Coriolis force on cyclone formation

Coriolis Effect

The article explains the Coriolis effect and how it affects our planet.

Key words: coriolis forces, coriolis effect, hurricane science, hurricane motion, wind movement

Introduction

The Coriolis effect occurs when on a rotating body, an inertial force acts at right angles to its direction of motion.

When a secondary object (say a ball) is rolled on the rotating primary body the ball even if rolled in straight path initially follows a curved path (Figure 1). The Coriolis effect (also called the Coriolis force) is based on the laws of motion introduced by Sir Issac Newton (1642–1727).

 

Objects Under the Coriolis Effect

Within rotating coordinate system, the ball in Figure 1 acted on by the Coriolis effect appears to experience a force that would deflect it from its path of motion. This force is not as strong as the centrifugal force however; a force is exerted on an object moving towards or away from the axis of rotation in a rotating system.

Figure 1

The Coriolis Effect Applications

It is equally important in understanding the dynamics of our atmosphere as well, which includes the manner in which winds and storms move. It also explains the motions of oceanic currents. 

Formation of cyclones

Hurricanes (Also called cyclones and typhoon depending on their location of occurrence) are the most powerful storms on Earth. The scientific term for all these storms is tropical cyclone as from the name suggest these are formed around the tropics (i.e tropics of cancer and Capricorn).

 

As depicted in the figure 2 below, the tropical Cyclones rotation is always anticlockwise whereas in the southern hemisphere the rotation is always in clockwise direction.

 

Figure 2

As we know Earth rotates toward the east and this rotation causes fluids, such as air and currents, to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

The Coriolis Effect causes these winds to be deflected toward the right in the Northern Hemisphere (Figure 1) and toward the left in the Southern Hemisphere. This motion of winds generates a torque which results in rotation around the low pressure area and further cyclonic formation.

Winds from areas of high pressure, tend to blow toward the low pressure area. Therefore, these winds blowing toward the low pressure system in the Northern Hemisphere do not reach the center of the low pressure system, but are deflected slightly towards right and starts to circulate in anticlockwise direction. In the Southern Hemisphere, the winds blowing towards the center of the low pressure system tend to deflect towards left there by giving a clockwise rotation to the winds.

 

Other Applications:

Coriolis Effect is also used in some of the important areas below:

• It also has major significance in Motions including aircraft, its launching and orbiting.
• PSLV and GSLV Satellite orbit calculation and correction
• Mechanics of machinery, 
• Rotating motors and turbines,
• The Coriolis effect has utmost importance when it comes to  Astrophysics that relate to Planet Earth and all other celestial motions.  In the field of astronomy, astrophysics the Coriolis effect explains the rotation of sunspots and the true directions of light seen on Earth from the stars.