Interdecadal variability of the large-scale extreme hot event frequency over the middle and lower reaches of the Yangtze River basin and its related atmospheric patterns

Abstract

Based on daily maximum temperature data from Chinese weather stations for the period 1960–2013, the characteristics of the interdecadal variability of large-scale extreme hot event (EHE) frequency over the middle and lower reaches of the Yangtze River basin (MLYR) are analyzed. It is found that the frequency of large-scale EHE over the MLYR experiences two significant interdecadal changes, around the early 1970s and early 2000s, having a more–less–more variability shape during the past half century. Furthermore, the EHE frequency interdecadal variability–related atmospheric circulation patterns are diagnosed. The results indicate the western Pacific subtropical high could not be the dominant atmospheric circulation associated with the interdecadal variability of the large-scale EHE frequency over the MLYR. In contrast, the dominant teleconnection pattern over the Eurasian continent, which is represented by the second empirical orthogonal function mode of the 200 hPa geopotential height, is closely related to the interdecadal variability of the EHE frequency over the MLYR. The results of this study deepen our understanding of the variability of the EHE frequency over the MLYR and its possible mechanism.

Keywords

• Extreme hot event
• decadal variability
• teleconnection
• EOF