Temporal and spatial characteristics of irrigated rice in JERS-1 L-band SAR data

Abstract

Multi-temporal JERS-1 SAR (Japanese Earth Resource Satellite 1 Synthetic Aperture Radar) data have been used in this study to investigate the temporal and spatial characteristics of irrigated rice in LHH-band SAR data. The two test sites chosen represent areas that are characterized by manual and mechanical planting practices that turn out to have a significant effect on the L-band backscatter. The results show a clear relationship between L-band backscatter and plant growth in manually planted areas. A dynamic range of about 8dB has been measured with no apparent saturation of the signal. Areas in which mechanical planting is practiced, however, display a more complex relationship where the radar response is strongly dependent on parameters related to the spatial distribution of the plants. The backscatter displays a strong dependency on planting orientation and plant spacing, where fields planted in the radar illumination direction with a certain plant spacing display extreme dynamic ranges of up to more than 20dB due to resonant scattering. Fields planted in other directions generally experience attenuation of the signal and dynamic ranges do not change by more than a few decibels. Despite these artifacts, however, a correlation between plant growth and backscatter has been observed for all fields, independent of plant spacing and field orientation.