When one stands on a terrace or a tall tower, winds often feel stronger than on the ground; wind speeds can increase with height. Taking the Beijing area, when the wind speed at 10 m altitude is 1.1 m / s, it is 3.6 m / s at 50 m, 100 m is 4.4 m / s, 150 m is 4.9 m / s. If the height increases, the wind speed also increases. Not until a certain height. The weather conditions determine this limited height at that time. The high site wind is generally stronger than the low place, but how much is the difference between the high wind speed from the low point relative to the different weather conditions.
On clear days with strong sunlight and strong convection in air, the wind speed difference between high and low places is not very large. So the wind speed of the place is moderately high, the low is not very small. On dark days, the air convection is weak, then the difference in wind speed between the high and low places is relatively large; that is, the low wind is weak, even standing still, and the wind is strong above.
Why is the wind stronger in the sky than below? Because the movement of the wind is influenced by friction. The air layer near the ground bears the greatest friction, especially in uneven mountainous areas, and the air is prone to swirly movement. The altitude increases, friction decreases, so the wind speed increases. The same area because the air temperature on the ground is different. Some places are high, some places are low, so at the same altitude, the temperature is not uniform, causing the pressure to be uneven (called pressure difference) the wind speed will increase.
