The wind at 3,000 ft AGL is close to which type of wind speed?

• A. Surface wind speed
• B. Geostrophic wind speed
• C. Gradient wind speed
• D. Low-level wind speed

Answer: (B)

The wind at 3,000 feet AGL typically corresponds closely to geostrophic wind speed. Geostrophic winds are those that result from a balance between the Coriolis force and the pressure gradient force and occur at higher altitudes in the atmosphere where friction is minimal.

At 3,000 feet, the effects of surface friction are significantly reduced compared to what is experienced at ground level. As a result, the wind speed observed at this altitude is often more aligned with the theoretical values calculated using tropospheric pressure systems, which is characteristic of geostrophic winds.

This understanding is important for pilots and meteorologists as it helps them determine wind conditions that could affect flight operations at altitudes that are relevant to cruising altitudes for many aircraft. In contrast, low-level wind, gradient wind, and surface wind speeds demonstrate different characteristics, especially influenced by friction, terrain features, and more localized weather phenomena, which makes them less representative of what is typically experienced at 3,000 feet AGL.