In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 23, No. 3 ( 2023-02-03), p. 1879-1892
Abstract:
Abstract. Brown carbon (BrC) in the atmosphere can greatly
influence aerosol's radiative forcing over the Tibetan Plateau (TP) because
it has the non-negligible capacity of light absorption compared to black
carbon (BC); however, our understanding of optical properties, sources,
and atmospheric processes of BrC in this region remains limited. In this study,
a multiple-wavelength Aethalometer coupled with a quadrupole aerosol
chemical speciation monitor was deployed to investigate the highly time
resolved BrC in the submicron aerosol at the southeastern edge of the TP
during the pre-monsoon season. The results showed that BrC made
substantial contributions (20.0 %–40.2 %) to the light absorption of
submicron aerosol from 370 to 660 nm. Organic aerosol (OA), an alternative
to BrC, was split into a biomass burning OA (BBOA) with aging processes and a
photochemical-oxidation-processed oxygenated OA (po-OOA) by a hybrid
environmental receptor model analysis. Combined with the light absorption
coefficient of BrC (babs-BrC), the source-specific mass absorption cross
sections of BBOA (0.61–2.78 m2 g−1) and po-OOA (0.30–1.43 m2 g−1) at 370–660 nm were retrieved. On average,
babs-BrC from po-OOA (1.3–6.0 Mm−1) was comparable to that from
BBOA (1.3–6.0 Mm−1) at all wavelengths. The concentration-weighted
trajectory analysis showed that the most important potential source regions
for babs-BrC values from BBOA and po-OOA were located in northern
Myanmar and along the China–Myanmar border, indicating the cross-border
transport of BrC from Southeast Asia. A “simple forcing efficiency”
evaluation further illustrated the importance of the BrC radiative effect with
the high fractional radiative forcing by two OAs relative to BC (48.8 ± 15.5 %). This study highlights a significant influence of BrC of
biomass burning origin and secondary formation on climate change over the TP
region during the pre-monsoon season.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-23-1879-2023
DOI:
10.5194/acp-23-1879-2023-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2023
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
Permalink