Quality Control of CyGNSS Reflectivity for Robust Spatiotemporal Detection of Tropical Wetlands
The aim of this study was to develop a robust methodology for evaluating the spatiotemporal dynamics of the inundation status in tropical wetlands with the currently available Global Navigation Satellite System-Reflectometry (GNSS-R) data by proposing a new quality control technique called the “prec...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
| Language: | Inglés |
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MDPI
2022
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10568/125976 |
| _version_ | 1855516680819572736 |
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| author | Arai, Hironori Zribi, Mehrez Oyoshi, Kei Dassas, Karin Huc, Mireille Sobue, Shinichi Thuy Le Toan |
| author_browse | Arai, Hironori Dassas, Karin Huc, Mireille Oyoshi, Kei Sobue, Shinichi Thuy Le Toan Zribi, Mehrez |
| author_facet | Arai, Hironori Zribi, Mehrez Oyoshi, Kei Dassas, Karin Huc, Mireille Sobue, Shinichi Thuy Le Toan |
| author_sort | Arai, Hironori |
| collection | Repository of Agricultural Research Outputs (CGSpace) |
| description | The aim of this study was to develop a robust methodology for evaluating the spatiotemporal dynamics of the inundation status in tropical wetlands with the currently available Global Navigation Satellite System-Reflectometry (GNSS-R) data by proposing a new quality control technique called the “precision index”. The methodology was applied over the Mekong Delta, one of the most important rice-production systems comprising aquaculture areas and natural wetlands (e.g., mangrove forests, peatlands). Cyclone Global Navigation Satellite System (CyGNSS) constellation data (August 2018–December 2021) were used to evaluate the spatiotemporal dynamics of the reflectivity Γ over the delta. First, the reflectivity Γ, shape and size of each specular footprint and the precision index were calibrated at each specular point and reprojected to a 0.0045° resolution (approximately equivalent to 500 m) grid at a daily temporal resolution (Lv. 2 product); then, the results were obtained considering bias-causing factors (e.g., the velocity/effective scattering area/incidence angle). The Lv. 2 product was temporally integrated every 15 days with a Kalman smoother (+/− 14 days temporal localization with Gaussian kernel: 1σ = 5 days). By applying the smoother, the regional-annual dynamics over the delta could be clearly visualized. The behaviors of the GNSS-R reflectivity and the Advanced Land Observing Satellite-2 Phased-Array type L-band Synthetic Aperture Radar-2 quadruple polarimetric scatter signals were compared and found to be nonlinearly correlated due to the influence of the incidence angle and the effective scattering area. |
| format | Journal Article |
| id | CGSpace125976 |
| institution | CGIAR Consortium |
| language | Inglés |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | MDPI |
| publisherStr | MDPI |
| record_format | dspace |
| spelling | CGSpace1259762025-12-08T10:29:22Z Quality Control of CyGNSS Reflectivity for Robust Spatiotemporal Detection of Tropical Wetlands Arai, Hironori Zribi, Mehrez Oyoshi, Kei Dassas, Karin Huc, Mireille Sobue, Shinichi Thuy Le Toan climate change food systems deltas climate change mitigation The aim of this study was to develop a robust methodology for evaluating the spatiotemporal dynamics of the inundation status in tropical wetlands with the currently available Global Navigation Satellite System-Reflectometry (GNSS-R) data by proposing a new quality control technique called the “precision index”. The methodology was applied over the Mekong Delta, one of the most important rice-production systems comprising aquaculture areas and natural wetlands (e.g., mangrove forests, peatlands). Cyclone Global Navigation Satellite System (CyGNSS) constellation data (August 2018–December 2021) were used to evaluate the spatiotemporal dynamics of the reflectivity Γ over the delta. First, the reflectivity Γ, shape and size of each specular footprint and the precision index were calibrated at each specular point and reprojected to a 0.0045° resolution (approximately equivalent to 500 m) grid at a daily temporal resolution (Lv. 2 product); then, the results were obtained considering bias-causing factors (e.g., the velocity/effective scattering area/incidence angle). The Lv. 2 product was temporally integrated every 15 days with a Kalman smoother (+/− 14 days temporal localization with Gaussian kernel: 1σ = 5 days). By applying the smoother, the regional-annual dynamics over the delta could be clearly visualized. The behaviors of the GNSS-R reflectivity and the Advanced Land Observing Satellite-2 Phased-Array type L-band Synthetic Aperture Radar-2 quadruple polarimetric scatter signals were compared and found to be nonlinearly correlated due to the influence of the incidence angle and the effective scattering area. 2022-11-02 2022-12-14T11:20:23Z 2022-12-14T11:20:23Z Journal Article https://hdl.handle.net/10568/125976 en Open Access MDPI Arai, H., Zribi, M., Oyoshi, K., Dassas, K., Huc, M., Sobue, S. and Toan, T.L. 2022. Quality Control of CyGNSS Reflectivity for Robust Spatiotemporal Detection of Tropical Wetlands. Remote Sensing 14(22):5903. https://doi.org/10.3390/rs14225903 |
| spellingShingle | climate change food systems deltas climate change mitigation Arai, Hironori Zribi, Mehrez Oyoshi, Kei Dassas, Karin Huc, Mireille Sobue, Shinichi Thuy Le Toan Quality Control of CyGNSS Reflectivity for Robust Spatiotemporal Detection of Tropical Wetlands |
| title | Quality Control of CyGNSS Reflectivity for Robust Spatiotemporal Detection of Tropical Wetlands |
| title_full | Quality Control of CyGNSS Reflectivity for Robust Spatiotemporal Detection of Tropical Wetlands |
| title_fullStr | Quality Control of CyGNSS Reflectivity for Robust Spatiotemporal Detection of Tropical Wetlands |
| title_full_unstemmed | Quality Control of CyGNSS Reflectivity for Robust Spatiotemporal Detection of Tropical Wetlands |
| title_short | Quality Control of CyGNSS Reflectivity for Robust Spatiotemporal Detection of Tropical Wetlands |
| title_sort | quality control of cygnss reflectivity for robust spatiotemporal detection of tropical wetlands |
| topic | climate change food systems deltas climate change mitigation |
| url | https://hdl.handle.net/10568/125976 |
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