92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Monday, 23 January 2012: 11:45 AM
WRF-Chem Estimates of Lightning NOx and Biomass Burning Contributions to Middle and Upper Tropospheric Ozone Enhancement During the AEROSE II Cruise
Room 342 (New Orleans Convention Center )
Jonathan W. Smith, Howard University, Washington, DC; and G. Jenkins and K. E. Pickering

The AEROSE II observed enhanced ozone mixing ratios in the middle and upper troposphere in the equatorial latitudes of 23W in June 2006. For first order estimates of the contributions (biomass burning, lightning) and transport of ozone precursors to 23W, the WRF-Chem model is used. At this time, there is biomass burning in Angola and the southern Democratic Republic of Congo and deep convection is concentrated along the Virunga Mountains, the Sahel, and the Gulf of Guinea Coast. This separation results in minimal convective transport to the upper troposphere and subsequent low percentage increases of ozone 23W. This relatively small contribution makes ozone production of nitrogen oxides convection in the Sahel very important. To estimate this ozone production, observed lightning flash locations were gridded into WRF-Chem and are proxies for nitrogen oxide. The nitrogen oxide and the ozone they produce are transported to the equatorial region of 23W by easterly flow regimes such as the African Easterly Jet, Tropical Easterly Jet and the counter-clockwise flow around a persistent middle and upper tropospheric ridge over central Africa. The model suggests that percentage increases in ozone at 23W are two to five times greater than those from biomass burning in June 2006.

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