Journal Article
Atmospheric Chemistry and Physics, vol. 21, iss. 13, pp. 10745-10761, 2021
Authors
Liangying Zeng, Yang Yang, Hailong Wang, Jing Wang, Jing Li, Lili Ren, Huimin Li, Yang Zhou, Pinya Wang, Hong Liao
Abstract
Abstract. El Niño–Southern Oscillation (ENSO), a phenomenon of periodic changes in
sea surface temperature in the equatorial central-eastern Pacific Ocean, is
the strongest signal of interannual variability in the climate system with a
quasi-period of 2–7 years. El Niño events have been shown to have
important influences on meteorological conditions in China. In this study, the
impacts of El Niño with different durations on aerosol concentrations and
haze days during December–January–February (DJF) in China are quantitatively
examined using the state-of-the-art Energy Exascale Earth System Model
version 1 (E3SMv1). We find that PM2.5 concentrations are increased
by 1–2 µg m−3 in northeastern and southern China and
decreased by up to 2.4 µg m−3 in central-eastern China during
El Niño events relative to the climatological means. Compared to long-duration (LD) El Niño events, El Niño with short duration (SD) but
strong intensity causes northerly wind anomalies over central-eastern China,
which is favorable for aerosol dispersion over this region. Moreover, the
anomalous southeasterly winds weaken the wintertime prevailing northwesterly
in northeastern China and facilitate aerosol transport from southern and southeast Asia, enhancing aerosol increase in northeastern China during SD El Niño events relative to LD El Niño events. In addition, the modulation
effect on haze days by SD El Niño events is 2–3 times more than that by LD El Niño events in China. The aerosol variations during El Niño events are
mainly controlled by anomalous aerosol accumulation/dispersion and transport
due to changes in atmospheric circulation, while El Niño-induced
precipitation change has little effect. The occurrence frequency of SD El Niño events has been increasing significantly in recent decades,
especially after the 1940s, suggesting that El Niño with short duration has
exerted an increasingly intense modulation on aerosol pollution in China over the
past few decades.
