Turbulent heat fluxes in the atmospheric surface layer: comparison of scintillometer measurements with eddy-covariance and gradient methods

Scintillometery and its usefulness in the calculation of turbulent fluxes has been explored over the last 40 years. It plays an important role on the generation of spatially representative datasets within the roughness sublayer, especially over regions with irregular surfaces. Although scintillometers have been shown to be effective instruments for the measurement of line-integrated turbulent heat fluxes under certain conditions, the strength of these datasets still needs to be evaluated and contrasted with datasets produced by alternative measurement platforms.

In order to compare scintillometer-derived heat fluxes with those derived from sonic anemometers and from conventional tower data, a field campaign was carried out during the summer of 2007. Measurements were made over a suburban grassy surface on the Southern Great Plains of the United States, next to the Norman, Oklahoma MESONET site. A scintillometer and a sonic anemometer were operated from June through September next to the MESONET tower. Heat flux data were derived from the three datasets available by applying eddy-covariance methods to the sonic anemometer data and conventional gradient methods to the MESONET tower data. The behavior of the fluxes produced by the three approaches is here compared and evaluated over different sections of the diurnal cycle and varied weather conditions.