Research scientist Christian Frankenberg of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, first noticed the Four Corners signal years ago in SCIAMACHY
Dr Michael Buchwitz and Oliver Schneising from the Institute of Environmental Physics at the University of Bremen in Germany processed the SCIAMACHY
data from 2003-09, using a retrieval algorithm developed at the University of Bremen.
The following day, scientists from the Brussels-based Belgian Institute for Space Aeronomy identified high bromine concentrations in the vicinity of the volcano with Envisat's SCIAMACHY
instrument and the Global Ozone Monitoring Experiment-2 (GOME-2) instrument aboard MetOp-A.