NOAA's Geophysical Fluid Dynamics Laboratory (GFDL) has been constructing the next generation Earth System Model (ESM) to advance our understanding of how the Earth's biogeochemical cycles, including human actions, interact with the climate system. Like GFDL's current models, this simulation tool is based on an atmospheric circulation model coupled with an oceanic circulation model, with representations of land and sea ice dynamics. These models have been a large collaborative effort for GFDL scientists to construct a set of mathematical equations for fluid flow devised by climate modelers to study weather, climate, and potential changes, both natural and anthropogenic.

The atmospheric component includes physical features such as aerosols (both natural and anthropogenic), cloud physics, and precipitation. The land component includes precipitation and evaporation, streams, lakes, rivers, and runoff. The oceanic component includes features such as free surface, to capture wave processes; water fluxes, or flow; currents; sea ice dynamics; and a state-of-the-art representation of ocean mixing.

Carbon is the basic building block of ecosystems and undergoes extensive ocean chemistry. An ESM adds, to all of these processes, the interactive carbon cycles, and associated chemical and ecological tracers, which determine nutrients, plant biomass and productivity. Chemical tracers also keep track of reactions as they move along in the water or air. For example, a cloud would be a tracer of air movement because a cloud is easily visible. The ESM also captures numerous types of emissions, variations of land surface albedo due to both natural vegetation changes and land use history, including agriculture and forestry, and aerosol chemistry. Adding these different components to the ESM represents a major step towards simulating the Earth's ecological systems.

Our vision of global modeling is an integrated ESM, projecting not only climate variability on seasonal to centennial timescales, but also biogeochemical and ecosystem cycling and biospheric feedbacks on the climate system. It will allow us to study coastal ocean ecosystems and is an important step toward ecological prediction. This is a comprehensive effort, requiring incorporation of climate dynamics, ecological processes and human activity.

For more information, please contact one of the Earth System Model Team leaders:
John P. Dunne (John.Dunne@noaa.gov)
or
Ron Stouffer (Ronald.Stouffer@noaa.gov).