Kinetic energy-conserving hyperdiffusion can improve low resolution atmospheric models

© 2015. The Authors. © 2015 American Geophysical Union. P.Z.G is funded by grant CGL2012-30641 by the Ministry of Economy and Research of Spain. The results presented in this work were obtained using the spectral dynamical core available at http://www.gfdl.noaa.gov/fms and the kinetic energy-conserving subgrid scheme described in the manuscript. The output data for all simulations in the paper are stored in the Geophysical Fluid Dynamics Laboratory archive system and can be obtained from the first author (pzurita@alum.mit.edu) upon request. We are grateful to Ed Gerber and an anonymous reviewer for their thorough reviews and pertinent suggestions.
Motivated by findings that energetically consistent subgrid dissipation schemes can improve eddy-permitting ocean simulations, this work investigates the impact of the subgrid dissipation scheme on low-resolution atmospheric dynamical cores. A kinetic energy-conserving dissipation scheme is implemented in the model adding a negative viscosity term that injects back into the eddy field the kinetic energy dissipated by horizontal hyperdiffusion. The kinetic energy-conserving scheme enhances numerical convergence when horizontal resolution is changed with fixed vertical resolution and gives superior low-resolution results. Improvements are most obvious for eddy kinetic energy but also found in other fields, particularly with strong or little scale-selective horizontal hyperdiffusion. One advantage of the kinetic energy-conserving scheme is that it reduces the sensitivity of the model to changes in the subgrid dissipation rate, providing more robust results.
Ministerio de Economia y Competitividad (MINECO), España
Depto. de Física de la Tierra y Astrofísica
Fac. de Ciencias Físicas
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