Arctic-North Pacific coupled impacts on late autumn cold over North America

Abstract

It is examined about a physical linkage between the North Pacific SST and cold weather over North America as well as an underlying modulation effect by arctic condition during October to November. A representative oceanic variability in the North Pacific, the Pacific Decadal Oscillation (PDO), is known to bring anomalous cold over North America while its phase corresponds to positive. This study finds that the cold anomaly tends to intensify when the arctic surface exhibits pronounced warming over the Chukchi and East Siberian Sea regions. The modulation effect by arctic temperature manifests as an altered Rossby wave response to transient vorticity forcing resulting from equatorward storm track shift which is induced collaboratively by the PDO and warm arctic. In order to support observational evidences, arctic restoring experiments using CM2.1 model and stationary wave model (SWM) results are presented.