The octave project aims at substantially improving our appraisal of the global budget of key OVOCs and of their role in tropical regions, relying on an integrated approach combining in situ measurements, satellite retrievals and global modelling. The specific objectives are:

• To generate a 2-year dataset of atmospheric measurements of OVOCs (methanol, acetaldehyde and acetone) and related compounds by mass spectrometry (PTR-MS) and remote sensing infrared spectroscopy (FTIR) at the high-altitude site of Maïdo (2200 m a.s.l.) on Reunion Island, in the Indian Ocean. Campaign measurements will be performed also at a different location in the area between the Maïdo observatory and the coastline.
• To identify and quantify OVOC sources contributing to the measurements at Reunion Island, with the help of multivariate statistical analysis, backtrajectory calculations and 3-dimensional modelling.
• To apply an innovative methodology to generate improved and better characterized global distributions of the column abundances of methanol and other VOCs using multi-annual remote sensing data from the IASI sensor on the MetOp satellite.
• To perform an updated model evaluation of the budget of OVOCs, based on spaceborne data (for CH3OH) and a wide collection of aircraft, ship-based and ground-based measurements, including those obtained at Reunion Island.