The deflection of moving air due to Earth's rotation is known as the

• A. Coriolis effect
• B. Friction Force
• C. Buoyancy
• D. Gravitational Gradient

Answer: (A)

Coriolis effect is the deflection of moving air caused by Earth's rotation. It happens because the planet spins beneath a moving parcel, so the ground under it changes speed with latitude while the air keeps its original east–west velocity. In the Northern Hemisphere this makes winds bend to the right of their path, while in the Southern Hemisphere they bend to the left. The strength of this deflection increases with wind speed and latitude, and it is zero at the equator and greatest toward the poles. This apparent deflection helps shape large-scale wind patterns and weather systems, such as trade winds and cyclones. Near the surface, friction can weaken the deflection and allow winds to cross pressure gradients more, whereas buoyancy involves vertical motion from density differences and gravitational gradient refers to gravity changes—not the horizontal deflection described here.