Relationship between Arctic Oscillation and Pacific Decadal Oscillation on decadal timescale

The relationship between the Pacific Decadal Oscillation (PDO) and the Arctic Oscillation (AO) on decadal timescale in the extended winter (November-March) is investigated in this study. The results indicate that AO plays an important role in the low frequency variability of PDO. When AO leads PDO by 7-8 years, the lagging correlation between them becomes the strongest with correlation coeffi- cient 0.77. The leading decadal variability of AO pro- vides a valuably precursory signal for predicting the variability of PDO. The results of regression and lag- ging correlation reveal the possible mechanism for the AO-PDO coupling: A strong AO would lead to an enhanced Aleutian Low that is linked to PDO by ocean-atmosphere interaction in the North Pacific, and vice versa.