A model to compute soil moisture was developed using the ESTAR (Electronically Steered Thin Arrary Radiometer) microwave radiometer. The radiometer is able to sense changes in the temperature of the soil (Brightness Temperature, or TB). Data were collected for eight days during June 1992 over the Little Washita Watershed, Oklahoma.
| Step 1: Eobs=TB/Ts | Normalize TB using deep soil temperature |
| Step 2: Esur=1+(Eobs-1)exp(2bWv) | Remove vegetation effects using estimate of vegetation water content (Wv) derived from land use and NDVI |
| Step 3: Esoil=1+(Esur-1)exp(h) | Remove surface roughness effects using estimate of rms height (h) - minor effect |
| Step 4: k=((1-Esoil)exp (0.5)-1)/((1-Esoil) exp (0.5)+1))exp(2) | Compute soil dielectric constant (k) |
| Step 5: Soil moisture = f(k, soil texture) | Compute soil moisture using a dielectric mixing model and soil texture |
Contact: Dr. Tom Jackson tjackson@hydrolab.arsusda.gov
Model Input imagery: ESTAR TB and
Soil Texture, Land Cover, NDVI Model results: Soil Moisture Maps
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