The temporal and spatial structures of recent and future trends in extreme indices over Korea from a regional climate projection

摘要

The temporal and spatial characteristics of trends in extreme indices over Korea between 1971 and 2100 are investigated using daily minimum (Tmin) and maximum (Tmax) temperature and precipitation data from a regional climate projection at 20 km grid spacing. Five temperature-based indices and five precipitation-based indices are selected to comprehensively consider the frequency, intensity, and persistence of extreme events. In addition, Mann-Kendall tests are used to detect the statistical significance of trends in these indices. For validation during the reference period (1971-2000), the model reasonably simulates the temporal and spatial pattern of the trend. The model captures observed direction and magnitude well in various types of extremes. Indices based on Tmin show a considerable change towards warmer climate conditions while indices based on Tmax do not reveal any distinct trend, implying an asymmetric response of Tmin and Tmax to global warming. Indices of the frequency and intensity of heavy precipitation show a significant increase, whereas the duration of dry and wet consecutive days shows no change. For future projections, the temperature-based indices exhibit a much more significant and consistent trend than the precipitation-based indices, with statistical significance at the 95% confidence level for all indices. The frequency and intensity of heavy precipitation are projected to increase in the 21st century, continuing the trend of the reference climate. Although the future projected changes in the duration of consecutive dry and wet days are not statistically significant, the signal becomes more pronounced with respect to the reference simulation.