최근 10년간 한반도에서 관측된 봄철 황사의 특성 분석

Abstract

The Asian dust that stays over the Korea peninsula for a long time shows a high density in ist concentration. As the Asian dust duration time increases, its negative effects increase on the living environment. Therefore, it is important to analyze the relationship between the synoptic condition and the Asian dust duration time in Korea and to review with previous studies on the Asian dust duration time. In this study, for the Asian dust cases for the recent 10 years (2002-2011), the relationship between the synoptic system and duration time in the Asian dust was analyzed via the analysis of the average hourly particulate matter (PM10) density and surface/upper air charts (850, 500 and 300 hPa) and satellite images, classifying the Asian dust cases into a long-period and a short-period case and verifing previous studies on the duration time. Asian dust was observed 67 times and for 129 days in spring for the recent 10 years in Korea. Their average duration was approximately two days (1.9 days). Asian dust was observed 28 times in March, 25 times in April and 14 times in May. Unlike in the period from 1981 to 2010, in which the average Asian dust days in April showed highest as 2.4 days (47%), the average number of Asian dust days of the recent 10 years (2002~2011) was greatest in March (2 days; 35%). result of recently 10 years average dates showed that Asian dust days has recently increased. The Asian dust affected the Korea peninsula originated 16 times from Manchuria, and 51 times from the Gobi Desert and inner Mongolia. No Asian dust from Manchuria affected Korea peninsula for the past 10 years (1983 – 1993), but its occurrence from Manchuria has recently increased. The duration of three days or more (>48 h) was defined as a long-period case (12 times), and the duration of less than one day was defined as a short-period case (26 times). In the long-period cases, Asian dust appeared in March, April and May for 6, 3 and 3 times with 23, 11 and 10 Asian dust days, respectively. In the short-period cases, Asian dust appeared 11, 10 and 5 times with 11, 10 and 5 Asian dust days, respectively. The total average particulate matter (PM10) values for the long and short-period cases were 145 ㎍m-3and 84㎍m-3, respectively. In the long-period cases, all of the 12 cases (100%) rose from the Gobi Desert and inner Mongolia. In the short-period cases, 13 cases (50%) rose from Manchuria, There were no Asian dust events from Manshuria and Loess Pasteau that affected Korea peninsula in the long-period cases. and 13 cases (50%), from the Gobi Desert and inner Mongolia. When the Asian dust rises from the Gobi Desert and inner Mongolia and comes to Korea via the Gulf of Balhae, it can affect Korea for over three days (>48 h). Because Manchuria and Korean Peninsula are relatively close to each other, the Asian dust originating from Manchuria can affect Korea in one day (<24 h). These must be considered in forecasting Asian dust. In the 12 long-period cases, the numbers of pressure troughs that passed over the Korean Peninsula were one, two and three in three, six and three cases, respectively. In the short-period cases, only one pressure trough passed through in all of the 26 times. On average, two pressure troughs passed in 3.67 days in the long-period cases, while one pressure trough passed in a day in the short-period cases. This indicated that the pressure trough moved faster in the short-period cases than in the long-period cases. The study results of both the long- and short-period cases coincided with those of Chun et al. (2001a) in that the crossing of the pressure gradient and temperature gradient causes the baroclinic instability and thus the Asian dust, and with those of Yun (1990) and Jeon (1991) in that the west․northwest wind on the 850 hPa plane with a velocity of 15-25ms-1 delivers the Asian dust to Korea. In the long-period cases, the study results coincided with those of Jeon(1999) in that the southward movement of the cold core in the upper layer is clearly seen in the delivery of Asian dust.