The Optical Trapezoid Model (OPTRAM)-based soil moisture estimation using Landsat 8 data

Soil moisture is an important factor that can be used for referring to flood situations, monitoring drought estimation, and changes in the environment such as storms and soil erosion. The Optical Trapezoid Model (OPTRAM) estimates surface soil moisture using shortwave infrared transformed reflectance (STR) and the Normalised Difference Vegetation Index (NDVI) in trapezoidal space. In this study, Landsat 8 satellite data were acquired for May (2019) and October (2019) and used for analysis in the Narmadapuram district of Madhya Pradesh, India. Validation of the retrieved soil moisture was done using microwave satellite data available on the VEDAS portal. The output maps show that soil moisture values vary from 0.0235 (m(3)/m(3)) to 0.162 (m(3)/m(3)) for May 2019 and from 0.417 to 0.781 (m(3)/m(3)) for October 2019. The data obtained from the VEDAS portal has the average change in soil moisture values in May and October 2019 as 0.04 m(3)/m(3) and 0.55 m(3)/m(3), respectively. The outcome of the study shows that the model has nearly the same accuracy as the VEDAS (Visualisation of Earth Observation Data and Archival System) portal data.