Impacts of Changing Arctic Cryosphere on Extreme Temperature Events in East Asia
The purpose of this study is to examine the trends of extreme temperature events in East Asia over the past 40 years (1979-2018) and their potential relationships with recent changes in the Northern Hemisphere cryosphere. Analyses of Sen’s slope and Mann-Kendall tests are performed for time series data of extreme temperature events extracted from NCEP-DOE reanalysis II Gaussian grid daily 2-m air temperature data. As the result, it is found that extreme high temperature events exceeding the 99th percentile show more noticeable increasing trends than the magnitude of the decreasing extreme low temperature events below the 1st percentile particularly in Mongolia, Korean Peninsula and southern China due to unexpected cold events since the late 2000s. Correlation analyses based on Kendall’s tau indicate that the reduction of spring-early summer Eurasian snow cover (data from Rutgers University Global Snow Lab.) may lead to the increasing tendency of extreme high temperature events in East Asia through snow albedo feedbacks, while paradoxically the reducing autumn-early winter Arctic sea ice (data from NSIDC) due to global warming seems to cause more frequent extreme low temperature events in recent years through the amplification of Rossby waves. Thus, it is needed to continue monitoring the feedbacks between changing Arctic cryosphere and East Asian climate systems in the warmer 21st century.