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How does uneven heating by the Sun drive atmospheric circulation?

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Wispy cirrus clouds stretch across a bright blue sky above trees and a river at Pinawa Dam Provincial Park in Manitoba, Canada, with sunlight illuminating the scene. — Atmosphere The atmospheres of planets in the solar system are composed of various gases, particulates, and liquids. They are also dynamic places that redistribute heat and other forms of energy. On Earth, the atmosphere provides critical ingredients for living things. Here, feathery cirrus clouds drift across the deep blue sky over Pinawa Dam Provincial Park, near Pinawa, Manitoba, Canada.

Uneven heating by the Sun is the primary driver of Earth's atmospheric circulation, acting as a vast heat engine that redistributes energy from the tropics toward the poles.12

Because Earth is a sphere, solar radiation is absorbed more intensely at low latitudes than at high latitudes. This creates a significant temperature gradient. In the tropics, intense heating causes air to warm, become less dense, and rise through convection, often forming deep cumulonimbus clouds.2314

As this air reaches the upper troposphere, it diverges and moves poleward. Constrained by the stable stratosphere, the air eventually cools, becomes denser, and descends in subtropical regions, creating high-pressure zones. This cycle—rising at the equator, moving poleward, descending in the subtropics, and returning equatorward as trade winds—is known as the Hadley cell.14

The Coriolis effect, caused by Earth's rotation, further deflects these moving air masses, shaping the complex global wind patterns that compensate for the planet's radiative imbalance.14