How fast does wind speed change with height above ground: Vertical wind speed profile calculator
/QUESTION: How fast does wind speed change with height above ground?
ANSWER: Wind speed significantly increases the higher you go in the atmosphere. Ground obstacles slow down air movement and create turbulence and create strong mixing of air near the ground. Interaction between the ground surface with obstacles and air is what also causes air near the surface to be warmer than air high above. High above, where jetliners fly the air temperature is -40 °C to -50 °C. Air near the ground in deserts near the equator can reach over +50 °C during day time. Thats a 100 °C (180 °F) swing!
While air temperature decreases with altitude above ground, wind speed increases with height and is also more stable away from the ground. That is why large wind turbines are built tall, so that the bottom of their blades is as far above the ground as possible and the top of their blades is as high up as possible. This way they stay as far away from the highly turbulent, slow moving warm air near the ground. Warm air near the ground is also less dense, lighter, (That is why hot air balloons rise) which also limits wind energy production near the ground.
For meteorology and weather forecasting, the placement of wind sensors far enough above ground is also important, since wind sensors two meters (six feet) above ground where air temperature is measured will be subject to measuring only turbulence and thus producing wind noise measurements. That is one of the factors why all-in-one weather stations near the ground are more of “random number generators” than real measurement instruments for wind and why serious measurement of wind speed happens at heights where wind speed is much more stable; on 10 meter (10 yard) masts or towers. While such a tall wind sensor installation is not always practical, care should be taken to separate the wind sensor from other instruments and place it as high as possible above all other instrumentation.
To give you an idea of how wind speed varies with height above ground within the earth’s boundary layer, we recreated our calculator so that you can change the ground surface obstacles (roughness scale) on the ground and see the resulting affect on wind speed at different heights relative to your wind sensor (anemometer) measurement point height.