First global observation of organic compounds from the IASI infrared sounder
Federico Karagulian(1), Razavi Ariane(1), Clarisse Lieven(1), Hurtmans Daniel(1), Clerbaux Cathy(2) and Coheur Pierre-François(1)
(1) Univeristé Libre de Bruxelles (ULB), CP160/09, avenue F.D. Roosevelt 50, 1050 Brussels, Belgium
(2) UPMC Univ Paris 06, CNRS UMR8190, 4 place Jussieu, 75005 Paris, France
The Infrared Atmospheric Sounding Interferometer instrument (IASI), on board of the MetOP satellite, provides excellent spatial sampling and coverage using a nadir-like geometry. Satellite data allow the measurement of large number of key- tropospheric trace gases, including short-lived organic compounds.
Among the biogenic and anthropogenic organic pollutants, the small oxygenated species formic acid (HCOOH) and methanol (CH3OH) play an important role in the chemistry of the troposphere, through their connection with the ozone cycles and their significant influence on the oxidative capacity of the atmosphere given their oxidation with the OH radical. However, there is still considerable uncertainty in the sources and sinks of these two gases and at this time, only few measurements from space has already been performed. In this work we stress out the reliability of the IASI measurements to provide large-scale observations of formic acid and methanol using brightness temperature differences. The choice of the most suitable spectral features in the IASI spectra for the identification of HCOOH and CH3OH is discussed. In addition, preliminary retrievals of their concentrations are presented. Local to global scale analyses are performed, with emphasis on the identification of sources and transport pathways
In order to follow the seasonal variation of the emission sources, global monthly observations were carried out and these will be presented for a period of somewhat less than one year.