Estimation of Rice Growth Parameter and Crop Phenology with Conjunctive Use of Radarsat and Envisat

This paper assesses the synergy of RADARSAT and ENVISAT data for rice monitoring. Crop growth profile derived from the analysis of temporal backscatter of RADARSAT SCNB (July-August) and ENVISAT of IS4 and IS5 (September-November) enables to classify early, normal and late sown crop with 10-12 dB difference throughout the growth cycle. An inversion algorithm relating backscatter and plant height was used to retrieve transplantation date whereas the peak vegetative stage was retrieved from peak backscatter value of the temporal profile. Good correlation was observed between backscatter and crop growth parameters obtained from field measurements. Linear relation between polarization ratio (HV/HH) and fresh biomass indicated that even though ENVISAT data were acquired during vegetative stage, rice biomass could be retrieved with less uncertainty. Rice map was generated using decision rule algorithm with 94.8% accuracy. The results appear promising and increase the possibility of acquiring higher temporal data for rice crop research.