A Calibration/Disaggregation Coupling Scheme for Retrieving Soil Moisture at High Spatio-Temporal Resolution: Synergy between SMAP Passive Microwave, MODIS/Landsat Optical/Thermal and Sentinel-1 Radar Data
Abstract
:1. Introduction
2. Materials and Methods
2.1. Study Area and In Situ Data
2.2. Remote Sensing Data
2.2.1. SMAP
2.2.2. MODIS
2.2.3. Landsat
2.2.4. Sentinel-1
2.2.5. Vegetation Descriptors
2.3. Remote Sensing Method
2.3.1. DISPATCH
2.3.2. Active Microwave Radiative Transfer Models
2.3.3. Coupling DISPATCH Data with Sentinel-1-Based SM Retrieval Algorithms
2.3.4. Calibration Parameters
3. Results
3.1. Accuracy of DISPATCH SM
3.2. Evaluation of Calibration Parameters
3.3. Evaluation of SM Estimates
3.3.1. Temporal Analysis
3.3.2. Spatio-Temporal Analysis
3.3.3. Gain in Accuracy at the Fine Scale Compared to SMAP
4. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Vegetation Descriptors | Chichaoua | Sidi Rahal | ||
---|---|---|---|---|
Linear | Calibration parameter (dB*)/(dB) | NDVI | 19/−3/−14 | 20/−0.7/−18 |
PR | 16/−6/−12 | 20/−4/−16 | ||
CO | 15/3/−16 | 17/3/−19 | ||
Standard error percentage std(%)/std(%)/std(%) | NDVI | 17/28/2 | 15/124/3 | |
PR | 12/11/3 | 10/21/3 | ||
CO | 16/18/3 | 14/30/3 | ||
Non-linear | Calibration parameter (dB*)/(dB)/(dB)/(dB) | NDVI | 18/−3/−14/−0.28 | 19/−0.7/−18/−0.04 |
PR | 11/−6/−11/−0.9 | 17/−4/−16/−0.4 | ||
CO | 18/3/−17/0.2 | 18/3/−19/0.15 | ||
Standard error percentage std(%)/std(%)/std(%)/std(%) | NDVI | 13/28/2/21 | 14/124/3/175 | |
PR | 11/11/4/12 | 11/21/4/26 | ||
CO | 14/18/3/14 | 14/30/4/33 |
Vegetation Descriptors | Chichaoua | Sidi Rahal | ||
---|---|---|---|---|
Linear | Calibration parameter (dB*(dB)/(dB) | NDVI | 34/−7/−14 | 26/−4/−12 |
PR | 19/−9/−11 | 19/−6/−12 | ||
CO | 23/5/−18 | 11/4/−16 | ||
Standard error percentage std(%)/std(%)/std(%) | NDVI | 27/46/6 | 38/47/10 | |
PR | 29/24/8 | 41/27/8 | ||
CO | 28/29/7 | 121/67/9 | ||
Non-linear | Calibration parameter (dB*)/(dB)/(dB)/(dB) | NDVI | 20/−7/−13/−0.76 | 19/−4/−12/−4 |
PR | 10/−9/−10/−2 | 14/−6/−11/−0.78 | ||
CO | 25/5/−18/0.27 | 12/4/−16/0.24 | ||
Standard error percentage std(%)/std(%)/std(%)/std(%) | NDVI | 25/46/6/41 | 41/47/11/54 | |
PR | 32/24/12/31 | 44/27/9/31 | ||
CO | 29/29/8/30 | 122/67/9/67 |
Calibration | In Situ SM Datasets | DSIAPTCH SM Datasets | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Model | R (-) | Slope (-) | MB (m/m) | RMSD (m/m) | ubRMSD (m/m) | R (-) | Slope (-) | Absolute MB (m/m) | RMSD (m/m) | ubRMSD (m/m) | |
Linear | NDVI | 0.43 | 0.43 | 0.01 | 0.10 | 0.08 | 0.54 | 0.42 | 0.13 | 0.15 | 0.07 |
PR | 0.45 | 0.48 | 0.01 | 0.10 | 0.08 | 0.47 | 0.53 | 0.10 | 0.13 | 0.08 | |
Non-linear | NDVI | 0.43 | 0.43 | 0.01 | 0.10 | 0.08 | 0.51 | 0.50 | 0.11 | 0.14 | 0.07 |
PR | 0.43 | 0.48 | 0.01 | 0.10 | 0.08 | 0.33 | 0.40 | 0.10 | 0.14 | 0.09 |
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Ojha, N.; Merlin, O.; Amazirh, A.; Ouaadi, N.; Rivalland, V.; Jarlan, L.; Er-Raki, S.; Escorihuela, M.J. A Calibration/Disaggregation Coupling Scheme for Retrieving Soil Moisture at High Spatio-Temporal Resolution: Synergy between SMAP Passive Microwave, MODIS/Landsat Optical/Thermal and Sentinel-1 Radar Data. Sensors 2021, 21, 7406. https://doi.org/10.3390/s21217406
Ojha N, Merlin O, Amazirh A, Ouaadi N, Rivalland V, Jarlan L, Er-Raki S, Escorihuela MJ. A Calibration/Disaggregation Coupling Scheme for Retrieving Soil Moisture at High Spatio-Temporal Resolution: Synergy between SMAP Passive Microwave, MODIS/Landsat Optical/Thermal and Sentinel-1 Radar Data. Sensors. 2021; 21(21):7406. https://doi.org/10.3390/s21217406
Chicago/Turabian StyleOjha, Nitu, Olivier Merlin, Abdelhakim Amazirh, Nadia Ouaadi, Vincent Rivalland, Lionel Jarlan, Salah Er-Raki, and Maria Jose Escorihuela. 2021. "A Calibration/Disaggregation Coupling Scheme for Retrieving Soil Moisture at High Spatio-Temporal Resolution: Synergy between SMAP Passive Microwave, MODIS/Landsat Optical/Thermal and Sentinel-1 Radar Data" Sensors 21, no. 21: 7406. https://doi.org/10.3390/s21217406
APA StyleOjha, N., Merlin, O., Amazirh, A., Ouaadi, N., Rivalland, V., Jarlan, L., Er-Raki, S., & Escorihuela, M. J. (2021). A Calibration/Disaggregation Coupling Scheme for Retrieving Soil Moisture at High Spatio-Temporal Resolution: Synergy between SMAP Passive Microwave, MODIS/Landsat Optical/Thermal and Sentinel-1 Radar Data. Sensors, 21(21), 7406. https://doi.org/10.3390/s21217406