What is the Hadley cell and how does it influence climate in subtropical regions?

• A. A globally defined desert region.
• B. A circulation moving warm air from the equator toward 30°N/S with rising at the equator and dry descent at 30°, creating subtropical deserts.
• C. A deep ocean current.
• D. A weather phenomenon causing monsoons.

Answer: (B)

The Hadley cell is a large-scale atmospheric circulation driven by intense heating at the equator. Warm air rises there and releases heavy rainfall; as it moves poleward aloft and cools, it sinks around about 30° latitude, creating a dry, stable layer at the surface. The air then returns toward the equator near the surface, forming the trade winds.

In subtropical regions, the sinking air around 30° latitude suppresses convection, leading to low precipitation and dry conditions. This is why deserts and arid climates commonly lie in those subtropical belts. The Hadley cell’s downward motion at these latitudes establishes the characteristic dry subtropical climate, often with clear skies and hot temperatures. Seasonal shifts in the cell can influence monsoon patterns in some regions, but the defining impact on subtropics is the persistent dryness produced by this descending air.