期刊
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
卷 15, 期 -, 页码 4072-4092出版社
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
DOI: 10.1109/JSTARS.2022.3165644
关键词
Soil; Land surface temperature; Soil moisture; Land surface; Hydraulic systems; Vegetation mapping; Spatial resolution; Agriculture; hydrology; microwave remote sensing; soil moisture active passive (SMAP); soil moisture
类别
资金
- NASA Applied Sciences and Terrestrial Hydrology programs
A thermal hydraulic disaggregation of soil moisture (THySM) algorithm was implemented to downscale NASA's soil moisture active passive (SMAP) enhanced soil moisture (SM) product to 1 km. Combining thermal inertia theory and a soil hydraulic-based approach, the algorithm considers fine-scale SM spatial distribution driven by both heat fluxes and hydraulic conductivity. The algorithm's accuracy was evaluated using in situ SM measurements and showed higher accuracy than the SMAP/Sentinel-1 1 km SM product.
A thermal hydraulic disaggregation of soil moisture (THySM) algorithm was implemented to downscale NASA's soil moisture active passive (SMAP) enhanced soil moisture (SM) product to 1 km over the continental United States (CONUS). This algorithm was developed by combining thermal inertia theory with a soil hydraulic-based approach that considers fine-scale SM spatial distribution driven by both heat fluxes and hydraulic conductivity in soils. Relative soil wetness values were estimated using land surface temperature and normalized difference vegetation index for the thermal inertia model and using soil properties for the hydraulic model. The relative soil wetness values at 1 km from both models were then combined by using weighting functions whereby the spatial distribution of SM was governed more by thermal fluxes during times of strong heat transport and infiltration during moisture abundant soil conditions. THySM values were evaluated using in situ SM measurements from SMAP Core Validation Sites (CVS), the US Department of Agriculture Soil Climate Analysis Network, and the National Oceanic and Atmospheric Administration Climate Reference Network over CONUS. THySM shows higher accuracy than the SMAP / Sentinel-1 (SPL2SMAP_S) 1 km SM product when compared to in situ measurements. The accuracy of THySM is 0.048 m(3)/m(3) based on unbiased root mean square error (ubRMSE), outperforming SPL2SMAP_S by 0.01-0.02 m(3)/m(3). The ubRMSE of THySM 1 km SM over the SMAP grassland/rangeland-dominated CVS sites is better than 0.04 m(3)/m(3), which meets the SMAP mission SM accuracy requirement applied at 9 and 36 km.
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