SOFTWARE that can recognise rapidly changing events on the Earth鈥檚 surface from space is set to warn of flash floods, volcanic eruptions and oil spills far more quickly than has been possible until now.
It can take weeks to spot new features in the deluge of data beamed back to Earth from remote-sensing spacecraft. For instance, Europe鈥檚 premier Earth observation satellite, Envisat, generates 140 gigabytes of image data each day. Analysing the images to find new features such as flash floods can take weeks or even months. But that is set to change.
A team of hydrologists led by Felipe Ip, James Dohm and Victor Baker at the University of Arizona in Tucson are developing software that will quickly recognise flood activity. This will allow a spacecraft to keep track of its progress automatically on subsequent orbits and eventually lead to faster flood forecasts.
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They wrote the software after recognising telltale signatures for different types of water on the Earth鈥檚 surface. Clear water, muddy rivers or milky glacial meltwater all reflect distinctive ratios of two particular wavelengths of light in the visible and near infrared, they found. By looking for such patches of water in subsequent images they can see if a river has burst its banks, for instance. Their software continuously compares images captured by the satellite鈥檚 visible and infrared cameras, looking for pixels with the characteristic ratio of the two wavelengths. If the number of such pixels dramatically increases in subsequent images of the same region, the software will generate an alert.
NASA has beamed the software to a computer in its EO-1 satellite, to see whether the floods it highlights tally with floods reported on the ground.
Meanwhile, a team led by Ashley Davies at NASA鈥檚 Jet Propulsion Lab in Pasadena, California, is seeking similar unique spectral signatures that will let satellites predict volcanic eruptions. Eventually, it hopes to design spacecraft that capture fleeting events on distant planets and moons, where mission controllers currently face frustrating time delays after issuing instructions.
鈥淭hink of volcanic eruptions on Jupiter鈥檚 moon Io, dust storms on Mars, or the possibility of water springs there,鈥� says Dohm. 鈥淭o be able to home in on these things in real time would be fabulous.鈥�
