Observed decadal tropical Pacific–North Atlantic teleconnections

Abstract

Observations of the last century are considered to investigate the decadal scale Pacific/North Atlantic teleconnections. By using wavelet analysis we find a significant low‐frequency coherency between major indices of climate variability. In particular, at periods between 10 and 20 yr, the North Atlantic Oscillation (NAO) tends to be out of phase with the El Niño/Southern Oscillation (ENSO) (strong Icelandic low during La Niña) and the Pacific Decadal Oscillation (PDO), but in phase with the North Pacific Index (NPI). Hence, the Icelandic low is strong during La Niña, but the Aleutian low is weak. The band‐pass SST pattern shows a close relationship between the “decadal‐ENSO” mode in the Pacific and the sea surface temperature anomaly tripole in the Atlantic, consistent with the low‐frequency global teleconnections. The spatial sea level patterns corresponding to the band‐pass filtered indices suggest that the Aleutian‐Icelandic Low seesaw is a main interbasin link on decadal time scale, consistent with the larger coherency of the NPI with the NAO than with ENSO.