An Airborne Campaign to Quantify and Reduce Atmospheric Transport Errors in Regional Estimates of Greenhouse Gas Fluxes

Atmospheric transport is one of the primary contributors to uncertainty in atmospheric inverse estimates of greenhouse gas (GHG) fluxes. This source of uncertainty is not well quantified, and attempts to quantify transport errors are limited by the fact that flux and transport errors are difficult to disaggregate. We present a research plan to quantify and reduce transport errors utilizing a multi-year airborne mission, the Atmospheric Carbon and Transport (ACT) America mission, to be conducted across the eastern United States from 2016 through 2018. ACT America will measure atmospheric GHG mole fractions, meteorological variables (e.g. wind speed and direction, atmospheric boundary layer depth) and trace gases indicative of GHG sources and sinks (e.g. 14CO2, COS, CO, C2H6) across the synoptic weather systems responsible for transport of GHGs across and within the midlatitudes. These measurements will take place across all four seasons, and will cover three regions of the eastern United States representing important source/sink regions and a range of meteorological conditions. These airborne data will be confronted with model ensembles include both variations in atmospheric transport and GHG fluxes. We hypothesize that the density and extent of airborne sampling will enable us to prune the model ensemble to eliminate unrealistic flux and transport members. This pruned model ensemble will enable more accurate and precise atmospheric inverse estimates of GHG sources and sinks, and will be applied to long-term atmospheric inversions using the operational GHG observation network. We will present our research plan and results to date utilizing existing measurement networks.