Identification of atmospheric transport and dispersion of Asian dust storms
Backward trajectories of individual Asian dust storm (ADS) events were calculated using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) at four representative stations in Korea. A total of 743 ADS events and associated 2229 (endings of altitudes at 1000, 1500, and 2000 m per ADS event) backward trajectories from four stations were traced from January 2003 to August 2015. Regardless of the locations of the observed stations and the threshold time divide, a recent increase in the ADS occurrence rate was statistically significant with a 99.9 % confidence limit. Winter and spring were high-occurrence seasons for the ADS, while it rarely occurred in summer. Angular distributions of dust transport indicated a dominance of northwesterly wind, as more than two-thirds of ADS events are azimuthally confined from 290 to 340°. In addition, there is a tendency for stronger PM 10 dust air concentration to be from the northwest. We found a strong inverse correlation between the number of days with ADS events and cumulative PM 10 dust air concentration, indicating that the total amount of cumulative PM 10 discharge was rather constant over time. If so, relatively shorter transport distances and a more continental dust passage over the Shandong peninsular would yield less PM 10 in a shorter transport path but with a stronger concentration.