Journal Article

The distinct PNA pattern induced by the South China Sea

Liang, X. San, Zhang, Yinchen

2023

Overview

The Pacific–North American (PNA) teleconnection pattern has recently been found to be influenced by the South China Sea (SCS) sea surface temperature anomaly (SSTA). This study further demonstrates that, the SCS SSTA can induce a new type of PNA response. The SCS-induced PNA pattern and its evolution are shown to be distinctly different from its conventional counterparts and, particularly, the ENSO-induced pattern. In contrast to the observed conventional patterns, the SCS-induced PNA seems to agree remarkably well with the classical theory of Rossby wave propagation on a sphere by Hoskins and Karoly (1981), with the centers following the great circle route, and it shows a more zonally oriented new pathway of evolution led by a precursory center not seen before. Further study of the dynamical processes underlying the new PNA response reveals a specific air-sea interaction triggered by SCS SSTA, which results in an upper-level Rossby wave source and induces the precursory center. We remark that, although the SCS SSTA is relatively small in amplitude, it has an effect on PNA almost as conspicuous as that from ENSO.

• Publisher: Springer Nature B.V
• Subject: Air-sea interaction / Atmospheric sciences / Climate / El Nino / El Nino phenomena / El Nino-Southern Oscillation event / Evolution / Great circles / Pacific-North American (PNA) pattern / Planetary waves / Rossby wave propagation / Rossby waves / Sea surface / Sea surface temperature / Sea surface temperature anomalies / Southern Oscillation / Surface temperature / Teleconnection patterns / Temperature anomalies / Wave propagation