Faraday rotation correction and total electron content estimation using ALOS-2/PALSAR-2 full polarimetric SAR data

摘要

The properties of ionosphere govern the way in which radar signals traverse, predominantly at the L-band and lower frequencies. The interaction of ions with the traversing radar signal cause rotation of polarization vector, commonly called as Faraday rotation (FR). For a well calibrated monostatic radar, the backscatter measurement reciprocity is disrupted due to FR and other system parameters, like system noise. With the knowledge of full polarimetric ALOS-2/PALSAR-2 data available, FR estimation and compensation is described in this study over Mumbai, India. T4 coherency matrix based estimated Faraday rotation angle is applied to correct PALSAR data. The work is extended to calculate total electron content (TEC) and compare the Y4R and G4U scattering power decompositions. The mean two way FR values of 8.47° was observed with the mean TEC over Mumbai calculated to be 7.069 TECU. Scattering powers results show a significant increase in the double bounce powers over the region.