The MOZAIC programme (Measurement of OZone and water vapour by AIrbus in-service airCraft) was initiated in 1993 by European scientists, aircraft manufacturers and airlines. Its goal is to collect experimental data on atmospheric composition and it is changes under the influence of human activity, with particular interest in the effects of aircraft. In MOZAIC, regular measurements of ozone (O3), water vapour (H2O), carbon monoxide (CO) and nitrogen oxides (NOy) are made by autonomous instruments deployed aboard five long range passenger airliners of the type AIRBUS A340-300. The large database of in-situ measurements collected in the course of MOZAIC allows detailed studies of chemical and physical processes in the atmosphere, and hence to validate global chemistry transport models. MOZAIC data provide detailed climatologies at the cruise altitude of subsonic aircraft between 9 and 12 km. At midlatitudes this region covers the tropopause which is critical for climate change and the exchange between stratosphere and troposphere and still imperfectly described in global models.

Three phases of MOZAIC have been funded by the European Commission from 1994 to February 2004. In the first phase of MOZAIC (1994-1996) automatic devices for measurements of ozone and water vapour were installed on five Airbus A340 operated by Lufthansa, Air France, Austrian and Sabena, who fly the MOZAIC instrumentation free of charge. In the second phase of MOZAIC (1997-2000), ozone and water vapour measurements were continued while new devices for measurements of carbon monoxide (CO) and nitrogen oxides (NOy) were built. In the third phase of MOZAIC (2001-2004), the new devices for CO and NOy were installed onboard the aircraft and the new data were analysed. Since 2004, the MOZAIC programme is provisionally maintained by Laboratoire d’Aérologie in Toulouse, Forschungszentrum Jülich, and Meteo France under a new Memorandum of Understanding between the MOZAIC partners, the airlines and Airbus for continuation of the programme until December 2007. MOZAIC has been recognized by the french organisation INSU/CNRS as an observation service of the Earth’s atmosphere. It is hoped to establish MOZAIC as a longterm sustainable European research infrastructure with enhanced capabilities and geographical coverage through the ongoing Design Study IAGOS (Integration of routine Aircraft measurements into a Global Observing System).