Long-Term Trend of Surface Wind Speed in Korea: Physical and Statistical Homogenizations

Abstract

The long-term trend of surface wind speed in Korea is estimated by correcting wind measurements at 29 KMA weather stations from 1985 to 2019 with physical and statistical homogenization. The anemometer height changes at each station are first adjusted by applying physical homogenization using the power-law wind profile. The statistical homogenization is then applied to the adjusted data. A standard normal homogeneity test (SNHT) is particularly utilized Approximately 40% of inhomogeneities detected by the SNHT match with the sea-level-height change of each station, indicating that an SNHT is an effective technique for reconciling data inhomogeneity. The long-term trends are compared with homogenized data. Statistically significant negative trends are observed along the coast, while insignificant trends are dominant inland. The mean trend, averaged over all stations, is -0.03 +/- 0.07 m s(-1) decade(-1). This insignificant trend is due to a trend change across 2001. A decreasing trend of -0.10 m s(-1) decade(-1 )reverses to an increasing trend of 0.03 m s(-1) decade(-1) from 2001. This trend change is consistent with midlatitude wind change in the Northern hemisphere, indicating that the long-term trend of surface wind speed in Korea is partly determined by large-scale atmospheric circulation.