North America Carbon Cycle Diagnoses Using Flux and Mixing Ratio Observations, and High-Resolution Regional Transport Modeling

The goal of the project is to improve the understanding of the carbon balance of the terrestrial ecosystems of North America, including understanding of uncertainty and resolution in space and time of these fluxes, leading ultimately to an understanding of the processes governing these fluxes and their variability in space and time. The project will thus undertake the following: 1) maintain collection of CO2 mixing ratio data at 4 AmeriFlux towers; 2) run continental-scale atmospheric inversions at 40 km spatial and weekly temporal resolution using the Weather Research and Forecast model and the Lagrangian Particle Dispersion Model for the time period from 2007-2011 using all available continental CO2 mixing ratio measurements, using CarbonTracker for boundary conditions, and integrating the North American flux tower network into the prior flux estimate; 3) perform a wide range of sensitivity studies on our regional inversion including tests of atmospheric transport, prior fluxes and prior uncertainty, structure of the inverse solution, and large-scale boundary conditions (both meteorological and CO2); 4) better define the uncertainty in the inverse estimates via these sensitivity studies; 5) examine the degree to which the inversion is able to resolve North American CO2 fluxes in space and time; and 6) conduct systematic comparisons to CarbonTracker, including efforts to diagnose the causes of differences by controlling the differences between the two inverse systems.