Oceanic Circulation and Currents

Oceanic Circulation

• Oceans redistribute global energy, receiving ~⅔ of solar energy hitting Earth's surface.
• Oceans retain heat longer than land.
• Ocean currents transport ~25% of Earth's heat budget.

Ocean Currents

• Ocean currents are horizontal water movements.
• Warm currents move warmer water from lower latitudes (nearer equator) to higher latitudes (nearer poles).
• Cold currents move colder water from higher latitudes to lower latitudes.
• Temperature of water in currents depends on its comparison to typical temperatures at that latitude, not necessarily on absolute value.
• Driven by wind and thermohaline circulation.

How Ocean Currents Work

• Wind friction moves surface waters.
• Coriolis Effect deflects wind-driven currents right in the Northern Hemisphere and left in the Southern Hemisphere.
• Thermohaline: related to heat (thermo) and salinity (haline).
• Temperature and salinity affect water density (colder and saltier water is denser).
• Precipitation, evaporation, and river runoff influence salinity.
• Cold salt water (unlike fresh water) continues to become denser until freezing.
• Dense, cold, salty water sinks near Antarctica and Greenland.
• In Antarctica, brine left behind when sea ice forms makes water denser.
• In Greenland, warm, salty water becomes colder and denser than surrounding water.
• Horizontal currents flow from low to high density.

Pattern of Ocean Currents

• Currents flow in circular loops (gyres).
• Gyres are found in both hemispheres.
• Northern Hemisphere gyres flow clockwise; Southern Hemisphere gyres flow counter-clockwise.
• Strong, warm, poleward flows are concentrated along western edges of ocean basins. Examples include Gulf Stream, Kuroshio Current, Agulhas Current.
• Atlantic, Pacific, and Indian Ocean currents exhibit similar patterns, but the Atlantic has stronger vertical circulation.
• Southern Ocean currents have stronger, deeper flow eastward, with less noticeable poleward flow due to lack of landmasses connecting to Antarctica.

Explore the fascinating world of oceanic circulation and currents in this quiz. Learn how oceans play a critical role in redistributing global energy, the differences between warm and cold currents, and the effects of wind and thermohaline processes. Test your knowledge on this important aspect of Earth's climate system.