Articles | Volume 5, issue 12
Research article
18 Dec 2012
Research article |  | 18 Dec 2012

Direct measurement of the oceanic carbon monoxide flux by eddy correlation

B. W. Blomquist, C. W. Fairall, B. J. Huebert, and S. T. Wilson

Abstract. This report presents results from a field trial of ship-based air–sea flux measurements of carbon monoxide (CO) by direct eddy correlation with an infrared-laser trace gas analyzer. The analyzer utilizes Off-Axis Integrated-Cavity-Output Spectroscopy (OA-ICOS) to achieve high selectivity for CO, rapid response (~2 Hz) and low noise. Over a two-day sea trial, peak daytime seawater CO concentrations were ~1.5 nM and wind speeds were consistently 10–12 m s−1. A clear diel cycle in CO flux with an early afternoon maximum was observed. An analysis of flux error suggests the effects of non-stationarity are important, and air–sea CO flux measurements are best performed in regions remote from continental pollution sources.