Teleconnection patterns impacting on the summer consecutive extreme rainfall in Central‐Eastern China

Abstract

Consecutive extreme rainfall (CER) events can cause enormous damage to human society and the environment in eastern China. This study analyses persistent atmospheric circulation patterns related to dominant CER modes over Central‐Eastern China. Results reveal that the two leading modes together explain 30% of the total CER variance. The circulation patterns related to the first CER mode manifest a barotropic Eurasian (EU) pattern teleconnection 4 days before the CER events occur in the southern Yangtze River. The second CER mode is associated with a negative Pacific‐Japan (PJ) teleconnection pattern, which persists for 5 days until the onset of CER events in the Yangtze River Valley. Furthermore, the stagnant double blocking highs around the Urals and the Sea of Okhotsk and the vapour transport from the western North Pacific (WNP) distinguish the persistent circulations of the second CER mode from the first mode. Therefore, the configuration of persistent circulation patterns is likely responsible for the occurrence of CER events. Further analysis suggests that the Rossby waves, in association with dipolar sea surface temperature (SST) anomalies in the northeastern Atlantic, propagate eastward towards East Asia, generating an EU‐like teleconnection 4 days prior to CER event onset. Furthermore, cold SST anomalies in the warm pool and warm SST anomalies in the tropical WNP‐South China Sea and the western Indian Ocean induce poleward‐propagating Rossby waves, creating a negative PJ teleconnection pattern up to 5 days prior to CER events. These results are supported by ray paths originating from base points of EU and PJ teleconnections.

Persistent precipitation extremes in the Yangtze River Valley prolonged by opportune configuration among atmospheric teleconnections

“…Prolonged weather extremes result dynamically from long‐lived atmospheric flow patterns, whose duration spans from days to weeks (Higgins and Mo, ; Stadtherr et al., ; Mann et al., ; Kornhuber et al., ). Recurrent atmospheric teleconnections composed of adjacent cyclones/anticyclones are deemed one major source for the persistence of weather extremes (Chen and Zhai, ; Lü et al ., ; Steptoe et al., ). Monthly‐/seasonal‐scale indices of atmospheric teleconnections used to be employed in explaining, monitoring and predicting climate anomalies at interannual to inter‐decadal time‐scales (Wallace and Gutzler, ; Nitta and Hu, ; Kubota et al., ).…”

The sea surface temperature configuration of Greenland Sea–subpolar region of North Atlantic and the summer rainfall anomaly in low‐latitude highlands of China

“…Their results suggest that the anomalous southerlies over the northwest flank of the western Pacific subtropical high are unfavourable for the convergence of warm moist air from the south and cold dry air from the north. Recently, Lü et al () suggested that dipolar SST anomalies in the northeastern Atlantic are related to consecutive extreme rainfall events in central eastern China through generating an EU‐like teleconnection. The location of SST anomalies in the northeastern Atlantic in their study is close to the quasi‐north–south SST anomaly pattern revealed in the present study (Figure b).…”

“…Some studies indicated that the coupled relationship between the North Atlantic tripole SST and North Atlantic Oscillation could lead to a strong EASM via modulating the blocking highs in the Ural Mountain and Okhotsk Sea (Wu et al, 2009;Wu et al, 2011;Zuo et al, 2012;. Lü et al (2017) revealed that a dipolar SST anomaly in the northeastern Atlantic is closely related to consecutive extreme rainfall events over central eastern China through the propagation of Rossby waves.…”

“…Previous studies indicated that SST anomalies in the Atlantic could cause atmospheric circulation anomalies extending to East Asia via wave energy dispersion and further influence the East Asian summer climate (Palmer and Sun, ; Czaja and Frankignoul, ; Watanabe, ; Wu et al, ; ; Liu et al, ; Lü et al, ). To test whether the GS–NASR SST configuration connects with the CLLH rainfall variations via dispersing wave energy from the GS–NASR to CLLH, the composite differences of geopotential height anomalies between positive‐anomaly and negative‐anomaly years are calculated.…”

“…Lü et al . () revealed that a dipolar SST anomaly in the northeastern Atlantic is closely related to consecutive extreme rainfall events over central eastern China through the propagation of Rossby waves.…”