A Teleconnection between the West Siberian Plain and the ENSO Region

TheWalker circulation is linked to extratropical waves that are deflected from theNorthernHemisphere polar regions and travel southeastward over central Asia toward the western Pacific warm pool during northern winter. The wave pattern resembles the east Atlantic–west Russia pattern and influences the El Niño–Southern Oscillation (ENSO) region. A tripole pattern between theWest Siberian Plain and the two centers of action of ENSO indicates that the background state of ENSO with respect to global sea level pressure (SLP) has a significant negative correlation to theWest Siberian Plain. The correlationwith the background state, which is defined by the sumof the two centers of action of ENSO, is higher than eachof the pairwise correlationswith either of theENSO centers alone. The centers are defined with a clustering algorithm that detects regions with similar characteristics. The normalizedmonthly SLP time series for the two centers of ENSO (aroundDarwin, Australia, and Tahiti) are area averaged, and the sumof both regions is considered as the background state of ENSO.This wave train can be detected throughout the troposphere and the lower stratosphere. Its origins can be traced back to Rossby wave activity triggered by convection over the subtropical North Atlantic that emanates wave activity toward theWest Siberian Plain. The samewave train also propagates to the central PacificOcean aroundTahiti and can be used to predict the background state over the ENSO region. This background state also modifies the subtropical bridge between tropical eastern Pacific and subtropical North Atlantic leading to a circumglobal wave train.