Volume 16, No. 11, November 2016, Pages 2786-2801 PDF(7.55 MB)
In-Situ and Remotely-Sensed Observations of Biomass Burning Aerosols at Doi Ang Khang, Thailand during 7-SEAS/BASELInE 2015
Andrew M. Sayer1,2, N. Christina Hsu2, Ta-Chih Hsiao3, Peter Pantina2,4, Ferret Kuo5, Chang-Feng Ou-Yang5, Brent N. Holben2, Serm Janjai6, Somporn Chantara7, Shen-Hsiang Wang5, Adrian M. Loftus2,8, Neng-Huei Lin5, Si-Chee Tsay2
1 GESTAR/USRA, Columbia, Maryland, USA
2 NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
3 Graduate Institute of Environmental Engineering, National Central University, Chung-Li 32001, Taiwan
4 Science Systems and Applications, Inc, Lanham, Maryland, USA
5 Department of Atmospheric Sciences, National Central University, Chung-Li 32001, Taiwan
6 Silpakorn University, Nakorn Pathom, Thailand
7 Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
8 ESSIC, University of Maryland, College Park, Maryland, USA
- 7-SEAS/BASELInE deployed ground-based aerosol monitoring sensors at Doi Ang Khang, Thailand.
- MODIS Deep Blue AOD compares well to AERONET in this complicated environment.
- Surface and column single scattering albedo are well-correlated but offset.
- The PM-to-AOD ratio is dependent on planetary boundary layer depth.
The spring 2015 deployment of a suite of instrumentation at Doi Ang Khang (DAK) in northwestern Thailand enabled the characterization of air masses containing smoke aerosols from burning predominantly in Myanmar. Aerosol Robotic Network (AERONET) Sun photometer data were used to validate Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6 ‘Deep Blue’ aerosol optical depth (AOD) retrievals; MODIS Terra and Aqua provided results of similar quality, with correlation coefficients of 0.93–0.94 and similar agreement within expected uncertainties to global-average performance. Scattering and absorption measurements were used to compare surface and total column aerosol single scatter albedo (SSA); while the two were well-correlated, and showed consistent positive relationships with moisture (increasing SSA through the season as surface relative humidity and total columnar water vapor increased), in-situ surface-level SSA was nevertheless significantly lower by 0.12–0.17. This could be related to vertical heterogeneity and/or instrumental issues. DAK is at ~1,500 m above sea level in heterogeneous terrain, and the resulting strong diurnal variability in planetary boundary layer depth above the site leads to high temporal variability in both surface and column measurements, and acts as a controlling factor to the ratio between surface particulate matter (PM) levels and column AOD. In contrast, while some hygroscopic effects were observed relating to aerosol particle size and Ångström exponent, relative humidity variations appear to be less important for the PM:AOD ratio here.
Biomass burning; Aerosol; Remote sensing; In situ; 7-SEAS BASELInE.