Estimation of IFOV Inter-Channel Deviation for Microwave Radiation Imager Onboard FY-3G Satellite
The Microwave Radiation Imager (MWRI) onboard the FengYun satellite plays a crucial role in global change monitoring and numerical weather prediction. Estimating and correcting geolocation errors are important to retrieving accurate geophysical variables. However, the instantaneous field of view (IF...
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MDPI AG
2024-09-01
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| author | Pengjuan Yao Shengli Wu Yang Guo Jian Shang Kesong Dong Weiwei Xu Jiachen Wang |
| author_facet | Pengjuan Yao Shengli Wu Yang Guo Jian Shang Kesong Dong Weiwei Xu Jiachen Wang |
| author_sort | Pengjuan Yao |
| collection | DOAJ |
| description | The Microwave Radiation Imager (MWRI) onboard the FengYun satellite plays a crucial role in global change monitoring and numerical weather prediction. Estimating and correcting geolocation errors are important to retrieving accurate geophysical variables. However, the instantaneous field of view (IFOV) inter-channel deviation, which is mainly caused by the structure mounting error and measurement error of feedhorns, is less studied. In this present study, we constructed a general theoretical model to automatically estimate the IFOV inter-channel deviations suitable for conical-scanning instruments. The model can automatically detect the along-track and across-track vectors that pass through the land–sea boundary points and are perpendicular to the actual coastlines. Regarding the midpoints of the vectors as the brightness temperature (Tb) inflection points, the IFOV inter-channel deviation is the pixel offset or distance of the maximum gradients of the Tb near the inflection points for each channel relative to the 89-GHz V-pol channel. We tested the model’s operational performance using the FY-3G/MWRI-Rainfall Mission (MWRI-RM) observations. Considering that parameter uploading adjusted the IFOV inter-channel deviations, the model’s validity was verified by comparing the adjustments calculated by the model with the theoretical changes caused by parameter uploading. The result shows that the differences between them for all window channels are less than 100 m, indicating the model’s effectiveness in evaluating the IFOV inter-channel deviation for the MWRI-RM. Furthermore, the estimated on-orbit IFOV inter-channel deviations for the MWRI-RM show that all channel deviations are less than 1 km, meeting the instrument’s design requirement of 2 km. We believe this study will provide a foundation for IFOV inter-channel registration of passive microwave payloads and spatial matching of multiple payloads. |
| format | Article |
| id | doaj-art-2c1fb3ea814b4b4090189809442baed1 |
| institution | OA Journals |
| issn | 2072-4292 |
| language | English |
| publishDate | 2024-09-01 |
| publisher | MDPI AG |
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| series | Remote Sensing |
| spelling | doaj-art-2c1fb3ea814b4b4090189809442baed12025-08-20T01:47:34ZengMDPI AGRemote Sensing2072-42922024-09-011619357110.3390/rs16193571Estimation of IFOV Inter-Channel Deviation for Microwave Radiation Imager Onboard FY-3G SatellitePengjuan Yao0Shengli Wu1Yang Guo2Jian Shang3Kesong Dong4Weiwei Xu5Jiachen Wang6National Satellite Meteorological Center (National Center for Space Weather), Beijing 100081, ChinaNational Satellite Meteorological Center (National Center for Space Weather), Beijing 100081, ChinaNational Satellite Meteorological Center (National Center for Space Weather), Beijing 100081, ChinaNational Satellite Meteorological Center (National Center for Space Weather), Beijing 100081, ChinaShanghai Aerospace Electronic Technology Institute, Shanghai 201109, ChinaNational Satellite Meteorological Center (National Center for Space Weather), Beijing 100081, ChinaNational Satellite Meteorological Center (National Center for Space Weather), Beijing 100081, ChinaThe Microwave Radiation Imager (MWRI) onboard the FengYun satellite plays a crucial role in global change monitoring and numerical weather prediction. Estimating and correcting geolocation errors are important to retrieving accurate geophysical variables. However, the instantaneous field of view (IFOV) inter-channel deviation, which is mainly caused by the structure mounting error and measurement error of feedhorns, is less studied. In this present study, we constructed a general theoretical model to automatically estimate the IFOV inter-channel deviations suitable for conical-scanning instruments. The model can automatically detect the along-track and across-track vectors that pass through the land–sea boundary points and are perpendicular to the actual coastlines. Regarding the midpoints of the vectors as the brightness temperature (Tb) inflection points, the IFOV inter-channel deviation is the pixel offset or distance of the maximum gradients of the Tb near the inflection points for each channel relative to the 89-GHz V-pol channel. We tested the model’s operational performance using the FY-3G/MWRI-Rainfall Mission (MWRI-RM) observations. Considering that parameter uploading adjusted the IFOV inter-channel deviations, the model’s validity was verified by comparing the adjustments calculated by the model with the theoretical changes caused by parameter uploading. The result shows that the differences between them for all window channels are less than 100 m, indicating the model’s effectiveness in evaluating the IFOV inter-channel deviation for the MWRI-RM. Furthermore, the estimated on-orbit IFOV inter-channel deviations for the MWRI-RM show that all channel deviations are less than 1 km, meeting the instrument’s design requirement of 2 km. We believe this study will provide a foundation for IFOV inter-channel registration of passive microwave payloads and spatial matching of multiple payloads.https://www.mdpi.com/2072-4292/16/19/3571IFOV inter-channel deviationautomatic estimation modelmicrowave radiation imagerremote sensingcoastline inflection pointFY-3G satellite |
| spellingShingle | Pengjuan Yao Shengli Wu Yang Guo Jian Shang Kesong Dong Weiwei Xu Jiachen Wang Estimation of IFOV Inter-Channel Deviation for Microwave Radiation Imager Onboard FY-3G Satellite Remote Sensing IFOV inter-channel deviation automatic estimation model microwave radiation imager remote sensing coastline inflection point FY-3G satellite |
| title | Estimation of IFOV Inter-Channel Deviation for Microwave Radiation Imager Onboard FY-3G Satellite |
| title_full | Estimation of IFOV Inter-Channel Deviation for Microwave Radiation Imager Onboard FY-3G Satellite |
| title_fullStr | Estimation of IFOV Inter-Channel Deviation for Microwave Radiation Imager Onboard FY-3G Satellite |
| title_full_unstemmed | Estimation of IFOV Inter-Channel Deviation for Microwave Radiation Imager Onboard FY-3G Satellite |
| title_short | Estimation of IFOV Inter-Channel Deviation for Microwave Radiation Imager Onboard FY-3G Satellite |
| title_sort | estimation of ifov inter channel deviation for microwave radiation imager onboard fy 3g satellite |
| topic | IFOV inter-channel deviation automatic estimation model microwave radiation imager remote sensing coastline inflection point FY-3G satellite |
| url | https://www.mdpi.com/2072-4292/16/19/3571 |
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