| 초록 |
The characteristics of meteorological conditions relevant to Asian dust (AD) outbreaks and their occurrence frequencies were analyzed in four source regions (R1 to R4) during spring months (March to May) of 1995-2002. Moreover, the concentration variations of AD (e.g., $PM_{10}$ ) observed in Korea were investigated during the study period. In the relationship between AD outbreaks and three meteorological parameters (i.e., air temperature, wind speed, and aridity), the largest AD outbreaks in April ( ${ sim}250$ observations) mostly occurred in R2 when air temperature ranging from 10.0 to $15^{ circ}C$ and surface wind speed from 7 to $9m ;s^{-1}$ were recorded. Moreover, the aridity ( $ geq4$ ) in April was significantly high in R2 with the maximum frequency of AD outbreaks (i.e., 206 observations). On the other hand, the number (percentage) of days belonging to AD events observed in five Korean cities were found to be 116 (44%), 121 (46%), and 26 days (10%) in March, April, and May, respectively. The mean $PM_{10}$ concentrations were found to range from 150 to 220, 150 to 200, and 95 to $120{ mu}g ;m^{-3}$ in March, April, and May, respectively. Consequently, this implied that the AD events in Korea were found to be gradually frequent in early spring and to be affected from the large AD outbreaks observed in the source regions. |
