RegCM3: Description

For a full description, please see the model documentation (pdf/ps).

• Dynamical Core: primitive equation, hydrostatic, compressible, sigma-vertical coordinate model based on the hydrostatic version of the NCAR/PSU Mesoscale Model version 5 (MM5; Grell et al. 1994).
• Physics:
  
• Radiative Transfer: NCAR CCM3 (Kiehl et al. 1996).
  
• Precipitation:
  
• Resolvable (or large-scale) Precipitation: SUB-grid EXplicit moisture scheme (SUBEX) (Pal et al. 2000)
• Convective Precipitation:
• Modified Anthes-Kuo (Anthes 1977; Giorgi 1991)
• Grell (Grell 1993)  with (Arakawa and Schubert 1974) and (Fritsch and Chappell 1980) closures
• Massachusetts Institute of Technology (MIT) (Emanuel 1991; Emanuel and Zivkovi´c Rothman 1999)
  
• Planetary Boundary Layer: Holtslag et al. (1990) and Holtslag and Boville (1993)
• Biosphere: BATS version 1e (Dickinson et al. 1993)
  
• Water Bodies:
  
• Open (e.g., oceans):
• BATS (Dickinson et al. 1993)
• Zeng scheme (Zeng et al. 1998)
• Closed (e.g., lakes): one-dimensional, energy balance lake model (Hostetler and Bartlen 1990: Hostetler et al. 1993: Small et al. 1999)
  
• Atmospheric Aerosols and Chemistry (sulfate, organic carbon, and black carbon aerosols): Qian et al. (2001) and Solmon et al. (2005).

RegCM3 History

The first version of the RegCM series was completed by Dickinson et al. (1989), Giorgi and Bates (1989), and Giorgi (1990) at the National Center for Atmospheric Research (NCAR). It was built upon the NCAR-Pennsylvania State University (PSU) Mesoscale Model version 4 (MM4) (Anthes et al. 1987). However, to adapt the MM4 to long-term climate simulations, the radiative transfer package of Kiehl et al. (1987) was added along with Biosphere-Atmosphere Transfer Scheme (BATS) version 1a (Dickinson et al. 1986). In addition, the existing convective precipitation (Anthes 1977) and planetary boundary layer (PBL) (Deardorff 1972) parameterizations were improved upon. The second version of the RegCM series was developed by Giorgi et al. (1993a,b). The dynamical core was upgraded to the hydrostatic version of the NCAR-PSU Mesoscale Model version 5 (MM5) (Grell et al. 1994). The radiative transfer package was also upgraded according to that of Community Climate Model version 2 (CCM2) (described by Briegleb (1992)). The Grell (1993) convective parameterization was included as an option, and the explicit cloud and precipitation scheme of Hsie et al. (1984) was used. BATS was updated from version 1a to 1e (Dickinson et al. 1993) and the non-local PBL parameterization of Holtslag et al. (1990) was implemented. An intermediate version, REGional Climate Model version 2.5 (RegCM2.5), was developed as described in Giorgi and Mearns (1999). It included an option for the Zhang and McFarlane (1995) convection scheme, the Community Climate Model version 3 (CCM3) radiative transfer package (Kiehl et al. 1996), a simplified version of the Hsie et al. (1984) explicit cloud and precipitation scheme (SIMEX) (Giorgi and Shields 1999), and a simple interactive aerosol model (Qian and Giorgi 1999).

RegCM3 is an integration of the main improvements that have been made to RegCM2.5 since the description in Giorgi and Mearns (1999). These improvements are in the representation of precipitation physics, surface physics, atmospheric chemistry and aerosols, model input fields, and the user interface. In addition, the dynamical code has been modified for parallel computing. An important aspect of the RegCM3 is that it is user-friendly and operates on a variety of computer platforms. To that end, substantial changes have been made to the pre-processing, running, and post- processing of the model. Furthermore, the RegCM3 has options to interface with a variety of reanalysis and General Circulation Model (GCM) boundary conditions.