Synergy of optical and radar remote sensing in agricultural applications

Ability to estimate crop information from remotely sensed imagery is fundamental in precision agriculture. Traditional approach using optical remote sensing is often limited by cloud-free quality imagery while microwave radar has not been fully explored to infer crop conditions. There is a need to develop an alternative to infer crop information that overcomes these limitations. In this study, an optical/radar synergy was developed and used to examine its potential for extracting soil and plant information. The synergy uses a microwave scattering model developed by Karam and his colleagues but modified to (1) take into account underneath soil backscattering properties and (2) use optical remote sensing as direct input variables to the model. The synergistic method was applied to two data sets from Maricopa Agricultural Center, Maricopa, Arizona, and the experimental fields of the National Institute for Agro-Environmental Sciences, Tsukuba, Japan. The data sets included images from Landsat and ERS satellites as well as some ground based soil and plant measurements. The preliminary results indicate that radar imagery can be effectively integrated with optical imagery for extracting both soil and plant information. There exist potentials to use such synergy for site-specific agricultural management practices.