HR: 1340h
AN: A13A-0902    [Abstracts]
TI: Nonlinear or Linear; Hydrostatic or Nonhydrostatic Mesoscale Dynamics?
AU: * Leoncini, G
EM: leoncini@atmos.colostate.edu
AF: Colorado State University, Atmospheric Science Department, Fort Collins, CO 80523 United States
AU: Pielke, R A
EM: pielke@atmos.colostate.edu
AF: Colorado State University, Atmospheric Science Department, Fort Collins, CO 80523 United States
AB: In the past, investigators have evaluated under which conditions and to what extent, the hydrostatic approximations holds in the mesoscale atmosphere. There have also been numerous studies regarding the linearization of advection. The goal is to decrease the computational cost of the numeric integration of the full Navier-Stokes equation. We are exploring this issue further. For example, if a particular weather pattern can be well approximated by a linear model then it is possible to use an analytical solution which has the advantage of being exact and runs considerably faster. Another possibility, with similar advantages, is to use an analytical solution for the linear component and integrate numerically only the nonlinear components. A third possible application consists in knowing whether the atmosphere is prevalently hydrostatic, because in this case pressure and temperature profiles can easily and quickly be obtained from each other, increasing the importance of remote sensing observations of one or the other variable. In our study we address these two issues (linearity of advection, and hydrostatics) for the mesoscale, with a more general methodology. Following the framework set by Dalu et al. (2003), we used a modified version of the Regional Atmospheric Modeling System (RAMS) to investigate the effects of surface forcing at a wide range of temporal and spatial scales. More specifically, individual terms (Coriolis, buoyancy, etc.) of the Navier-Stokes equations, both with and without the hydrostatic approximation, are evaluated at the mesoscale for the cases of linearized advection, and fully nonlinear advection, as well with the hydrostatic approximation. Reference: Dalu, G.A., M. Baldi, R.A. Pielke Sr., and G. Leoncini, 2003: Mesoscale nonhydrostatic and hydrostatic pressure gradient forces: Theory and parameterization. J. Atmos. Sci., 60, 2249-2266. Acknowledgments: This research is supported by the DoD Center for Geoscience/Atmospheric Research at Colorado State University under cooperative agreement DAAD19-02-2-0005 with the Army Research Laboratory.
DE: 1847 Modeling
DE: 3200 MATHEMATICAL GEOPHYSICS (0500, 4400, 7833)
DE: 3300 ATMOSPHERIC PROCESSES
DE: 3329 Mesoscale meteorology
DE: 3332 Mesospheric dynamics
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005