We conducted sensitive experiments using a regional climate model coupled with a chemical model to explore the influence of sulphate aerosols on the climate in eastern China. The model results showed that rainfall decreased in the Beijing–Tianjin–Hebei area and Yangtze River delta but increased in the Huang-Huai River region during 1999–2008, compared with 1989–1998. The change in the decadal rainfall pattern in the model is similar to that actually observed.

Further analysis showed that the decreased (increased) rainfall is caused by anomalous downward (upward) currents associated with the uneven distribution of sulphur dioxide emissions. Large amounts of emitted sulphur dioxide result in downward air motion over the Beijing–Tianjin–Hebei area and Yangtze River delta. Because there are strong downward currents to the south and north of the Huang-Huai River region, an upward current is formed in this area thanks to a compensation effect.

In the present work, we only considered the climatology of the atmospheric circulation and did not consider indirect effects. In the future, the annual variation of the atmospheric circulation needs to be considered, and we intend to explore the indirect effect of sulphate aerosols on decadal rainfall change.

Related links