Tropical Tropospheric Ozone and Smoke Interactions: Satellite Observations During the 1997 Indonesian Fires

Biomass burning generates hydrocarbons, nitrogen oxides and carbon monoxide that lead to tropospheric ozone pollution. Other combustion products form soot and various aerosol particles that make up smoke. Since early 1997 smoke and tropospheric ozone have been monitored in real-time from TOMS (Total Ozone Mapping Spectrometer) at toms.gsfc.nasa.gov (smoke aerosol) and metosrv2.umd.edu/-tropo (tropospheric ozone). The striking increase in smoke and tropospheric ozone observed during the 1997 Indonesian fires was the first extreme episode observed. During the August-November period, plumes of excess ozone and smoke coincided at times but were decoupled at other times, a phenomenon followed with trajectories. Thus, trans-boundary evolution of smoke and ozone differed greatly. The second discovery of the 1997 TOMS record was a dynamical interaction of ozone with the strong El Nino Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) that led to a jump in tropospheric ozone in March 1997 over the entire Indian Ocean, well ahead of the intense burning period. A climatology of smoke and tropospheric ozone from a 1980's TOMS instrument shows offsets in the timing of these pollutants - further evidence that factors other than biomass burning exert a strong influence on tropical tropospheric ozone.