/10.3390/ijgi9050336 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95134 [article]

Coverage of the Taiwan island by InSAR with Sentinel-1 and ALOS images / Bénédicte Fruneau (2019)  

Public Titre : Coverage of the Taiwan island by InSAR with Sentinel-1 and ALOS images Type de document : Article/Communication Auteurs : Bénédicte Fruneau , Auteur ; Erwan Pathier, Auteur ; Marie-Pierre Doin, Auteur ; Jyr-Ching Hu, Auteur ; Hsin Tung, Auteur Editeur : Champs/Marne : Université Paris-Est Marne-la-Vallée UPEM Année de publication : 2019 Conférence : LPS 2019, ESA Living Planet Symposium 13/05/2019 17/05/2019 Milan Italie programme sans actes Langues : Français (fre) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] image ALOS-PALSAR [Termes IGN] image Sentinel-SAR [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] surveillance géologique [Termes IGN] Taïwan Résumé : (auteur) Taiwan Island, resulting from oblique collision between Philippine sea plate and Eurasian plate converging at a rate of about 8 cm per year, is one of the most active tectonic region in the world. With a subtropical environment, it is faced to different hazards, including earthquakes, debris flow, landslides, and flooding. The precise measurement of the present-day ground displacements at the scale of the whole Taiwan Island is thus essential in several domains of Earth Sciences, in particular for earthquake cycle study and earthquake hazard assessment, for subsidence and landslide monitoring, and also to better understand the kinematics and mechanics of mountain building. Taiwan benefits from a remarkable GNSS network. However, due to a complex geodynamical context and high strain rate, the pattern of deformation is not well solved by GNSS. In complement, INSAR shows its contribution with respect to GNSS, as it allows to dramatically increase the spatial information. Combining SAR dataset provided by ALOS-1, ALOS-2 and Sentinel-1 enables to generate consistent time series and dense maps of ground displacements by InSAR on the whole island over different periods. This possibility of long time series of observations is particularly interesting for earthquake cycle study. Our processing uses NSBAS interferometric chain (Doin et al., 2015), based on a SBAS approach, that includes several corrections applied before unwrapping, in particular correction of atmospheric delays predicted from the global atmospheric re-analysis ERA-Interim model, and local DEM error correction. These corrections are of particular importance as they reduce the variance of the phase across regions with high topographic gradients, like the Central Range in Taiwan, hence facilitating unwrapping step. Using the full archive of ALOS-1 PALSAR images, a first complete deformation map of Taiwan has been derived over the period 2007-2011. Our InSAR results offer an unprecedented continuous view of deformation field of the entire Island. For instance, in the Central Range, the LOS velocity map shows a clear pattern of deformation, consistent with a rapid uplift (cm/y) of the Central Range South of the island. This uplift, already partially documented by GPS and leveling, is clearly mapped here and seems to show an overall continuity. In southwestern Taiwan, the InSAR LOS velocity map provides a good coverage in the foothills area, revealing several localized areas of interseismic deformation that were overlooked in GNSS, and that can be correlated with tectonic structures. Among them, is the 15 km-long Lungchuan anticline, showing relative surface displacement toward satellite by several cm/year. Those observations, combined with a geological study and field survey (Le Beon et al., 2017), suggest the existence of a back-thrust fault that reaches the surface on western side of Lungchuan ridge and roots on the ~4 km deep Tainan detachment. This structure has also been activated during 2010 Mw 6.3 Jia-Shian Earthquake and the Meinong earthquake (02/05/2016, Mw6.4). A time series analysis can also be conducted on 2014-2018 period with Sentinel-1 data. Since end of 2014, we benefit from S1 SAR images, acquired in C-band, thus less favorable than PALSAR L-band on Taiwan Island. However, this drawback is balanced thanks to the high frequency of image acquisitions (12 days on Taiwan with S1-A and S1-B). We can also take advantage of the 2 different geometries of acquisition (both ascending and descending) to derive horizontal and vertical components of the deformation. The combination of ALOS and Sentinel-1 InSAR results, in addition to their high density of measure, covers different time periods and gives the opportunity to investigate temporal evolution of the deformation. Some areas, in particular in SW Taiwan, show changes in the tectonic deformation pattern, thus revealing transient behavior of some structures. Those observations can also be completed on several areas with previous ERS and Envisat INSAR results, offering an unique monitoring of more than 20 years. Numéro de notice : C2019-055 Affiliation des auteurs : LaSTIG+Ext (2016-2019) Thématique : IMAGERIE Nature : Poster nature-HAL : ComSansActesPubliés-Unpublished DOI : sans En ligne : https://lps19.esa.int/NikalWebsitePortal/living-planet-symposium-2019/lps19/Agen [...] Format de la ressource électronique : vers le résumé Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96644

New evidences for active folding in SW Taiwan from Sentinel-1 InSAR / Erwan Pathier (2019)    

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Detecting newly grown tree leaves from unmanned-aerial-vehicle images using hyperspectral target detection techniques / Chinsu Lin in ISPRS Journal of photogrammetry and remote sensing, vol 142 (August 2018)  

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Active tectonics of the onshore Hengchun Fault using UAS DSM combined with ALOS PS-InSAR time series (Southern Taiwan) / Benoit Deffontaines in Natural Hazards and Earth System Sciences, vol 18 n° 3 ([01/03/2018])  

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Cartographie des déformations de surface sur l’île de Taiwan par interférométrie RADAR Sentinel-1 / Miloud Fekaouni (2018)

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Shallow geological structures triggered during the Mw 6.4 Meinong earthquake, southwestern Taiwan / Maryline Le Béon in Terrestrial Atmospheric Oceanic sciences journal, vol 28 n° 5 (October 2017)  

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Reconstruction of time-varying tidal flat topography using optical remote sensing imageries / Kuo-Hsin Tseng in ISPRS Journal of photogrammetry and remote sensing, vol 131 (September 2017)  

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Active interseismic shallow deformation of the Pingting terraces (Longitudinal Valley – Eastern Taiwan) from UAV high-resolution topographic data combined with InSAR time series / Benoit Deffontaines in Geomatics, Natural Hazards and Risk, vol 8 (2017)  

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Present-day deformation in Taiwan mountain belt as monitored by InSAR / Bénédicte Fruneau (2017)

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Structure and deformation of the Southern Taiwan accretionary prism: The active submarine Fangliao Fault Zone offshore west Hengchun Peninsula / Benoit Deffontaines in Tectonophysics, vol 692 part B (5 December 2016)  

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DEM measurements of a gravel-bed surface using two scales of images / Chi-Kuei Wang in Photogrammetric record, vol 30 n° 152 (December 2015 - February 2016)  

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