Developing Tools to Evaluate the Simulation and Representation of CO2 in the Energy Exascale Earth System Model

Abstract:

Atmospheric CO₂ plays a key role in the global carbon cycle and influences the climate trajectory. A forthcoming version of the Energy Exascale Earth System Model (E3SM) will simulate global CO₂ transport and its impacts on global biogeochemical feedbacks, using land, ocean, and fossil fuel CO₂ fluxes as boundary conditions to the atmosphere. However, E3SM’s existing suite of tools for comparison of modeled biogeochemistry with observational estimates does not include diagnostics for atmospheric CO₂ and its agreement with available observational data products. To evaluate E3SM’s performance with regard to historic atmospheric CO₂ concentrations and fluxes, we have developed diagnostic tools to facilitate comparison with carbon data and reanalysis products, such as from the NASA Orbiting Carbon Observatory (OCO-2), the Greenhouse gases Observing Satellite (GOSAT), and gridded multi-sensor products available through the Observations for Model Intercomparisons Project. Model results are compared to observations and to simulation results from other CMIP models. These tools will help to evaluate and improve model estimates of global CO₂ sources and sinks.