In common usage,
wind gradient, more specifically
wind speed gradient or
wind velocity gradient, or alternatively
shear wind, is the vertical
gradient of the mean horizontal
wind speed in the lower
atmosphere. It is the rate of increase of wind strength with unit increase in height above ground level. In metric units, it is often measured in units of meters per second of speed, per kilometer of height (m/s/km), which reduces to the standard unit of
shear rate, inverse seconds (s
-1).