Analysis on temporal behaviour of rice backscatter based on ENVISAT ASAR images

Combined with field experiments of rice in Lixiahe region of Jiangsu Province in 2004 and 2006, temporal behavior of rice backscatter was analyzed based on multi-polarization advanced synthetic aperture radar(ASAR)data with incidence angle of 23o, together with the analysis of relationships between rice backscatter coefficient and rice growth parameters such as leaf area index, fresh biomass, and plant height×plant water content, for the further work on rice parameter inversion and research of rice backscatter physical mechanism. Meanwhile, temporal behavior of σ°HH/VV and relationships between σ°HH/VV and rice parameters were also analyzed. As a result, VV and HH backscatter before rice heading stage showed quite different temporal behavior from those after rice heading stage. σ°HH/VV increased with rice growth, and then decreased at ripening stage that indicated the noticeable difference between VV and HH backscatter in the whole rice cycle. The correlation coefficients of rice backscatter coefficient of VV and HH polarization and the chosen rice growth parameters all reached above 0.75, however, the correlation coefficient was above 0.9 between rice backscatter coefficient of VV and HH polarization and rice fresh biomass. Otherwise, the strong relationship between σ°HH/VV and rice growth parameters is observed in the paper with correlation coefficients of above 0.85, which shows that σ°HH/VV can be considered as a new variable in rice parameter inversion based on multi-polarization radar data.