The earth’s terrestrial biosphere has been a strong net sink of atmospheric CO2 for roughly three decades, substantially slowing the rate of accumulation of CO2 in the atmosphere due to combustion of fossil fuels. The causes of this net sink and its likely evolution in the future, however, both remain quite uncertain, yielding substantial uncertainty in our projections of future climate. Understanding the terrestrial carbon cycle remains a high priority for understanding climate change and is of great importance in the southeastern U.S. in part because terrestrial biosphere models have shown that the largest uncertainty in simulated NEP of CO2 in North America to be in the southeastern U.S. The region is a dynamic and relatively poorly constrained contributor to the terrestrial carbon balance of North America.
Furthermore, the forests of the southeastern U.S. are important for the North American carbon balance because they are one of the most productive biomes on the continent, have large biological fluxes, and are sensitive to climate change.
The Gulf Coast Intensive (GCI) project seeks to apply recent advances in atmospheric inversion methodology and observational technology to study the carbon balance of North America as a whole with special emphasis, including new terrestrial inventory assessments, on the dynamic and relatively understudied southeastern United States. The network of CO2 measurements sites (blue dots in the above map) was designed to minimize anthropogenic influences (e.g., power plants) while maximizing the data impact of each site. Factors that were taken into consideration were existing observations, land coverage, Net Ecosystem Productivity, fossil fuel emission estimates from Vulcan, and large emission sources such as power plants.