]> Relatively strong winds concentrated within a narrow stream in the atmosphere. The region of a jet stream axis with the greatest winds. The axis of maximum wind speed in a jet stream. The wind system, occupying most of the Tropics, that blows from the subtropical highs toward the equatorial trough; a major component of the general circulation of the atmosphere. A zonal circulation of the atmosphere confined to equatorial regions and driven principally by the oceanic temperature gradient. In the Pacific, air flows westward from the colder, eastern area to the warm, western ocean, where it acquires warmth and moisture and subsequently rises. A return flow aloft and subsidence over the eastern ocean complete the cell In meteorology, the flow of air along a latitude circle; more specifically, the latitudinal (east or west) component of existing flow. A measure of strength of the middle-latitude westerlies, usually expressed as the horizontal pressure difference between 35 and 55N latitude, or as the corresponding geostrophic wind. The kinetic energy of the mean zonal wind, obtained by averaging the component of the wind along a fixed latitude circle.