ENSO-like Interdecadal Variability: 1900–93

摘要: A number of recent studies have reported an ENSO-like EOF mode in the global sea surface temperature (SST) field, whose time variability is marked by abrupt change toward a warmer tropical eastern Pacific and colder extratropical central North 1976‐77. The present study compares this pattern with structure interannual associated ENSO cycle documents its history back to 1900. analysis primarily based on leading EOFs SST anomaly ‘‘anomaly deviation’’ fields various domains expansion coefficient (or principal component) series, which are used construct regression maps SST, level pressure (SLP), related variables. use deviations’’ (i.e., departures local anomalies from concurrent global-mean anomaly) reduces influence trends upon their series. An important auxiliary series ‘‘Southern Oscillation index’’ marine observations. By means several different techniques, field separated into two components: one identified ‘‘ENSO cycle-related’’ timescale, other linearly independent ‘‘residual’’ comprising all interdecadal record. components exhibit rather similar spatial signatures SLP, wind stress fields. signature residual less equatorially confined it relatively more prominent over Pacific. corresponding SLP also stronger Pacific, counterpart cold season 500-mb height closely resembles PNA pattern. amplitude reflects above-mentioned shift 1976‐77, as well features, including opposite polarity during 1940s.