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| Titel |
The BISA GEM-Mars GCM |
| VerfasserIn |
Lori Neary, Frank Daerden |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250082415
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| Zusammenfassung |
| GEM-Mars is a three-dimensional general circulation model of the Mars atmosphere extending from the surface to approximately 170 km based on the latest version of the GEM (Global Environmental Mesoscale) model, the operational data assimilation and weather forecasting system for Canada [Côté et al., 1998].
The dynamical core is an implicit two-time-level semi-Lagrangian scheme on an Arakawa C-grid with a terrain-following, log-hydrostatic-pressure vertical coordinate discretized on a Charney-Phillips grid. The model has both a hydrostatic and non-hydrostatic formulation, providing a single platform for simulations on a variety of horizontal scales. The model code is fully parallelized using OMP and MPI.
The GCM includes the relevant physical processes such as CO2 condensation, planetary boundary layer mixing, gravity wave drag and surface parameterizations. A simple water cycle, basic gas-phase chemistry and passive tracers are also included in the model. Because of the vertical extent of the model, UV heating, non-LTE effects and molecular diffusion are also included.
Dust is prescribed using the MGS scenario for total opacities and a Conrath profile shape. In the dust radiative transfer code, dust optical properties are based on the Wolff et al [2006, 2009] data. Temperatures in the lower and middle atmosphere have been evaluated using TES [Smith, 2004] and MCS [Kleinbohl et al. 2009] data. Winds and atmospheric circulation (mass stream functions) have been compared with the literature and show a good correspondence to other Mars GCMs. In parallel, active lifting and settling of size-distributed dust has also been implemented.
The soil model has been improved to better match surface and near-surface temperatures from the Viking Landers, Phoenix [Davy et al. 2010], and TES. Near-surface winds and friction velocities have been compared with the literature and show reasonable performance.
Condensation of CO2 in surface ice has been validated using CO2 ice mass data from HEND [Litvak et al. 2004] and GRS [Kelly et al. 2006]. The effect of the polar cap formation on the pressure cycle is found to be in very good agreement with the Viking Landers and Phoenix [Taylor et al. 2010] data.
References:
Côté J., S. Gravel, A. Méthot, A. Patoine, M. Roch and A. Staniforth, The operational CMC-MRB Global Environmental Multiscale (GEM) model: Part I – Design considerations and formulation, Mon. Wea. Rev., 126, 1373-1395.
Davy, R., J. A. Davis, P. A. Taylor, C. F. Lange, W. Weng, J. Whiteway, and H. P. Gunnlaugson (2010), Initial analysis of air temperature and related data from the Phoenix MET station and their use in estimating turbulent heat fluxes, J. Geophys. Res., 115, E00E13, doi:10.1029/2009JE003444.
Kelly, N. J., W. V. Boynton, K. Kerry, D. Hamara, D. Janes, R. C. Reedy, K. J. Kim, and R. M. Haberle (2006), Seasonal polar carbon dioxide frost on Mars: CO2 mass and columnar thickness distribution, J. Geophys. Res., 111, E03S07, doi:10.1029/2006JE002678 [printed 112(E3), 2007].
Kleinbohl, A., J. T. Schofield, D. M. Kass, W. A. Abdou, C. R. Backus, B. Sen, J. H. Shirley,W. G. Lawson, M. I. Richardson, F. W. Taylor, N. A. Teanby, and D. J. McCleese (2009). "Mars Climate Sounder limb profile retrieval of atmospheric temperature, pressure, dust and water ice opacity," J. Geophys. Res., 114, E10006, doi:10.1029/2009JE003358.
Litvak, M. L., et al. (2004), Seasonal carbon dioxide depositions on the Martian surface as revealed from neutron measurements by the HEND instrument onboard the 2001 Mars Odyssey Spacecraft, Sol. Syst. Res., 38, 167 – 177.
Smith M. D. (2004), Interannual variability in TES atmospheric observations of Mars during 1999-2003, Icarus 167, 148 -165.
Taylor, P. A., et al. (2010), On pressure measurement and seasonal pressure variations during the Phoenix mission, J. Geophys. Res., 115, E00E15, doi:10.1029/2009JE003422.
Wolff, M. J., et al. (2006), Constraints on dust aerosols from the Mars Exploration Rovers using MGS overflights and Mini-TES, J. Geophys. Res., 111, E12S17, doi:10.1029/2006JE002786
Wolff, M. J., M. D. Smith, R. T. Clancy, R. Arvidson, M. Kahre, F. Seelos, S. Murchie, and H. Savijärvi (2009), Wavelength dependence of dust aerosol single scattering albedo as observed by the Compact Reconnaissance Imaging Spectrometer, J. Geophys. Res., 114, E00D04, doi:10.1029/2009JE003350 |
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