Quantifying UK emissions of carbon dioxide using an integrative measurement strategy

Abstract:

The main objective of the Greenhouse gAs Uk and Global Emissions (GAUGE) programme is to quantify the magnitude and uncertainty of CO2, CH4 and N2O fluxes from the UK. GAUGE builds on the tall tower network established by the UK Government to estimate fluxes from England, Northern Ireland, Scotland, and Wales. The GAUGE measurement programme includes two additional tall tower sites (one in North Yorkshire and one downwind of London); regular measurements of CO2 and CH4 isotopologues; instrumentation installed on a ferry that travels daily along the eastern coast of the UK from Scotland to Belgium; a research aircraft that has been deployed on a campaign basis; and a high-density network over East Anglia that is primarily focused on the agricultural sector. We have also included satellite observations from the Japanese Greenhouse gases Observing SATellite (GOSAT) through ongoing activities within the UK National Centre for Earth Observation. In this presentation, we will present new CO2 flux estimates for the UK inferred from GAUGE measurements using a nested, high-resolution (25 km) version of the GEOS-Chem atmospheric transport model and an ensemble Kalman filter. We will present our current best estimate for CO2 fluxes and a preliminary assessment of the efficacy of individual GAUGE data sources to spatially resolve CO2 flux estimates over the UK. We will also discuss how flux estimates inferred from the different models used within GAUGE can help to assess the role of transport model error and to determine an ensemble CO2 flux estimate for the UK.