한반도 풍수기의 정의 및 발생 특성

Abstract

This study defines the Water Abundant Season (WAS hereafter) that represents the season when water is relatively abundant than other seasons, and investigates common characteristics of WAS in whole South Korea and each station (60 stations), using Available Water Resources Index (AWRI; Byun and Lee, 2002, unit: ㎜) that is the accumulated value of the daily precipitation for 365 days with time dependent function. Then the WAS is defined quantitatively as the duration that has bigger value of AWRI than the criterion and lasts for more than 75 days. The criterion of WAS is defined by the median value of a daily AWRI for 30 years for each station. The biggest and the smallest value of the criteria of AWRI are shown in Seongsan (270.72 ㎜) and Uiseong (135.88 ㎜), respectively. With this definition, we got very valuable data as followings. The WAS in South Korea as a whole begins on the 2nd July, ends on the 22nd December, and has the duration of 174 days on average. In each station, the earliest onset date of the WAS is the 15th June at Seogwipo and the latest one is the 25th July at Sokcho on average, and the difference between these two is 44 days, that is not small. And the earliest end date is 3rd December at Tongyeong and the latest is the 17th January of the following year in Uljin on average. The difference between these two is 47 days. The region with the shortest duration is Yoesu (164 days) and with the longest duration is Uljin (208 days) on average. The beginning date of WAS of whole South Korea is getting earlier with the trend of 3.1 days/decade, the end date is becoming later with the trend of 2.3 days/decade and the duration is increasing with the trend of 5.4 days/decade. By comparing with the Changma (the rainy season), it was found that the onset date of WAS be very similar to the onset date of Changma, that it be more useful than Changma to show the seasonal condition on water resources, and that the Changma in qualitative concept be changed to the WAS in quantitative concept. Key words: Water Abundant Season (WAS), Available Water Resources Index, the Changma