Decadal Changes in the Interannual Variability of Heatwaves in East Asia Caused by Atmospheric Teleconnection Changes

Abstract

The heatwave in East Asia is examined by using EOF analysis to isolate dominant heatwave patterns in the ground-based temperature observations over Korea and China and related large-scale atmospheric circulations obtained from the National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis I during 1973–2012. This study focuses particularly on the interannual variability of heatwaves and its decadal change. The analysis identifies two major atmospheric teleconnection patterns playing an important role in developing typical heatwave patterns in East Asia – the Scandinavian (SCAND) and the Circumglobal Teleconnection (CGT) patterns, which exhibit a significant decadal change in the interannual variability in the mid-1990s. Before the mid-1990s, the heatwave occurrence was closely related to the CGT pattern, whereas the SCAND pattern is more crucial to explain the heatwave variability in the recent period. The stationary wave model experiments suggest an intensification of the SCAND pattern in the recent period driven by the increase in land-atmosphere interaction over Eurasia and the decadal change in the dominant heatwave patterns in East Asia.