In a strongly heated area near the Earth's surface, what usually happens to the surface air pressure, and why does this change occur?

Introduction / Context:
The formation of pressure belts and local wind systems depends strongly on how heating and cooling affect air density and pressure. When a region is strongly heated by the Sun, such as a tropical land surface at noon, the behaviour of air near the ground changes. Understanding how surface pressure responds to intense heating is essential for explaining low pressure areas, sea breezes, and monsoon circulations.

Given Data / Assumptions:

• A land or sea surface is heated strongly by solar radiation.
• The air in contact with this surface warms up.
• No major external disturbances such as strong fronts or storms are assumed initially.
• We focus on the immediate physical response of air to heating.

Concept / Approach:
Heating air raises its temperature, which in turn reduces its density if pressure is allowed to adjust. Warmer air expands, occupying a larger volume, and becomes lighter compared with the surrounding cooler air. This lighter air tends to rise, creating an upward motion. As air rises away from the surface, the amount of air in the near surface column is reduced. With less mass of air pressing down on the surface, the surface pressure decreases and a low pressure area tends to form.

Step-by-Step Solution:

Verification / Alternative check:
Weather observations show that hot continental interiors during summer, such as the Asian landmass, often develop semi permanent low pressure cells. Local scale phenomena like sea breezes also support this concept: heated land develops lower pressure compared with cooler sea, drawing in winds from the ocean. These real world patterns confirm that strong heating tends to lower surface pressure through rising air.

Why Other Options Are Wrong:
Option A is incorrect because warm air becomes less dense, not more dense, so it does not press more on the ground. Option B wrongly assumes air accumulates near the surface; in reality it rises away. Option D denies the clear physical link between temperature, density, and pressure. Option E suggests randomness, which contradicts the consistent behaviour seen in basic thermodynamics and climatology.

Common Pitfalls:
Students sometimes assume that heating increases pressure simply because they associate heat with expansion and force. The key is to remember that expansion reduces density, allowing air to rise and thereby removing mass from the surface column. Another pitfall is forgetting that low pressure is often a sign of rising motion and potential cloud formation.

Final Answer:
The correct explanation is that surface air pressure decreases because the heated air expands, becomes lighter, and rises upward, creating a low pressure area.