10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Impact of Springtime Southeast Asia Biomass Burning on a High-mountain Background Station in East Asia: Aerosol Composition and Light Extinction
SHANTANU KUMAR PANI, Neng-Huei Lin, Chung-Te Lee, Ta-Chih Hsiao, Sheng-Hsiang Wang, National Central University, Taiwan
Abstract Number: 686 Working Group: Aerosol Chemistry
Abstract Biomass burning (BB) is well-documented as a significant source of aerosols and trace gases in the atmosphere. Emissions from tropical BB impact the physicochemical and optical properties of the atmosphere. BB affects the Earth-atmosphere energy budget by directly scattering and absorbing the incoming solar radiation and also by indirectly modifying the cloud microphysical properties. BB activities in the form of wildland forest fires and agricultural crop burning are very pronounced over peninsular Southeast Asia (PSEA) mainly in spring (late February to April) season. Springtime regional transport of PSEA BB was investigated over downwind locations in East Asia, for example, the Lulin Atmospheric Background Station, Taiwan (LABS, 23.47°N 120.87°E, 2862 m asl), has been an international well-known site for PSEA BB outflow monitoring. As a part of the Seven South East Asian Studies/Biomass-burning Aerosols & Stratocumulus Environment: Lifecycles & Interactions Experiment (7-SEAS/BASELInE) 2013 campaign, the physical, chemical, and optical properties of aerosols were measured at Doi Ang Khang (DAK, 19.93°N, 99.05°E, 1536 m above sea level, asl), an upwind near-source BB location in northern PSEA, where BB activities were densely distributed in the surroundings. The DAK is an excellent site for investigating the characteristics of near-source fresh BB aerosols and their impacts on regional radiative budget, while the LABS is an ideal site to conduct measurements of long-range transported BB. The objective of the present study is two-fold. Firstly, it investigates the detailed BB signature profiles with reference to water soluble inorganic ions, carbonaceous fractions, monosaccharide anhydrides, and low-molecular-weight dicarboxylic acids in PM2.5. Secondly, it estimates the impact and role of aerosol chemical composition on light extinction over both locations. This is the first-time attempt of optical closure study at a high-altitude dynamic aerosol environment. BB aerosols are found more water-soluble in the downwind than the near-source location. Organic matter, ammonium sulfate, and ammonium nitrate are found to be the major contributors to the total light extinction, indicating the dominance of scattering type aerosols than over the absorbing type. This study provides needful information to understand the effect of PSEA long-transported BB on the aerosol composition and radiation budget over a remote and free-tropospheric location in East Asia.