The first principal component (PC1) of seasonal rainfall anomalies in central Chile during winter (June–August) is used to analyze the circulation anomalies related to wet and dry conditions, when near-normal or neutral SST anomalies are observed in the equatorial Pacific, i.e., during non-ENSO conditions. Eight wet and eight dry winter seasons were defined as the upper and lower terciles of PC1 for 24 non-ENSO winters in the period 1958–2000. Unlike the single process attributed to ENSO, during non-ENSO winter seasons, there are several sources triggering or modifying the propagation of the stationary waves that impact the rainfall regime in central Chile. Unfortunately, the multiple processes that seem to be involved in the modulation of the interannual rainfall variability in central Chile, as seen in this work, limit the predictability of rainfall during non-ENSO conditions.
Rossby Wave Empirical Orthogonal Function Indian Ocean Dipole Rainfall Anomaly Empirical Orthogonal Function Mode
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We wish to thank H. Graβl and an anonymous reviewer for their helpful comments on the original manuscript. This work was supported by Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)-Chile through grant Fondecyt 1080058. NCEP–NCAR reanalysis data were provided by the Climate Diagnostic Center (NOAA). Rainfall data was supplied by the National Weather Service (DMC) and the Bureau of Water Management (DGA-MOP). Most figures were produced with the Grid Analysis and Display System (GrADS).
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