태풍의 약화 시 한국에서의 시공간적 강수량 분포

Abstract

Spatiotemporal characteristics of precipitation in Korea, associated with the weakening of Tropical Cyclones(TCs) around the Korean Peninsula(32-36°N, 122-132°E) over the last 30 years(1979-2008), were investigated. Weakened TCs are classified as WEC(Weakened to Extratropical Cyclone) and WTD(Weakened to Tropical Depression). In WEC, precipitation was evenly distributed all over the Korean Peninsula and the greater precipitation was recorded in the southern coast. In WTD, the most precipitation was recorded in the southern coast but low precipitation was recorded in the central and inland areas of Korea. The difference of precipitation between WEC and WTD was not statistically significant in Region 2(Jeollanam-do, Gyeongsangnam-do, southeastern part of Gyeongsangbuk-do, Jeju-do); however, the precipitation resulting from WEC was greater than that resulting from WTD in Region 1(central area of Korea, Jeollabuk-do, inland of Gyeongsangbuk-do). In WEC, the developed upper-level potential vorticity(PV) and low-level temperature trough shifted to the northwest of TCs approaching Korea. In addition, an upper-level jet stream and strong divergence field were observed to the northeast of the TCs. It was assumed that these meteorological factors had induced baroclinic instability and diabatic process, which created a large precipitation area around the TCs. However, the intense PV, temperature trough, jet stream were not observed in WTD, which created a small precipitation area around the TCs. In addition, spatial proportions of heavy rainfall area around the representative TC events for WEC and WTD(MINDULLE 0407 and NEIL 9905, respectively) are discussed on the basis of data obtained from the Tropical Rainfall Measuring Mission(TRMM). The heavy rainfall proportion had decreased from before the TC NEIL(9905) was weakened to tropical depression. On the other hand, the large heavy rainfall proportion continued or expanded even though the TC MINDULLE(0407) had weakened to extratropical cyclone.