시공간과 시간해상도에 따른 강우침식인자 분석

Abstract

Soil erosion causes farmland degradation and water pollution in nearby rivers. The intensification of soil erosion is linked to increasing rainfall intensityand the frequency of extreme precipitation events, highlighting the need to analyze the impacts of climate change on soil erosion. This study calculatedthe rainfall erosivity factor (R factor) at the Universal Soil Loss Equation (USLE), using 1-hour rainfall data from 1973 to 2023 at 60 sites. Mann-Kendall test and Sen’s slope were used to assess its spatio-temporal variation. Furthermore, the influence of temporal resolution on the R factorwas examined by comparing R factors derived from 1-minute and 1-hour rainfall data over the past 24 years. The study revealed a significant increasein R factors at 20 sites. The highest increasing tendency of R factors were observed in the southern coastal regions and Jeju Island, identified as themost vulnerable to the effects of climate change. Conversely, most inland areas showed no trend of increasing R factors, except the northern regionsof the Sobaek Mountains. Additionally, R factors calculated using 1-minute rainfall data were approximately 272 MJ⋅mm/ha/hr/yr higher than thosederived from 1-hour rainfall data. This discrepancy highlights the limitations of estimating the maximum 30-minute rainfall intensity (I30) using 1-hourrainfall data. To complement temporal resolution, new I30 conversion factors has been proposed. The findings underscore the necessity of periodicrecalibration of R factors to account for the impacts of climate change and emphasize the importance of high-resolution temporal rainfall data foraccurate R factor estimation.