Comparison of regional surface fluxes from boundary‐layer budgets and aircraft measurements above boreal forest

Daytime surface sensible and latent heat fluxes ( H s and λ E s ) above boreal forest, derived independently from the boundary‐layer budgets of heat and water vapor and by eddy correlation from the Twin Otter aircraft, are compared. The aircraft and boundary‐layer budget values of H s + λ E s underestimated surface available energy by 25% and 4%, respectively, when the sum of the minor surface energy balance terms (storage and photosynthesis) was estimated as 17% of net radiation. The boundary‐layer budget estimate of the regional Bowen ratio (1.05) agreed to within 15% of the aircraft measurement (0.91). Both methods clearly have value for estimating land‐surface fluxes at a regional scale.