Ocean Currents: Download Ocean Currents Notes for UPSC

What is an Ocean Current?

Ocean currents are the directional movement of saltwater that is continuous and predictable. It is a large flow of ocean water created and affected by a number of factors. They resemble oceanic river flows. There are various forces and factors are responsible for directing an ocean current, such as-

• Wind
• Insulation or Sun Light
• Water Salinity
• The Coriolis Effect
• Gravitational Force

Characteristics of Ocean Currents

The ocean current is the horizontal movement of the stream of an ocean on a very large scale.

• The ocean currents are a continuous flow of water covering a large distance.
• The wind, Coriolis effect, gravity, temperature, etc. play a deciding role in the direction of the flow of ocean currents.
• These ocean currents are responsible for multiple climatic conditions across the world.
• The ocean currents mainly carry hot water or cold water. The current flowing from the equator carries warm water while the current flowing from the equator carries cold water.
• The ocean currents play a very significant role in heat distribution from the poles to the equator.

Types of Ocean Currents

Ocean currents can be differentiated on the basis of their depth. Therefore there are two types of ocean currents-

• Surface Currents: Surface currents are created by the global wind that gets energy from the Sun. As they trap the heat of the Sun, they transfer this heat to the polar region.
• Deep-Water Currents: Deepwater ocean currents are caused by changes in the water density which is further due to the variations in temperature and salinity of the water. This phenomenon is also called thermohaline circulation

Warm and Cold Ocean Currents

Ocean Currents can also be categorized based on temperature - Warm and Cold. Warm and Cold Ocean Currents UPSC Topic is often asked in the examination.

• Warm Ocean Current: The warm currents usually carry water from the equatorial region to the polar region as the cold water present at the poles sinks.
• Cold Ocean Current: Cold currents mostly flow from the polar regions to the equatorial regions and give a chilling effect to the surrounding land where they pass by.

List of Warm and Cold Ocean Currents

Below mentioned is the list of Cold Ocean currents,

Check the list of warm ocean currents below,

Factors Responsible for Ocean Currents

There are certain factors that are responsible for the occurrence and movement of ocean currents, let us explore them all-

Wind Cause the Ocean Currents

The wind is the most dominant force for ocean currents. It has been observed that most of the oceanic currents follow the direction of the planetary winds such as trade winds, westerlies, and polar easterlies.

Sunlight Causes the Ocean Currents

Sunlight is the other factor that affects ocean currents in an extensive manner. Sunlight mostly creates two differences: the first one is temperature difference sunlight being direct on the equatorial region heats up the water over there while the other one is salinity difference, where the water in regions away from equators has a low temperature as the sunlight is not direct and intense there.

Salinity and Ocean Currents

The presence of salt in ocean water determines the density of water as more salt content in water will make the water denser while less amount of salt results in less water density.

Coriolis Effects of Ocean Currents

Another very significant force responsible for the movement of ocean currents is the Coriolis force or Coriolis effect.

• Due to the movement of the earth that is from west to east direction the flow of water from the equator to the poles is never in a straight line. The deflective forces deflect the path of ocean currents, this deflective force is known as the Coriolis effect caused by the rotation of the earth.
• Because of the Coriolis effect, all the dynamic bodies are deflected in the clockwise direction in the northern hemisphere whereas they will be deflected in the anti-clockwise direction in the southern hemisphere.
• Similarly, the flow of ocean currents is also deflected in the northern hemisphere in the clockwise direction while in the anti-clockwise direction in the southern hemisphere

Ocean Currents UPSC Notes PDF

Ocean current is an essential and unavoidable concept of oceanography in world geography. To understand the oceans and the behavior of oceans it is a must for an aspirant to prepare this topic comprehensively because without understanding the oceanography in detail the concepts of world geography cannot be understood. Hence for a complete and thorough UPSC Exam preparation, all the concepts of world geography should be clear.

To prepare the Ocean Currents and other relevant concepts in more detail download the NCERT Booksfor UPSC or the UPSC Books. Ocean currents are quite an essential topic in regard to UPSC Prelims and Mains as well.

The aspirants willing to appear in the IAS Exam this year can also get UPSC Syllabus and Geography Books for UPSC here. Here the aspirants are also facilitated with the UPSC Previous Years Question Papers.

➩ Download Ocean Currents UPSC Notes PDF

Ocean Current UPSC Question

Q.1 Consider the following factors: [UPSC Prelims-2014]

1. Rotation of the earth
2. Air pressure and Wind
3. Density of the Ocean Water
4. Revolution of the Earth

Which of the above factors influence the ocean currents?

1. 1 and 2
2. 1,2,3
3. 1 and 4
4. 2,3,4

Answer:- Option 2

Q2. Consider the following statements: [UPSC Prelims 2002]

1. Ocean currents are slow to surface movement of water in ocean
2. Ocean currents assist in maintaining the earth’s heat balance
3. Ocean currents are set in motion primarily by prevailing winds
4. Tropical currents are affected by the configuration of the ocean

Which of the statements are correct?

1. 1 and 2
2. 2,3 and 4
3. 1,3 and 4
4. 1,2,3 and 4

Answer:- Option 2