FY2010 - Oak Ridge National Laboratory

Director’s R&D Fund—
Understanding Climate Change Impact: Energy, Carbon, and Water
represent climate–biogeochemistry–land use feedbacks. The integration delivered here bridges that gap,
making it possible to now evaluate critical assumptions and hypotheses in climate change assessments
that require full consideration of climate change feedbacks.
Mission Relevance
This project directly addresses the research priorities within the Climate Change Research subprogram of
the DOE Office of Biological and Environmental Research (DOE BER) by improving global climate
predictions and exploring the interactions between rising CO 2 , other anthropogenic factors, and the
Earth’s climate system. In particular, this pioneering research is a critical step toward strengthening
connections between the integrated assessment and climate modeling research communities, an explicit
focus of the Climate Change Modeling component of the BER subprogram. The model development tasks
for this preliminary effort are designed in part to facilitate the future introduction of additional prognostic
components from the IAM domain. The delivered coupling interface is amenable to coupling with
components of IAMs other than IMAGE as proposed, allowing investigations of uncertainty arising from
the specific assumptions of different IAMs. In addition, this subject aligns with earth science missions of
the National Aeronautics and Space Administration (NASA) but needs proof of principle. Finally, this
advanced model is able to address bioenergy sustainability issues around land use change, possibly
benefitting DOE BER, the DOE Office of Energy Efficiency and Renewable Energy, and the U.S.
Department of Agriculture. Early results from this project were instrumental is securing DOE BER
funding for a multilaboratory collaboration on coupled Earth System and Integrated Assessment
Modeling (ORNL PI: P. E. Thornton).
Results and Accomplishments
We have completed development and testing of land use transition logic in the Community Land Model
with coupled Carbon and Nitrogen cycles (CLM-CN). This development included introduction of a
rotational forest harvest algorithm, shown to be a significant component of land use dynamics at the
global scale. A full suite of factorial simulations for the period 1850–2005 has been completed,
examining the interactions among land use, rising CO 2 concentration, and changing anthropogenic
nitrogen deposition. We have acquired the source code for the IMAGE model from our collaborators in
the Netherlands and have compiled and executed benchmark simulations on local hardware, validating
results against known standards from the IMAGE developers. We have rewritten the IMAGE model as a
module that can be called directly as a subroutine from CLM-CN and have validated that the module
version returns answers identical to the original stand-alone version. We have written and tested the
interface to pass climate information from CLM-CN back to the IMAGE module. We have prototyped the
interface for processing IMAGE module land use change results in real-time to pass forward to CLM-CN,
and we are collaborating closely with George Hurtt at the University of New Hampshire to operationalize
this step of the coupling process. Results from offline CLM-CN simulations are being prepared as a
manuscript for submission.
We have exercised the full CLM-IMAGE interface in fully coupled mode and have accomplished the
two-way exchange of information with the Global Land Model (GLM) code of George Hurtt, having
maintained contacts with his group as he transitioned this year from University of New Hampshire to
University of Maryland. As an operational demonstration of the generality of our coupling approach, we
have now made the modifications necessary to perform two-way coupling with a second integrated
assessment model, the GCAM model developed at Pacific Northwest National Laboratory. Two
additional manuscripts describing the results of this coupling framework are being prepared for
submission.
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