Eddy Covariance (EC) has been proposed as a surface monitoring solution for long-term deployment at CCS sites. However, its suitability when applied to a highly inhomogeneous source area- as would be the case for a small-scale CO2 surface leak- has been poorly established. For this reason, EC has been implemented for two controlled CO2 releases conducted at the Ginninderra controlled release facility, with the aim of determining the technique's suitability for the location, detection and quantification of a small magnitude CO2 leak (144 kg/d). By comparing results from the two release experiments, this poster highlights the variable success of using EC for detection, and how this may depend on changing experimental and climatic variables such as leak location, tower height and depth to groundwater. The detection significance of grouped EC measurements will be established through statistical analysis using Cramer-Von Mises tests. In addition, the application of two EC towers concurrently for leak detection and location will be explored, with a second tower deployed for the latter portion of the 2013 release experiment. Quantification of the leak using EC was attempted, but due to the problems in the fundamental assumptions of the technique, no substantive progress could be made. This will be explained with respect to the 'lost' CO2 from the system in part due to advection and diffusion. Presented at the 2014 CO2CRC Research Symposium

The Arcturus greenhouse gas (GHG) monitoring station began operation in July 2010 50 km southeast of Emerald, Queensland. The station was part of a collaborative project between Geoscience Australia (GA) and CSIRO Marine and Atmospheric Research (CMAR) to establish and operate a high precision atmospheric monitoring facility for measurement of baseline greenhouse gases in a geological carbon dioxide capture and storage (CCS) region. The primary purpose of the station was to establish newly developed greenhouse gas monitoring technology and demonstrate best practice for regional baseline atmospheric monitoring appropriate for geological storage of carbon dioxide. An Eddy Covariance (EC) flux tower was installed at the station to compliment baseline atmospheric measurements by providing; supplementary meteorlogical measurements, atmospheric turbulence and stability parameters, the net vertical transport of water vapour and CO₂ to (and from) the surface, establishing the energy, water and carbon balance for the area. The site is located in a semi-arid, subtropical clime with a summer (Dec-Feb) wet season. The site lies on the boundary between pasture to the west, and cropping to the east, split north to south. EC measurements were taken at 10 Hz frequency and used to prepare 30 minute averages. Data was collected for 2.5 years from 10 June 2011 to 31 December 2013. It was processed using standard OzFlux methods, involving rigorous QA/QC to ensure the output of high quality data. For more information on the site location, installation and instrument set-up see the Installation Report for Arcturus (Berko et al., 2012), while for more information on the metadata and data store for the EC and baseline monitoring instruments see the Metadata Report: Arcturus atmospheric greenhouse gas monitoring (Etheridge et al. 2014).