A North Pacific Short-Wave Train during the Extreme Phases of ENSO

Abstract

Abstract Sea surface temperatures (SSTs) exhibit an interannual seesaw between the eastern and western tropical Pacific in concert with the El Nino–Southern Oscillation (ENSO) cycle. Evidence accumulated from previous studies suggests that a teleconnection link may exist between enhanced rainfall/convection in the western Pacific and precipitation/severe weather over North America. The aforementioned link could possibly be established by a teleconnection wave pattern induced by the anomalously warm/cold SST anomalies in the western tropical Pacific. To demonstrate this possibility, a Fourier scale separation was introduced to divide the ENSO anomalous circulation into two wave regimes: long wave (waves 1–3) and short wave (waves 4–15). The classic Pacific–North American teleconnection pattern is formed by the long-wave regime. In contrast, emerging in the short-wave regime is a well organized wave train that propagates from the western subtropical Pacific along the North Pacific rim into North America. In...