An investigation on microwave transmissivity at frequencies of 18.7 and 36.5 GHz for diverse forest types during snow season
Forests have invariably been considered as an obstacle in retrieving land surface parameters from spaceborne passive microwave brightness temperature (TB) observations. For quantifying the effect of forests on microwave signals, several models have been developed. However, these models rarely reveal...
| 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/10.1080/17538947.2021.1955985 |
| _version_ | 1797678515026395136 |
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| author | Wang Guangrui Li Xiaofeng Chen Xiuxue Jiang Tao Zheng Xingming Wei Yanlin Wan Xiangkun Wang Jian |
| author_facet | Wang Guangrui Li Xiaofeng Chen Xiuxue Jiang Tao Zheng Xingming Wei Yanlin Wan Xiangkun Wang Jian |
| author_sort | Wang Guangrui |
| collection | DOAJ |
| description | Forests have invariably been considered as an obstacle in retrieving land surface parameters from spaceborne passive microwave brightness temperature (TB) observations. For quantifying the effect of forests on microwave signals, several models have been developed. However, these models rarely reveal the dependence of microwave radiation on forest types, which can hardly meet the needs of high-accuracy retrieval of terrestrial parameters in forested regions. A ground-based microwave radiometric observation experiment was designed to investigate the dependence of microwave radiation on frequency, polarization, and forest type. Downward TB at 18.7- and 36.5-GHz for horizontal- and vertical-polarization from the forest canopy was measured at 14 sample plots in Northeast China, along with snowpack and forest structural parameters. By providing fits to experimental data, new empirical transmissivity models for three forest types were developed, as a function of woody stem volume and depending on the frequency/polarization. The proposed models give diverse asymptotic transmissivity saturation levels and the corresponding saturation point of woody stem volume for different forest types. Root-mean-square error results between TB simulations and Advanced Microwave Scanning Radiometer-2 observations are approximately 3–6 K. This study provides an experimental and theoretical reference for further development of inversion models for snow parameters in forested areas. |
| first_indexed | 2024-03-11T23:00:55Z |
| format | Article |
| id | doaj.art-ce4e77110eb34c898689f9d591826e70 |
| institution | Directory Open Access Journal |
| issn | 1753-8947 1753-8955 |
| language | English |
| last_indexed | 2024-03-11T23:00:55Z |
| publishDate | 2021-10-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | International Journal of Digital Earth |
| spelling | doaj.art-ce4e77110eb34c898689f9d591826e702023-09-21T14:57:10ZengTaylor & Francis GroupInternational Journal of Digital Earth1753-89471753-89552021-10-0114101354137910.1080/17538947.2021.19559851955985An investigation on microwave transmissivity at frequencies of 18.7 and 36.5 GHz for diverse forest types during snow seasonWang Guangrui0Li Xiaofeng1Chen Xiuxue2Jiang Tao3Zheng Xingming4Wei Yanlin5Wan Xiangkun6Wang Jian7Northeast Institute of Geography and Agroecology, Chinese Academy of SciencesNortheast Institute of Geography and Agroecology, Chinese Academy of SciencesNortheast Institute of Geography and Agroecology, Chinese Academy of SciencesNortheast Institute of Geography and Agroecology, Chinese Academy of SciencesNortheast Institute of Geography and Agroecology, Chinese Academy of SciencesNortheast Institute of Geography and Agroecology, Chinese Academy of SciencesNortheast Institute of Geography and Agroecology, Chinese Academy of SciencesDongbei University of Finance and EconomicsForests have invariably been considered as an obstacle in retrieving land surface parameters from spaceborne passive microwave brightness temperature (TB) observations. For quantifying the effect of forests on microwave signals, several models have been developed. However, these models rarely reveal the dependence of microwave radiation on forest types, which can hardly meet the needs of high-accuracy retrieval of terrestrial parameters in forested regions. A ground-based microwave radiometric observation experiment was designed to investigate the dependence of microwave radiation on frequency, polarization, and forest type. Downward TB at 18.7- and 36.5-GHz for horizontal- and vertical-polarization from the forest canopy was measured at 14 sample plots in Northeast China, along with snowpack and forest structural parameters. By providing fits to experimental data, new empirical transmissivity models for three forest types were developed, as a function of woody stem volume and depending on the frequency/polarization. The proposed models give diverse asymptotic transmissivity saturation levels and the corresponding saturation point of woody stem volume for different forest types. Root-mean-square error results between TB simulations and Advanced Microwave Scanning Radiometer-2 observations are approximately 3–6 K. This study provides an experimental and theoretical reference for further development of inversion models for snow parameters in forested areas.http://dx.doi.org/10.1080/17538947.2021.1955985forest transmissivitysnowwoody stem volumemicrowave radiometryhut |
| spellingShingle | Wang Guangrui Li Xiaofeng Chen Xiuxue Jiang Tao Zheng Xingming Wei Yanlin Wan Xiangkun Wang Jian An investigation on microwave transmissivity at frequencies of 18.7 and 36.5 GHz for diverse forest types during snow season International Journal of Digital Earth forest transmissivity snow woody stem volume microwave radiometry hut |
| title | An investigation on microwave transmissivity at frequencies of 18.7 and 36.5 GHz for diverse forest types during snow season |
| title_full | An investigation on microwave transmissivity at frequencies of 18.7 and 36.5 GHz for diverse forest types during snow season |
| title_fullStr | An investigation on microwave transmissivity at frequencies of 18.7 and 36.5 GHz for diverse forest types during snow season |
| title_full_unstemmed | An investigation on microwave transmissivity at frequencies of 18.7 and 36.5 GHz for diverse forest types during snow season |
| title_short | An investigation on microwave transmissivity at frequencies of 18.7 and 36.5 GHz for diverse forest types during snow season |
| title_sort | investigation on microwave transmissivity at frequencies of 18 7 and 36 5 ghz for diverse forest types during snow season |
| topic | forest transmissivity snow woody stem volume microwave radiometry hut |
| url | http://dx.doi.org/10.1080/17538947.2021.1955985 |
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