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Deriving a frozen area fraction from Metop ASCAT backscatter based on Sentinel-1 / Helena Bergstedt in IEEE Transactions on geoscience and remote sensing, vol 58 n° 9 (September 2020)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 58 n° 9 (September 2020) . - pp 6008 - 6019 Titre : Deriving a frozen area fraction from Metop ASCAT backscatter based on Sentinel-1 Type de document : Article/Communication Auteurs : Helena Bergstedt, Auteur ; Annett Bartsch, Auteur ; Anton Neureiter, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 6008 - 6019 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] Autriche [Termes IGN] bande C [Termes IGN] courbe de Pearson [Termes IGN] dégel [Termes IGN] Finlande [Termes IGN] fonte des glaces [Termes IGN] hétérogénéité spatiale [Termes IGN] image MetOp-ASCAT [Termes IGN] image radar moirée [Termes IGN] image Sentinel-SAR [Termes IGN] pergélisol [Termes IGN] rétrodiffusion [Termes IGN] série temporelle [Termes IGN] télédétection en hyperfréquence [Termes IGN] température au sol Résumé : (auteur) Surface state data derived from spaceborne microwave sensors with suitable temporal sampling are to date only available in low spatial resolution (25–50 km). Current approaches do not adequately resolve spatial heterogeneity in landscape-scale freeze–thaw processes. We propose to derive a frozen fraction instead of binary freeze–thaw information. This introduces the possibility to monitor the gradual freezing and thawing of complex landscapes. Frozen fractions were retrieved from Advanced Scatterometer (ASCAT, C-band) backscatter on a 12.5-km grid for three sites in noncontinuous permafrost areas in northern Finland and the Austrian Alps. To calibrate the retrieval approach, frozen fractions based on Sentinel-1 synthetic aperture radar (SAR, C-band) were derived for all sites and compared to ASCAT backscatter. We found strong relationships for ASCAT backscatter with Sentinel-1 derived frozen fractions (Pearson correlations of −0.85 to −0.96) for the sites in northern Finland and less strong relationships for the Alpine site (Pearson correlations −0.579 and −0.611, including and excluding forested areas). Applying the derived linear relationships, predicted frozen fractions using ASCAT backscatter values showed root mean square error (RMSE) values between 7.26% and 16.87% when compared with Sentinel-1 frozen fractions. The validation of the Sentinel-1 derived freeze–thaw classifications showed high accuracy when compared to in situ near-surface soil temperature (84.7%–94%). Results are discussed with regard to landscape type, differences between spring and autumn, and gridding. This article serves as a proof of concept, showcasing the possibility to derive frozen fraction from coarse spatial resolution scatterometer time series to improve the representation of spatial heterogeneity in landscape-scale surface state. Numéro de notice : A2020-525 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2020.2967364 Date de publication en ligne : 13/03/2020 En ligne : https://doi.org/10.1109/TGRS.2020.2967364 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95702 [article]

Statistical atmospheric parameter retrieval largely benefits from spatial–spectral image compression / Joaquín García-Sobrino in IEEE Transactions on geoscience and remote sensing, vol 55 n° 4 (April 2017)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 55 n° 4 (April 2017) . - pp. 2213 - 2224 Titre : Statistical atmospheric parameter retrieval largely benefits from spatial–spectral image compression Type de document : Article/Communication Auteurs : Joaquín García-Sobrino, Auteur ; Joan Serra-Sagristà, Auteur ; Valero Laparra, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp. 2213 - 2224 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] compression d'image [Termes IGN] données météorologiques [Termes IGN] humidité de l'air [Termes IGN] image infrarouge couleur [Termes IGN] image MetOp-IASI [Termes IGN] interférométrie [Termes IGN] température de l'air Résumé : (Auteur) The infrared atmospheric sounding interferometer (IASI) is flying on board of the Metop satellite series, which is part of the EUMETSAT Polar System. Products obtained from IASI data represent a significant improvement in the accuracy and quality of the measurements used for meteorological models. Notably, the IASI collects rich spectral information to derive temperature and moisture profiles, among other relevant trace gases, essential for atmospheric forecasts and for the understanding of weather. Here, we investigate the impact of near-lossless and lossy compression on IASI L1C data when statistical retrieval algorithms are later applied. We search for those compression ratios that yield a positive impact on the accuracy of the statistical retrievals. The compression techniques help reduce certain amount of noise on the original data and, at the same time, incorporate spatial-spectral feature relations in an indirect way without increasing the computational complexity. We observed that compressing images, at relatively low bit rates, improves results in predicting temperature and dew point temperature, and we advocate that some amount of compression prior to model inversion is beneficial. This research can benefit the development of current and upcoming retrieval chains in infrared sounding and hyperspectral sensors. Numéro de notice : A2017-173 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2016.2639099 En ligne : http://dx.doi.org/10.1109/TGRS.2016.2639099 Format de la ressource électronique : URL bulletin Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84722 [article]

