Pacific centre of the Arctic Oscillation: product of high local variability rather than teleconnectivity

Abstract

The North Pacific centre appears to be the weakest link in the concept of the Arctic Oscillation (AO), mainly because of its very low correlations with the other two centres, located over the Arctic and in the North Atlantic. Its latitudinal position and horizontal extent differ considerably in dependence on whether a covariance or correlation matrix is used as an input to principal component analysis. In the correlation-based analysis, the Pacific centre is much weaker and shifted 15◦ southwards. The teleconnectivity of the Pacific centre in the covariance- and correlation-based solutions is widely dissimilar. The coincidence of the covariance-based Pacific centre with an area of a high local variability and the lack of its correlations with remote areas imply that the Pacific centre of the AO is a result of a high local variability rather than teleconnectivity. This idea is supported by a simple three-component artificial example.