Radarsat data analysis for monitoring and evaluation of irrigation projects in the monsoon

The availability of multi-look angle HH polarization C band SAR data of different swaths and resolutions from Radarsat, in addition to VV polarization C band SAR data from ERS, has raised hopes for separating individual crops and for estimating soil moisture, enabling monitoring and evaluation of irrigation projects even under cloud cover conditions. Under the Radarsat ADRO Project, an attempt was made to identify irrigated crops in the Bhadra project command area, Karnataka state, India, using temporal, multi-look angle and dual polarization C-band SAR data from Radarsat and ERS. Preliminary analysis included data quality evaluation, rectification, speckle suppression and separability comparison of different land use and land cover classes. Evaluation of Radarsat data quality showed consistency in spatial resolution. Radarsat data acquired on different dates in shallow (S7 mode) and steep (S2 mode) angles and concurrent ERS-2 data were processed and analysed for possible discrimination of individual crops. It was observed that Radarsat data showed better separability of land use and land cover classes than ERS data. Principal Component Analysis was used on multi-look angle and dual polarization data from both ERS and Radarsat to reduce data dimensionality and the results were better with the first three components.