Measurement report: quantifying source contribution of fossil fuels and biomass-burning black carbon aerosol in the southeastern margin of the Tibetan Plateau
<p>Anthropogenic emissions of black carbon (BC) aerosol are transported from Southeast Asia to the southwestern Tibetan Plateau (TP) during the pre-monsoon; however, the quantities of BC from different anthropogenic sources and the transport mechanisms are still not well constrained because th...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-01-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/21/973/2021/acp-21-973-2021.pdf |
| Summary: | <p>Anthropogenic emissions of black carbon (BC) aerosol are transported from
Southeast Asia to the southwestern Tibetan Plateau (TP) during the
pre-monsoon; however, the quantities of BC from different anthropogenic
sources and the transport mechanisms are still not well constrained because
there have been no high-time-resolution BC source apportionments. Intensive
measurements were taken in a transport channel for pollutants from Southeast
Asia to the southeastern margin of the TP during the pre-monsoon to investigate
the influences of fossil fuels and biomass burning on BC. A receptor model
that coupled multi-wavelength absorption with aerosol species concentrations was
used to retrieve site-specific Ångström exponents (AAEs) and mass
absorption cross sections (MACs) for BC. An “aethalometer model” that used
those values showed that biomass burning had a larger contribution to BC
mass than fossil fuels (BC<span class="inline-formula"><sub>biomass</sub>=57</span> % versus BC<span class="inline-formula"><sub>fossil</sub>=43</span> %). The potential source contribution function indicated that
BC<span class="inline-formula"><sub>biomass</sub></span> was transported to the site from northeastern India and
northern Burma. The Weather Research and Forecasting model coupled with
chemistry (WRF-Chem) indicated that 40 % of BC<span class="inline-formula"><sub>biomass</sub></span>
originated from Southeast Asia, while the high BC<span class="inline-formula"><sub>fossil</sub></span> was
transported from the southwest of the sampling site. A radiative transfer model
indicated that the average atmospheric direct radiative effect (DRE) of BC
was <span class="inline-formula">+</span>4.6 <span class="inline-formula">±</span> 2.4 W m<span class="inline-formula"><sup>−2</sup></span>, with <span class="inline-formula">+</span>2.5 <span class="inline-formula">±</span> 1.8 W m<span class="inline-formula"><sup>−2</sup></span> from
BC<span class="inline-formula"><sub>biomass</sub></span> and <span class="inline-formula">+</span>2.1 <span class="inline-formula">±</span> 0.9 W m<span class="inline-formula"><sup>−2</sup></span> from BC<span class="inline-formula"><sub>fossil</sub></span>. The DRE
of BC<span class="inline-formula"><sub>biomass</sub></span> and BC<span class="inline-formula"><sub>fossil</sub></span> produced heating rates of 0.07 <span class="inline-formula">±</span> 0.05 and 0.06 <span class="inline-formula">±</span> 0.02 K d<span class="inline-formula"><sup>−1</sup></span>, respectively. This study provides
insights into sources of BC over a transport channel to the southeastern TP
and the influence of the cross-border transportation of biomass-burning
emissions from Southeast Asia during the pre-monsoon.</p> |
|---|---|
| ISSN: | 1680-7316 1680-7324 |