My OEFS course project was an attempt to find an indicator for soil moisture using a radiation or heat budget analysis. The inputs were a subset of a Landsat TM scene, a digital elevation model, and temperature and humidity atmospheric soundings for a nearby vertical profile. Over 25 layers were computed using ENVI band math and the results were fed into a simple radiation balance equation to obtain a product that shows latent heat of evaporation, a scaled version of evaporation. This product was found to correlate strongly with NDVI, rather than soil moisture.
This current project will continue the previous research, looking for satellite-based environmental variables that provide information on soil moisture.