광주에서 집중호우를 유발하는 뇌우의 특성 분석

Abstract

Thunderstorm is considered a major phenomenon for the very-short-range forecast because it often involves thunder and lightning or hail, strong wind and heavy rainfall, and rapidly develops in a short time to locally cause a severe damage. Therefore, the study on thunderstorm is important and necessary. This study analyzed the thunderstorm accompanied by heavy rainfall for the past 10years (2001-2010) in Gwangju There have been 44 heavy rainfalls for the past 10 years in Gwangju, mostly in July, which is the rainy season. The thunderstorm accompanied by heavy rainfall occurred 29 times in total. Frontal thunderstorms accounted for the greatest number of days because of the seasonal rain front in summer. The characteristics of the thunderstorm that is accompanied by heavy rainfall in Gwangju are summarized as follows. The air-mass thunderstorm had a higher instability at the time of formation than 6 hours ago, and was likely to form with a small vapor volume and a low vertical wind shear in the bottom layer, and with a high instability and vertical wind shear in the top layer. It had a high precipitation per hour, showing highly intense rainfall in a short duration. In 2003, when the air-mass thunderstorm was frequent, the air pressure distribution was south-high-north-low, the pressure ridge was located over the south area of Korea, and there was a strong northeasterly wind from the East Sea. The frontal thunderstorm had a higher instability 6 hours before the formation than at the time of formation in terms of CAPE, and was likely to form with a large vapor volume and a high vertical wind shear in the bottom layer, and with a low instability and vertical wind shear in the top layer. In addition, the precipitation duration was long and the daily precipitation was high, showing a continuous precipitation. The analysis results of the satellite image showed that the frontal thunderstorm had higher cloud top temperature and height than air-mass thunderstorm. This was because a very large quantity of latent heat was discharged due to the vapor condensation. In 2009, when the frontal thunderstorm was frequent, the influence of low pressure expanded, and the pressure trough located from the north of China to the East Sea caused much rainfall. In addition, the counterclockwise air current made the northwesterly wind converge.