Measurements of the air-sea flux of ozone from the Ronald H. Brown

Human activities have doubled the concentration of ozone in the global troposphere. Ozone is a highly reactive gas and is the third most important 'greenhouse' gas. A significant term in the global ozone atmospheric budget is the uptake by ocean surfaces, but direct observations are quite rare and uncertain. Due to our limited knowledge of the physical and chemical processes involved in the oceanic ozone destruction, climate models typically use only one singular ozone deposition value for all the world's oceans. In order to improve these models, and to have a better understanding of the deposition process into the sea, direct measurements of the air-sea flux of ozone have been made aboard the NOAA Ship Ronald H. Brown during cruises in the Gulf of Mexico (TexAQS and GOMECC) and on the Southern Ocean GasEx cruise. The ozone concentration was measured by a fast-response instrument deployed by INSTAAR, in collaboration with CIRES and NOAA ESRL/PSD researchers. This fast response sensor operates on the chemiluminescence principle and, when combined with sonic anemometer vertically velocity, is used to estimate the ozone flux over the ocean by direct eddy correlation. The preliminary results show a median value for the ozone deposition in the SOGasEx region of about 0.015 cm/s. We will present results from the various deployments of the system, but we will concentrate on the analysis from the SOGasEx cruise. Implications to the NOAA/COARE parameterization will be discussed.