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Ocean Currents. A penguin walks into a bar and asks the pharmacist for Chapstick . After grabbing the Chapstick , the pharmacist asks the penguin, “ How would you like that ?” The penguin replies, “ Just put it on my bill.”. Why is Ocean Circulation Important?.
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A penguin walks into a bar and asks the pharmacist for Chapstick. • After grabbing the Chapstick, the pharmacist asks the penguin, “How would you like that?” • The penguin replies, “Just put it on my bill.”
Why is Ocean Circulation Important? • Transport heat • Equator to poles • Transport nutrients and organisms • Influences weather and climate • Influences commerce
Major Ocean Currents • An Ocean Current is a large volume of water flowing in a certain direction. • Wind-driven currents are called surface currents. • Surface currents carry warm or cold water horizontally across the ocean’s surface
Ocean Currents • Surface Currents • The upper 400 meters of the ocean (10%). • Deep Water Currents • Thermal/Salinity currents (90%)
Transport by Currents • Surface currents play significant roles in transport heat energy from equatorial waters towards the poles • Currents also involved with gas exchanges, especially O2 and CO2 • Nutrient exchanges important within surface waters (including outflow from continents) and deeper waters (upwelling and downwelling) • Pollution dispersal • Impact on fisheries and other resources
90o 60o Surface Currents • Forces • Solar Heating (temp, density) • Winds • Coriolis 30o 0o 30o 60o 90o
Coriolis Effect • The Coriolis Effect is the movement of wind and water to the right or left that is caused by Earth’s rotation. • It causes fluids such as air and water to curve to the right in the Northern hemisphere, in a clockwise direction. • The Coriolis effect also cases fluids to curve to the left in the southern hemisphere, in a counterclockwise direction.
Coriolis Effect • The shapes of continents and other land masses affect the flow and speed of currents. • Currents form small or large loops and move at different speeds, depending on the land masses they contact.
What do Nike shoes, rubber ducks, and bottles have to do with currents?
Duckie Progress • January 1992 - shipwrecked in the Pacific Ocean, off the coast of China • November 1992 - half had drifted north to the Bering Sea and Alaska; the other half went south to Indonesia and Australia • 1995 to 2000 - spent five years in the Arctic ice floes, slowly working their way through the glaciers2001 - the duckies bobbed over the place where the Titanic had sunk • 2003 - they were predicted to begin washing up onshore in New England, but only one was spotted in Maine • 2007 - a couple duckies and frogs were found on the beaches of Scotland and southwest England.
Surface and Deep-Sea Current Interactions “Global Ocean Conveyor Belt”
Density Currents • Density Currents are a type of vertical current that carries water from the surface to deeper parts of the ocean. • Density Currents are caused by changes in density rather than wind. • Density currents circulate thermal energy, nutrients and gases.
Thermohaline Circulation Global ocean circulation that is driven by differences in the density of the sea water which is controlled by temperature and salinity.
Thermohaline Circulation White sections represent warm surface currents. Purple sections represent deep cold currents
Great Ocean Conveyor Belt • The Great Ocean Conveyor Belt is the name for a model of the large system of ocean currents that affects weather and climate by circulating thermal energy around Earth. • In this model, high salinity water cools and sinks in the North Atlantic, and deep water returns to the surface in the Indian and Pacific Oceans through upwelling
Great Ocean Conveyor Belt • Scientists estimate that the Great Ocean Conveyor Belt model takes about 1,000 years to complete a cycle.
Impacts of Weather and Climate • Warm-water currents and cold-water currents affect weather and climate in different ways • Regions near warm-water currents are often warmer and wetter than regions near cold-water currents
Impacts on Weather and Climate • The Gulf Stream is a warm-water current that affects coastal areas of the southwestern United States by transferring lots of thermal energy and moisture to the surrounding air. • The cold California Current affects coastal areas of the southwestern United States.
Where does seaweed look for a job? In the kelp-wanted ads!
Upwelling • Upwelling is the vertical movement of water toward the ocean’s surface. • Upwelling occurs when wind blows across the ocean’s surface and pushes water away from an area. Deeper colder water then rises to replace it. • Upwelling often occurs along coastlines. • Upwelling brings cold, nutrient-rich water from deep in the ocean to the ocean’s surface.
Upwelling and downwelling Vertical movement of water • Upwelling = movement of deep water to surface • Hoists cold, nutrient-rich water to surface • Produces high productivities and abundant marine life • Downwelling = movement of surface water down • Moves warm, nutrient-depleted surface water down • Not associated with high productivities or abundant marine life
upwelling downwelling
El Niño-Southern Oscillation (ENSO) • El Niño= warm surface current in equatorial eastern Pacific that occurs periodically around December • Southern Oscillation= change in atmospheric pressure over Pacific Ocean accompanying El Niño • ENSO describes a combined oceanic-atmospheric disturbance
El Niño • Oceanic and atmospheric phenomenon in the Pacific Ocean • Occurs during December • 2 to 7 year cycle • Sea Surface Temperature • Atmospheric Winds • Upwelling
Non El Niño El Niño 1997
Non El Niño upwelling El Niño Thermocline – layer of ocean right beneath the “mixed layer” where temperatures decrease rapidly.
El Niño events over the last 64years El Niño warmings (red) and La Niña coolings (blue) since 1950. Source: NOAA Climate Diagnostics Center
World Wide Effects of El Niño • Weather patterns • Marine Life • Economic resources El Nino Animation
