Error Evaluation of L-Band <i>InSAR</i> Precipitable Water Vapor Measurements by Comparison with <i>GNSS</i> Observations in Japan
Interferometric synthetic aperture radar (<i>InSAR</i>) enables us to obtain precipitable water vapor (<i>PWV</i>) maps with high spatial resolution through the phase difference caused by refraction in the atmosphere. Although previous studies have evaluated the error level o...
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| Format: | Article |
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MDPI AG
2021-11-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/13/23/4866 |
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| author | Keita Matsuzawa Yohei Kinoshita |
| author_facet | Keita Matsuzawa Yohei Kinoshita |
| author_sort | Keita Matsuzawa |
| collection | DOAJ |
| description | Interferometric synthetic aperture radar (<i>InSAR</i>) enables us to obtain precipitable water vapor (<i>PWV</i>) maps with high spatial resolution through the phase difference caused by refraction in the atmosphere. Although previous studies have evaluated the error level of <i>InSAR</i><i>PWV</i> observations, they validated it only with C-band <i>InSAR</i><i>PWV</i> observations. Since ionospheric disturbance seriously contaminates the <i>InSAR</i> phase in the case of the lower-frequency SAR system, it is necessary for a <i>PWV</i> error level evaluation correcting the ionospheric effect appropriately if we use lower-frequency SAR systems, such as the Advanced Land Observing Satellite-2 (ALOS-2). In this paper, we evaluated the error level of the L-band <i>InSAR</i><i>PWV</i> observation obtained from ALOS-2 data covering four areas in Japan. We compared the <i>InSAR</i> observations with global navigation satellite system (<i>GNSS</i>) atmospheric observations and estimated the L-band <i>InSAR</i><i>PWV</i> error value by utilizing the error propagation theory. As a result, the L-band <i>InSAR</i><i>PWV</i> absolute error reached 2.83 mm, which was comparable to traditional <i>PWV</i> observations. Moreover, we investigated the impacts of the seasonality, the interferometric coherence, and the height dependence on the <i>PWV</i> observation accuracy in <i>InSAR</i>. |
| first_indexed | 2024-03-10T04:46:32Z |
| format | Article |
| id | doaj.art-87b40fc228b24e57a4e44cd4d644e688 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T04:46:32Z |
| publishDate | 2021-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-87b40fc228b24e57a4e44cd4d644e6882023-11-23T02:57:33ZengMDPI AGRemote Sensing2072-42922021-11-011323486610.3390/rs13234866Error Evaluation of L-Band <i>InSAR</i> Precipitable Water Vapor Measurements by Comparison with <i>GNSS</i> Observations in JapanKeita Matsuzawa0Yohei Kinoshita1Graduate School of Systems and Information Engineering, University of Tsukuba, Tsukuba 3058573, JapanFaculty of Engineering, Information and Systems, University of Tsukuba, Tsukuba 3058573, JapanInterferometric synthetic aperture radar (<i>InSAR</i>) enables us to obtain precipitable water vapor (<i>PWV</i>) maps with high spatial resolution through the phase difference caused by refraction in the atmosphere. Although previous studies have evaluated the error level of <i>InSAR</i><i>PWV</i> observations, they validated it only with C-band <i>InSAR</i><i>PWV</i> observations. Since ionospheric disturbance seriously contaminates the <i>InSAR</i> phase in the case of the lower-frequency SAR system, it is necessary for a <i>PWV</i> error level evaluation correcting the ionospheric effect appropriately if we use lower-frequency SAR systems, such as the Advanced Land Observing Satellite-2 (ALOS-2). In this paper, we evaluated the error level of the L-band <i>InSAR</i><i>PWV</i> observation obtained from ALOS-2 data covering four areas in Japan. We compared the <i>InSAR</i> observations with global navigation satellite system (<i>GNSS</i>) atmospheric observations and estimated the L-band <i>InSAR</i><i>PWV</i> error value by utilizing the error propagation theory. As a result, the L-band <i>InSAR</i><i>PWV</i> absolute error reached 2.83 mm, which was comparable to traditional <i>PWV</i> observations. Moreover, we investigated the impacts of the seasonality, the interferometric coherence, and the height dependence on the <i>PWV</i> observation accuracy in <i>InSAR</i>.https://www.mdpi.com/2072-4292/13/23/4866<i>InSAR</i>ALOS-2water vaporerror propagation theory |
| spellingShingle | Keita Matsuzawa Yohei Kinoshita Error Evaluation of L-Band <i>InSAR</i> Precipitable Water Vapor Measurements by Comparison with <i>GNSS</i> Observations in Japan Remote Sensing <i>InSAR</i> ALOS-2 water vapor error propagation theory |
| title | Error Evaluation of L-Band <i>InSAR</i> Precipitable Water Vapor Measurements by Comparison with <i>GNSS</i> Observations in Japan |
| title_full | Error Evaluation of L-Band <i>InSAR</i> Precipitable Water Vapor Measurements by Comparison with <i>GNSS</i> Observations in Japan |
| title_fullStr | Error Evaluation of L-Band <i>InSAR</i> Precipitable Water Vapor Measurements by Comparison with <i>GNSS</i> Observations in Japan |
| title_full_unstemmed | Error Evaluation of L-Band <i>InSAR</i> Precipitable Water Vapor Measurements by Comparison with <i>GNSS</i> Observations in Japan |
| title_short | Error Evaluation of L-Band <i>InSAR</i> Precipitable Water Vapor Measurements by Comparison with <i>GNSS</i> Observations in Japan |
| title_sort | error evaluation of l band i insar i precipitable water vapor measurements by comparison with i gnss i observations in japan |
| topic | <i>InSAR</i> ALOS-2 water vapor error propagation theory |
| url | https://www.mdpi.com/2072-4292/13/23/4866 |
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