cP 확장시 대기파동에 의한 충청지방의 대설연구

Abstract

Korea has strong local properties especially in relation to heavy snowfall in winter because it is a peninsula and has complicated topograph. The Chungcheong province lies east and west and has been supplied with enough moisture because it is located to the western coastal area. And the property of air mass could change in quality easily while it passes the west sea in case of expansion of the continental high pressure(cP). Besides it is located between the Charyeong Mountains to the north and the Noryeong Mountains to the south so it satisfies conditions of the heavy snowfall. The heavy snowfall case has seemed as the typical pattern of expansion of cP so the analysis of that case had been done through upper-air observation data in Osan on 4 Jan. 2003. The investigations into the changes of altitude in case of heavy snowfall and no snow, the changes of lifting condensation level(LCL), tropopause(T/P), thickness between 1,000 and 700hPa, solenoidal index, Showalter stability index(SSI), K-index(KI) and the difference of surface pressure were carried out using the latest data(from Dec. 1999 to Mar. 2003). As a result, the heavy snowfall in Chungcheong provinces was closely connected with LCL, T/P, thickness between 1,000 and 700hPa, solenoid, maximum wind height, difference of surface pressure(850hPa, 36.5N, 115～130E), SSI and KI of which could be made light in adiabatic chart analysis. The LCL in case of snowing hit a new low at 300～700gpm and then the depth of snow cover was the deepest when LCL was 600～1,000gpm. Though, in case of no snow, the lowest LCL was 600～900gpm and rose suddenly over 1,000gpm. There was the maximum depth of snow cover when the T/P was 6,000～12,000gpm and before hitting a new low. As a whole, there was a heavy snowfall(over 10cm) when the T/P was about 6,000～7,000gpm. The depth of snow cover was the deepest when 1,000/700 thickness was 2,650～2,700gpm which had the lowest 1,000/700 thickness. 1,000/700 thickness tended to hit the new low over 2,700gpm in case of no rain. When the solenoid was 20～25, the depth of snow cover was less than 10cm and than the solenoid was over 25, the depth of snow cover was more than 15cm. There was a tendency to have a heavy snowfall when the wind speed in 500hPa was over 80kts and there was a cold core which was below -40 degrees.