TY - JOUR
T1 - Impacts of brown carbon from biomass burning on surface UV and ozone photochemistry in the Amazon Basin
AU - Mok, Jungbin
AU - Krotkov, Nickolay A.
AU - Arola, Antti
AU - Torres, Omar
AU - Jethva, Hiren
AU - Andrade, Marcos
AU - Labow, Gordon
AU - Eck, Thomas F.
AU - Li, Zhanqing
AU - Dickerson, Russell R.
AU - Stenchikov, Georgiy L.
AU - Osipov, Sergey
AU - Ren, Xinrong
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: J.M. and Z.L. were supported by ESSIC–NASA Master grant (5266960), the National Science Foundation (AGS1118325, AGS1534670), MOST (2013CB955804), and NSFC (91544217). G.S. and S.O. were supported by the King Abdullah University of Science and Technology (KAUST) and used the resources of the Supercomputing Laboratory at KAUST in Thuwal, Saudi Arabia. The authors acknowledge support from NASA Earth Science Division, Radiation Sciences and Atmospheric Composition programs. The authors also thank the AERONET and UV-B Monitoring and Research Program team members.
PY - 2016/11/11
Y1 - 2016/11/11
N2 - The spectral dependence of light absorption by atmospheric particulate matter has major implications for air quality and climate forcing, but remains uncertain especially in tropical areas with extensive biomass burning. In the September-October 2007 biomass-burning season in Santa Cruz, Bolivia, we studied light absorbing (chromophoric) organic or “brown” carbon (BrC) with surface and space-based remote sensing. We found that BrC has negligible absorption at visible wavelengths, but significant absorption and strong spectral dependence at UV wavelengths. Using the ground-based inversion of column effective imaginary refractive index in the range 305–368 nm, we quantified a strong spectral dependence of absorption by BrC in the UV and diminished ultraviolet B (UV-B) radiation reaching the surface. Reduced UV-B means less erythema, plant damage, and slower photolysis rates. We use a photochemical box model to show that relative to black carbon (BC) alone, the combined optical properties of BrC and BC slow the net rate of production of ozone by up to 18% and lead to reduced concentrations of radicals OH, HO2, and RO2 by up to 17%, 15%, and 14%, respectively. The optical properties of BrC aerosol change in subtle ways the generally adverse effects of smoke from biomass burning.
AB - The spectral dependence of light absorption by atmospheric particulate matter has major implications for air quality and climate forcing, but remains uncertain especially in tropical areas with extensive biomass burning. In the September-October 2007 biomass-burning season in Santa Cruz, Bolivia, we studied light absorbing (chromophoric) organic or “brown” carbon (BrC) with surface and space-based remote sensing. We found that BrC has negligible absorption at visible wavelengths, but significant absorption and strong spectral dependence at UV wavelengths. Using the ground-based inversion of column effective imaginary refractive index in the range 305–368 nm, we quantified a strong spectral dependence of absorption by BrC in the UV and diminished ultraviolet B (UV-B) radiation reaching the surface. Reduced UV-B means less erythema, plant damage, and slower photolysis rates. We use a photochemical box model to show that relative to black carbon (BC) alone, the combined optical properties of BrC and BC slow the net rate of production of ozone by up to 18% and lead to reduced concentrations of radicals OH, HO2, and RO2 by up to 17%, 15%, and 14%, respectively. The optical properties of BrC aerosol change in subtle ways the generally adverse effects of smoke from biomass burning.
UR - http://hdl.handle.net/10754/621860
UR - http://www.nature.com/articles/srep36940
UR - http://www.scopus.com/inward/record.url?scp=84994850757&partnerID=8YFLogxK
U2 - 10.1038/srep36940
DO - 10.1038/srep36940
M3 - Article
C2 - 27833145
SN - 2045-2322
VL - 6
JO - Scientific Reports
JF - Scientific Reports
IS - 1
ER -
