Long-term variations of dust storms and associated dustfall and related climate factors in Korea during 1997~2016

Abstract

The large-scale transport of dust storms originating from Mongolia and northern China has been observed for dustfall days by meteorological observers in South Korea since 1960. Furthermore, the Korea Centre for Atmospheric Environment Research (KCAER) has been observing dustfall days by using standards of ground-based mass concentrations in central South Korea since 1997. In the spatial distribution, annual dustfall days gradually decreased southeastward in South Korea due to wind speed reduction for the long-range transport of dust storms. During the last 20 years, 19 dustfall days in 1997 were reduced to 3 days in 2016 with a decreasing rate of − 0.8 ± 0.1 day year−1. The warming in northern Mongolia reduced the meridional temperature gradient between Mongolia and northern China. Decreases in the air temperature gradient affect wind speed reduction in the origins of dust storms. A noticeable decrease in PM10 mass concentrations is related to decreases in higher mass concentration days from dustfall in central South Korea during winter and spring. During summer and fall, the decreasing trend of TSP is related to the high level of moisture of the Northwest Pacific air masses.