Oceanography

Terminologies

Tidal range

Difference in height between mean high water and mean low water, measured in feet or meters.

Tidal bore very rapid rise of the tide in which the advancing water forms an abrupt front;occurs in certain shallow estuaries having large tidal range.

Tidal bulge(tidal crest) long-period wave associated with the tide-producing forces of the moon and sun identified with the rising and falling of the tide. The trough located between the two tidal bulges present at any give time on the earth is known as the tidal trough.

Tidal constituent an element in a mathematical expression for the tide-generating forced, tides, or tidal currents. Each constituent represents a periodic change or variation in the relative positions of the Earth, moon, and sun.

Tidal current alternating horizontal movement of water associated with the rise and fall of the tide.

Tidal day interval between two successive upper transits of the moon over a location. A mean tidal day, some times called a lunar day, is 24 hours, 50 minutes.

Tidal flats marshy or muddy areas which are covered and uncovered by the rise and fall of the tide; also called tidal marshes. Usually covered by plants.

Tidal period elapsed time between successive high or low waters.

Tidal range difference in height between consecutive high and low waters.

Tide periodic rise and fall of the ocean and atmosphere, caused by the gravitational attraction of moon and sun acting on the Earth.

Tide curve presentation of the rise and fall of tide; time (in hours or days) is plotted against height of the tide.

Tide producing forces slight local difference between the gravitational attraction of two astronomical bodies and the centrifugal force that holds them apart. Gravitational attraction predominates at the surface point nearest to the other body while centrifugal “repulsion”predominates at the surface point farthest from the other body.

Tide pool depression-usually water filled-in the intertidal zone, alternately submerged and exposed by the rise and fall of tide or wave action.

Tide tables tables that predict the times and heights of tidal phenomena at specified locations.

Tide wave long-period gravity wave that has its origin in the tide-producing force; manifests itself in the rising and falling of the tide.

Tide winds wind system, in most of the tropics, which blow from the subtropical highs toward the equatorial lows. Trade winds are from the northeast in the northern Hemisphere,fromm the southeast in the Southern Hemisphere.

Thermocline marked vertical temperature change in a body of water; also a layer in which such a temperature change occurs.

Thermohaline circulation circulation induced by differences on water density which is controlled primarily by temperature and salinity.

Spring tide tide of increased range that occurs about every 2 weeks when the moon is new or full.

Neap tide lowest range of the tide, occurring near the times of the first and last quarters of the moon.