Users of the data from SACSThe Volcanic Ash Advisory Centres (VAACs) are the official organisations charged with gathering information on the presence and motion of volcanic clouds and to assess the hazard to aviation. On the basis of this they issue advices and warnings to airline and air traffic control organisations on the possible danger of volcanic clouds.
The nine VAACs are part of an international system set up by the International Civil Aviation Organization (ICAO) called the International Airways Volcano Watch (IAVW), and they were founded at an ICAO meeting in 1995. The IAVW was set up in the early 1980s in response to a number of serious incidents in which jet transport aircraft had encountered volcanic ash in flight and lost power on one or more engines.
VAAC responsibilities to aviation users include to utilise satellite data, pilot reports, and other sources of information to detect and track ash clouds, and to use trajectory and dispersion models to forecast the motion of ash plumes.
Satellite observations of SO2 can assist the VAACs in their tasks, though SO2 is not officially part of the VAAC responsibilities: SO2 measurements can help pinpoint the presence of volcanic ash clouds, in particular during the first few days after an eruption. In general the ash will drop due to gravity effects faster than the SO2, so that some distance away from the volcano the ash and SO2 clouds may be separated.
The core users of the SACS data are the Toulouse VAAC (located at Meteo France) and London VAAC (located at the UK Met Office), who cover Europe and Africa. But the Service is not restricted to Europe and Africa: it covers the whole world.
Other users of the Service are organisations responsible for monitoring volcanic activity and for public safety, researchers, etc. Anyone interested in the Service can subscribe to the email notification service