equatorial trough

meteorology

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July 17, 2026

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The equatorial trough, also known as the intertropical convergence zone (ITCZ), is a belt of converging trade winds and rising air that encircles Earth's lower atmosphere near the Equator. This rising air leads to significant cloudiness, frequent thunderstorms, and heavy rainfall. The ITCZ shifts seasonally with the Sun, playing a crucial role in slowing the mixing of air between the Northern and Southern hemispheres.1

The ITCZ is characterized by deep cumulonimbus convection, where rising air parcels transport moisture and heat to the upper troposphere. This vigorous mixing results in a high tropopause in the tropics. The divergence of this air aloft contributes to a low-pressure area at the surface, forming the equatorial trough. While historically referred to as an "equatorial front," modern meteorologists prefer the term "equatorial-trough disturbance," as its behavior differs from fronts in middle latitudes.23

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atmosphere
Convection, circulation, and deflection of air
…in an area called the equatorial trough). As the diverted air in the troposphere moves toward the poles, it tends to retain the angular momentum of the near-equatorial region, which is large as a result of Earth’s rotation. As a result, the poleward-moving air is deflected toward the right in…
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…in an area called the equatorial trough). As the diverted air in the troposphere moves toward the poles, it tends to retain the angular momentum of the near-equatorial region, which is large as a result of Earth’s rotation. As a result, the poleward-moving air is deflected toward the right in…
Read More