Ocean Circulation

Flashcards covering key concepts related to ocean circulation, currents, and their effects on climate and marine life.

What are ocean currents?

Moving loops of water that redistribute global heat.

What influences ocean currents?

Surface winds, distribution of continents, gravity, friction, and the Coriolis effect.

What drives surface currents?

Wind-driven, primarily horizontal motion.

What drives deep currents?

Differences in density caused by temperature and salinity.

What is thermohaline circulation?

Deep ocean circulation driven by temperature and density differences in water.

What is the significance of ocean currents?

They affect marine life and serve as a source of energy.

What do surface currents affect?

Only about 10% of ocean water on Earth.

How much wind energy is transferred to the ocean surface?

About 2% of wind energy.

What are subtropical gyres?

Five large, circular loops of moving water centered around 30 degrees latitude.

What creates high and low pressure in ocean currents?

Wind piling up water creates high pressure and areas from which water is taken creates low pressure.

What is the Ekman spiral?

A model that explains the relationship between friction and the Coriolis effect in ocean currents.

What is net Ekman transport?

Average movement of surface waters, 90 degrees to the right in the Northern Hemisphere and left in the Southern Hemisphere.

What is Antarctic Bottom Water (ABW)?

Cold, dense surface seawater that sinks at polar regions.

What effect does the Gulf Stream have?

It warms the east coast of the United States and northern Europe.

What does the term 'La Niña' refer to?

The cool phase of the El Niño-Southern Oscillation, characterized by cooler ocean temperatures.

What is the typical duration of El Niño events?

About 12 to 18 months.

What phenomenon is linked with the Pacific Decadal Oscillation (PDO)?

El Niño events may be part of this long-term natural climate cycle lasting 20-30 years.

How do El Niño conditions affect upwelling?

They cause downwelling and lower biological productivity.

What conditions characterize a normal Walker Circulation?

Higher air pressure in the eastern Pacific with strong southeast trade winds.

What happens during an El Niño event?

Weaker trade winds, warmer waters in the eastern Pacific, and a deeper thermocline.

What created the unique algorithm involved in ocean current mapping?

A fleet of 30,000 rubber toys that fell off a cargo ship helped study ocean currents.

How do currents impact marine ecosystems?

They influence nutrient delivery and temperature variations vital for marine life.

What are warm-core and cold-core rings?

Warm-core rings are warmer water trapped in a loop surrounded by cooler water; cold-core rings are cooler water trapped in loops surrounded by warmer water.

What additional current also affects the North Atlantic region?

Norwegian Current.

What is the density-driven circulation model developed by V. Walfrid Ekman?

Ekman spiral.

What role does the Coriolis effect play in ocean currents?

It causes the deflection of currents to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Why is the Gulf Stream significant to climate?

It significantly warms the climate of the eastern United States and western Europe.

What is the average sea surface temperature anomaly during La Niña conditions?

Typically cooler than normal seawater.

What are the primary currents of the North Atlantic gyre?

North Equatorial Current, Gulf Stream, North Atlantic Current, and Canary Current.

What does 'density' in water relate to?

Temperature and salinity differences.

What is a stressor in the context of ocean currents?

Factors such as wind that drive the movement of ocean water.

What area is uniquely characterized by holopelagic Sargassum?

Sargasso Sea.

What happens to temperature during El Niño events?

Ocean temperatures rise in the eastern and central Pacific.

What is the role of coastal winds in current dynamics?

They impact the upwelling and mixing of ocean waters.

What trend does the Multivariate ENSO Index reflect?

Changes in ENSO warm phase (El Niño) and cool phase (La Niña) occurrences.

What does the term 'upwelling' explain?

Cold water rising to the surface to replace warm water displaced by wind.

How do winds influence ocean surface currents?

Winds drive the frictional drag that initiates movement in ocean currents.

What is meant by 'thermocline'?

A layer in which temperature changes rapidly with depth.

How do ocean currents contribute to global heat redistribution?

They transport warm water from the equator towards the poles and cold water back to the equator.

What is an implication of negative sea surface temperature anomalies?

They indicate cooler than normal seawater during certain climatic events.

What conditions are necessary for thermohaline circulation to occur?

Cold, dense water must sink in high latitude regions to drive deep ocean currents.

How do ocean currents affect precipitation patterns?

They influence weather by transporting heat and moisture around the globe.

What phenomenon occurs when trade winds weaken and the warm water pool shifts eastward?

El Niño.

What current flows along the U.S. East Coast?

Gulf Stream.

How do currents interact with marine biology?

They transport nutrients that support marine ecosystems.

Describe the Gulf Stream’s flow pattern.

It moves northward and is characterized by meanders and loops.

What is the primary function of the Antarctic Circumpolar Current?

It circulates cold Antarctic waters around the continent.