한반도 극한 기온의 선형 및 비선형 변화 경향

Abstract

This study explores the long-term trends of surface air temperatures in 11 KMAstations over the period of 1960~2012. Both linear and nonlinear trends are examined for the95th, 50th, and 5th percentiles of daily maximum (Tmax) and minimum temperatures (Tmin) byusing quantile regression method. It is found that in most stations linear trends of Tmax and Tminare generally stronger in winter than in summer, and warming trend of the 5th percentile temperature(cold extreme) is stronger than that of the 95th percentile temperature (warm extreme)in both seasons. The nonlinear trends, which are evaluated by the second order polynomial fitting,show a strong nonlinearity in winter. Specifically, winter temperatures have increaseduntil 2000s but slightly decreased afterward in all percentiles. This contrasts with the 95th and50th percentiles of summer Tmin that show a decreasing trend until 1980s then an increasingtrend. While this result is consistent with a seasonal dependence of the recent global warminghiatus, most of the nonlinear trends are statistically insignificant, making a quantitative attributionof nonlinear temperature trends challenging.