Estimate surface-to-air sensible heat exchange in seconds accurately. Select convective, bulk, or resistance approach today. Get flux and rate results, then export instantly here.
Temperature differences are computed in kelvin, but you may enter °C, K, or °F.
| Scenario | Method | Inputs (summary) | Output |
|---|---|---|---|
| Heated panel | Convective | h = 35 W/m²·K, A = 1.0 m², Ts = 40°C, T∞ = 25°C | q'' = 525 W/m², Q = 525 W |
| Daytime land surface | Bulk | ρ = 1.20 kg/m³, Cp = 1005 J/kg·K, Cₕ = 0.0012, U = 4 m/s, Ts = 308 K, Ta = 303 K | H ≈ 24.1 W/m² |
| Moderate turbulence | Resistance | ρ = 1.22 kg/m³, Cp = 1005 J/kg·K, rₐ = 60 s/m, Ts = 30°C, Ta = 27°C | H ≈ 61.3 W/m² |
Sensible heat flux describes how quickly heat energy is exchanged between a surface and the air through turbulence. It is a key term in surface energy balance studies, weather forecasting, building microclimate design, and environmental monitoring. Positive values typically indicate heat moving upward from a warmer surface to cooler air. In climate studies, it links land cover changes to temperature trends and boundary-layer development.
This calculator uses a bulk aerodynamic approach. Instead of resolving turbulent eddies directly, it estimates exchange using air density, specific heat, a transfer coefficient, wind speed, and the temperature difference between air and surface. It is widely used when high-frequency turbulence measurements are unavailable.
The flux magnitude scales linearly with wind speed and the temperature gradient. Doubling wind speed doubles the estimated flux, assuming other inputs remain constant. The coefficient (CH) bundles surface roughness and atmospheric stability effects, so it strongly influences results.
Air density varies with altitude, temperature, and pressure. Specific heat is commonly treated as nearly constant for dry air. Use measured or site-appropriate values when possible. For wind speed, select a representative height and avoid sheltered locations that understate the true exchange.
For land surfaces, sensible heat flux often ranges from tens to several hundred W/m² on sunny days, while nighttime values may be near zero or negative. In humid or well-watered conditions, latent heat can dominate, reducing sensible heat compared with arid environments.
Professional validation is commonly done using eddy covariance systems, which compute fluxes from fast (10–20 Hz) wind and temperature data. Bulk estimates like this tool can be calibrated by tuning CH to match field observations for similar terrain and stability conditions.
Large errors arise from incorrect surface temperature, non-representative wind speeds, and using a generic transfer coefficient. Stable nighttime layers can suppress turbulence, while strongly unstable daytime layers can enhance it. If you expect strong stability effects, treat results as first-order estimates.
Use sensible heat flux estimates to compare surfaces (asphalt vs vegetation), assess heat stress in urban canyons, support irrigation and drought studies, and evaluate boundary-layer conditions for air-quality modeling. Pairing this output with net radiation and latent heat improves full energy-balance analysis.
A negative value typically indicates heat transfer from warmer air to a cooler surface. This often happens at night when the ground cools by radiation while the air remains relatively warmer.
CH depends on surface roughness and stability. If you do not have a measured value, start with a literature-based estimate for similar terrain, then refine it using local measurements or sensitivity testing.
Yes, the same bulk approach is used over water, but CH and surface temperature behavior differ. Use water-appropriate coefficients and ensure wind speed is representative of the measurement height.
Bulk estimates can be reasonable for comparisons and screening, but accuracy depends on CH and input quality. Eddy covariance is generally more direct and robust when properly installed and processed.
Prefer matched measurement heights or apply standard corrections. Mixing heights can bias results because wind and temperature gradients vary strongly near the surface, especially in stable conditions.
Humidity mainly affects latent heat, but it slightly influences air density and thermal properties. In most practical cases, treating cp as constant and focusing on temperature and turbulence gives a useful estimate.
Compare against typical ranges for your surface and time of day. If you see thousands of W/m², revisit units, the temperature difference sign, wind speed, and the chosen coefficient.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.