Impacts of 2006 Indonesian fires and dynamics on tropical upper tropospheric carbon monoxide and ozone L. Zhang1,2, Q. B. Li1,2, J. Jin3, H. Liu4, N. Livesey3, J. H. Jiang3, Y. Mao1,2, D. Chen1,2, M. Luo3, and Y. Chen5 1Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA 2Joint Institute for Regional Earth System Science and Engineering, University of California, Los Angeles, CA, USA 3Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA 4National Institute of Aerospace, Hampton, VA, USA 5Department of Earth System Science, University of California, Irvine, CA 92697, USA
Abstract. We investigate the relative impacts of biomass burning
emissions and dynamics on tropical upper tropospheric carbon monoxide (CO)
and ozone (O3) over western and central Indonesia during the
August–November 2006 fires in equatorial Asia by using a global
three-dimensional model of tropospheric chemistry (GEOS-Chem) and by
comparing model results with Microwave Limb Sounder (MLS) observations of
upper tropospheric CO and O3. GEOS-Chem CO and O3 show
similarities with MLS observed enhancements from convective lifting of fire
emissions. In the tropical upper troposphere (UT), fire effluents from
equatorial Asia are primarily transported southwestward to the eastern
tropical Indian Ocean, driven by the high-pressure systems along
10° N–15° N and 10° S–15° S latitudes, and northeastward to southeast
Asia and beyond, driven by the western North Pacific subtropical high. A
characteristic feature of these CO enhancements is that they lag behind
biomass burning emissions (by 2–3 weeks) at the three pressure levels 215,
147 and 100 hPa, resulting from the decreasing influence of deep convective
lifting with altitude in the tropical UT. Inclusion of biomass burning
injection height significantly improves model comparison with observations.
We estimate the fire influences by contrasting one model simulation with
year-specific and another with climatological biomass burning emissions.
Biomass burning accounts for about 50–150 ppbv of CO and 5–15 ppbv of
O3 in the tropical UT below 100 hPa during October and November, with
temporal variations driven by biomass burning and deep convection. We
estimate the dynamic impacts by examining the difference between a model
simulation for 2006 (El Niño) and another for 2005 (neutral). The
dynamic impacts are far more complex and account for up to 100 ppbv of CO
and 30 ppbv of O3 in the tropical UT below 100 hPa. The temporal
variation of the dynamic impact on CO is driven by deep convection. The
variation of the dynamic impact on O3 depends on deep convection as
well as the associated lightning NOx emissions and also reflects
non-linearity of O3 chemistry.
Citation: Zhang, L., Li, Q. B., Jin, J., Liu, H., Livesey, N., Jiang, J. H., Mao, Y., Chen, D., Luo, M., and Chen, Y.: Impacts of 2006 Indonesian fires and dynamics on tropical upper tropospheric carbon monoxide and ozone, Atmos. Chem. Phys., 11, 10929-10946, doi:10.5194/acp-11-10929-2011, 2011.