Quasi‐decadal spectral peaks of tropical western Pacific SSTs as a precursor for tropical cyclone threat

A recent study identified significant spectral peaks in sea surface temperatures (SSTs) at quasi‐decadal frequency bands, which were unique to the tropical western Pacific (TWP). Using the multitaper method for spectral and coherence analysis, this study finds that the TWP SSTs at these quasi‐decadal time scales are coherent with western Pacific tropical cyclone threat [as measured by the power dissipation index (PDI)], but that the PDI lags TWP SSTs by about two years. Thus, the quasi‐decadal peaks in TWP SSTs may be a precursor for enhanced tropical cyclone threat two years later. Composite analyses are shown to illustrate how areal tropical cyclone frequencies and relevant atmospheric fields evolve following the quasi‐decadal peaks in TWP SSTs. The fields during peak PDI years strongly resemble those observed during El Niño events.