MIPAS measurements of upper tropospheric C2H6 and O3 during the southern hemispheric biomass burning season in 2003 T. von Clarmann1, N. Glatthor1, M. E. Koukouli2, G. P. Stiller1, B. Funke3, U. Grabowski1, M. Höpfner1, S. Kellmann1, A. Linden1, M. Milz1,*, T. Steck1,**, and H. Fischer1 1Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe, Germany 2Laboratory of Atmospheric Physics, Physics Department, Aristotle University of Thessaloniki, Thessaloniki, Greece. 3Instituto de Astrofísica de Andalucía CSIC, Granada, Spain *now at: Institutionen för Rymdvetenskap, Luleå Tekniska Universitet, Kiruna, Sweden **now at: Kepler Gymnasium, Ulm, Germany
Abstract. Under cloud free conditions, the Michelson Interferometer
for Passive Atmospheric Sounding (MIPAS) provides measurements
of spectrally resolved limb radiances down to the upper troposphere.
These are used to infer global distributions of mixing ratios of
atmospheric constituents in the upper troposphere and the stratosphere.
From 21 October to 12 November 2003, MIPAS observed enhanced
amounts of upper tropospheric C2H6 (up to about 400 pptv)
and ozone (up to about 80 ppbv). The absolute values of C2H6,
however, may be systematically low by about 30% due to uncertainties
of the spectroscopic data used. By means of trajectory
calculations, the enhancements observed in the southern hemisphere
are, at least partly, attributed to a biomass burning plume, which
covers wide parts of the Southern hemisphere, from South America,
the Atlantic Ocean, Africa, the Indian Ocean to Australia.
The chemical composition of the part of the plume-like pollution
belt associated with South American fires, where rainforest burning
is predominant appears different from the part of the plume associated
with southern African savanna burning. In particular, African savanna
fires lead to a larger ozone enhancement than equatorial American
fires. In this analysis, MIPAS observations of high ozone were
disregarded where low CFC-11 (below 245 pptv) was observed, because
this hints at a stratospheric component in the measured signal.
Different type of vegetation burning (flaming versus smouldering
combustion) has been identified as a candidate explanation for the different plume compositions.
Citation: von Clarmann, T., Glatthor, N., Koukouli, M. E., Stiller, G. P., Funke, B., Grabowski, U., Höpfner, M., Kellmann, S., Linden, A., Milz, M., Steck, T., and Fischer, H.: MIPAS measurements of upper tropospheric C2H6 and O3 during the southern hemispheric biomass burning season in 2003, Atmos. Chem. Phys., 7, 5861-5872, doi:10.5194/acp-7-5861-2007, 2007.