Essentials of Oceanography, Trujillo Chapter 7 Flashcards
What are the 2 main ways ocean circulation occurs
Density difference and wind
What currents are produced from wind circulation
surface currents, horizontal movement of water
What currents are produced from density difference circulation
Deep currents, vertical movement of water
What percent of wind energy is transferred into ocean currents
2 percent
What are gyres
Large circular circulation of ocean water
Where are gyres found
the centers of gyres are located at subtropical latitudes(subtropical gyres), and subpolar gyres
What are the 5 main subtropical gyres
North Atlantic, South Atlantic, North Pacific, South Pacific, and Indian gyres
What are equatorial currents
currents created by the trade winds at the equators that form form the equatorial boundary current of subtropical gyres. 2 main types: North equatorial current and South equatorial current
What comprises the western boundary currents of gyres
Warm equatorial currents
What comprises the Northern and Southern boundary currents of gyres
Prevailing westerlies creates Northern and Southern Boundary currents
What are eastern boundary currents of gyres
When currents flow back across the ocean basin,
the Coriolis effect and continental barriers turn them toward the equator,
What are equitorial countercurrents
volume of water is driven westward by
the north and south equatorial currents and piles up water on the western side of an
ocean basin near the equator, creating higher sea level there As a result, this bulge
of water flows downhill toward the east under the influence of gravity. This current,
called the equatorial countercurrent, is a narrow, easterly flow of water that occurs counter to and between the adjoining equatorial currents
What are subpolar gyres
when northern boundary currents move into subpolar latitudes, they are driven in a westerly direction by the polar easterlies and form subpolar gyres that rotate opposite the adjacent subtropical gyres
What is the ekman spiral
describes the speed and direction of
flow of surface waters at various depths.
What is eekman transport
net 90 degree movement of ocean currents due to coriolis effect and wind
What occurs at the center of a gyre
convergence and downwelling
What are geostrophic ocean currents
Balance between pressure force and coriolis effect, leading to a large-scale ocean current where the force of the pressure gradient is balanced by the Coriolis effect, causing the water to flow parallel to lines of equal pressure
what is caused by geostrophic ocean currents at the center of gyres
Water at the center of the gyres do not flow down the hill and instead flow in a circular pattern around the hill.
What is western intesification
due to the hill of water not being exactly in the center of the gyre and it being slightly to the west, western boundary currents are faster and narrower than other currents
What is equitorial upwelling
upwelling at the equator due to divergence of water
Main current in antarctic waters
Antarctic circumpolar current
What causes the ACC to form
strong westerly winds blowing across the Southern Ocean, which push the surface water eastward around Antarctica, creating a continuous current due to the lack of landmass obstructing its flow
What is the antarctic ocean current convergence
where colder, denser Antarctic waters
converge with (and sink sharply below) warmer, less-dense sub-Antarctic waters at
about 50 degrees south latitude.
What is the east wind drift
a surface current propelled by the polar easterlies,
moves from an easterly direction around the margin of the Antarctic continent.
What is the antarctic ocean current divergence
a divergence of currents along the boundary between the ACC and the east wind drift
What is the gulf stream
best studied ocean current. It
moves northward along the East Coast of the United States, warming coastal states
and moderating winters in these and northern European regions
describe downwelling and upwelling conditions at high latitudes
downwelling and upwelling happens often at high latitudes due to the absence of a pycnocline
What is antarctic bottom water
Extremely dense ocean water formed at southern areas around the antarctica continent due to rapid winter freezing
What does global thermohaline circulation cause
formation of global conveyer belt of water caused by thermohaline circulation.
Where does the global conveyer belt begin
north atlantic, where cold, salty water becomes dense and sinks to the ocean floor
What is the global conveyer belt called
Atlantic meridional overturning current
