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 restrictive by cloud-free quality imagery while microwave radar has not been fully explored to inferring crop conditions. In this study, an optical/radar synergy is developed to examine its potential for extracting soil and plant information. The synergy employs a microwave scattering model developed by Karam et al. (1992) but modified due to 1) taking into account underneath soil backscattering properties and 2) using optical remote sensing as direct input variables to the model. The synergistic method is 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 include the 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 apply such synergy for site-specific agricultural management practices.