A solid decade of ERS-2 observations has helped cement a worldwide community of more than 3000 users. Demand for ERS-2 data is ever increasing, spurred on by the fact that the spacecraft keeps on updating its data archives as it orbits the Earth at more than seven kilometres a second.
When the Asian tsunami struck in December 2004, satellites provided rapid damage mapping. The continued availability of ERS-2 enabled the only change assessment via radar, complementing optical satellite views because radar can see through tropical clouds. A new January 2005 ERS-2 high-resolution radar image of the Nicobar Islands north of Sumatra, near the epicentre of the tsunami, was combined with an archived image acquired in 1992 by sister spacecraft ERS-1.
The resulting multi-temporal composite highlights the stricken state of the islands' west coast. The composite was only possible due to the wide coverage of the 15-year combined ERS archive.
ERS-2 is also regularly utilised for disaster mapping during activations of the International Charter on Space and Major Disasters, which provides space-derived information to emergency responders.
ERS-2 acquisitions for InSAR analysis
The continuing availability of new ERS-2 images along with its archive is proving very useful for a technique called SAR Interferometry or InSAR. Growing in popularity, InSAR involves mathematically combining different radar images of the same spot to create digital elevation models (DEMs) and also revealing otherwise undetectable changes occurring between image acquisitions.
In effect InSAR works like a sophisticated version of 'spot the difference', identifying millimetre-scale ground movement to r
Contact: Mariangela D'Acunto
European Space Agency