Chapter 10 - Pacific Ocean

Abstract

This chapter discusses the Pacific Ocean. The Pacific Ocean is the largest of the three major oceans. It has well-developed wind-driven circulation systems in the subtropics, subpolar North Pacific, and tropics. In the south, the Pacific circulation transitions to the Southern Ocean, which connects it to the other oceans. The Pacific is also connected at low latitudes to the Indian Ocean through passages in the Indonesian archipelago. It is connected to the Arctic through the very shallow Bering Strait. The Pacific is the freshest of the three major oceans because of small differences in net evaporation/precipitation between the oceans. Compared with the North Atlantic, this freshness completely inhibits formation of deep waters and weakens formation of intermediate water in the northern North Pacific. At this global scale, the Pacific is one of the broad regions of deep upwelling that returns deep waters formed elsewhere back to mid-depths or even the surface. Because of its weak thermohaline circulation, the North Pacific upper ocean circulation is mostly associated with wind forcing. Therefore, it is useful to study the wind-driven circulation first in the context of the North Pacific and equatorial Pacific, followed by study of the other oceans. The chapter discusses concepts of wind and buoyancy forcing, and north Pacific circulation. It also provides details on Pacific Ocean mesoscale eddy variability and depth dependence of the Pacific Ocean circulation.