Assessing the active-passive approach at variant incidence angles for microwave brightness temperature downscaling
The Terrestrial Water Resources Satellite (TWRS) campaign is a planned Chinese candidate satellite mission, and a one-dimensional synthetic aperture technology will be used, resulting in variant incidence angles for collecting synchronous active-passive observations at L-band, which would make brigh...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Taylor & Francis Group
2021-10-01
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| Series: | International Journal of Digital Earth |
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1080/17538947.2021.1907461 |
| _version_ | 1827811134428676096 |
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| author | Peng Guo Tianjie Zhao Jiancheng Shi Hongxin Xu Xiuwei Li Shengda Niu |
| author_facet | Peng Guo Tianjie Zhao Jiancheng Shi Hongxin Xu Xiuwei Li Shengda Niu |
| author_sort | Peng Guo |
| collection | DOAJ |
| description | The Terrestrial Water Resources Satellite (TWRS) campaign is a planned Chinese candidate satellite mission, and a one-dimensional synthetic aperture technology will be used, resulting in variant incidence angles for collecting synchronous active-passive observations at L-band, which would make brightness temperature (Tb) downscaling especially challenging when aiming to improve the spatial resolution of soil moisture measurements. In this study, two active-passive Tb downscaling algorithms, the time-series regression (TSR) and spectral analysis (SA) algorithms, are assessed comprehensively based on airborne experimental datasets. The results with data collected during the Soil Moisture Experiment 2002 (SMEX02) showed that both approaches could provide a reliable downscaled Tb at the same incidence angle. Based on the ground and airborne active-passive observations under variant incidence angles from the Soil Moisture Experiment in the Luan River (SMELR) it can be shown that the linear relationship between Tb and σ is still robust under the case of variant incidence angles, and Tb (both h- and v-pol) is better correlated to σvv for most cases than σhh. Both downscaling approaches can be applied to active-passive observations under varying incidence angles. Moreover, SA method performed better than the TSR method according to the lower RMSE values and higher correlation. |
| first_indexed | 2024-03-11T23:00:51Z |
| format | Article |
| id | doaj.art-c13e11faa216429681b7dc3437ae429e |
| institution | Directory Open Access Journal |
| issn | 1753-8947 1753-8955 |
| language | English |
| last_indexed | 2024-03-11T23:00:51Z |
| publishDate | 2021-10-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | International Journal of Digital Earth |
| spelling | doaj.art-c13e11faa216429681b7dc3437ae429e2023-09-21T14:57:10ZengTaylor & Francis GroupInternational Journal of Digital Earth1753-89471753-89552021-10-0114101273129310.1080/17538947.2021.19074611907461Assessing the active-passive approach at variant incidence angles for microwave brightness temperature downscalingPeng Guo0Tianjie Zhao1Jiancheng Shi2Hongxin Xu3Xiuwei Li4Shengda Niu5College of Information Science and Engineering, Shandong Agricultural UniversityState Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of SciencesNational Space Science Center, Chinese Academy of Sciences, Beijing, People’s Republic of ChinaShanghai Academy of Spaceflight Technology, Shanghai, People’s Republic of ChinaShanghai Academy of Spaceflight Technology, Shanghai, People’s Republic of ChinaShanghai Academy of Spaceflight Technology, Shanghai, People’s Republic of ChinaThe Terrestrial Water Resources Satellite (TWRS) campaign is a planned Chinese candidate satellite mission, and a one-dimensional synthetic aperture technology will be used, resulting in variant incidence angles for collecting synchronous active-passive observations at L-band, which would make brightness temperature (Tb) downscaling especially challenging when aiming to improve the spatial resolution of soil moisture measurements. In this study, two active-passive Tb downscaling algorithms, the time-series regression (TSR) and spectral analysis (SA) algorithms, are assessed comprehensively based on airborne experimental datasets. The results with data collected during the Soil Moisture Experiment 2002 (SMEX02) showed that both approaches could provide a reliable downscaled Tb at the same incidence angle. Based on the ground and airborne active-passive observations under variant incidence angles from the Soil Moisture Experiment in the Luan River (SMELR) it can be shown that the linear relationship between Tb and σ is still robust under the case of variant incidence angles, and Tb (both h- and v-pol) is better correlated to σvv for most cases than σhh. Both downscaling approaches can be applied to active-passive observations under varying incidence angles. Moreover, SA method performed better than the TSR method according to the lower RMSE values and higher correlation.http://dx.doi.org/10.1080/17538947.2021.1907461downscalingbrightness temperatureactive-passivevariant incidence anglesmelr |
| spellingShingle | Peng Guo Tianjie Zhao Jiancheng Shi Hongxin Xu Xiuwei Li Shengda Niu Assessing the active-passive approach at variant incidence angles for microwave brightness temperature downscaling International Journal of Digital Earth downscaling brightness temperature active-passive variant incidence angle smelr |
| title | Assessing the active-passive approach at variant incidence angles for microwave brightness temperature downscaling |
| title_full | Assessing the active-passive approach at variant incidence angles for microwave brightness temperature downscaling |
| title_fullStr | Assessing the active-passive approach at variant incidence angles for microwave brightness temperature downscaling |
| title_full_unstemmed | Assessing the active-passive approach at variant incidence angles for microwave brightness temperature downscaling |
| title_short | Assessing the active-passive approach at variant incidence angles for microwave brightness temperature downscaling |
| title_sort | assessing the active passive approach at variant incidence angles for microwave brightness temperature downscaling |
| topic | downscaling brightness temperature active-passive variant incidence angle smelr |
| url | http://dx.doi.org/10.1080/17538947.2021.1907461 |
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