Ocean Circulation

1. wind driven

2. thermohaline circulation

two main types of ocean circulation:
1. (affects the upper layer)
2. (controls deep water below the pycnocline)

density differences

what drives thermohaline circulation?

surface water moves at 45 degrees to the right of the wind direction

how does the coriolis for affect surface water direction in the northern hemisphere?

90 degrees to the right of the wind

what is the net direction of water transport in the total mixed layer?

wind stress and the coriolis force

what two forces balance to create the ekman spiral?

geostrophic gyre

a large circular current maintained by a balance between the pressure gradient and the coriolis effect

western boundary

currents that are warm, narrow, deep, and fast (ex: Gulf Stream)

eastern boundary

currents that are cold, broad, shallow, and weak (ex: Canary Current)

the magnitude of the coriolis force increases with latitude, causing the center geostrophic hill to shift west

why are subtropical gyres “intensified” or offset to the West?

antarctic circumpolar current

which current carries the largest transport of any in the world?

coastal upwelling in Northern hemisphere

winds blowing along a coast that move surface water away from shore cause

brings nutrients to the surface

biological benefits of upwelling?

easterly winds

in louisiana, what wind direction causes coastal flooding?

westerly winds

what wind direction in Louisiana causes upwelling?

cold core Eddie (cyclonic)

sea surface lows, shallow thermocline, upwelling, nutrient rich

warm core Eddie (anticyclonic)

sea surface highs, deep thermocline, downwelling, nutrient poor

up to one year (reach depths of 1000m)

how long can a warm core eddy in the Gulf of Mexico last?

oceanic desert

warm core eddies are nutrient poor _____ _____

oasis

cold core eddies are nutrient rich _____

90%

what percent of the ocean’s volume is involved in thermohaline circulation?

weddell sea in Antarctica

where does the denser water mass form? (due to freezing sea ice)

great ocean conveyor belt

a global cycle of deep and surface currents; it takes roughly 1000 years for newly formed North Atlantic deep water to reach north pacific

because evaporation is such higher than precipitation in the Mediterranean

why does mediterranean deep water flow out of the Straits of Gibraltar?

sverdrup

a unit of volume transport equal to 1 million cubic m/s

Lagrangian

follows a parcel of water (ex: drifters, rubber ducks, etc)

eulerian

measures current from a fixed point (ex: moorings)

1. CFCs

2. Tritium

what chemicals are used to date water masses?:
1.
2.