An Apparent Thermal Inertia Based Trapezoid Model for Downscaling ESA CCI Soil Moisture Products
Existing long-term soil moisture (SM) products are relatively coarse in spatial resolution, limiting their applications in heterogeneous scales. Various spectral information derived from optical satellite data, such as the land surface temperature-vegetation parameter (LST-VP), have been widely empl...
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IEEE
2025-01-01
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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/10829995/ |
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| author | Shulin Li Minfeng Xing Taifeng Dong |
| author_facet | Shulin Li Minfeng Xing Taifeng Dong |
| author_sort | Shulin Li |
| collection | DOAJ |
| description | Existing long-term soil moisture (SM) products are relatively coarse in spatial resolution, limiting their applications in heterogeneous scales. Various spectral information derived from optical satellite data, such as the land surface temperature-vegetation parameter (LST-VP), have been widely employed to detect spatiotemporal variability of SM under different regional hydrological scales. In this study, inspired by the concept of LST-VI space, an ATI-VP (apparent thermal inertia-vegetation parameter) was proposed and assessed for downscaling the ESA CCI SM product from 25 to 1 km. Different vegetation indices (including NDVI, EVI, NIRv, and MSAVI) and biophysical variables (LAI and fPAR) derived from MODIS satellites were first assessed as inputs of the ATI-VP space to estimate AVDI (apparent thermal inertia/vegetation drought index). The AVDI was then applied to the weight decomposition model for SM downscaling. Overall, LAI for the ATI-VP space achieved the best AVDI performance. The accuracy of SM estimation was validated using in situ SM collected from the Murrumbidgee soil moisture monitoring network. The results showed that the accuracy of the downscaled 1 km SM (R = 0.637, bias = 0.038 m<sup>3</sup>/m<sup>3</sup>) was close to that of the CCI SM (R = 0.661, bias = 0.030 m<sup>3</sup>/m<sup>3</sup>). However, the downscaled SM data exhibited enhanced spatial detail compared to CCI SM data. Further analysis based on the time series SM indicated that both the CCI SM and the downscaled SM are in good agreement in terms of temporal evolution. The downscaling method shows high potential for application in SM mapping across semiarid regions. |
| format | Article |
| id | doaj-art-8405bf3e3fc64fd8b951c3eeca837038 |
| institution | Kabale University |
| issn | 1939-1404 2151-1535 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IEEE |
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| series | IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing |
| spelling | doaj-art-8405bf3e3fc64fd8b951c3eeca8370382025-02-04T00:00:18ZengIEEEIEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing1939-14042151-15352025-01-01184473448610.1109/JSTARS.2024.352530510829995An Apparent Thermal Inertia Based Trapezoid Model for Downscaling ESA CCI Soil Moisture ProductsShulin Li0Minfeng Xing1https://orcid.org/0000-0002-5369-4638Taifeng Dong2https://orcid.org/0000-0002-0203-295XSchool of Resources and Environment, University of Electronic Science and Technology of China, Chengdu, ChinaSchool of Resources and Environment, University of Electronic Science and Technology of China, Chengdu, ChinaOttawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON, CanadaExisting long-term soil moisture (SM) products are relatively coarse in spatial resolution, limiting their applications in heterogeneous scales. Various spectral information derived from optical satellite data, such as the land surface temperature-vegetation parameter (LST-VP), have been widely employed to detect spatiotemporal variability of SM under different regional hydrological scales. In this study, inspired by the concept of LST-VI space, an ATI-VP (apparent thermal inertia-vegetation parameter) was proposed and assessed for downscaling the ESA CCI SM product from 25 to 1 km. Different vegetation indices (including NDVI, EVI, NIRv, and MSAVI) and biophysical variables (LAI and fPAR) derived from MODIS satellites were first assessed as inputs of the ATI-VP space to estimate AVDI (apparent thermal inertia/vegetation drought index). The AVDI was then applied to the weight decomposition model for SM downscaling. Overall, LAI for the ATI-VP space achieved the best AVDI performance. The accuracy of SM estimation was validated using in situ SM collected from the Murrumbidgee soil moisture monitoring network. The results showed that the accuracy of the downscaled 1 km SM (R = 0.637, bias = 0.038 m<sup>3</sup>/m<sup>3</sup>) was close to that of the CCI SM (R = 0.661, bias = 0.030 m<sup>3</sup>/m<sup>3</sup>). However, the downscaled SM data exhibited enhanced spatial detail compared to CCI SM data. Further analysis based on the time series SM indicated that both the CCI SM and the downscaled SM are in good agreement in terms of temporal evolution. The downscaling method shows high potential for application in SM mapping across semiarid regions.https://ieeexplore.ieee.org/document/10829995/Apparent thermal inertia (ATI)downscalingESA CCI SMMODISsoil moisture (SM)vegetation parameter (VP) |
| spellingShingle | Shulin Li Minfeng Xing Taifeng Dong An Apparent Thermal Inertia Based Trapezoid Model for Downscaling ESA CCI Soil Moisture Products IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Apparent thermal inertia (ATI) downscaling ESA CCI SM MODIS soil moisture (SM) vegetation parameter (VP) |
| title | An Apparent Thermal Inertia Based Trapezoid Model for Downscaling ESA CCI Soil Moisture Products |
| title_full | An Apparent Thermal Inertia Based Trapezoid Model for Downscaling ESA CCI Soil Moisture Products |
| title_fullStr | An Apparent Thermal Inertia Based Trapezoid Model for Downscaling ESA CCI Soil Moisture Products |
| title_full_unstemmed | An Apparent Thermal Inertia Based Trapezoid Model for Downscaling ESA CCI Soil Moisture Products |
| title_short | An Apparent Thermal Inertia Based Trapezoid Model for Downscaling ESA CCI Soil Moisture Products |
| title_sort | apparent thermal inertia based trapezoid model for downscaling esa cci soil moisture products |
| topic | Apparent thermal inertia (ATI) downscaling ESA CCI SM MODIS soil moisture (SM) vegetation parameter (VP) |
| url | https://ieeexplore.ieee.org/document/10829995/ |
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