Comparisons of surface flux measurement systems used in FIFE 1989

Several types of Bowen ratio energy balance and eddy correlation systems were used to estimate sensible and latent heat fluxes during FIFE. To provide information on the ability of these systems to make representative measurements of sensible and latent heat fluxes at individual sites, several systems were compared by operating them side by side. The different Bowen ratio systems produced estimates that were usually in close agreement; most of the discrepancies were minor and were due to differing estimates of Rn and G . Comparisons between results of Bowen ratio systems and eddy correlation systems at sites 906 (2133‐ECA) and 926 (8739‐ECB), however, were less satisfactory. The discrepancies were occasionally large and seemed to vary in complex terrain with local conditions such as wind direction, upwind slope aspect, and solar zenith angle.