Hadley cell and Held–Hou model

Summary

The Hadley cell is the overturning circulation of the tropical atmosphere. Air rises near the equator, flows poleward aloft, sinks in the subtropics and returns towards the equator near the surface. The Held–Hou model is the simplest theory of this cell, for an axisymmetric atmosphere in which the poleward-moving air conserves its angular momentum. It predicts the latitude at which the cell ends, the subtropical jet at its edge and the easterly trade winds below.