Volume 16, No. 11, November 2016, Pages 2742-2756 PDF(7.33 MB)
Supplementary MaterialPDF (1.75 MB)
Investigation of the CCN Activity, BC and UVBC Mass Concentrations of Biomass Burning Aerosols during the 2013 BASELInE Campaign
Ta-Chih Hsiao1, Wei-Cheng Ye1, Sheng-Hsiang Wang2, Si-Chee Tsay3, Wei-Nai Chen4, Neng-Huei Lin2, Chung-Te Lee1, Hui-Ming Hung5, Ming-Tung Chuang6, Somporn Chantara7
1 Graduate Institute of Environmental Engineering, National Central University, Chung-Li 32001, Taiwan
2 Department of Atmospheric Sciences, National Central University, Chung-Li 32001, Taiwan
3 Goddard Space Flight Center, NASA, Greenbelt, Maryland, USA
4 Research Center for Environmental Changes, Academia Sinica, Taipei 11529, Taiwan
5 Department of Atmospheric Sciences, National Taiwan University, Taipei 10617, Taiwan
6 Graduate Institute of Energy Engineering, National Central University, Chung-Li 32001, Taiwan
7 Environmental Science Program, Chiang Mai University, Chiang Mai, Thailand
- Microphysical properties and CCN activity of BB aerosols in SEA were characterized.
- Different diurnal patterns were observed under two distinct weather systems.
- AR and κ value were analyzed with fire counts, GMD, BC conc., and Delta-C values.
- ARs of BB aerosols in BB source regions and receptor areas were compared.
Biomass-burning (BB) aerosols, acting as cloud condensation nuclei (CCN), can influence cloud microphysical and radiative properties. In this study, we present CCN measured near the BB source regions over northern Southeast Asia (Doi Ang Khang, Thailand) and at downwind receptor areas (Lulin Atmospheric Background Station, Taiwan), focusing exclusively on 13–20 March 2013 as part of 2013 spring campaign of the Seven SouthEast Asian Studies (7-SEAS) intensive observation. One of the campaign’s objectives is to characterize BB aerosols serving as CCN in SouthEast Asia (SEA). CCN concentrations were measured by a CCN counter at 5 supersaturation (SS) levels: 0.15%, 0.30%, 0.45%, 0.60%, and 0.75%. In addition, PM2.5 and black carbon mass concentrations were analyzed by using a tapered element oscillating microbalance and an aethalometer. It was found the number-size distributions and the characteristics of hygroscopicity (e.g., activation ratio and κ) of BB aerosols in SEA have a strong diurnal pattern, and different behaviors of patterns were characterized under two distinct weather systems. The overall average κ value was low (0.05–0.1) but comparable with previous CCN studies in other BB source regions. Furthermore, a large fraction of UV-absorbing organic material (UVBC) and high Delta-C among BB aerosols were also observed, which suggest the existence of substantial particulate organic matter in fresh BB aerosols. These data provide the most extensive characterization of BB aerosols in SEA until now.
Cloud condensation nuclei; Biomass burning aerosol; Long-range transport; Diurnal cycle; Hygroscopicity.