What causes wind velocity to increase?

• A. The differential heating of the Earth
• B. The rotation of the Earth
• C. The friction with terrain
• D. The presence of moisture

Answer: (A)

Wind speeds rise when there’s a stronger horizontal pressure gradient created by differential heating of the Earth's surface. Differences in solar heating produce regions of higher and lower pressure; air moves from high to low pressure, and the pressure-gradient force accelerates this motion. The bigger the temperature difference and resulting pressure difference, the faster the air can move, so wind velocity increases. The rotation of the Earth (Coriolis effect) mainly redirects winds rather than directly increasing their speed, while friction with terrain tends to slow winds near the surface, and moisture changes density and stability but isn’t the primary driver of stronger winds. So, uneven heating that creates strong pressure differences is what boosts wind velocity.