Ocean Currents – Meaning, Types, Effects, Hot And Cold Ocean Currents

Meaning of Ocean Currents

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

Importance 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 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 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. Questions are often asked pertaining to this topic. The complete details of the warm and cold ocean currents are presented here.

• 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 have a chilling effect on the surrounding land where they pass by.

List of Important Ocean Currents

The details pertaining to the warm and cold water currents have been listed here. You can check here, the regions from where it is originating. Below mentioned is the list of Cold Ocean currents.

Cold Ocean Currents List	Region	Features of Ocean Currents
Kurile or Oya shio Current	North Pacific Ocean	It is rich in nutrients
Humboldt or Peruvian Current	South Pacific Ocean	Characterized by low salinity.
Falkland Current	South Atlantic Ocean	The segment of the Antarctic Circumpolar Current. Also renowned as Malvinas current.
Canary Current	North Atlantic Ocean	Characterized by low salinity. It forms the major sink of the freshwater.
Western Australian Current	Southern Ocean & South Indian Ocean	Renowned as west wind drift
South Indian Ocean Current	South Indian Ocean	The cold current originating from the South Indian ocean
Eastern Greenland Current	Arctic Ocean & North Atlantic Ocean	It is characterized by low salinity
Labrador Current	North Atlantic Ocean	The amalgamation of the cold currents originating from the Labrador and warm from the Gulf stream forms an effective fishing ground.
Northeast Monsoon Current	North Indian Ocean	The route of the Northeast current is through the equator.
Benguela Current	South Atlantic Ocean	Characterized by low salinity possesses a fishing zone.
California Current	Pacific Ocean	The segment of the Pacific Gyre
Somali Current	West Indian Ocean	Monsoon is a major influencer of the Somali current
Antarctic Circumpolar Current	Southern Ocean	Also renowned as West Wind drift

Here is the list of the warm ocean currents and the regions from where they are originating.

Warm Ocean Currents List	Region	Features of Ocean Currents
Florida Current	South Atlantic Ocean & Caribbean Sea	Its route is Florida Peninsula
Agulhas Current	South-West Indian Ocean	It flows towards the southern direction
Gulf Stream	North Atlantic Ocean	Current motivated by wind stress
South Equatorial Current	Atlantic Ocean, Pacific Ocean, and the Indian Ocean	The route of the South equatorial current is from east to west
Southwest Monsoon Current	Indian Ocean	It occurs during the monsoon period in the Indian Ocean from June- October
El Nino Current	Central & East-Central Equatorial Pacific	The direction of the flow is eastern
Mozambique Current	Indian Ocean	The route of the flow is towards Mozambique and to the island of Madagascar
Brazilian Current	South Atlantic Ocean	It flows to the coast of Brazil
Norwegian Current	North Sea (Atlantic Ocean) & Barents Sea (Arctic Ocean)	It comprises two Arctic inflows of water
East Australian Current	South-Western Pacific Ocean	This transfers the tropical fauna of the habitats to sub-tropical regions
North Pacific Current	Pacific Ocean	The collide of Kuroshio and Oyashio resulted in the formation of the North Pacific current
Equatorial Counter Current	Atlantic Ocean, Pacific Ocean, and the Indian Ocean	The location and the route of the Equatoria counter current are in between North and South equatorial currents, the flow of the equatorial current is from west to east.
North Equatorial Current	Pacific Ocean & Atlantic Ocean	The route of the North equatorial current is from East to West
Tsushima Current	Sea of Japan	It flows through the north-eastward segment
Kuroshio Current	Pacific Ocean	Also renowned as Japan current and Black current
Irminger Current	North Atlantic Ocean	Combination of warm and saline waters
Antilles Current	North Atlantic Ocean	The route is northeasterly through the island that segregates the Caribbean sea from the Atlantic ocean
Alaskan Current	North Pacific Ocean	It is a consequence of the Northward part of the Pacific Ocean

Factors Responsible for Ocean Currents

Certain factors are responsible for the occurrence and movement of ocean currents, let us explore them all. The factors influencing ocean currents comprise wind, sunlight, and other factors such as salinity.

Wind Causes 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.

Characteristics of Ocean Currents

Ocean currents are massive movements of seawater that flow through the world’s oceans. Some of the main characteristics of ocean currents include-

• Ocean currents flow in specific directions, driven by various factors, including wind patterns, differences in water density, and the shape of the ocean basins.
• The Coriolis force causes warm currents originating from low latitudes to shift towards the right in the northern hemisphere and towards the left in the southern hemisphere.
• Ocean currents can vary in speed depending on their location, with some currents moving slowly and others moving rapidly.
• Ocean currents can occur at various depths within the ocean, with some currents occurring near the surface and others occurring at deeper depths.

Coriolis Effects of Ocean Currents

Another significant force responsible for the movement of ocean currents is the Coriolis force or Coriolis effect. Due to the movement of the earth from west to east, 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. In contrast, 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.

Effects of Ocean Currents

The ocean currents impact and contribute to being the major influencer of the climatic patterns, rainfall, in the formation of deserts, fogs etc. Check here the complete list of effects of ocean currents that have been provided here.

• Climatic patterns– The warm and cold ocean currents influence climatic conditions. The warm currents influence by surging the temperature of the region, whereas the cold currents lower the temperature of the area.
• Rainfall– The winds over warm currents also influence the rainfalls and play an instrumental role in cooling the area.
• Formation of Fog– The congregation of the warm and cold currents can influence the fog’s formation.
• Formation of Desert– The cold currents are responsible and are an influencer in the formation of deserts.
• It also influences trade and commerce by providing directions to the ships.

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 oceanography in detail, the concepts of world geography cannot be understood. For a comprehensive preparation for the exam, all the fundamentals of world geography ought to be distinct and clear.

Ocean Currents UPSC PDF

To get in touch with the core concepts of the Ocean Currents and other pertaining concepts and bring forth a methodical strategy, the candidates can get access to the NCERT Books for UPSC. Ocean currents are an extremely important topic with respect to UPSC Prelims and Mains as well.

Ocean Current Questions

The aspirants who are preparing and eyeing the IAS Exam can also check out the UPSC Syllabus and refer to the Geography books for UPSC. The candidates can track their performance level by practicing the questions that have been asked in previous years. The candidates can practice the questions that have been presented here.

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 influences 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

UPSC Notes
Ocean Acidification	India Deep Ocean Mission
Indian Ocean Dipole	River System in India
Local Winds	Types of Winds
Climate Change	Mediterranean Climate
Green Climate Fund	Environmental Impact Assessment