Oceanography
| External images | |
|---|---|
| Animation of the tides in Cook Strait – NIWA | |
| Animation of the lunar (M2) tide component around NZ | |
| Cook Strait currents before and after high tide at Wellington – Te Ara: Encyclopedia of New Zealand. | |
| Underwater topography of Cook Strait – NIWA | |
The waters of Cook Strait are dominated by strong tidal flows. The tidal flow through Cook Strait is unusual in that the tidal elevation at the ends of the strait are almost exactly out of phase with one another, so high water on one side meets low water on the other. Strong currents result, with almost zero tidal height change in the centre of the strait. Although the tidal surge should flow in one direction for six hours and then the reverse direction for six hours, a particular surge might last eight or ten hours with the reverse surge enfeebled. In especially boisterous weather conditions the reverse surge can be negated, and the flow can remain in the same direction through three surge periods and longer. This is indicated on marine charts for the region. Furthermore the submarine ridges running off from the coast complicate the ocean flow and turbulence.
There are numerous computer models of the tidal flow through Cook Strait. While the tidal components are readily realizable, the residual flow is more difficult to model.
Read more about this topic: Cook Strait