Occurrence of heatwave in Korea by the displacement of South Asian high

Abstract The South Asian high (SAH) index was defined using the 200 hPa geopotential height for 1973–2019. Of movements of SAH center in north–south, east–west, northwest-southeast, and southwest-northeast directions, northwest-southeast direction showed highest positive correlation with heatwave days (HWDs) Korea. Thirteen years values northwestward shift (positive years) 13 southeastward (negative were selected from a time series indices which linear trend removed, differences between these two groups analyzed. An analysis vertical meridional circulation averaged along 120°–130° E that latitude zones containing Korea, anomalous downward flows pressures formed entire troposphere coincided anomaly air temperature specific humidity. stream heights years, anticyclones developed North Pacific, America, Western Europe, Iranian Plateau. These had wavenumber-5 pattern more distinct barotropic structures at higher altitudes, resembled circumglobal teleconnection (CGT) pattern. maintenance CGT depends on interaction Indian summer monsoon (ISM), has major influence mid-latitude atmosphere. Strengthening ISM results formation upper-level northwestern Plateau produces continuous downstream cells waveguide due to Rossby wave dispersion. When diabatic heating by precipitation is strengthened, strengthened northwest India, formed. As result, all layers Korean troposphere, resulting heatwaves, tropical nights, droughts exacerbated