Eddy Correlation Measurements of Ozone Fluxes over Coastal Waters West of Ireland

Abstract

Measurements of ozone fluxes using the eddy-correlation (EC) technique were carried out for the first time at the Mace Head atmospheric research station, on the west coast of Ireland between August-October 2009. Vertical exchange of ozone was measured from a tower platform at 22 m above mean sea level to study fluxes over coastal waters excluding the tidal region. The results were averaged over 30 min and exhibited predominantly downward but also upward transport of ozone in the boundary layer. Data quality was found to be high based on inspection of cospectra and micrometeorological measurements. During the study period, a major physical influence onO3fluxes was found to be wind speed. Measured fluxes were of the same magnitude as reported in previous open ocean studies ranging from approximately+0.2to−0.5 μgm−2 s−1(−0.017 μgm−2 s−1on average, corresponding to a deposition velocity of 0.25 mms−1or a surface resistance of 4.13 smm−1). These results are considered to represent ozone fluxes over shallow coastal waters west of Ireland for conditions during summer and fall not affected by phytoplankton blooms.