Water vapor measurements by mobile Raman lidar over the Mediterranean Sea in the framework of HyMeX: application to multi-platform validation of moisture profiles / Julien Totems in EPJ Web of Conferences, vol 119 (2016)  

Public [article]  inEPJ Web of Conferences > vol 119 (2016) Titre : Water vapor measurements by mobile Raman lidar over the Mediterranean Sea in the framework of HyMeX: application to multi-platform validation of moisture profiles Type de document : Article/Communication Auteurs : Julien Totems, Auteur ; Patrick Chazette, Auteur ; Xiaoxia Shang, Auteur ; Cyrille Flamant, Auteur ; Jean-Christophe Raut, Auteur ; Alexis Doerenbecher, Auteur ; Véronique Ducrocq, Auteur ; Olivier Bock , Auteur ; Fabien Marnas, Auteur Année de publication : 2016 Conférence : ILRC 2016, 27th International Laser Radar Conference 05/07/2016 10/07/2016 New York City New-York - Etats-Unis OA Proceedings Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] Baléares, îles [Termes IGN] données météorologiques [Termes IGN] humidité de l'air [Termes IGN] image MetOp-IASI [Termes IGN] lidar Raman [Termes IGN] Méditerranée, mer [Termes IGN] teneur en vapeur d'eau Résumé : (auteur) The Water Aerosol Lidar (WALI) system, deployed for 14 weeks during 2012 & 2013 on the island of Menorca, provided the Hydrological cycle in the Mediterranean eXperiment (HyMeX) with an opportunity to perform a multi-platform comparison on moisture retrievals at the timescales relevant for extreme precipitation events in the West Mediterranean basin. After calibration, the WALI lidar yields nighttime profiles of water vapor with ~7% accuracy from the ground up to 7 km, and daytime coverage of the lower layers, alongside common aerosol retrievals. It is used to characterize the water vapor profile product given by the IASI instrument on-board MetOp-B, and the fields simulated by the Météo-France AROME-WMED model and the open-source WRF model. IASI is found to be reliable above 1 km altitude, and the two models obtain similar high scores in the middle troposphere; WRF beneficiates from a more accurate modelling of the planetary boundary layer. Numéro de notice : A2016--187 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1051/epjconf/201611926006 Date de publication en ligne : 07/06/2016 En ligne : https://doi.org/10.1051/epjconf/201611926006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91826 [article]

Comparison of IASI water vapour products over complex terrain with COPS campaign data / Guido Masiello in Meteorologische Zeitschrift, vol 22 n° 4 (August 2013)  

