chapter 14 ocean motions Flashcards
ocean tides
daily or twice-daily changes in local sea level.
tide gauges
an instrument used to measure tides
lunar tides
means that the moon effects the tides more than the sun.
spring tide
when the sun works with the moon and the tide is higher than high.
neap tide
when the sun and moon work together to form a lower than low tide.
bay of fundy
in new brnswick, the tide rises over 52 ft.
surface currents
are set in motion by winds.
gyres
when currents form great circling flows.
eddies
swirling patterns
walfrid elkman
swedish physicist who came up with the elkman spiral.
downwelling
opposite of upwelling. occurs were sea level is higher that average as surface currents cause the ocean to pile up.
coastal upwelling
can occur near coastlines when prevailing winds drive surface waters away from shore.
subsurface currents
surrents deep in the oceans that are much larger than surface surrents
density currents
gravity derived currents that result from density differences.
thermohaline currents
the most significant of the deep density currents are the deep circulation.
turbidity curent
another kind of density current that is similiar to an under water mudslide or lahar.
water wave
uses the repeated motion of the matter in water to transfer mechanical energy from one place to another.
wave base
deepest depth below the ocean’s surface that is affected by the wave’s passage.
wave period
time beetween one wave crest and the next as they pass a stationary point
wave speed
how fast a wave crest moves.
longshore current
a current that flows parallel to the shore.
