Teleconnection Patterns Appearing in the Streamfunction Field

Abstract

Teleconnection patterns in boreal winter were sought by using the streamfunction based on one-point covariance analysis. As a result, five patterns with two new patterns, i.e., the North and South Pacific Oscillation pattern (PO) and the Middle Atlantic pattern (MA), were obtained. The PO is an interhemispheric pattern with major centers in the Pacific, related to the El Niño/La Niña. The MA has a similar structure with the East Atlantic pattern (EA), though the orientation of the pattern and the difference in the sustaining mechanism, as well as a relatively low correlation between the two indices, distinguish the MA from the EA, with the primary importance of the MA from several pieces of evidence. The PO and MA have significant relations to the surface air temperature mostly through the temperature advection. By comparing the result of the combined EOF for the zonal and meridional winds, the appropriateness of the use of the streamfunction in association with wind variations was also confirmed.