Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 6 3 2006 10.5194/acpd-6-3945-2006 http://www.atmos-chem-phys-discuss.net/6/3945/2006/ http://www.atmos-chem-phys-discuss.net/6/3945/2006/acpd-6-3945-2006.html http://www.atmos-chem-phys-discuss.net/6/3945/2006/acpd-6-3945-2006.pdf 3945 3963 2006-05-18 First space-borne measurements of methanol inside aged tropical biomass burning plumes using the ACE-FTS instrument G. Dufour C. D. Boone C. P. Rinsland P. F. Bernath Laboratoire de Météorologie Dynamique/Institut Pierre Simon Laplace, Palaiseau, France Department of Chemistry, University of Waterloo, Ontario, Canada NASA Langley Research Center, Hampton, VA, USA First measurements from space of upper tropospheric and lower stratospheric methanol profiles within aged fire plumes are reported. Elevated levels of methanol at 0–45° S from 30 September to 3 November 2004 have been measured by the high resolution infrared spectrometer ACE-FTS onboard the SCISAT satellite. Methanol volume mixing ratios higher than 4000 pptv are detected and are strongly correlated with other fire products such as CO, C₂H₆, and HCN. A sensitivity study of the methanol retrieval, accounting for random and systematic contributions, shows that the retrieved methanol profile is reliable from 8.5 to 16.5 km, with an accuracy of about 20% for measurements inside polluted air masses. The upper tropospheric enhancement ratio of methanol with respect to CO is estimated from the correlation plot between methanol and CO for aged tropical biomass burning plumes. This ratio is in good agreement with the ratio measured in the free troposphere (up to 12 km) by recent aircraft studies and does not suggest any secondary production of methanol by oxidation in aged biomass burning plumes.