Reply on RC1

Abstract

Dust is an important aerosol affecting air quality in China in winter and spring that is potentially influenced by the interannual climate variability associated with El Niño. In this study, the effects of different temporal and spatial types of El Niño on dust pollution in winter and spring in China and the potential mechanisms are investigated using the Energy Exascale Earth System Model version 1 (E3SMv1). We find that the Eastern Pacific (EP) and Central Pacific (CP) El Niño both increase wintertime dust concentrations by 5–50 µg m-3 over central-eastern China. Due to a stronger wind and lower relative humidity, which favor dust emissions near sources, and a strengthened northwesterly and reduced precipitation, which are conducive to dust transport, dust concentrations during the CP El Niño are 5–20 µg m-3 higher in northern China than during the EP El Niño. El Niño with a short duration (SD) increases winter dust concentrations by 20–100 µg m-3 over northern China relative to the climatological mean, while there is a decrease of 5–50 µg m-3 during the long duration (LD) El Niño, which are also related to the El Niño-induced changes in atmospheric circulation, precipitation, and relative humidity. In the following spring season, all types of El Niño events lead to an increase in dust over the northern China, but only the increase during the LD El Niño is statistically significant, suggesting that the weaker intensity but longer duration of the LD El Niño events can significantly affect spring dust in China. Our results contribute a better understanding of the influence of different types of El Niño events on dust pollution in China, which have profound implications for air pollution control and dust storm prediction.