Use of Landsat Thermal‐IR Data and GIS in Soil Moisture Assessment

Abstract

Landsat satellite Thematic Mapper (TM) data were explored as an alternative for monitoring regional soil moisture conditions. The theoretical method of using single daily temperature data sets to estimate root zone soil moisture was tested with ground‐based observations. Results indicated that the percentage gravimetric soil moisture content in the 0–24‐cm depth was inversely related to the soil surface temperature. A demonstration of Landsat‐TM based soil moisture estimation was performed for Lee County in southwestern Florida. The thermal‐infrared (IR) data from TM band 6 were overlain onto four principal land‐use categories (agricultural/irrigated, urban/clearings, forest/wetlands, water) using a geographic information system (GIS). The thermal‐IR data were used to assess four qualitative soil moisture conditions (water/very wet, wet, moist, and dry) within each land‐use category. Integration of Landsat thermal‐IR data with land‐use through GIS under certain conditions may be a useful technique for assessing regional soil moisture conditions, and further research to refine and quantify this technique is recommended.