Integration of Observations and Modeling Results in the North American Carbon Program (Invited)

The North American Carbon Program (NACP) is designed to quantify the magnitudes and distributions of carbon sources and sinks, explain the processes controlling them, and produce a consistent analysis of North America’s carbon budget. To accomplish this goal, the NACP Science Plan calls for an unprecedented level of coordination among observational and modeling efforts for the terrestrial, atmospheric, and human components of the carbon cycle. Because available observations are localized and widely separated in both space and time, we depend heavily on models as a key integrating component within NACP. One modeling approach involves process-based ecosystem models that estimate carbon sources and sinks. The other modeling approach —atmospheric inverse models— estimates land-atmospheric fluxes that are optimally consistent with measurements of the wind fields and atmospheric carbon dioxide content. These two modeling approaches combine to provide improved understanding of carbon fluxes from land surfaces. This overview talk will describe and present summary results from model-data intercomparisons at two scales: individual sites, in which observations and ecosystems models are compared, and continental scale, in which observations, ecosystem models and inverse models are compared. The results from this work will provide feedback to the terrestrial ecosystem and inverse modeling communities that will help improve the diagnosis of carbon sources and sinks across North America. Ultimately, the synthesis will improve the predictive capacity of terrestrial ecosystem models through a rigorous evaluation framework designed to assess model performance against observations, inversions, and other forward models.