Monitoring of sulphur dioxide emissions from satellite as part of GSE PROMOTE ============================================================================= Jos van Geffen, Michel Van Roozendael, Isabelle De Smedt, Caroline Fayt (1) Pieter Valks (2) Ronald van der A (3) (1) BIRA-IASB, Brussels, Belgium (2) DLR, Oberpfaffenhofen, Germany (3) KNMI, De Bilt, The Netherlands Sulphur dioxide (SO2) enters the atmosphere as a results of both natural phenomena and anthropogenic activities, such as fossil fuel combustion, oxidation of organic materials in soils, volcanic eruptions and biomass burning. Changes in the abundance of SO2 have an impact on atmospheric chemistry and on the radiation field, and hence on the climate. Effects of volcanic eruptions may have an impact on air traffic, as such eruptions are important sources of ash (aerosols) and SO2. Consequently, global observations of SO2 are important for atmospheric and climate research and for air traffic organisations. Monitoring of SO2 concentrations is done on the basis of UV-Visible measurements by satellite based instruments, such as GOME and SCIAMACHY. In view of the two main sources of SO2, the monitoring is divided in two services: the Volcanic SO2 Service concentrates on regions with volcanoes known to have erupted after 1800, and the Air Quality SO2 Service concentrates on industrialised areas. The data is delivered to users and the public via the web sites of the TEMIS and PROMOTE projects; see http://www.temis.nl/aviabtion/so2.php and http://www.temis.nl/airpollution/so2.php, respectively. These pages provide an archive of SO2 data based SCIAMACHY observations. This archive will be extended further and is intended to include data from other instruments as well. And in view of the possible effects of volcanic eruptions on air traffic, a service is set up to deliver SO2 data in near-real-time, i.e. within about 6 hours after observation. The web site also provides some background and data product information. For the Volcanic SO2 Service there are close contacts with the Volcanic Ash Advisory Centres (VAACs) at Meteo France (Toulouse) and the UK Met Office (Exeter), who are particularly interested in a near-real-time service of SO2 data to aid them in monitoring volcanic eruptions. For the Air Quality SO2 Service the data users are environmental agencies of several countries, who are interested in both the archive and the near-real-time services.