Feasibility Study of Paddy Rice Monitoring Using Dual Polarization PALSAR Data

Abstract

This paper describes the feasibility of rice growth monitoring using the Fine Beam Dual polarization (FBD) mode data of Phased Array type L-band Synthetic Aperture Radar onboard Advanced Land Observing Satellite (ALOS/PALSAR). The relationship between the rice parameters acquired by ground truth and those acquired by HH-HV polarimetric correlation coefficients is investigated. The scattering mechanism with air/rice canopy/ground interaction is considered and compared with ground truth measurements. We found that the contribution to backscatter from the paddy rice canopy is larger than that from ground surfaces. The dominant scattering component is double bounce scattering from the interaction between paddy rice and water in the vegetative growth and reproductive growth periods. On the other hand, in the grain filling period it changes to a direct scattering component from paddy rice. The HH/HV correlation coefficient was also examined to confirm the change in the scattering mechanism between the reproductive growth and grain filling periods. Thus, the estimation of optimal harvest timing can be predicted by monitoring the cumulative change rate of the HH/HV polarimetric correlation coefficient.