Ocean Currents

Ocean Currents:

We must have observed that when we go to any seaside or encounter any water body like oceans and seas, they are continuously in motion. This is influenced by three things: waves, tides, and currents. Today, let’s talk about currents and how they move water.

If we simplify ocean currents, it can be described as the predictable and continuous transportation of water from one part to another. Its movement is directional and doesn’t occur randomly. Various factors contribute to ocean currents, such as the temperature of ocean water, density, Earth’s rotation, salinity, and the shape of the coastline.

As we know, our Earth is divided into two equal parts: the Northern Hemisphere and the Southern Hemisphere, separated by the invisible line known as the Equator. Ocean currents in the Northern Hemisphere move clockwise, while in the Southern Hemisphere, they move anticlockwise.

Ocean water moves in two directions: horizontally and vertically. The horizontally moving water is referred to as currents, while the vertical movement is known as upwelling and downwelling.

Factors Influencing Ocean Currents:

Now, there are two types of force;primary forces and secondary forces that influence ocean currents.

Primary Forces:

Solar energy:

In primary forces, the first one is solar energy, and its influence can be understood by noting that when we boil water, it rises. Similarly, when sunlight falls on the oceans, the water gets heated and rises. The hottest part of the Earth is known to be around the Equator where the most sunlight is received, causing the water level to be approximately 8 cm higher.

Winds:

In primary forces, the second factor is winds. When strong winds blow, they also influence ocean currents

Gravity:

Another factor is gravity, as we know that beneath the ocean, there is the oceanic crust, which is the Earth’s outermost layer. Gravity from there pulls the water.

Coriolis force:

Lastly, there is the Coriolis force. This force is influenced by the Earth’s continuous rotation around its axis, and it also plays a role in affecting ocean currents.

Secondary Forces:

Now, the second force that influences ocean currents is secondary forces, which involve two factors. Firstly, temperature, and secondly, density.

Temperature:

The water temperature is high around the Equator and very low near the North and South Poles, creating a freezing climate. As a result, the cold water near the poles moves towards the equator, and the warm water near the equator moves towards the poles.

Density:

The second factor is density; cold water is denser and tends to move towards the lower layers, while warmer water, being less dense, moves towards the upper layers. These movements contribute to the functioning of ocean currents.

Types of Currents:

Ocean currents are divided into four types: two based on water depth and the other two based on temperature.

Based on depth 

Surface Ocean Currents:

The ocean can be divided into three parts: the surface of the ocean, the sea belt, and the middle part of the ocean. The currents generated in the upper 400 meters are called surface ocean currents. These currents move from the tropics region to the polar region, influenced by factors such as solar energy, temperature, and wind. Out of all the oceans on Earth, only 10% have surface ocean currents. These currents play a crucial role in shaping the Earth and influencing climate. Understanding them is essential for shipping routes and marine activities.

Deep Water Ocean Currents:

Ocean currents which occur under the depth of water not on the surface that’s called deep ocean current.From all the currents which are occuring under the water so deep ocean currents contributes 90% of that. It starts after the 400km from the surface and occurs in the sea belt.Temperature of deep water is cold so it tries to upwell through this ocean currents work.

Based on Temperature 

Cold Ocean Currents:

In the polar regions, temperatures are extremely cold, and the oceans there also experience cold conditions. Cold currents are generated in the polar oceans and move from the polar region towards the equatorial region. These cold ocean currents significantly impact weather conditions, shipping routes, climate, and marine life.

Warm Ocean Currents:

On the equatorial side of the Earth, the oceans have very high temperatures. Warm water currents move from these warm equatorial oceans towards the cold oceans in polar regions. These currents actually move from the equator to the polar regions.

Major Currents:

North Equatorial Current:

Due to winds blowing towards the west, water is pushed in that direction, accumulating and causing higher water levels. The currents formed in this process are known as North Equatorial Currents. These currents are mostly found near the equator in the Pacific and Atlantic oceans, typically between 5° to 20°. They are caused by easterly trade winds.

South Equatorial Current:

Below the equator lies the Southern Hemisphere. When trade winds move from east to west, they carry water with them. This leads to higher water levels on the southwest side. These currents occur in the Pacific and Atlantic oceans, typically between 0° to 50°.

Counter Equatorial Current:

Now, on both the southern and northern sides, trade winds generate currents. However, at the center of the Earth, there is an Inter-Tropic Convergence (ITC) zone, also known as the calm zone, where there are no winds. The water that has accumulated on the western side, both in the southern and northern hemispheres, now starts moving towards the equator. In simple terms, due to the influence of trade winds, the water that was on the west side begins moving in a counter-clockwise direction towards the east.

Antartic Circumpolar Current:

This is the biggest current it moves from west to east around Antarctica.It moves clock wise.it is also known as West Wind Drift.

Importance Of Ocean Currents:

Humans are living on Earth, and we often witness the miracles of nature that help us survive, such as the atmosphere, solar system, and biosphere. However, another miracle in nature for marine life is the ocean currents. It is not wrong to call it a miracle because these currents distribute nutrients to areas where sunlight doesn’t easily reach, allowing phytoplankton to use light energy to produce their food. Additionally, these currents influence weather and climate by spreading heat and coldness across entire oceans.

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