HR: 1340h
AN: P33B-1306    [Abstracts]
TI: Sensitivity of Simplified Venus General Circulation Models to Numerical Parameterizations
AU: * Lee, C
EM: lee@gps.caltech.edu
AF: Division of Geological and Planetary Sciences. California Institute of Technology, 1200 E. California Blvd M/C 150-21, Pasadena, CA 91125, United States
AU: Richardson, M I
EM: mir@gps.caltech.edu
AF: Division of Geological and Planetary Sciences. California Institute of Technology, 1200 E. California Blvd M/C 150-21, Pasadena, CA 91125, United States
AB: General circulation models (GCMs) of the Venus atmosphere are currently forced using only simplified parameterizations of the radiative forcing and boundary conditions, such as those discussed in Yamamoto and Takahashi (JAS, 2003) or Lee, Lewis and Read (JGR, 2007). Using these parameterizations, suitable dynamical cores produce a qualitatively realistic circulation with super-rotation and transient planetary waves. The quantitative accuracy of the GCMs varies with dynamical core and the particular numerical parameterizations employed. However, all current GCMs exhibit sensitivity to the numerical parameterizations used to describe the behavior of the boundary conditions and the sub grid-scale eddy activity. These parameterizations are often used to reduce the grid-scale noise and unwanted propagating waves caused by discretization in the models We discuss the response of the numerical cores used in a number of simplified Venus GCMs using their various boundary layer and sub grid-scale parameterizations, and forcing with the radiative parameterizations outlined in Lee, Lewis and Read (JGR, 2007). The numerical cores tested include the PlanetWRF model (Caltech/NCAR), FMS (GFDL/NOAA) and HadAM3 (Oxford/Hadley Centre). We also discuss a possible physical interpretation of the sensitivities we have investigated and suggest corrections to the parameterizations used in these simplified GCMs. These corrections should provide more physically reasonable parameterizations for the thick Venus atmosphere, and in turn reduce the sensitivity to the numerical parameterizations such as the horizontal hyper-diffusion used to damp grid-scale waves, or the Rayleigh friction used to damp vertically propagating waves.
DE: 3319 General circulation (1223)
DE: 3346 Planetary meteorology (5445, 5739)
DE: 3389 Tides and planetary waves
DE: 6295 Venus
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting