Observed trends in extreme temperature events over northern part of the Korean Peninsula during 1960–2019 and a comparative overview

Abstract

The aim of the study is to estimate the trend in extreme temperature events in the northern part of Korean Peninsula during 1960–2019, as well as to conduct a comparison experiment with the other representative results, all trends are examined based on quality-controlled daily maximum and minimum temperature data from 37 weather stations. Results are as follows. First, frost days (FD0) and ice days (ID0) showed a clear downward trend, whereas warm days (SU25) and warm nights (TR20) experienced an obvious uptrend, with SU25 exceeding TR20, while very hot days (TX35), extreme hot days (TX37) and very extreme hot days (TX39) showed abrupt increasing trends, especially twice in TX37 and six times in TX39, respectively. Both of cold nights (TN10) and cold days (TX10) decreased by about −0.7d/decade, hot nights (TN90) and hot days (TX90) increased by 0.6d and 1.0d/decade, respectively. Second, as compared with to representative results in global by the relevant reference and study period, all uptrends in TR20, SU25 and annual maximum of daily maximum temperature (TXx) were significantly higher than those in most regions in China, SU25 and TR20 were mostly greater than those in most regions, except for some regions in Europe. In particular, TR20 upward trend exceeded any other region's results. Meanwhile, TX10 and TNn experienced stronger downward and upward tendencies than those in whole China respectively. Especially, TNn experienced the strongest upward trend in comparing with the others. Overall, results revealed hot weather frequency and nighttime warm events over the study area have experienced a larger increasing trend than those in global land.