lmd_LEGACY1982_abstracts.html

1982 .

R. Sadourny and J.-M. Hoyer. Inhibition of Baroclinic Instability in Low-Resolution Models. Journal of Atmospheric Sciences, 39:2138-2143, October 1982. [ bib | DOI | ADS link ]

The inhibition of baroclinic instability in low-resolution quasi-geostrophic models is studied using a simplified second-order closure approximation. It is shown that this inhibition, which results in systematic overestimation of baroclinic energy and systematic underestimation of barotropic energy, is the result of spurious energy dissipation due to the use of inadequate lateral diffusion. Consequently, a possible methodology for the parameterization of baroclinic instability in low-resolution models is proposed, based on the construction of diffusion operators able to dissipate potential enstrophy while conserving energy exactly.

J.-M. Hoyer and R. Sadourny. Closure Modeling of Fully Developed Baroclinic Instability. Journal of Atmospheric Sciences, 39:707-721, April 1982. [ bib | DOI | ADS link ]

Simple second-order closure models of quasi-geostrophic turbulence are derived, applying either to two-layer flows within isentropic boundaries, or to Eady-type frontogenesis with vanishing potential vorticity; homogeneity and horizontal isotropy are used as simplifying assumptions. Long-term numerical integrations of the two models are performed to obtain the structure of regime flows under stationary large-scale baroclinic forcing. The various cascade processes and the corresponding inertial ranges are discussed and visualized, showing characteristic differences between fully developed baroclinic instability and the linear theory. Further applications of such models may include studies of truncation effects on the efficiency of baroclinic instability.