Comparison of two high frequency ozone instruments for eddy-covariance flux of an urban orchard: UV versus Chemical luminescence

Quantifying the amount of ozone (O3) taken up by whole ecosystems is an important tool for understanding ozone pollution distribution in urban areas, or the potential toxicity incurred by polluted forests. We tested a new configuration of an ultra violet (UV) ozone sensor (2B Technologies) which has been modified to record ozone concentrations at high frequencies (10 Hz) in order to correspond with high frequency wind velocity vectors, and to derive ecosystem fluxes using eddy covariance methods. Concurrent high frequency ozone concentrations were measured using a chemical luminescence sensor and corresponding fluxes were determined. Preliminary analysis finds relatively good correspondence between the two methods of flux measures, though atmospheric humidity was a factor in the degree of correspondence. In practice, the electrical power requirements differed significantly between the two methods. Finally, both EC methods resulted in lower ozone flux estimates than fluxes determine by the ozone gradient method.