FREQUENCY-DEPENDENCE OF POLARIZATION PHASE DIFFERENCE

Polarimetric AIRSAR data of 13 July 1990 acquired over Mahantango wate rshed area were processed for the identification of cornfields and for ested areas. Polarization Phase Difference (PPD) values were computed for the cornfields at P-, L- and C- bands and studied as a function of frequency. The results compare well with the model calculations at 24 degrees incidence angle, whereas the locations of cornfields were com puted to be at 35 degrees incidence angle. The discrepancy is attribut ed to a lack of accurate ground truth and the undulating topography of the cornfields. Another study reported here deals with the usefulness of the Polarization Index (PI) for the study of vegetation. PI was fo und to be dependent on the frequency for the cornfields, whereas for f orest trees no such dependence was noticed. PIHH,HV is a more useful p arameter than PIHH,VV even for the study of cornfields.