Coriolis Effect

This effect is a key influence on the practice of Meteorology and Oceanography, and can be a little difficult to understand. The Coriolis Effect is not precisely a force like Gravity, Pressure, or Friction, but is rather a relationship. Everything that exists on the Earth exists on an object that is rotating, 15° an hour. While a particle or object sits still on the Earth, this rotation can be largely ignored, so we can just think about other forces.

However, when a particle or objects starts to pick up speed, an extra effect starts to be exerted on the object due to it’s existence on a rotating object. This effect is called the Coriolis Effect. The complete explanation of this can take a while, but here are the facts regarding the Coriolis Effect, as stated by Knauss & Garfield (2016) [KG06]:

  1. The Coriolis force is proportional to the velocity of the particle relative to the earth; if there is no velocity, there is no Coriolis Force.

  2. The Coriolis force increases with increasing latitude; it is at maximum at the North and South Pole, but with the opposite sign, and is zero at the equator.

  3. The Coriolis force always acts at right angles to the direction of motion. In the Northern Hemisphere, it acts to the right (for an observer looking in the direction of motion); in the Southern Hemisphere (where the sine of the latitude is negative), the Coriolis force acts to the left.


J Knauss & N Garfield. 2016. Introduction to Physical Oceanography. Waveland Press.