Coupling radar data and rice growth model for yield estimation

The objective of this paper is to assess the use of satellite radar data to estimate rice yield. The approach consists in combining the information retrieved from radar data with a rice crop growth model to predict the final yield. Data acquired by different spaceborne radar systems have been evaluated in terms of their ability to provide rice crop parameters. The radar backscattering coefficient at C-band (5.3 GHz) measured by ERS, and to a lesser extent, RADARSAT, have been proven to be related to rice plant age, height and biomass. The rice growth model ORYZA1 was used to simulate rice growth with sowing date and biomass values retrieved from ERS and RADARSAT SAR data as input parameters. Test sites in both tropical and temperate regions were selected to develop the methodology. The simulated yields were found to lie within 10% from in-situ measured yield when ERS data were used and 15% with RADARSAT data. These results appear very promising for rice yield estimation. The work needs to be extended to a wide range of environmental conditions in order to estimate the method robustness