Thermohaline Circulation Flashcards
What are primary drivers of deep-water?
Temperature, and salinity
What is thermohaline circulation?
vertical circulation caused by changes in density that are driven by variations in temperature and salinity.
What is a mixing line?
when two water types having the same density, but different values of salinity and temperature, are mixed, they form a new water type that lies on a mixing line.
What are water masses?
large volume of water that has the same salinity and temperature.
How are water masses identified?
by similar patterns of temperature and salinity from surface to depth
What are the mechanisms of internal mixing of ocean layers
winds, tidea, eddies, turbulent flow
What are the characteristics of layered oceans?
salinity, temperature, and density at the surface.
What does water density controls?
the depth to which the water sinks
What does sinking water do?
slowly mixes with adjacent layers eventually rises at another location.
How do winds impact internal mixing?
drive waves and currents that supply energy for mixing in shallow water
How do tides impact internal mixing?
create currents at all depths stirring together water.
How do eddies impact internal mixing?
form at boundaries of currents that homogenize deeper water masses.
How do tides impact internal mixing?
occurs when speed of a fluid at a point is continuously undergoing changes in magnitude and direction such that chaotic patterns emerge.
What are the layers in the Atlantic Ocean?
North Atlantic Deep Water
Antarctic Bottom Water
Mediterranean Intermediate
Antarctic Intermediate Water
South Atlantic Surface Water
How is North Atlantic Deep Water formed?
Surface water from arctic moves south, while surface water from low latitudes moves north along the coast of North America and then east across the North Atlantic.
How does Sea Ice form in the North Atlantic?
Downwelling of dense, salty water starts thermohaline circulation.
How is the Mediterranean Intermediate Water formed?
Water from the Mediterranean leaves the straight of Gibralter and mixes with NADW forming an intermediate layer.
How is the Arctic Intermediate Water formed?
Surface current convergence at 40°S forms less dense, warmer surface water between Equator and Antarctic. Remains above NADW and forms intermediate layer.
How is the South Atlantic Surface Water formed?
Divergence zone at 60°S brings mixed NADW & Antarctic Intermediate water to surface to form South Atlantic Surface water which moves northward.
How is Antarctic Bottom Water formed?
Formed along Antarctica. Is cold and salty from ice formation. It sinks below NADW but only up western side of Atlantic.
How fast is mixing are water masses in the Pacific?
Very slow
