BIOMASS BURNING AND DEEP CONVECTION IN SOUTHEASTERN ASIA - RESULTS FROM ASHOE MAESA/

There was extensive biomass burning in Indonesia, northern Australia, and New Guinea during September and October 1994. This paper discusses two accidental encounters of biomass plumes from the 1994 Airborne So uthern Hemisphere Ozone Experiment and Measurements for Assessing the Effects of Stratospheric Aircraft campaign (ASHOE/MAESA). During the O ctober 23 descent into Fiji, and an ascent from Fiji on October 24, th e NASA ER-2 passed through layers highly enhanced in NO, NOy, CO, and O-3. These layers occurred near an altitude of 15 km. Back trajectorie s and satellite images indicate that the layers probably originated as outflow from a convective disturbance near New Guinea. The measuremen ts indicate that deep convection can inject emissions from southeast A sian biomass burning to near tropical tropopause altitudes. Deep conve ction magnifies the impact of biomass burning on tropospheric chemistr y because of the much longer residence times and chemical lifetimes of species in the upper tropical troposphere. Transport of the products of southeast Asian biomass burning into the upper tropical troposphere , followed by southward high-level outflow and advection by the subtro pical jet, may play a significant role in dispersing these emissions o n a global scale. Anthropogenic emissions from countries in southeast Asia are likely to increase in the future as these countries become mo re highly industrialized. This transport mechanism may play a role in increasing the impact of these types of emissions as well.