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 lambda 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 + lambda 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.