Identifying Soil Freeze/Thaw States Using Scattering and Coherence Time Series of High-Resolution <italic>C-</italic>Band Synthetic Aperture Radar in the Qinghai-Tibet Plateau
The soil freeze/thaw (F/T) cycles play an important role in the climate system and human activities. However, the harsh environment in the Qinghai-Tibet Plateau (QTP) poses great challenges for both in-situ observation and remote-sensing monitoring of the soil F/T pr...
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| Format: | Article |
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IEEE
2022-01-01
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| Series: | IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing |
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| Online Access: | https://ieeexplore.ieee.org/document/9658174/ |
| _version_ | 1819283139384573952 |
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| author | Xin Zhou Zhengjia Zhang Qikai Shen Qihao Chen Xiuguo Liu |
| author_facet | Xin Zhou Zhengjia Zhang Qikai Shen Qihao Chen Xiuguo Liu |
| author_sort | Xin Zhou |
| collection | DOAJ |
| description | The soil freeze/thaw (F/T) cycles play an important role in the climate system and human activities. However, the harsh environment in the Qinghai-Tibet Plateau (QTP) poses great challenges for both in-situ observation and remote-sensing monitoring of the soil F/T process. In this article, the time series of scattering and coherence of the high-resolution Sentinel-1 <italic>C-</italic>band synthetic aperture radar (SAR) is analyzed to identify the soil F/T state. The time series of scattering, including intensity and decomposition parameters, and coherence, are analyzed based on three typical landcover types (i.e., desert, grassland, and meadow) in the QTP. They are given the mathematical description by second-order and fourth-order Fourier functions, respectively. Based on Fourier functions, the initial F/T time points of the soil are detected in each pixel to draw the F/T map of the entire study area. The experiment results are cross-validated with the initial F/T time points of the soil calculated from the MODIS land surface temperatures, showing that the differences in days are less than one revisit cycle of Sentinel-1 (i.e., 12 days). Furthermore, the possible impacts of environmental factors acquired from the Wudaoliang meteorological station, including air temperature, ground surface temperature, snow depth, and precipitation, on scattering and coherence are discussed. This study explores that Sentinel-1 has great potential for soil F/T monitoring in the QTP, which can indicate F/T states of the surface soil as well as F/T information of the deeper soil with a high spatial–temporal resolution. |
| first_indexed | 2024-12-24T01:26:44Z |
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| id | doaj.art-fce8b6ab81b544d6bc3a8a42e633bf00 |
| institution | Directory Open Access Journal |
| issn | 2151-1535 |
| language | English |
| last_indexed | 2024-12-24T01:26:44Z |
| publishDate | 2022-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing |
| spelling | doaj.art-fce8b6ab81b544d6bc3a8a42e633bf002022-12-21T17:22:29ZengIEEEIEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing2151-15352022-01-011551953210.1109/JSTARS.2021.31371879658174Identifying Soil Freeze/Thaw States Using Scattering and Coherence Time Series of High-Resolution <italic>C-</italic>Band Synthetic Aperture Radar in the Qinghai-Tibet PlateauXin Zhou0https://orcid.org/0000-0003-1321-510XZhengjia Zhang1Qikai Shen2Qihao Chen3https://orcid.org/0000-0002-7250-8781Xiuguo Liu4School of Geography and Information Engineering, China University of Geosciences, Wuhan, ChinaSchool of Geography and Information Engineering, China University of Geosciences, Wuhan, ChinaSchool of Geography and Information Engineering, China University of Geosciences, Wuhan, ChinaSchool of Geography and Information Engineering, China University of Geosciences, Wuhan, ChinaSchool of Geography and Information Engineering, China University of Geosciences, Wuhan, ChinaThe soil freeze/thaw (F/T) cycles play an important role in the climate system and human activities. However, the harsh environment in the Qinghai-Tibet Plateau (QTP) poses great challenges for both in-situ observation and remote-sensing monitoring of the soil F/T process. In this article, the time series of scattering and coherence of the high-resolution Sentinel-1 <italic>C-</italic>band synthetic aperture radar (SAR) is analyzed to identify the soil F/T state. The time series of scattering, including intensity and decomposition parameters, and coherence, are analyzed based on three typical landcover types (i.e., desert, grassland, and meadow) in the QTP. They are given the mathematical description by second-order and fourth-order Fourier functions, respectively. Based on Fourier functions, the initial F/T time points of the soil are detected in each pixel to draw the F/T map of the entire study area. The experiment results are cross-validated with the initial F/T time points of the soil calculated from the MODIS land surface temperatures, showing that the differences in days are less than one revisit cycle of Sentinel-1 (i.e., 12 days). Furthermore, the possible impacts of environmental factors acquired from the Wudaoliang meteorological station, including air temperature, ground surface temperature, snow depth, and precipitation, on scattering and coherence are discussed. This study explores that Sentinel-1 has great potential for soil F/T monitoring in the QTP, which can indicate F/T states of the surface soil as well as F/T information of the deeper soil with a high spatial–temporal resolution.https://ieeexplore.ieee.org/document/9658174/CoherenceQinghai-Tibet Plateau (QTP)scatteringSentinel-1soil freeze/thaw (F/T) cyclesynthetic aperture radar (SAR) |
| spellingShingle | Xin Zhou Zhengjia Zhang Qikai Shen Qihao Chen Xiuguo Liu Identifying Soil Freeze/Thaw States Using Scattering and Coherence Time Series of High-Resolution <italic>C-</italic>Band Synthetic Aperture Radar in the Qinghai-Tibet Plateau IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Coherence Qinghai-Tibet Plateau (QTP) scattering Sentinel-1 soil freeze/thaw (F/T) cycle synthetic aperture radar (SAR) |
| title | Identifying Soil Freeze/Thaw States Using Scattering and Coherence Time Series of High-Resolution <italic>C-</italic>Band Synthetic Aperture Radar in the Qinghai-Tibet Plateau |
| title_full | Identifying Soil Freeze/Thaw States Using Scattering and Coherence Time Series of High-Resolution <italic>C-</italic>Band Synthetic Aperture Radar in the Qinghai-Tibet Plateau |
| title_fullStr | Identifying Soil Freeze/Thaw States Using Scattering and Coherence Time Series of High-Resolution <italic>C-</italic>Band Synthetic Aperture Radar in the Qinghai-Tibet Plateau |
| title_full_unstemmed | Identifying Soil Freeze/Thaw States Using Scattering and Coherence Time Series of High-Resolution <italic>C-</italic>Band Synthetic Aperture Radar in the Qinghai-Tibet Plateau |
| title_short | Identifying Soil Freeze/Thaw States Using Scattering and Coherence Time Series of High-Resolution <italic>C-</italic>Band Synthetic Aperture Radar in the Qinghai-Tibet Plateau |
| title_sort | identifying soil freeze x002f thaw states using scattering and coherence time series of high resolution italic c italic band synthetic aperture radar in the qinghai tibet plateau |
| topic | Coherence Qinghai-Tibet Plateau (QTP) scattering Sentinel-1 soil freeze/thaw (F/T) cycle synthetic aperture radar (SAR) |
| url | https://ieeexplore.ieee.org/document/9658174/ |
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