Biological and Environmental Research - Earth and Environmental System Sciences
Earth and Environmental System Modeling

Energy Considerations in the Community Atmosphere Model (CAM)

TitleEnergy Considerations in the Community Atmosphere Model (CAM)
Publication TypeJournal Article
Year of Publication2015
AuthorsWilliamson, David L., Olson Jerry G., Hannay Cecile, Toniazzo Thomas, Taylor Mark, and Yudin Valery
JournalJournal of Advances in Modeling Earth Systems
Volume7
Number3
Pages1178-1188
Abstract / Summary

An error in the energy formulation in the Community Atmosphere Model (CAM) is identified and corrected. Ten year AMIP simulations are compared using the correct and incorrect energy formulations. Statistics of selected primary variables all indicate physically insignificant differences between the simulations, comparable to differences with simulations initialized with rounding sized perturbations. The two simulations are so similar mainly because of an inconsistency in the application of the incorrect energy formulation in the original CAM. CAM used the erroneous energy form to determine the states passed between the parameterizations, but used a form related to the correct formulation for the state passed from the parameterizations to the dynamical core. If the incorrect form is also used to determine the state passed to the dynamical core the simulations are significantly different. In addition, CAM uses the incorrect form for the global energy fixer, but that seems to be less important. The difference of the magnitude of the fixers using the correct and incorrect energy definitions is very small.

URLhttps://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015MS000448
DOI10.1002/2015MS000448
Journal: Journal of Advances in Modeling Earth Systems
Year of Publication: 2015
Volume: 7
Number: 3
Pages: 1178-1188
Publication Date: 07/2015

An error in the energy formulation in the Community Atmosphere Model (CAM) is identified and corrected. Ten year AMIP simulations are compared using the correct and incorrect energy formulations. Statistics of selected primary variables all indicate physically insignificant differences between the simulations, comparable to differences with simulations initialized with rounding sized perturbations. The two simulations are so similar mainly because of an inconsistency in the application of the incorrect energy formulation in the original CAM. CAM used the erroneous energy form to determine the states passed between the parameterizations, but used a form related to the correct formulation for the state passed from the parameterizations to the dynamical core. If the incorrect form is also used to determine the state passed to the dynamical core the simulations are significantly different. In addition, CAM uses the incorrect form for the global energy fixer, but that seems to be less important. The difference of the magnitude of the fixers using the correct and incorrect energy definitions is very small.

DOI: 10.1002/2015MS000448
Citation:
Williamson, DL, JG Olson, C Hannay, T Toniazzo, M Taylor, and V Yudin.  2015.  "Energy Considerations in the Community Atmosphere Model (CAM)."  Journal of Advances in Modeling Earth Systems 7(3): 1178-1188.  https://doi.org/10.1002/2015MS000448.