A comparative evaluation of multiband radar for detecting and mapping wetland inundation

The aim of this paper is to compare radar backscatter response from imaging SAR systems operating in C-, L- and P-band wavelengths over wetland environments found in the Kakadu World Heritage Region, Northern Territory, Australia. Determining the spatial pattern of inundation in monsoonally domination wetlands and the sequence of floodplain drying is an important first step to understanding the hydrologic, geomorphic and ecological processes operating in these landscapes. SIR-C data acquired in 1994 and AIRSAR multiband imagery obtained over the study site in October 1993 and again in November 1996 were available for analysis along with MOMS-2P optical data. Radarsat imagery was acquired on a near monthly basis during 1998 for the study site. The data were calibrated, geo-referenced and overlain in order to determined water boundaries and to map the pattern of receding water levels. Both Standard Beam 4 and ScanSAR data has been analysis to evaluate the usefulness of C-band horizontally polarised data for wetland mapping. The identification of saturated condition under open canopies commonly found in Australian monsoonal forests can be demonstrated at all three wavelengths. Significantly multirate radarsat imagery proved used in detecting the distribution and extent of water under trees in all seasonal conditions; in mapping the pattern of floodwater recession and in assessing the drying out phases observed in this wetland environment.