Understanding interannual variations of biomass burning from Peninsular Southeast Asia, part II: Variability and different influences in lower and higher atmosphere levels
A synthetic study including model, ground observation, sounding profiles, and satellite retrievals was applied to investigate the interannual variations of biomass burning from Peninsular Southeast Asia (PSEA) in terms of its emission, transport and impacts over the local and downwind areas. Study period ranged from 2006 to 2010 during March and April which was the PSEA biomass burning season. Analysis of geopotential height indicated that PSEA biomass burning plume was rapidly uplifted by the lee side trough over Yungui Plateau into free troposphere which favors the long-range transport down to East Asia (EA). Lightning data from NASA demonstrated deep convection was weak over PSEA during the burning season and it may only play a minor role for uplifting. Although PSEA biomass burning had large annual variation such as the emission in 2010 was 65% higher than that in 2008, its impact at near surface layer for CO, O3 and PM2.5 within 0e1 km height had less variability since most of the plume was uplifted into free troposphere. At lower part of free troposphere within 1 kme3 km however, impact of PSEA biomass burning at downwind areas showed consistent annual variations with the emission changes. Sounding observations demonstrated PSEA biomass burning may have almost no impact on thenear surface layer O3 over Taiwan but contributed more than 30% of O3 at free troposphere within 1 e6 km height during massive burning events. PSEA biomass burning also significantly affected aerosol optical depth (AOD) over EA, with the contributions ranged from 0.1 to 0.3 (25%e45% in total AOD) in 2008 to 0.2e0.6 (50%e70% in total AOD) in 2010. Our analysis indicated that although PSEA biomass burning may have relatively stable impact on air quality over EA from year to year, it will cause significant disturbance to the free troposphere over EA for both atmospheric chemistry and radiative forcing budget.
Dong, Xinyi , Fu, Joshua S.
Atmospheric Environment , 2015
Peninsular Southeast Asia , Biomass burning , Interannual variation, Uplift transport