Wednesday 30 December 2015

The Circulation of the Pacific Ocean

The pattern of circulation in the Pacific is similar to that of the Atlantic except in Modifications which can be expected from the greater size and the more open nature of the Pacific.
The North Equatorial Current flows westwards with a compensating Equatorial Counter Current running in the opposite direction. Due to the greater expanse of the Pacific and the absence of an obstructing land mass the volume of water is very much greater than that of the Atlantic equatorial current. The North-East Trade winds blow the North Equatorial Current off the coasts of the Philippines and Formosa into the East China Sea as the Kuroshio or Kuro Siwo or japan Current. Its warm waters are carried polewards as the North Pacific Drift, keeping the ports of the Alaskan coasts ice-free in winters. The cold Bering Current or Alaskan Current creeps southwards from the narrow Bering Strait  and is joined by the Okhotsk Current to meet the warm Japan Current as the Oyashio, off Hokkaidi. The cold water eventually sinks beneath the warmer waters of the North pacific Drift. Part of it drifts eastwards as the cool Californian current along the coasts of the western U.S.A. and coalesces with the North Equatorial Current to complete the clockwise Circulation.
The current system of the South Pacific is the same as that of South Atlantic. The Sputh Equatorial Current, driven by the south-east Trade Winds, flows southwards along the coasts of Queensland as the east Australian Current, bringing warm equatorial waters into temperate waters. The current turns eastwards towards new Zealand under the full force of the Westerlies in the Tasman sea and merges with part of the cold West Wind Drift as the South Pacific Current. Obstructed by the tip of southern Chile, the current turns northwards along the western coasts of South America as the cold Humboldt or Peruvian current. The cold water Chilean and Peruvian coasts are practically rainless. The region is rich in microscope marine plants and animals that attract huge shoals of fish. Consequently, millions of seabirds gather here to feed on the fish. Their droppings completely whiten the coastal cliffs and islands, forming thick deposits of guano, a valuable source of fertilizer. The Peruvian Current eventually links up with the South Equatorial Current and completes the cycle of the currents in the South Pacific.
For more updates stay tuned and subscribe via email.

No comments: