The Global Flood Detection System

A methodology for satellite based flood detection developed (Brakenridge et al, 2007) at Dartmouth Flood Observatory (DFO) was modified at the Joint Research Centre (JRC) of the European Commission and implemented on an automatic operational basis. The technique uses AMSR-E passive
microwave remote sensing data of the descending orbit, H polarization, 36 GHz band which is sensitive to water surface changes. The sensor revisits every place on Earth once per day and can therefore provide a daily temporal resolution. Sensor data is available 24 hours after acquisition.
Thresholding the signal of water surface change allows the detection of riverine inundation events. The comparison of gauging and satellite measurements show a significant correlation in the increase of river discharge on-site and changes in the observed signal of the sensor. Thus the technique for the detection of flood events in ungauged and inaccessible remote river channels is feasible from space. A procedure chain was developed at the JRC to automatically acquire and process the remotely sensed data in real time on an operational basis. After the validation of the satellite based Global Flood Detection System (GFDS) the remotely observed flood events are to be integrated into the Global Disaster Alert and Coordination System (www.gdacs.org/floods) including the estimation of its humanitarian impact. GDACS is running at the JRC providing near real-time alerts about humanitarian and natural disasters around the world and tools to facilitate response coordination, including news and maps.