Temporal Monitoring of SAR Polarimetric Parameters and Scattering Mechanism for Major Kharif Crops and Surrounding Land Use

Spatial and temporal monitoring of agricultural crop is one of the important aspects for the agricultural production estimation for India. Among the various remote sensing tools, role of polarimetric SAR is being evaluated for the assessment of its utility in providing improved information. In view of importance of polarimetric techniques, it is necessary to understand the role of polarimetric indices and decomposition techniques for improved identification and discrimination of different land cover classes. An attempt has been made to study temporal changes in polarimetric parameters and decomposition algorithm for monitoring landuse classes dominated by agricultural land using full polarimetric C-band radarsat-2 data set. Various polarimetric parameters like Radar Vegetation Index, polarimetric decomposition techniques like Freeman Durden, and Pauli Decomposition have been used to evaluate the capability of multi polarimetric and multi temporal SAR for landuse identification, discrimination and classification. Along with the above work, sub classification of RVI values and scattering behavior of the major Kharif crops and other land targets has been done. Temporal change in mean RVI value from 0.48 to 0.66 allowed to demarcate the aerial extent of agriculture/ vegetation cover. Based on the crop growth cycle during Kharif season, a very clear change in RVI value range from 0.4-0.6to 0.8-1.5 was noticed during crop growth. Cotton, Paddy and Gwar could be well discriminated based on change in RVI values with respect to their growth cycle. Freeman Durden Decomposition was found to have overall higher classification accuracy of 95%, followed by Pauli Decomposition (90%) and RVI parameter (49%). Temporally, in all cases, highest classification accuracy was obtained for three date data of July, August and September months.