Anthropogenic Forcing on Changes in the Wintertime Atmospheric Variability in the Pacific Sector

This study mainly examines changes in atmospheric circulation variability in the North Pacific sector during the past decades, and associated pattern shifts in the Pacific-North America (PNA) and North Pacific Oscillation (NPO) teleconnections in the observations. It is found that the observed variability of sea level pressure is significantly enhanced in the Alaska Gulf and along coast of North America since the late 1970s. The northern centers of action of wintertime PNA and NPO variability are located further northeastward than before since the late 1970s.

The possible roles of anthropogenic forcings in changes in the above atmospheric circulation variability is investigated through the simulations in the IPCC AR4/AR5 simulations.