American Meteorological Society Certification (AMS) Practice

What is the primary cause of wind?

1. Temperature variations

2. Differences in air pressure

3. Humidity levels

4. Earth's rotation

The correct answer is: Differences in air pressure

The primary cause of wind is differences in air pressure. Wind is generated when air moves from areas of higher pressure to areas of lower pressure in an effort to equalize the pressure differences in the atmosphere. This movement is due to the uneven heating of the Earth's surface, which creates variations in temperature and subsequently leads to differences in air pressure. Although temperature variations can contribute to the creation of pressure differences, it is the pressure disparity itself that directly drives wind. Similarly, humidity levels affect weather and can influence atmospheric conditions but are not the fundamental cause of wind. Earth's rotation also plays a role in the behavior and direction of wind patterns through the Coriolis effect, but it is not the primary cause of wind itself. Ultimately, the initiation and strength of winds are primarily linked to the disparities in air pressure established by the heating of the Earth's surface.