Drone Flight Calculator
Calculate accurate flight times for your drone based on real-world conditions including wind, temperature, altitude, and terrain.
Wind Profiles & Atmospheric Boundary Layer
Wind profiles describe how speed and direction change with altitude. Understanding boundary layer physics and wind shear helps pilots anticipate stronger winds aloft and avoid turbulence hazards.
Why Wind Profiles Matter
Last updated January 6, 2026. Educational guidance for conservative flight planning.
Near the surface, friction from terrain slows the wind. As altitude increases, friction decreases and wind speeds rise. This creates a wind speed gradient that can surprise pilots who only check ground-level readings.
The atmospheric boundary layer (ABL) is the lowest portion of the atmosphere and the region most influenced by terrain, sunlight, and surface heating. It is also where wind shear and turbulence can change rapidly over short distances.
Atmospheric Boundary Layer Overview
Typical ABL structure and how it affects drone operations
Surface Layer (0-100 m)
Highest friction, strongest turbulence, and the steepest wind gradient. Obstacles and terrain drive rapid changes in speed and direction.
Mixed Layer (100-1000 m)
More uniform wind speeds with reduced turbulence. Wind shear still occurs, but changes are generally smoother and more predictable.
Free Atmosphere
Above the boundary layer, wind is less affected by surface friction. Shear can still exist due to weather systems and temperature inversions.
Boundary layer depth varies with time of day, season, and weather. Expect a shallower ABL at night and a deeper, more turbulent ABL on sunny afternoons.
Power Law Wind Profile
A practical model for predicting wind speed changes with altitude
Formula
V(h) = V(h0) x (h / h0)^alphaThe exponent alpha (power law exponent) increases with terrain roughness. Larger alpha values mean stronger wind speed gradients with altitude.
Typical alpha values
- Open water: 0.10
- Open flat terrain: 0.15
- Agricultural land: 0.20
- Suburban: 0.30
- Urban: 0.40
Pilot takeaway
- Expect stronger wind increases over rough terrain.
- Short climbs can still create large wind jumps.
- Use conservative limits for gusty conditions.
Logarithmic Wind Profile (Concept)
Used in boundary layer meteorology for neutral stability conditions
Formula
V(z) = (u* / kappa) x ln(z / z0)This logarithmic wind profile uses friction velocity (u*), von Karman constant (kappa ~ 0.4), and roughness length (z0). It is common in atmospheric boundary layer research, but requires more inputs than the power law.
For most pilot planning, the power law model is faster to apply and provides conservative estimates when paired with real observations.
Terrain Effects and Wind Shear Hazards
How local surfaces and obstacles amplify wind gradients
Terrain impacts
- Buildings and trees generate turbulent wakes.
- Valleys and ridgelines channel and accelerate wind.
- Open terrain allows faster wind speeds aloft.
- Sharp transitions in terrain increase shear.
Wind shear risks
- Sudden power demand changes and battery drain.
- Unexpected yaw or pitch changes during hover.
- Reduced control margin during takeoff/landing.
- Higher chance of drift in GPS hold.
How Pilots Account for Wind Gradients
- Compare ground observations with winds aloft forecasts or local weather soundings.
- Plan for stronger headwinds at altitude and reserve extra battery for return legs.
- Fly a short low-altitude test climb to confirm stability before higher flight.
- Select launch sites with open upwind areas to reduce mechanical turbulence.
Wind Profile Calculator
Measured at the reference height below.
Commonly 33 ft (10 m) in aviation data.
Use the planned operating altitude.
Homes, trees, and moderate roughness
Power law
alpha = 0.30
Terrain exponent
Predicted wind at altitude
21.1 mph
Based on the power law profile.
Wind shear
11.1 mph
111% change from reference.
Boundary Layer Visualization
Profile bars show how wind speed typically increases with altitude for the selected terrain. Real-world profiles vary with stability, terrain, and time of day.
Quick Answers
How does wind speed change with altitude?
Wind speed generally increases with altitude because surface friction drops off. The rate of increase depends on terrain roughness and atmospheric stability.
What is the atmospheric boundary layer?
The ABL is the lowest portion of the atmosphere that responds directly to surface heating, cooling, and friction. It contains the strongest wind gradients.
How does terrain affect wind profiles?
Rough terrain increases friction and turbulence, which slows wind near the surface and steepens the wind gradient as you climb.
What is wind shear and why does it matter?
Wind shear is a rapid change in wind speed or direction. It can destabilize drones and quickly increase power demand.
How do pilots account for wind gradients?
They compare ground readings with winds aloft data, fly conservative test climbs, and maintain extra battery reserve to handle stronger winds.