HR: 14:55h
AN: A13H-05    [Abstracts]
TI: Understanding Elevated Tropical Tropospheric Ozone and CO During the 2006 El Niño using TES Observations and GEOS-Chem Simulations
AU: * Nassar, R
EM: ray@io.harvard.edu
AF: Harvard University, Pierce Hall, 29 Oxford St., Cambridge, MA 02138, United States
AU: Logan, J A
EM: jal@io.harvard.edu
AF: Harvard University, Pierce Hall, 29 Oxford St., Cambridge, MA 02138, United States
AU: Zhang, L
EM: lzh@io.harvard.edu
AF: Harvard University, Pierce Hall, 29 Oxford St., Cambridge, MA 02138, United States
AU: Murray, L T
EM: ltm@io.harvard.edu
AF: Harvard University, Pierce Hall, 29 Oxford St., Cambridge, MA 02138, United States
AU: Megretskaia, I A
EM: iam@harvard.edu
AF: Harvard University, Pierce Hall, 29 Oxford St., Cambridge, MA 02138, United States
AU: Team, T
EM: @
AB: The moderate El Niño in 2006 resulted in changes in tropical trace gas mixing ratios measured by the Tropospheric Emission Spectrometer (TES). We investigate the mechanisms for these changes through simulations using the chemical transport model GEOS-Chem, comparing 2006 TES data with 2005 (a neutral year with respect to Pacific sea surface temperatures in the region defining El Niño or La Niña). The most prominent tropospheric changes during 2006 in both TES and GEOS-Chem data were elevated levels of ozone and CO over Indonesia and the eastern Indian Ocean. During October to December 2006, ozone and CO exceeded the previous year's values by more than 30 ppb and 80 ppb, respectively. The elevated CO can be traced to increased biomass burning in Indonesia during the dry El Niño conditions. The elevated ozone can only be adequately modeled by satisfactorily accounting for multiple factors such as transport, convection, fire emissions and lightning NO_x. Overall, GEOS-Chem does a reasonable job of simulating the major ozone and CO features and inter-annual anomalies in the TES measurements. To further understand the importance of the factors contributing to elevated ozone, we test the sensitivity of the ozone anomaly to changes in fire emissions and lightning NO_x.
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
DE: 0394 Instruments and techniques
DE: 3324 Lightning
DE: 3333 Model calibration (1846)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting