资源环境科技发展态势分析平台

This study investigated the interannual variability of the frequency of extreme high-temperature events (FEHE) during summer over eastern China and associated mechanisms. Two leading modes of interannual variability of FEHE over eastern China during summer are obtained by Empirical Orthogonal Function (EOF) analysis. The first EOF (EOF1) mode of FEHE shows a diploe pattern characterized by positive (negative) anomalies in northeastern (southern) China. The second EOF (EOF2) mode of FEHE shows a monopole pattern characterized by positive anomalies in the Yangtze River valley (YRV) region. The potential mechanisms of the two leading modes are different. The EOF1 of FEHE is modulated by the EOF1 of 500-hPa geopotential height (Z500) over Eurasia, which exhibits a Eurasian wave train associated with the air-sea interaction over the North Atlantic. Besides, anomalous SSTs over the western tropical Pacific and associated anomalous convective activity over the Maritime continent may also exert an impact on the EOF1 of FEHE via stimulating a meridional wave train, the so-called "Pacific-Japan/East Asia-Pacific" teleconnection. The EOF2 of FEHE is mainly associated with the NAO mode.