Coriolis Force UPSC 2024

Consider the following statements regarding the Coriolis force:
1.It deflects the wind to the right direction in the northern hemisphere and to the left in the southern hemisphere.
2.It acts perpendicular to the pressure gradient force.
Which of the statements given above is/are correct?

A] 1 only

[B] 2 only

[C] Both 1 and 2

[D] Neither 1 nor 2

Answer: C

Notes:
Explanation: The rotation of the earth about its axis affects the direction of the wind. This force is called the Coriolis force after the French physicist who described it in 1844.

It deflects the wind to the right direction in the northern hemisphere and to the left in the southern hemisphere. The deflection is more when the wind velocity is high.
The Coriolis force is directly proportional to the angle of latitude. It is maximum at the poles and is absent at the equator. The Coriolis force acts perpendicular to the pressure gradient force.
The pressure gradient force is perpendicular to an isobar. The higher the pressure gradient force, the more the velocity of the wind and the larger is the deflection in the direction of wind.
As a result of these two forces operating perpendicular to each other, in the low-pressure areas the wind blows around it.
At the equator, the Coriolis force is zero and the wind blows perpendicular to the isobars.
The low pressure gets filled instead of getting intensified. That is the reason why tropical cyclones do not form near the equator

Source: NCERT – India Physical Environment

More About Coriolis Force

The Coriolis force is a perceived force resulting from the Earth’s rotation, impacting the movement of objects within a rotating frame of reference like the Earth’s surface. This force plays a crucial role in meteorology and oceanography, aiding in the comprehension of air mass and ocean current movements.

The Coriolis force can be expressed as:

Fc = 2m(v x ω)

Where:

Fc is the Coriolis force
m is the mass of the object
v is the velocity of the object
ω is the angular velocity of the Earth’s rotation
x denotes the cross product

The Earth rotates from west to east, causing different points on its surface to move at varying velocities based on latitude.
Moving objects are deflected due to this rotation, with objects in the Northern Hemisphere deflecting to the right and those in the Southern Hemisphere deflecting to the left.
The Coriolis force, an apparent force in a rotating frame of reference, influences atmospheric circulation, ocean currents, and the trajectories of projectiles and airplanes.
Understanding this force is essential for accurate weather forecasting, navigation, and comprehending geophysical phenomena.

Some Facts About Coriolis Force

the Coriolis force was named after the French mathematician and engineer Gaspard-Gustave de Coriolis, who first described the concept in 1835.

Not a True Force:

The Coriolis force is not a real force, but rather an apparent force that is experienced in a rotating frame of reference due to the Earth’s rotation.
Influence on Moving Objects:

The Coriolis force affects objects in a rotating system, such as air masses, ocean currents, airplanes, and missiles.
Meteorological Effects
Rotation of Cyclones and Anticyclones:

In the Northern Hemisphere, cyclones rotate counterclockwise and anticyclones rotate clockwise due to the Coriolis force. In the Southern Hemisphere, the rotation is reversed.
Impact on Trade Winds:

The Coriolis force causes trade winds to deflect in different directions in the Northern and Southern Hemispheres.
Role in Jet Streams:

Jet streams, fast-flowing air currents in the upper atmosphere, are influenced by the Coriolis force in their formation and direction.
Oceanographic Influence
Coriolis Effect on Ocean Currents:

Major ocean currents like the Gulf Stream are influenced by the Coriolis force, guiding their paths across the globe.
Creation of Gyres and Ekman Spiral:

The Coriolis force helps create ocean gyres and the Ekman spiral, affecting the flow of water in the ocean.
Practical Uses
Military and Aviation Considerations:

The Coriolis force must be taken into account in military calculations for long-range artillery and ballistic missiles, as well as in flight planning for pilots.
Weather Prediction:

Meteorologists use the Coriolis force to predict weather patterns and the movement of high and low-pressure systems.
Interesting Facts
Foucault Pendulum Demonstration:

The Coriolis force can be demonstrated with a Foucault pendulum, showcasing the Earth’s rotation through the pendulum’s changing plane of oscillation.
Debunking the Toilet Flush Myth:

Contrary to popular belief, the Coriolis force is too weak to influence the direction of toilet water flushing.
Everyday Impact:

While the Coriolis force has a significant impact on large-scale phenomena, it does not affect everyday actions like pouring water or driving a car.

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Coriolis Force UPSC 2024