24 terms

amphidromic point

the node(s) near center of an ocean basin; no tide pt in the ocean around which tidal crest rotates through 1 tidal cycle

astronomical tide

tides caused by inertia & the gravitational force of the sun & moon

diurnal tide

tidal cycle of 1 high tide & 1 low tide per day

dynamic theory of tides

model of tides that takes into account the effects of finite ocean depth, basin resonances, & the interference of contintents on tide waves

ebb current

water rushing out of an enclosed harbor or bay due to the fall in sea level as a tide trough approaches

equilibrium theory of tides

model of tides that considers Earth to be covered by an ocean of great & uniform depth capable of instantaneous response to the gravitational & inertial forces of the sun & moon

flood current

water rushing into an enclosed harbor or bay die to the rise in sea level as a tide crest approaches

high tide

high-water position corresponding to a tidal crest

low tide

low-water position corresponding to a tidal trough

lunar tide

tide caused by gravitational & inertial interaction of the moon & Earth

mean sea level

the height of the ocean surface averaged over a few years' time

meteorological tide

a tide influenced by the weather. Arrival of a storm surge will alter the estimate of a tide's height or arrival time, as will a strong , steady onshore or offshore wind

mixed tide

a complex tidal cycle, usually with 2 high tides & 2 low tides of unequal height per day

neap tide

time of smallest variation between high & low tides occurring when Earth, moon & sun align at right angles; alternate with spring tides, occurring at 2 week interverals

semidiurnal tide

a tidal cycle of 2 high tides & 2 low tides each lunar day, with the high tides of nearly equal height

slack water

a time of no tide-induced currents that occurs when the current changes direction

solar tide

tide caused by the gravitational & inertial interaction of the sun & Earth

spring tide

time of greatest variation between high & low tides occurring when Earth, moon, & sun form a straight line; alternate with neap tides, occurring at 2 week intervals

tidal bore

a high, often breaking wave generated by a tide crest that advances rapidly up an estuary or river

tidal current

mass flow of water induced by the raising or lowering of sea level owing to passage of tidal crests or troughs

tidal datum

the reference level (0,0) from which tidal height is measured

tidal range

difference in height between consecutive high & low tides

tidal wave

the crest of the wave causing tides; another name for tidal bore

tide

periodic short term change in the height of the ocean surface at a particular place, generated by long wavelength progressive waves; caused by interaction of gravitational force & inertia. Movement of Earth beneath tide crests results in the rhythmic rising & falling of sea level