Satellite data collected by orbiting observatories could be used to predict floods well in advance of any potential problems. NASA's orbiting outposts are able to predict which riverbanks are likely to overflow, by studying the gravitational pull of our home planet.
University of California (UC) Irvine researchers examined records from the Missouri River floods which struck the state in 2011. The team looked at data from NASA's Gravity Recovery & Climate Experiment (GRACE), which recorded information on groundwater in the area. They were able to show evidence of flood conditions showing five months before record precipitation set off the catastrophe.
The GRACE mission consists of a pair of satellites launched in March 2002, measuring local changes in the gravitational field of the Earth. By studying these small differences in gravity around the globe, investigators are able to ascertain the geophysical makeup of material under the surface. Areas soaked in water have a greater gravitational pull than regions with less moisture.
Current flood prediction models take rain and some snowfall into account. Using satellite data, researchers will be able to use detailed measurements of underground water into account in these simulations.
"These data can show us when river basins have been filling with water over several months. We're not talking about actual flooding but about the saturation level of the ground and its predisposition to flooding. When it finally rains and the basin is full, there is nowhere else for the water to go," Jay Famiglietti, senior water scientist at Jet Propulsion Laboratory, said.
Flooding in inland areas of the United States causes approximately four billion dollars each year in damage, and takes the lives of an average of 133 Americans. By having a better understanding of the mechanisms of flooding, the team hopes to develop better models of the process, allowing earlier warnings for people in affected areas.
The Missouri River floods lasted for months, fueled by a cool summer, which caused snow pack in the Rockies to melt more slowly than normal. This also played havoc with the schedule of dam releases required by the unusual event.
The GRACE satellites are expected to remain in orbit around the Earth until sometime in 2014 or 2015. The maps they have produced of gravitational variations around the globe are around 1,000 times more detailed than any previous study of its kind.
Study of how satellites can identify areas likely to experience floods was explained in the journal Nature Geoscience.