Seasonal change in the extent of inundation on floodplains detected by JERS-1 Synthetic Aperture Radar data

Abstract

Two sets of JERS-1 (Japanese Earth Resource Satellite–1) Synthetic Aperture Radar (SAR) data, coupled with ancillary datasets, were analysed in an effort to find a single algorithm to study the extent of inundation and its variation on floodplains at a regional scale. The SAR data were acquired on 14 January, 1993 and 9 August, 1994. The study area was ca 14 212 km², covering the lower portions of the Cape Fear, Lumber, Little Pee Dee and Waccamaw river basins within the states of North Carolina and South Carolina, USA. The analysis was based on the decision tree classification that classifies the study area into three aquatic categories, water, marsh and flooded forest, and two upland classes, field and non-flooded forest. From January 1993 to August 1994, the aquatic extent varied from 4872 km² to 3496 km², and upland 9340 km² to 10 717 km². The decrease of the water, marsh and flooded forest categories and the increase of the field and non-flooded forest classes were mainly caused by falls in water surface heights and discharges of the rivers and their tributaries from January 1993 to August 1994. The overall classification accuracy was near to 90%. The search for the single algorithm ended with promising results and also prompted additional research.

Acknowledgments

The author thanks two anonymous reviewers whose comments have greatly improved the quality of the paper. The JERS-1 SAR data were provided by NASDA through a grant to the Center for Geographic Information Science, East Carolina University.