In August 2014, over 30 scientists from GAUGE, GREENHOUSE and external practitioners from industry and research institutions tested various flux approaches to measure GHG emissions from a landfill site in Ipswich for two weeks. Grant Allen (Uni Manchester) has written an article about this landfill study for the Spring 2015 issue of the NERC journal Planet Earth.
Landfill sites are a perfect place to test many of the measurement and modelling techniques we use in top-down approaches, especially when dealing with so-called "hotspots" – places whose emissions are strong and concentrated, but spread over an area rather than coming from a single point like a chimney stack, for example. The study included eddy covariance towers, automated flux boxes, novel approaches to mass balancing, and promising proxy tracer release systems, where a proxy gas such as acetylene is emitted in a known quantity and measured downwind, so that the volume of naturally co-emitted methane can be calculated. An exciting development, first trialled at the Ipswich landfill, was the use of drone aircraft for automated measurements and wide 3D sampling, a technology that the Environment Agency are working with us to develop for regulatory use. Using powerful precision concentration measurements of not only CO2 and CH4, but also carbon-13 isotopes, ozone and many other trace gases, fluxes calculated from each of these independent methods will be intercompared. The aim will be to understand which methods work best for calculating net flux from hotspot sites.