Geography of Qava

Climate
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 over the North Paciﬁc (the Aleutian Low and the North Paciﬁc High) have intensiﬁed which has strengthened the winds along the western United States that cause deep water to rise to the surface, but has also strengthened the winds off Canada and South-East Alaska that cause surface waters to sink to deeper depths. The opposite gradient has occurred in the western North Paciﬁc. Ocean climate regimes are deﬁned on scales of decades, yet there are only 5 years of data available since 1998 with which to assess the new state. 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)