Polarization-Enhancement Effects for the Retrieval of Significant Wave Heights from Gaofen-3 SAR Wave Mode Data
In order to investigate the impact of utilizing multiple pieces of polarization information on the performance of significant wave height (SWH) estimation from Gaofen-3 SAR data, the extreme gradient boosting (XGBoost) models were developed, validated, and compared across 9 single-polarizations and...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-11-01
|
| Series: | Remote Sensing |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2072-4292/15/23/5450 |
| _version_ | 1797399658822107136 |
|---|---|
| author | Qiushuang Yan Chenqing Fan Tianran Song Jie Zhang |
| author_facet | Qiushuang Yan Chenqing Fan Tianran Song Jie Zhang |
| author_sort | Qiushuang Yan |
| collection | DOAJ |
| description | In order to investigate the impact of utilizing multiple pieces of polarization information on the performance of significant wave height (SWH) estimation from Gaofen-3 SAR data, the extreme gradient boosting (XGBoost) models were developed, validated, and compared across 9 single-polarizations and 39 combined-polarizations based on the collocated datasets of Gaofen-3 SAR wave mode imagettes matched with SWH data from ERA5 reanalysis as well as independent SWH observations from buoys and altimeters. The results show that the performance of our SWH inversion models varies across the nine different single-polarizations. The co-polarizations (HH, VV, and RL) and hybrid-polarizations (45° linear, RH, and RV) generally exhibit superior performance compared to the cross-polarizations (HV, VH, and RR) at low to moderate sea states, while the cross-polarizations are more advantageous for high SWH estimation. The combined use of multiple pieces of polarization information does not always improve the model performance in retrieving SWH from Gaofen-3 SAR. Only the polarization combinations that incorporate cross-polarization information have the potential to enhance the model performance. In these cases, the performance of our models consistently improves with the incorporation of additional polarization information; however, this improvement diminishes gradually with each subsequent polarization and may eventually reach a saturation point. The optimal estimation of SWH is achieved with the polarization combination of HV + VH + RR + RH + RV + 45° linear, which shows consistently lower RMSEs compared to ERA5 SWH (0.295 m), buoy SWH (0.273 m), Cryosat-2 SWH (0.109 m), Jason-3 SWH (0.414 m), and SARAL SWH (0.286 m). Nevertheless, it still exhibits a slight overestimation at low sea states and a slight underestimation at high sea states. The inadequate distribution of data may serve as a potential explanation for this. |
| first_indexed | 2024-03-09T01:44:19Z |
| format | Article |
| id | doaj.art-b6016f77d52a42acadbab304354924f3 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-09T01:44:19Z |
| publishDate | 2023-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-b6016f77d52a42acadbab304354924f32023-12-08T15:24:40ZengMDPI AGRemote Sensing2072-42922023-11-011523545010.3390/rs15235450Polarization-Enhancement Effects for the Retrieval of Significant Wave Heights from Gaofen-3 SAR Wave Mode DataQiushuang Yan0Chenqing Fan1Tianran Song2Jie Zhang3College of Oceanography and Space Informatics, China University of Petroleum, Qingdao 266580, ChinaTechnology Innovation Center for Maritime Silk Road Marine Resources and Environment Networked Observation, Ministry of Natural Resources, Qingdao 266580, ChinaCollege of Oceanography and Space Informatics, China University of Petroleum, Qingdao 266580, ChinaCollege of Oceanography and Space Informatics, China University of Petroleum, Qingdao 266580, ChinaIn order to investigate the impact of utilizing multiple pieces of polarization information on the performance of significant wave height (SWH) estimation from Gaofen-3 SAR data, the extreme gradient boosting (XGBoost) models were developed, validated, and compared across 9 single-polarizations and 39 combined-polarizations based on the collocated datasets of Gaofen-3 SAR wave mode imagettes matched with SWH data from ERA5 reanalysis as well as independent SWH observations from buoys and altimeters. The results show that the performance of our SWH inversion models varies across the nine different single-polarizations. The co-polarizations (HH, VV, and RL) and hybrid-polarizations (45° linear, RH, and RV) generally exhibit superior performance compared to the cross-polarizations (HV, VH, and RR) at low to moderate sea states, while the cross-polarizations are more advantageous for high SWH estimation. The combined use of multiple pieces of polarization information does not always improve the model performance in retrieving SWH from Gaofen-3 SAR. Only the polarization combinations that incorporate cross-polarization information have the potential to enhance the model performance. In these cases, the performance of our models consistently improves with the incorporation of additional polarization information; however, this improvement diminishes gradually with each subsequent polarization and may eventually reach a saturation point. The optimal estimation of SWH is achieved with the polarization combination of HV + VH + RR + RH + RV + 45° linear, which shows consistently lower RMSEs compared to ERA5 SWH (0.295 m), buoy SWH (0.273 m), Cryosat-2 SWH (0.109 m), Jason-3 SWH (0.414 m), and SARAL SWH (0.286 m). Nevertheless, it still exhibits a slight overestimation at low sea states and a slight underestimation at high sea states. The inadequate distribution of data may serve as a potential explanation for this.https://www.mdpi.com/2072-4292/15/23/5450Gaofen-3 SAR wave modeXGBoostSWH estimationmultiple polarizationsperformance improvement |
| spellingShingle | Qiushuang Yan Chenqing Fan Tianran Song Jie Zhang Polarization-Enhancement Effects for the Retrieval of Significant Wave Heights from Gaofen-3 SAR Wave Mode Data Remote Sensing Gaofen-3 SAR wave mode XGBoost SWH estimation multiple polarizations performance improvement |
| title | Polarization-Enhancement Effects for the Retrieval of Significant Wave Heights from Gaofen-3 SAR Wave Mode Data |
| title_full | Polarization-Enhancement Effects for the Retrieval of Significant Wave Heights from Gaofen-3 SAR Wave Mode Data |
| title_fullStr | Polarization-Enhancement Effects for the Retrieval of Significant Wave Heights from Gaofen-3 SAR Wave Mode Data |
| title_full_unstemmed | Polarization-Enhancement Effects for the Retrieval of Significant Wave Heights from Gaofen-3 SAR Wave Mode Data |
| title_short | Polarization-Enhancement Effects for the Retrieval of Significant Wave Heights from Gaofen-3 SAR Wave Mode Data |
| title_sort | polarization enhancement effects for the retrieval of significant wave heights from gaofen 3 sar wave mode data |
| topic | Gaofen-3 SAR wave mode XGBoost SWH estimation multiple polarizations performance improvement |
| url | https://www.mdpi.com/2072-4292/15/23/5450 |
| work_keys_str_mv | AT qiushuangyan polarizationenhancementeffectsfortheretrievalofsignificantwaveheightsfromgaofen3sarwavemodedata AT chenqingfan polarizationenhancementeffectsfortheretrievalofsignificantwaveheightsfromgaofen3sarwavemodedata AT tianransong polarizationenhancementeffectsfortheretrievalofsignificantwaveheightsfromgaofen3sarwavemodedata AT jiezhang polarizationenhancementeffectsfortheretrievalofsignificantwaveheightsfromgaofen3sarwavemodedata |