Teleconnection of Extreme Rainfall Events between the Yellow River Basin and Europe: A Complex Network Analysis

Extreme rainfall events (EREs) have recently been observed to exhibit teleconnection patterns across long spatial distances. Here we investigate the EREs over the Yellow River basin (YRB) using complex network-based event synchronization analysis. We found that EREs in the YRB are significantly synchronized with multiple regions worldwide, including both local regions and remote regions, and the spatial synchronization patterns exhibit time-scale dependence. Particularly, we found significant synchronization between the EREs in the YRB and those in Europe, with the YRB lags Eastern Europe by 3-5 days lag, while the YRB lags Western Europe by 5–7 days lag. Further analysis reveals that Rossby wave propagation plays a key role in the synchronization of EREs between Europe and the YRB. Wave trains originating in Europe propagate downstream of the Eurasian jet, inducing anomalous circulations over the YRB that enhance vertical upward motion and moisture transport, ultimately triggering EREs. Two distinct wave trains are observed across the Eurasian continent: one associated with Eastern Europe-YRB synchronization, occurring in the mid-latitude region and resembling Rossby wave patterns along the mid-latitude jet stream, with wave energy reaching the YRB after approximately 3 days; and another associated with Western Europe-YRB synchronization, positioned at higher latitudes and relates to Rossby waves along the polar front jet, with wave energy reaching the YRB in about 5 days. Our findings provide valuable insights into the predictability of EREs, offering critical guidance for improving forecasting and early warning capabilities for EREs in the YRB.