Sunlight is more direct at the equator but is further away as we move toward the poles. The reason is the Earth’s tilt. Earth’s axis has a tilt of 23.4° from the vertical. The north and south poles have sunlight during their summer months. The equator has sunlight all year around. The two regions are heated unevenly, resulting in a temperature difference.
How does Temperature Difference Affect Atmospheric Pressure
How does Pressure Difference Form Wind
Effect of Earth’s Rotation
Daily Wind Cycle
At the poles, air masses sink as they become dense. These sinking air masses come close to the surface, displacing other air masses. The air flows towards the equator along the ground. Polar air becomes warm as they move. The air moves from an area of high pressure to a place of low pressure due to diffusion. It is the same phenomenon that helps us smell the fragrance or odor. Due to the Earth’s rotation, the land and water near the poles travel from west to east at a few kilometers an hour, while near the equator, they are moving fast. It is found that the air masses near the equator move at an average speed of 465 meters per second. In contrast, those above 50 kilometers south of the North Pole travel 7.5 meters per second. Thus, differential rotation of the higher latitudes compared to the equator also affects air movement on Earth. In contrast, the air above the land surface cools faster at night than at sea. It causes cool air from the land to replace the relatively warm air over the water body, resulting in the land breeze. Large global wind systems occur due to the unequal heating of the Earth, which in turn drive the oceans’ surface currents. In contrast, local winds result from air moving between low and high-pressure systems within a small area.
