Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

A global hexagonal C‐grid non‐hydrostatic dynamical core (ICON‐IAP) designed for energetic consistency

A global hexagonal C‐grid non‐hydrostatic dynamical core (ICON‐IAP) designed for energetic... This study describes a new global non‐hydrostatic dynamical core (ICON‐IAP: Icosahedral Nonhydrostatic model at the Institute for Atmospheric Physics) on a hexagonal C‐grid which is designed to conserve mass and energy. Energy conservation is achieved by discretizing the antisymmetric Poisson bracket which mimics correct energy conversions between the different kinds of energy (kinetic, potential, internal). Because of the bracket structure this is even possible in a complicated numerical environment with (i) the occurrence of terrain‐following coordinates with all the metric terms in it, (ii) the horizontal C‐grid staggering on the Voronoi mesh and the complications induced by the need for an acceptable stationary geostrophic mode, and (iii) the necessity for avoiding Hollingsworth instability. The model is equipped with a Smagorinsky‐type nonlinear horizontal diffusion. The associated dissipative heating is accounted for by the application of the discrete product rule for derivatives. The time integration scheme is explicit in the horizontal and implicit in the vertical. In order to ensure energy conservation, the Exner pressure has to be off‐centred in the vertical velocity equation and extrapolated in the horizontal velocity equation. Test simulations are performed for small‐scale and global‐scale flows. A test simulation of linear non‐hydrostatic flow over a rough mountain range shows the theoretically expected gravity wave propagation. The baroclinic wave test is extended to 40 days in order to check the Lorenz energy cycle. The model exhibits excellent energy conservation properties even in this strongly nonlinear and dissipative case. The Held–Suarez test confirms the reliability of the model over even longer time‐scales. Copyright © 2012 Royal Meteorological Society http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Quarterly Journal of the Royal Meteorological Society Wiley

A global hexagonal C‐grid non‐hydrostatic dynamical core (ICON‐IAP) designed for energetic consistency

Loading next page...
 
/lp/wiley/a-global-hexagonal-c-grid-non-hydrostatic-dynamical-core-icon-iap-FlSnbxeAvk

References (50)

Publisher
Wiley
Copyright
Copyright © 2012 Royal Meteorological Society
ISSN
0035-9009
eISSN
1477-870X
DOI
10.1002/qj.1960
Publisher site
See Article on Publisher Site

Abstract

This study describes a new global non‐hydrostatic dynamical core (ICON‐IAP: Icosahedral Nonhydrostatic model at the Institute for Atmospheric Physics) on a hexagonal C‐grid which is designed to conserve mass and energy. Energy conservation is achieved by discretizing the antisymmetric Poisson bracket which mimics correct energy conversions between the different kinds of energy (kinetic, potential, internal). Because of the bracket structure this is even possible in a complicated numerical environment with (i) the occurrence of terrain‐following coordinates with all the metric terms in it, (ii) the horizontal C‐grid staggering on the Voronoi mesh and the complications induced by the need for an acceptable stationary geostrophic mode, and (iii) the necessity for avoiding Hollingsworth instability. The model is equipped with a Smagorinsky‐type nonlinear horizontal diffusion. The associated dissipative heating is accounted for by the application of the discrete product rule for derivatives. The time integration scheme is explicit in the horizontal and implicit in the vertical. In order to ensure energy conservation, the Exner pressure has to be off‐centred in the vertical velocity equation and extrapolated in the horizontal velocity equation. Test simulations are performed for small‐scale and global‐scale flows. A test simulation of linear non‐hydrostatic flow over a rough mountain range shows the theoretically expected gravity wave propagation. The baroclinic wave test is extended to 40 days in order to check the Lorenz energy cycle. The model exhibits excellent energy conservation properties even in this strongly nonlinear and dissipative case. The Held–Suarez test confirms the reliability of the model over even longer time‐scales. Copyright © 2012 Royal Meteorological Society

Journal

The Quarterly Journal of the Royal Meteorological SocietyWiley

Published: Jan 1, 2013

There are no references for this article.