High-resolution flood mapping from low-resolution passive microwave data

Author: John F. Galantowicz
November 7, 2002
Geoscience and Remote Sensing Symposium

J. F. Galantowicz, High-resolution flood mapping from low-resolution passive microwave data, Proc. of IGARSS’02, Toronto, Canada, June 24-28, III:1499-1502, 2002.

We have developed a new method for making high-resolution flood extent maps (e.g. at the 30-100 m scale of digital elevation models) in real-time from low-resolution (20-70 km) passive microwave observations. Microwave radiometric measurements are useful for flood monitoring because they sense surface water in clear-or-cloudy conditions and can provide more timely data (e.g. compared to radars) from relatively wide swath widths and an increasing number of available platforms (DMSP, ADEOS-II, Terra, NPOESS). The chief disadvantages for flood mapping are the radiometers' low resolution and the need for local calibration of the relationship between radiances and open-water fraction. We present our method for transforming microwave sensor-scale open water fraction estimates into high-resolution flood extent maps and show several animated examples of the method in action during a retrospective study of the 1993 Great Midwest Flood. The method builds a "flood-potential" database from elevations and historic flood imagery and uses it to create a flood-extent map consistent with the observed open water fraction. We discuss the method's potential improvement through as yet unimplemented algorithm enhancements and expected advancements in microwave radiometry (e.g. improved resolution and atmospheric correction).