This study investigates 10 Automated Synoptic Observing System stations in Gangwon Province that provide > 30 years of long-term observations. Using the hourly mean data during summer (June-August), the vapor pressure () and saturation vapor pressure () were calculated, and the vapor pressure deficit characteristics () were evaluated. The daily maximum vapor pressure and daily maximum of the hourly mean were used as sample extremes. Each station's record was divided into two subperiods, representing earlier and more recent decades, and the Generalized Extreme Value distribution was applied to estimate the location (μ) and scale (σ) using maximum likelihood estimation. The central tendency and variability of and were quantified using the estimated μ and σ, and temporal trends in these parameters were examined by quantitatively comparing the upper 5% extremes and year-to-year variations. Spatially, the Yeongdong coastal and mountainous stations exhibited increases in location and scale in the recent period, corresponding to higher mean levels and enhanced variability of and . Trends in extreme values showed that the upper-tail extremes were larger and more robust in coastal and mountainous regions. These findings highlight the importance of evaluating the extreme summer characteristics for drought risk management and water resource planning in Yeongdong.
Koo et al. (Mon,) studied this question.