1Department of Chemistry, University of York, York, UK
2Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada
3NASA Jet Propulsion Laboratory, California Inst. of Technology, Pasadena, California, USA
*also at: New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA
Abstract. We present the first near global upper tropospheric distribution of formic acid (HCOOH) observed from the space using solar occultation measurements from the Fourier transform spectrometer (FTS) on board the Atmospheric Chemistry Experiment (ACE) satellite. Using a new set of spectroscopic line parameters recently published for formic acid, we have retrieved the concentrations of HCOOH between 5 km and the tropopause for ACE-FTS observations from February 2004 to September 2007. We observe a significant seasonal dependence for the HCOOH concentrations related to vegetation growth and biomass burning. We estimate an emission ratio of 0.0051±0.0015 for HCOOH relative to CO for tropical South American fires using a selected set of data for September 2004. Results from the balloon-borne MkIV Fourier transform spectrometer are also presented and used to validate the ACE measurements.