Wind turbines are getting taller to generate more electricity efficiently. A study looked at wind patterns from 10 m to 250 m in Hamburg, Germany. They found that the wind speed can be overestimated if upper layer stability is ignored. Changes in atmospheric stability have a bigger impact on wind speed than changes in surface roughness. It's important to consider these factors when estimating wind speeds, especially at higher levels. Two models for estimating wind speed near the ground showed similar results, with surface roughness being the most important factor to consider.