gradient wind

gradient wind

[′grād·ē·ənt ‚wind] (meteorology) A wind for which Coriolis acceleration and the centripetal acceleration exactly balance the horizontal pressure force.

Gradient Wind

 

a horizontal, uniform motion of air in the absence of frictional force in a linear (geostrophic wind) or circular path that coincides with the isobars. The gradient wind blows when there is a balance between the active force of pressure gradient and inertial forces: centrifugal force and deflective force owing to the earth’s rotation—the Coriolis force. The gradient wind is the best approximation of the actual state of wind in a free atmosphere above the layer of friction (approximately 1,000 m above the earth’s surface).

gradient wind

gradient windGradient wind and balance of forces in a depression in the Northern Hemisphere.Any horizontal wind velocity tangent to the contour line of a constant pressure surface or an isobar. This movement of air is to the result of a combination of three forces: pressure gradient force, geostrophic force, and cyclostrophic force. In the Northern Hemisphere, the difference between the pressure gradient directed inward toward low pressure and the Coriolis force directed outward results in the centripetal force in a low-pressure area. Similarly, in anticyclonic motion, the difference between the Coriolis force and the pressure gradient results in the centripetal force.