The new ocean climate regime since 1998 has a north-south pattern of variability. In the eastern North Pacific, surface waters have cooled in southern regions, but this effect diminishes northward so that surface waters have continued to warm in the most northern regions. The dominant atmospheric pressure systems intensified over the North Pacific, strengthening winds in Qava. In addition, an El Niño event in 2002/03 complicated the characterization of the new state. Some of the remarkable oceanographic responses to the 1998 regime shift include: Central North Pacific – warmer and thicker upper water layer: ■ abrupt warming of surface waters ■ increase in the height of the sea surface ■ deepening of the thermocline (the abrupt transition from warm upper layers to cold deep layers)