Public [article]  inMeteorologische Zeitschrift > vol 22 n° 4 (August 2013) . - pp 471 - 487 Titre : Comparison of IASI water vapour products over complex terrain with COPS campaign data Type de document : Article/Communication Auteurs : Guido Masiello, Auteur ; Carmine Serio, Auteur ; Thomas Deleporte, Auteur ; Hervé Herbin, Auteur ; Paolo Di Girolamo, Auteur ; Cédric Champollion, Auteur ; Andreas Behrendt, Auteur ; Pierre Bosser , Auteur ; Olivier Bock , Auteur ; V. Wulfmeyer, Auteur ; Matthieu Pommier, Auteur ; Cyrille Flamant, Auteur Année de publication : 2013 Article en page(s) : pp 471 - 487 Note générale : bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] image MetOp-IASI [Termes IGN] lidar Raman [Termes IGN] positionnement par GPS [Termes IGN] Rhin (bassin) [Termes IGN] teneur en vapeur d'eau [Termes IGN] troposphère Résumé : (auteur) In this work, we compare IASI-retrieved vertical water vapour profiles and related precipitable water over a complex region, namely the Rhine Valley area, during the pre-operational period of IASI exploitation (June–August 2007). Both IASI water vapour mixing ratio profiles and integrated water vapour content are retrieved from L1C radiances spectra using two techniques and compared with water vapour related observations acquired during the Convective and Orographically-induced Precipitation Study (COPS) field campaign that took place in this area at that time (i.e. lidars, radiosoundings and a global positioning system - GPS - station network). This work addresses the issue of IASI vertical spatial resolution and its capability to detect two-layer water vapour structures such as those observed in a mountainous area and which play an important role in convective initiation or inhibition. We found that this capability mostly relies on the type of a-priori background vector (climatology or space-time colocated ECMWF analysis), which is used within the retrieval scheme. Systematic comparison of water vapour products derived from 71 IASI spectra confirms that IASI can retrieve water vapour amounts in 2 km width layers, in the lower troposphere, with an accuracy of approximately 10%. Numéro de notice : A2013-817 Affiliation des auteurs : LASTIG LOEMI+Ext (2012-2019) Thématique : POSITIONNEMENT Nature : Article DOI : 10.1127/0941-2948/2013/0430 Date de publication en ligne : 01/08/2013 En ligne : http://dx.doi.org/10.1127/0941-2948/2013/0430 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80103 [article]

GSICS inter-calibration of infrared channels of geostationary imagers using Metop-IASI / Tim J. Hewison in IEEE Transactions on geoscience and remote sensing, vol 51 n° 3 Tome 1 (March 2013)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 51 n° 3 Tome 1 (March 2013) . - pp 1160 - 1170 Titre : GSICS inter-calibration of infrared channels of geostationary imagers using Metop-IASI Type de document : Article/Communication Auteurs : Tim J. Hewison, Auteur ; Xiangqian Wu, Auteur ; Fangfang Yu, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 1160 - 1170 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] erreur systématique [Termes IGN] étalonnage relatif [Termes IGN] image Feng-Yun [Termes IGN] image GOES [Termes IGN] image hyperspectrale [Termes IGN] image Météosat [Termes IGN] image MetOp-IASI [Termes IGN] image thermique [Termes IGN] rayonnement infrarouge thermique [Termes IGN] régression linéaire Résumé : (Auteur) The first products of the Global Space-based Inter-Calibration System (GSICS) include bias monitoring and calibration corrections for the thermal infrared (IR) channels of current meteorological sensors on geostationary satellites. These use the hyperspectral Infrared Atmospheric Sounding Interferometer (IASI) on the low Earth orbit (LEO) Metop satellite as a common cross-calibration reference. This paper describes the algorithm, which uses a weighted linear regression, to compare collocated radiances observed from each pair of geostationary-LEO instruments. The regression coefficients define the GSICS Correction, and their uncertainties provide quality indicators, ensuring traceability to the selected community reference, IASI. Examples are given for the Meteosat, GOES, MTSAT, Fengyun-2, and COMS imagers. Some channels of these instruments show biases that vary with time due to variations in the thermal environment, stray light, and optical contamination. These results demonstrate how inter-calibration can be a powerful tool to monitor and correct biases, and help diagnose their root causes. Numéro de notice : A2013-123 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2013.2238544 En ligne : https://doi.org/10.1109/TGRS.2013.2238544 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32261 [article]

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Analysis of C-band scatterometer moisture estimations derived over a semiarid region / R. Amri in IEEE Transactions on geoscience and remote sensing, vol 50 n° 7 Tome 1 (July 2012)  

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Error assessment of the initial near real-time METOP ASCAT surface soil moisture product / S. Hahn in IEEE Transactions on geoscience and remote sensing, vol 50 n° 7 Tome 1 (July 2012)  

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