Simulated Atmospheric Carbon Concentrations

Carbon exists in many forms—e.g., carbon dioxide (CO₂), carbon monoxide (CO)—and continually cycles through Earth’s atmosphere, ocean, and terrestrial ecosystems. This visualization, created using data from the 7-km GEOS-5 Nature Run model, shows average column concentrations of atmospheric CO₂ (colored shades) and CO (white shades underneath) from January 1, 2006 to December 31, 2006.

CO₂ variations are largely controlled by fossil fuel emissions and seasonal fluxes of carbon between the atmosphere and land biosphere. For example, dark red and pink shades represent regions where CO₂ concentrations are enhanced by carbon sources, mainly from human activities. During Northern Hemisphere spring and summer months, plants absorb a substantial amount of CO₂ through photosynthesis, thus removing CO₂ from the atmosphere. Atmospheric CO, a pollutant harmful to human health, is produced mainly from fossil fuel combustion and biomass burning. Here, high concentrations of CO (white) are mainly from fire activity in Africa, South America, and Australia. Scientists use model output data such as these to help answer important questions about Earth’s climate and to help design future satellite missions.

These model simulations use fossil fuel emissions estimates provided by the Emissions Database for Global Atmospheric Research (EDGAR). NASA’s Quick Fire Emissions Dataset (QFED) estimates fire emissions using MODIS fire radiative power observations. Additional, observationally constrained estimates of CO₂ flux between the atmosphere and land and ocean carbon reservoirs were produced as part of NASA’s Carbon Monitoring System Flux Pilot Project (http://carbon.nasa.gov/cgi-bin/cms/inv_pgp.pl?pgid=581). Land biosphere fluxes come from the Carnegie-Ames-Stanford Approach Global Fire Emissions Database (CASA-GFED) model which incorporates MODIS vegetation classification and AVHRR Normalized Difference Vegetation Index (NDVI) data. Ocean fluxes are produced by the NASA Ocean Biogeochemical Model (NOBM) which incorporates MODIS chlorophyll observations.