Major Ocean Current Circulation: Features & Patterns

Instructor: Amanda Robb

Amanda holds a Masters in Science from Tufts Medical School in Cellular and Molecular Physiology. She has taught high school Biology and Physics for 8 years.

This lesson will describe the major features of several ocean currents, including the Antarctic Circumpolar Current and the Atlantic, Indian, and Pacific Ocean circulations.

What Are Ocean Currents?

Have you ever been out on a boat on the open ocean? The wind pushes your hair away from your face and the salt water splashes against the hull. Even if the motor isn't on, your boat will tend to drift on the water unless you anchor down. Why is that? The answer is ocean currents. Ocean currents are the movement of water in the ocean from one location to another. There are specific current patterns that occur in each ocean.

However, all currents are driven by three main factors. First, tides themselves can cause ocean currents near the shore. Tidal currents mainly affect shoreline communities, such as estuaries, mangrove forests, and bays. Second, wind is a major factor in driving ocean currents. Wind pushes water on the surface and can drive water patterns for thousands of miles in the open ocean. Lastly, thermohaline gradients affect current. The prefix ''thermo'' refers to temperature gradients and the suffix ''haline'' refers to the concentration of salt in the ocean. Thermohaline currents move much slower than currents driven by wind or the tides but can affect water in any part of the ocean.

Antarctic Circumpolar Current

The Southern Ocean is one of the most hostile environments on Earth. Circling the globe at latitudes between 40 and 60 degrees South, the Southern Ocean is the only open ocean that circles the entire globe. Large glaciers, ice flows, and harsh wind make this ocean incredibly difficult to navigate. The main current that prevails here is the Antarctic Circumpolar Current (ACC).

The Antarctic Circumpolar Current flows around the globe in the Southern Ocean

Due to the rotation of the Earth and prevailing winds, the Antarctic Circumpolar Current flows from west to east in direction. This ocean current connects the three oceans, Atlantic, Indian and Pacific. The Antarctic Circumpolar Current is important in regulating global climate as it redistributes heat within the three oceans, which in turn regulates weather and precipitation.

Atlantic Ocean Circulation

The Atlantic Ocean circulation brings warm water from the tropics to Europe and deep, cold water from the Arctic back to northern Canada. This current in the Atlantic is known as the Atlantic Meridional Overturning Circulation (AMOC). The AMOC is important for regulating global climate and temperature as well. The current moves in a counter-clockwise direction, starting from the tropics and flowing north towards the Arctic. This brings warm, salty water and warmer weather to the western countries of Europe and brings cooler water from the Arctic into Canada and Greenland.

Currently, scientists are concerned because the current seems to be slowing down. Research shows that the AMOC hasn't been running at full strength since the mid-1800's and is currently at a record low. This is important because it has implications for climate and weather patterns across the globe, as the AMOC is an important regulator of heat distribution. Scientists think that climate change has something to do with the slowing, as warmer temperatures are causing glacial melting that is diluting the surface seawater, making it lighter and less able to sink, which normally drives the AMOC.

Indian Ocean Circulation

The Indian Ocean circulation is unique because there are separate patterns for the north and south ocean currents. Unlike other oceans, the north Indian Ocean current actually changes directions based on the season. This change corresponds with the monsoon season, which is a major climatic feature of the area.

During the monsoon season (November through March) the Monsoon Drift, the main current in the Indian Ocean, flows west to southwest, crossing over the equator in a counter-clockwise direction. During the dry season, from April to October, the flow reverses and travels east in a clockwise direction, branching north into the Arabian Sea and the Bay of Bengal.

The southern Indian Ocean is less dependent on season and tends to behave like other oceans in the world. The current in the southern Indian Ocean is influenced by Pacific currents and flows east to west.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account