- Drift – Flows in the direction of the wind.
- Currents – It has limited changes and has a set direction. Currents are more effective than drift.
- Streams – All the rivers flowing into the sea are called streams.
Ocean Currents Divided into Two Parts
- Hot Currents
- Cold Currents
- An ocean current is a continuous movement of ocean water from one place to another.
- Ocean currents are caused by Earth’s motion and air pressure matter.
- Ocean currents are created by wind, water temperature, salt content and the gravity of the moon.
Factors Controlling Ocean Currents
- Gravitational force- (of moon and sun) and it is most in polar area, i.e. between 60°-70°-80°
- Earth’s rotation – Right north, left south.
- Winds- Sweeps water from East to West.
- Precipitation- Water becomes light and flows north and south.
- Temperature difference – Difference according to latitudes. Temperature is more effective factor.
Hot Ocean Currents and Climate
- Hot ocean currents, hot air on the coast.
- A warm current (e.g gulf stream) is hot and it also warms the coast.
- Warm, Humid air.
- Humid climate on the joining landmass.
Cool Ocean Currents
- Cool air at coast / cool currents of cool ocean.
- If there is a cold current on the coast, it makes the air there cool
- Cool, dry air
- Dry Climate on adjoining landmass.
Pacific Ocean starts from Australia. And it is up to Chile of South America. Pacific ocean is largest and deepest of Earth. The western part of America is known as the eastern part of the Pacific Ocean. And the eastern part of Asia is known as the western part of Pacific Ocean.
Pacific Ocean Circulation
North Pacific subtropical Gyre
- Kuroshio current – warm current
- Oyashio current
- California current
- North equatorial current
- Alaska current
1. Kuroshio current- It goes from bottom to top i.e. from 0°. And this current is hot because the temperature is higher at 0°. This current crosses Japan. The Kuroshio (black stream) is a fast moving warm current (24°c). The Kuroshio current heats the northern region of Japan. A small branch of this is the Tsushima Current, which flows into the sea from Japan.
2. Oyashio current- This current comes from polar meaning this current is cold. It is a cold sub-ocean current that flows south and circulates in the western, northern Pacific Ocean. The waters of the Oyashio current originate in the Arctic Ocean and flow southward through the Bering Sea. It passes through the Bering Strait and flows cold water from the Arctic Ocean into the Pacific Ocean.This current is also known as Okhotsk current.Currents emanating from the Pacific Ocean create a circle.
3. California current – California current is a Pacific ocean current that moves south along the west coast of North America. On reaching the Mexican coast, this current changes to the west ward and merges with the north equator. Temperature and salinity 9° to 26° and 32.5 to 34.5 parts per thousand respectively. And most importantly, this current is cold.
4. North equatorial current- The North equatorial current flows in the west direction of Mexico and reaches the Philippine coast after crossing a distance of 7500 seas. This is caused by the California Current and Northeast Monsoon. Occurs between North America and South America. Current speed is between 12 and 18 knots per day. This current is near the Equator hence the warm current.
5. Alaska current – Alaska current is exactly above California. Alaska current is warm. This current is between Canada and America.
And it is also believed that this current is important for fish. Most cyclones occur in the areas of Canada and America’s Alaska. Alaska current warms due to westerly winds and California force.
South Pacific Subtropical Gyre
- East Australian current
- Antarctic circumpolar current
- Peru current
- South equatorial current
- Equatorial counter current
1. East Australian current: The South Equatorial Current splits into a northern and southern branch near the coast of Australia. The southern branch flows south along the east coast of Australia as the East Australia Current. This is a hot current. and increases the temperature of the coast of eastern Australia. This current starts from the coast of Australia and extends up to 40° latitude (s).
2. antarctic circumpolar current: Antarctic circumpolar current is an ocean current that flows clockwise. Antarctic circumpolar current is also known as west wind drift. The Antarctic circumpolar current is the strongest current in the ocean and is known as the current that connects all the major oceans of the world. And this current is cold current.
3. Peru current: Peru current is also known as Humboldt current. Its flow capacity is 47 meters per day. It is a cold current because it comes from below i.e. from the glacier area. This current is called humbolt current because humbolt discovered this current.
4. South equatorial current: This current is near Equator ie near 0° so it is warm. This current extends from Peru to the Equator. And this is generated due to current trade winds.
5. Equatorial counter current – Trade winds tend to pile up large amounts of water in the western margin of the ocean, resulting in a general gradient of water from west to east.
Atlantic Ocean currents
North Atlantic (Hot Currents)
- North Atlantic drift
- Florida current
- Gulf stream
1. North Atlantic drift- This drift occurs at 0°-10°N. And this current is hot. Extends from West coast of Africa to Brazil. This drift is known for heavy rain fall.
2. Florida current – This hot current ahe, and from the Yucatán Channel to Cape Hatteras.
3.Gulf Stream – It flows between America and Canada. Its speed is high. Cape Hatteras to Grand Bank.
North Atlantic – (Cold currents)
- Labrador current
- Greenland current
- Canary current
1. Labrador current: This current comes from the polar area. It is formed by the melting of the current glacier. So, it is completely cold current. This current comes from the west part of Greenland.
2. Greenland current: This current comes from the East part of Greenland. Glacier melts and forms this current. Its direction is east.
3. Canary current: Starting from Madera, it goes to the coast of Africa / goes to the Sahara Desert and meets the North Atlantic.
South Atlantic Currents
South Atlantic Hot Currents
- South Atlantic Current
- Brazil Current
1. South Atlantic Drift (Hot Current): Its latitude is between 0°-12° south. It starts from Ambola coast to Brazil wind. These are formed from current trade winds.
2. Brazil Current: Its latitudes range from 12°-40° south. This is hot current. It starts from Brazil and extends to Argentina coast.
South Atlantic cold currents
- Falkland current
- Bangula current
- Westerly wind drift
1. Falkland current: It extends to the east coast of Argentina. Glacier melts and forms this current.
2. Bangula current: It extends to the Namibian coast of South Africa and trade winds are responsible for this.
3. Westerly wind drift: Trade winds are also responsible for this.
Indian Ocean Currents
North Indian Ocean currents (Hot)
South East Monsoon Current
This current is only in summer. It reaches the Indian sub-continent, up to Sumatra. And this is due to monsoon winds, it rains in India.
North East Monsoon Current
It comes only till winters. Its direction starts from Sumatra and goes to Samalia. This causes rain in India.
South Indian Ocean currents (Hot)
South Equatorial Current
It extends from Africa, roughly between 10°-15° axis. This current is from Africa to Australia.
lies in the eastern part of Australia. This is warm current.
This current is narrow, fast and strong. It is said to be the largest western boundary current. This current is happening.