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To test the applicability of the scintillation method over a heterogeneous area an experiment was carried out in the summer of 1998 in Flevoland (The Netherlands). In the patchy area only four crops were grown namely sugar beet, potatoes, wheat and onions. From eddy covariance measurements it was found that the heterogeneity was mainly caused by differences in thermal properties. No variations in the aerodynamics roughness length were observed. Two large aperture scintillometers were installed at a height of 11.6 and 20.4 m. A good resemblance was found between the sensible heat fluxes derived from both LAS instruments and the area-averaged fluxes obtained from the in-situ eddy covariance measurements. The slight underestimation of the lower LAS could be assessed using a blending height model and an analytical footprint model. The results also indicated that when scintillometer measurements are made below the blending height the violation to Monin–Obukhov Similarity Theory is small and that reasonable fluxes can be obtained from path-averaged structure parameters.

Scintillometer measurements were collected over an irrigated wheat field in a semi-arid region in northwest Mexico. Conditions were unstable in the morning and stable during the afternoon, while latent heat fluxes remained high throughout the day. Regional advection was observed during near-neutral conditions. Monin–Obukhov similarity relationships for the structure parameter of temperature were verified in both unstable and stable conditions, but were violated close to near-neutral conditions. We found that, using additional measurements of radiation, soil heat flux and windspeed, areally averages of both sensible and latent heat fluxes can be reliably predicted by large aperture scintillometer measurements, as long as the net radiation is greater than zero.