George Hadley (1685-1768), an English meteorologist who in 1736 provided the first complete explanation of global atmospheric circulation. Hadley was intrigued by the fact that winds that should have blown straight north had a pronounced westerly flow. He discovered that a rotating coordinate system should be used to describe the motions of the winds, and hence, that the Coriolis force was essential to account for. Hadley’s basic concept was that warm air rises in the vicinity of the equator, where the most heating from the sun occurs, and then moves away from the Earth’s surface in both hemispheres. The air then returns to the surface at about 30 degrees latitude, and returns to the equatorial region via winds near the surface called trade winds.