Atmospheric Carbon and Transport (ACT) - America: A multi-year airborne mission to study fluxes and transport of CO2 and CH4 across the eastern United States

The Atmospheric Carbon and Transport (ACT) - America mission is a NASA Earth Venture Suborbital mission that aims to improve our understanding of transport and fluxes of greenhouse gases (GHGs), and thus improve the accuracy and precision of regional inverse flux estimates of GHGs. ACT-America has conducted four field campaigns with two aircraft across three regions of the eastern United States spanning all four seasons. Simulations of atmospheric GHGs have been conducted for a subset of these field campaigns. The mission is built around three objectives: 1) quantifying and reducing uncertainties in simulated atmospheric transport of GHGs; 2) quantifying and reducing uncertainties in estimates of CH4 emissions and biogenic CO2 fluxes; and 3) evaluating the ability of the Orbiting Carbon Observatory - 2 (OCO-2) to observe spatial variations in tropospheric CO2.

Results to date include spatially-extensive, highly-resolved observations of the three-dimensional structure of GHGs across at least twenty distinct frontal boundaries, regional mapping of the evolution of boundary layer GHG mole fractions in response to surface fluxes of CO2 and CH4 in each region and season, and several 300-500 km under-flights of OCO-2. Airborne instruments include in situ observations of CO2 and CH4, lidar-based measurements of CO2 and boundary layer depth, in situ meteorological measurements, and an array of trace gases associated with GHG sources and sinks.

Project simulations of atmospheric GHGs encompass a range of spatial resolutions, meteorological ensembles, and flux ensembles. GHG sources are individually tracked to enhance our ability to understand simulated mole fractions and compare to observed GHG tracers. Model-data comparisons are underway to evaluate flux and transport models, prune model ensembles, and work towards calibrated, reduced uncertainty ensembles that can be used in regional inverse flux estimates.

This presentation will review the experimental design of the mission, major results to date, the availability of project data, and future research plans. Another objective of this presentation is to invite collaborative study of this rich data set and complex problem.