Description | C-band polarimetric synthetic aperture radar (PolSAR) data has been previously explored
for estimating the leaf area index (LAI) of rice. Although the rice-growing cycle was partially covered in
most of the studies, details for each phenological phase need to be further characterized. Additionally,
the selection and exploration of polarimetric parameters are not comprehensive. This study evaluates
the potential of a set of polarimetric parameters derived from multi-temporal RADARSAT-2 datasets
for rice LAI estimation. The relationships of rice LAI with backscattering coefficients and polarimetric
decomposition parameters have been examined in a complete phenological cycle. Most polarimetric
parameters had weak relationships (R2 < 0.30) with LAI at the transplanting, reproductive, and
maturity phase. Stronger relationships (R2 > 0.50) were observed at the vegetative phase. HV/VV
and RVIFD had significant relationships (R2 > 0.80) with rice LAI for the whole growth period. They
were utilized to develop empirical models. The best LAI inversion performance (RMSE = 0.81)
was obtained when RVIFD was used. The acceptable error demonstrated the possibility to use the
decomposition parameters for rice LAI estimation. The HV/VV-based model had a slightly lower
estimation accuracy (RMSE = 1.29) but can be a practical alternative considering the wide availability
of dual-polarized datasets. | en_US |