Impact of the Scandinavian Pattern on Long-Lived Cold Surges over the South China Sea

This study investigates the influence of the Scandinavian (SCA) pattern on long-lived cold surges over the South China Sea (SCS). The results show that, different from the short-lived ones, the majority of long-lived cold surges over the SCS are preceded by a negative phase of the quasi-stationary SCA pattern in the extratropics, which is characterized as a primary cyclonic center over the Scandinavian Peninsula and two anticyclonic ones over the North Atlantic and central Siberia. This connection is mainly conducted through a continuous amplification of the high pressure anomalies over East Asia. On the other hand, the SCA-related anomalies also reveal identical responses as an increase in sea level pressure over East Asia and northerly flows over the SCS. Besides, the SCA pattern may influence the long-lived cold surges over the SCS by facilitating blocking occurrences through the extensive and quasi-stationary anticyclone over central Siberia. The present results have an implication for the extended weather forecast: long-lasting circulation anomalies, such as the SCA pattern, can affect long-lasting weather phenomena in the regions that are located remotely in both the zonal and meridional directions, such as long-lived cold surges over the SCS.

Automated summary

This study investigates the influence of the Scandinavian (SCA) pattern on long-lived cold surges over the South China Sea (SCS). The results show that long-lived cold surges over the SCS are mainly preceded by a negative phase of the quasi-stationary SCA pattern in the extratropics, which is characterized by cyclonic and anticyclonic centers. This connection is mainly through the amplification of high pressure anomalies over East Asia, and the SCA pattern may also influence the long-lived cold surges by facilitating blocking occurrences through the anticyclone over central Siberia.