Tracing biomass burning plumes from the Southern Hemisphere during the AMMA 2006 wet season experiment C. H. Mari1, G. Cailley2, L. Corre1, M. Saunois1, J. L. Attié1, V. Thouret1, and A. Stohl3 1Université de Toulouse, CNRS/INSU, Laboratoire d'Aérologie, Toulouse, France 2SILOGIC, Toulouse, France 3Norwegian Institute for Air Research, Kjeller, Norway
Abstract. The Lagrangian particle dispersion model FLEXPART coupled with daily active fire products provided by the
MODIS instrument was used to forecast the intrusions of the
southern hemispheric fire plumes in the
Northern Hemisphere during the AMMA
(African Monsoon Multidisciplinary Analysis) fourth airborne campaign
from 25 July to 31 August 2006 (Special Operation Period SOP2_a2).
The imprint of the biomass burning plumes over
the Gulf of Guinea showed a well marked intraseasonal variability
which is controlled by the position and strength of the
southern hemispheric African Easterly Jet (AEJ-S).
Three different periods were identified which correspond to active and
break phases of the AEJ-S: 25 July–2 August (active phase),
3 August–8 August (break phase) and 9 August–31 August (active phase).
During the AEJ-S active phases, the advection of the biomass burning plumes
out over the Atlantic ocean was efficient in the mid-troposphere.
During the AEJ-S break phases, pollutants emitted by fires were trapped
over the continent where they accumulated. The continental circulation
increased the possibility for the biomass burning plumes to reach the
convective regions located further north. As a consequence, biomass burning
plumes were found in the upper troposphere over the Gulf of Guinea
during the AEJ-S break phase.
Observational evidences from the ozonesounding network at Cotonou and the
carbon monoxide measured by MOPITT confirmed the alternation of the
AEJ-S phases with low ozone and CO in the mid-troposphere
over the Gulf of Guinea during the break phase.
Citation: Mari, C. H., Cailley, G., Corre, L., Saunois, M., Attié, J. L., Thouret, V., and Stohl, A.: Tracing biomass burning plumes from the Southern Hemisphere during the AMMA 2006 wet season experiment, Atmos. Chem. Phys., 8, 3951-3961, doi:10.5194/acp-8-3951-2008, 2008.