Differential heating of land and sea leads to a sea breeze. What is the mechanism?

• A. Land heats rapidly, causing air over land to rise and draw in cooler air from the sea toward land
• B. Sea air heats up and rises
• C. The sun stops rays
• D. The air over land cools and becomes high pressure

Answer: (A)

Differential heating of land and sea creates a sea breeze because land heats up faster than the adjacent sea during the day. The intense heating makes the air over the land rise, creating a shallow low-pressure area along the coast. Cooler, denser air from over the sea moves toward the land to replace the rising air at the surface. This inflow from sea to land near the surface is the sea breeze, and as it moves inland it rises over the land, sustaining the circulation. The other options don’t fit because they describe heating of sea air, a stop in sunlight, or cooling over land that would produce high pressure—none of which produce the onshore flow seen in a sea breeze.