Models

This page is devoted to describe the models selected to perform CORDEX simulations in the Australasia region. A brief description of the different used configurations is also provided.

The Weather Research and Forecasting (WRF) model

The Weather Research and Forecasting (WRF) model is a mesoscale numerical weather prediction system used for operational forecast, atmospheric research and dynamical downscaling of both reanalysis and General Circulation Models (GCMs).

Two dynamical cores are implemented in the model, of which the Advanced Research WRF (ARW) is the most suitable for a wide range of applications including climate studies.

The most remarkable characteristics of the modes are:

  • A fully-compressible non-hydrostatic scalar-conserving formulation of flux form Euler equations
  • Flexibility in the domain configuration
  • Following terrain vertical coordinates (eta)
  • Availability of several map projections
  • Arakawa-C grid staggering
  • Runge-Kutta 2nd and 3rd order time integration options
  • Lateral boundary conditions specified using a relaxation zone
  • Observational and grid nudging, including spectral nudgin
  • A broad choice of parameterizations for land surface, planetary boundary layer (PBL), radiation, microphysics and cumulus convection.

For further information regarding WRF please visit: http://www.mmm.ucar.edu/wrf/users/

Configuration in the CCRC (UNSW)

In the CCRC a physical ensemble of models was built with members that have the same configuration except for the physical parameterisations of sub-grid scale processes. Below are detailed the schemes chosen as well a sample of the namelist used for each of the members.

Member Microphysics Radiation LW/SW Land Surface PBL Cumulus Namelist
R1 WRF Double-Moment 5 RRTM/Dudhia Noah LSM Mellor-Yamada-Janjic Kain-Fritsch R1 namelist
R2 WRF Double-Moment 5 RRTM/Dudhia Noah LSM Mellor-Yamada-Janjic Betts-Miller-Janjic  R2 namelist
R3 WRF Double-Moment 5 CAM3/CAM3 Noah LSM Yonsei University Kain-Fritsch  R3 namelist


COSMO-CLM

COSMO-CLM (CCLM) is the COSMO model in climate mode. COSMO model is a non-hydrostatic limited- area atmosphere–soil model originally developed by the Deutscher Wetterdienst for operational numerical weather prediction (NWP).
The COSMO physics and dynamics are designed for operational applications at horizontal resolutions of 1 to 50 km for NWP and RCM applications. The basis of this capability is a stable and efficient solution of the non-hydrostatic system of equations for the moist, deep atmosphere on a spherical, rotated, terrain-following, staggered Arakawa C grid with a hybrid z level coordinate. The model physics and dynamics are described in Doms et al. (2011) and Doms and Baldauf (2015) respectively. The features of the model are discussed in Baldauf et al. (2011).
The COSMO model’s climate mode (Rockel et al., 2008) is a technical extension for long-time simulations and all related developments are unified with COSMO regularly. The important aspects of the climate mode are time dependency of the vegetation parameters and of the prescribed SSTs and usability of the output of several global and regional climate models as initial and boundary conditions

Model Version COSMO4.8_CLM17 coupled to CLM3.5

Physical Parameterizations

Planetary Boundary Layer (3D prognostic turbulent energy, Raschendorfer, 2011)
Convection scheme (IFS scheme, Bechthold et al., 2008)
Cloud Microphysics (cloud liquid water and ice and prognostic equations for rain and snow, Seifert and Beheng, 2001)
Radiation (Delta-Two-Stream, Ritter and Geleyn, 1992)
Land surface / Soil (direct coupled Community Land Model 3.5, Dickinson et al. 2006)

References

Baldauf, M., Seifert, A., Foerstner, J., Majewski, D., Raschendorfer, M., and Reinhardt, T., 2011: Operational convective-scale numeri- cal weather prediction with the COSMO model: description and sensitivities, Mon. Weather Rev., 139, 3887–3905.
Bechtold P, Köhler M, Jung T, Doblas-Reyes F, Leutbecher M, Rodwell MJ, Vitart F, Balsamo G, 2008: Advances in simulating atmospheric variability with the ECMWF model: From synoptic to decadal time-scales, Q. J. R. Meteorol. Soc. 134, S. 1337–1351.
Dickinson RE, Oleson KW, Bonan G, Hoffman F, Thornton P, Vertenstein M, Yang Z-L, Zeng X (2006) The Community Land Model and Its Climate Statistics as a Component of the Community Climate System Model. Journal of Climate 19, (Issue 11), S. 2302–2324.
Doms, G., Förstner, J., Heise, E., Herzog, H.-J., Mironov, D., Raschendorfer, M., Reinhardt, T., Ritter, B., Schrodin, R., Schulz, J.-P., and Vogel, G., 2011: A Description of the nonhydro- static regional model LM, Part II: Physical Parameterization – LM_F90 4.20, Tech. rep., Deutscher Wetterdienst, P.O. Box 100465, 63004 Offenbach, Germany.
Doms, G. and Baldauf, M., 2015: A Description of the nonhydrostatic re- gional model LM, Part I: Dynamics and Numerics – COSMO V5.1, Tech. rep., Deutscher Wetterdienst, P.O. Box 100465, 63004 Offenbach, Germany, 2015.
Raschendorfer M, 2001: The new turbulence parameterization of LM. COSMO Newsl 1:90–98. http://www.cosmo-model.org/content/ model/documentation/newsLetters/default.htm
Ritter B, Geleyn J-F , 1992: A Comprehensive Radiation Scheme for Numerical Weather Prediction Models with Potential Applications in Climate Simulations. Monthly Weather Review 120, (Heft 2), S. 303–325.
Rockel, B., Will, A., and Hense, A., 2008: The Regional Climate Model CLM, Meteorol. Z., 17, 347–348.
Seifert A, Beheng KD, 2001: A double-moment parameterization for simulating autoconversion, accretion and selfcollection. Atmos Res 59–60:265–281


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