Evaluation of the CRTM Land Emissivity Model over Grass and Sand Surfaces Using Ground-Based Measurements
Microwave surface emissivity is complex and variable, leading to increased difficulty in accurately retrieving atmospheric parameters and assimilating satellite microwave observations over land. The Community Radiative Transfer Model (CRTM) land emissivity model is a useful tool for providing microw...
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| Format: | Article |
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MDPI AG
2023-12-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/16/1/95 |
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| author | Yidan Wang Wenying He Minzheng Duan Hailei Liu Hongbin Chen Congzhen Han Weidong Nan |
| author_facet | Yidan Wang Wenying He Minzheng Duan Hailei Liu Hongbin Chen Congzhen Han Weidong Nan |
| author_sort | Yidan Wang |
| collection | DOAJ |
| description | Microwave surface emissivity is complex and variable, leading to increased difficulty in accurately retrieving atmospheric parameters and assimilating satellite microwave observations over land. The Community Radiative Transfer Model (CRTM) land emissivity model is a useful tool for providing microwave emissivity over complex surfaces. By combining the model with ground measurements from a mobile multi-surface observing system at the Xianghe site, China, the performance of the land emissivity model is evaluated over grass and sand surfaces. The simulated and measured emissivity agrees at both polarizations over the grassland surface but a more significant difference is observed at the horizontal polarization over the sand surface. To solve this problem, the <i>Q/H</i> module for soil reflectance roughness correction in the CRTM emissivity model was replaced with the <i>Q<sub>p</sub></i> module for the sand surface. This results in a significant improvement in the horizontal polarization simulation, with the corresponding mean bias error (MBE) reducing from 0.08 in the <i>Q/H</i> module to less than 0.03. The adjustment demonstrates that the <i>Q<sub>p</sub></i> module more effectively corrects the roughness effect on horizontally polarized emissivity for bare soil surfaces. For grassland, the CRTM emissivity model with the <i>Q/H</i> module demonstrates accurate simulations, showing its suitability for vegetated land surfaces. |
| first_indexed | 2024-03-08T14:58:37Z |
| format | Article |
| id | doaj.art-ae4cbf5dddd14df7b7b726f400b14c77 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-08T14:58:37Z |
| publishDate | 2023-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-ae4cbf5dddd14df7b7b726f400b14c772024-01-10T15:07:24ZengMDPI AGRemote Sensing2072-42922023-12-011619510.3390/rs16010095Evaluation of the CRTM Land Emissivity Model over Grass and Sand Surfaces Using Ground-Based MeasurementsYidan Wang0Wenying He1Minzheng Duan2Hailei Liu3Hongbin Chen4Congzhen Han5Weidong Nan6Key Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaKey Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaKey Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaCollege of Electronic Engineering, Chengdu University of Information Technology, Chengdu 610225, ChinaKey Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaKey Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaKey Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaMicrowave surface emissivity is complex and variable, leading to increased difficulty in accurately retrieving atmospheric parameters and assimilating satellite microwave observations over land. The Community Radiative Transfer Model (CRTM) land emissivity model is a useful tool for providing microwave emissivity over complex surfaces. By combining the model with ground measurements from a mobile multi-surface observing system at the Xianghe site, China, the performance of the land emissivity model is evaluated over grass and sand surfaces. The simulated and measured emissivity agrees at both polarizations over the grassland surface but a more significant difference is observed at the horizontal polarization over the sand surface. To solve this problem, the <i>Q/H</i> module for soil reflectance roughness correction in the CRTM emissivity model was replaced with the <i>Q<sub>p</sub></i> module for the sand surface. This results in a significant improvement in the horizontal polarization simulation, with the corresponding mean bias error (MBE) reducing from 0.08 in the <i>Q/H</i> module to less than 0.03. The adjustment demonstrates that the <i>Q<sub>p</sub></i> module more effectively corrects the roughness effect on horizontally polarized emissivity for bare soil surfaces. For grassland, the CRTM emissivity model with the <i>Q/H</i> module demonstrates accurate simulations, showing its suitability for vegetated land surfaces.https://www.mdpi.com/2072-4292/16/1/95microwave land surface emissivityCRTM emissivity modelground-based measurementsreflectance roughness correction |
| spellingShingle | Yidan Wang Wenying He Minzheng Duan Hailei Liu Hongbin Chen Congzhen Han Weidong Nan Evaluation of the CRTM Land Emissivity Model over Grass and Sand Surfaces Using Ground-Based Measurements Remote Sensing microwave land surface emissivity CRTM emissivity model ground-based measurements reflectance roughness correction |
| title | Evaluation of the CRTM Land Emissivity Model over Grass and Sand Surfaces Using Ground-Based Measurements |
| title_full | Evaluation of the CRTM Land Emissivity Model over Grass and Sand Surfaces Using Ground-Based Measurements |
| title_fullStr | Evaluation of the CRTM Land Emissivity Model over Grass and Sand Surfaces Using Ground-Based Measurements |
| title_full_unstemmed | Evaluation of the CRTM Land Emissivity Model over Grass and Sand Surfaces Using Ground-Based Measurements |
| title_short | Evaluation of the CRTM Land Emissivity Model over Grass and Sand Surfaces Using Ground-Based Measurements |
| title_sort | evaluation of the crtm land emissivity model over grass and sand surfaces using ground based measurements |
| topic | microwave land surface emissivity CRTM emissivity model ground-based measurements reflectance roughness correction |
| url | https://www.mdpi.com/2072-4292/16/1/95 |
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