Abstract. Impacts of global climate change on the occurrence and development of air
pollution have attracted more attention. This study investigates impacts of
the warming Tibetan Plateau on air quality in the Sichuan Basin.
Meteorological observations and ERA-Interim reanalysis data reveal that the
plateau has been rapidly warming during the last 40 years (1979–2017),
particularly in winter when the warming rate is approximately twice as much as
the annual warming rate. Since 2013, the winter temperature over the plateau
has even risen by 2 ∘C. Here we use the WRF-Chem model to lay
emphasis on the impact of the 2 ∘C warming on air quality in
the basin. The model results show that the 2 ∘C warming causes
an enhanced easterly wind, an increase in the planetary boundary layer height
(PBLH) and a decrease in the relative humidity (RH) in the basin. Enhanced
easterly wind increases PM2.5 transport from the basin to the
plateau. The elevated PBLH strengthens vertical diffusion of PM2.5,
while the decreased RH significantly reduces secondary aerosol
formation. Overall, PM2.5 concentration is reduced by 17.5 %
(∼25.1 µg m−3), of which the reduction in primary and
secondary aerosols is 5.4 and 19.7 µg m−3, respectively. These
results reveal that the recent warming plateau has improved air quality in the
basin, to a certain extent mitigating the air pollution therein.
Nevertheless, the climate system is particularly complicated, and more studies are
needed to demonstrate the impact of climate change on air quality in the
downstream regions as the plateau is likely to continue warming.
Highlights
The Tibetan Plateau is rapidly warming, and the temperature has risen by 2 ∘C from 2013 to 2017. A warming plateau leads to an enhanced easterly wind, an increased PBLH and
a decreased RH in the Sichuan Basin. The 2 ∘C warming significantly reduces PM2.5 concentration
in the basin by 25.1 µg m−3, of which secondary aerosol is 19.7 µg m−3.
Supplementary material to "The Warming Tibetan Plateau improves winter air quality in the Sichuan Basin, China"