Zonal average of the zonal wind in m s ⁻¹, as a function of latitude and depth in the atmosphere. Yellow lines separate regions of positive (eastward) flow and negative (westward) flow. A strong super-rotating equatorial jet descends through much of the atmosphere. At the equator the maximum (eastward) zonal-average wind speed occurs where the radiative and advective timescales are comparable. Deep in the atmosphere, the minimum (peak westward) zonal-average wind speed occurs at the transition between radiatively forced and inert layers.