The Early 1990s Change in ENSO–PSA–SAM Relationships and Its Impact on Southern Hemisphere Climate

摘要: AbstractThis study uncovers an early 1990s change in the relationships between El Nino–Southern Oscillation (ENSO) and two leading modes of Southern Hemisphere (SH) atmospheric variability: southern annular mode (SAM) Pacific–South American (PSA) pattern. During austral spring, while PSA maintained a strong correlation with ENSO throughout period 1948–2014, SAM–ENSO changed from being weak before to afterward. Through connection, SAM became more in-phase correlated after 1990s. The is also time when dominated by eastern Pacific (EP) type central (CP) type. Analyses show that, EP can excite only PSA, CP both through tropospheric stratospheric pathway mechanisms. relationship impacted post-1990s Antarctic climate at least aspects:...