Test 2 Flashcards
(22 cards)
Surface Currents
Driven by wind. In horizontal motion. Above pycnocline. Follow wind belt pattern.
Deep Currents
Driven by differences in density caused by differences in temperature and salinity. In vertical and horizontal motions.
Subtropical Gyres
Large circular loops of moving water. centered around 30 degrees latitude.
Subtropical Gyre Currents
- equatorial Currents- travel westward.
- Western Boundary Currents - warm waters
- Northern or Southern Boundary Currents - Easterly Water Basin
- Eastern boundary currents- cool waters
Equatorial Countercurrents
eastward flow between north and south equatorial currents.
Subpolar gyres
rotate opposite subtropical gyres. Smaller and fewer than subtropical gyres.
Ekman Spiral
Surface currents move at an angle to the wind. describes speed an direction of seawater flow at different depths. layers move to the right in northern hemisphere.
Ekman Transport
Average movement of seawater under influence of wind. 90 degrees to the right of wind in northern hemisphere. 90 degrees to the left of wind in southern hemisphere.
Upwelling
vertical movement of cold nutrient rich water to surface. high biological productivity.
Downwelling
vertical movement of surface water downward in water column. Lack of marine life
Antarctic Circumpolar Current AKA West Wind Drift & Penguin Gyre
Only one to completely encircle earth. Moves more water than any other current.
Gulf Stream
Best studied of all ocean currents. meanders and loops. merges with Sargasso Sea.
Gulf Stream Core Rings
Cold- water trapped in loop surrounded by warmer water.
Warm- warmer sargasso sea water trapped in loop surrounded by cool water
North moving Currents
warm. US & Europe. like gulf stream.
South moving currents
cool. eastern canada. north africa. Canary & labrador.
Monsoon
seasonal reversal of winds over northern indian ocean. Northeast-winter. southwest- summer.
Indian ocean Monsoons
affect land weather, current circulation, phytoplankton productivity.
Walker circulation cell
normal conditions
Air pressure across equatorial Pacific is higher in eastern Pacific
Strong southeast trade winds
Pacific warm pool on western side of ocean
Thermocline deeper on western side
Upwelling off the coast of Peru
El Nino
disrupts walker cell circulation. warm. and downwelling. weaker trade winds
La Nina
Increased pressure differences. stronger trade winds. stronger upwelling. higher biological productivity.
ENSO Events
2-10 years. irregular. phases last about 1 year.
Thermocline circulation
deep ocean circulation driven by temperature and density differences in water. below pycnocline. slow. 90% of all water. High latitude surface ocean.
