RegCM4: model description and preliminary tests over multiple CORDEX domains

Abstract

A new version of the RegCM regional climate modeling system, RegCM4, has been recently developed and made available for public use. Compared to previous versions, RegCM4 includes new land surface, planetary boundary layer, and air-sea flux schemes, a mixed convection and tropical band configuration, modifications to the pre-existing radiative transfer and boundary layer schemes, and a full upgrade of the model code towards improved flexibility, portability, and user friendliness. The model can be interactively coupled to a 1D lake model, a simplified aerosol scheme (including organic carbon, black carbon, SO 4 , dust, and sea spray), and a gas phase chemistry module (CBM-Z). After a general description of the model, a series of test experiments are presented over 4 domains prescribed under the CORDEX framework (Africa, South America, East Asia, and Europe) to provide illustrative examples of the model behavior and sensitivities under different climatic regimes. These experiments indicate that, overall, RegCM4 shows an improved performance in several respects compared to previous versions, although further testing by the user community is needed to fully explore its sensitivities and range of applications.

Mistral and Tramontane wind systems in climate simulations from 1950 to 2100

“…RegCM4-3 (see Giorgi et al 2012) is a hydrostatic model. The RegCM4-3 runs were performed by the International Center for Theoretical Physics (ICTP).…”

Simulating the Impacts of Tree, C3, and C4 Plant Functional Types on the Future Climate of West Africa

“…The model has 18 vertical sigma levels extending from the surface to 50 hPa level, and provides different options for cumulus convection parameterizations and land surface schemes. A detailed description of the model is presented in References [41,42]. However, the Emmanuel scheme [43] and the Grell convective scheme [44] were adopted based on their suitability in the simulation of tropical convection [41,45].…”

Assessing the contribution of different factors in regional climate model projections using the factor separation method

“…We analyzed two sub-ensembles of experiments targeting different factors. Ensemble 1 (Ens1) includes four simulations using different driving GCMs (HadGEM and MPI) and convective schemes (Grell and Grell/Emanuel mixed convection, see Giorgi et al, 2012), while Ensemble 2 (Ens2) considers the different driving GCMs along with the effect of irrigation over crop covered areas.…”

“…The model used in this study is the latest version of RegCM4 (Giorgi et al, 2012), which is a hydrostatic and terrain following sigma vertical coordinate model with multiple physics options. Among those of interest in this study are: the Biosphere-Atmosphere Transfer Scheme (BATS) (Dickinson et al, 1993) for the representation of land surface processes and the cumulus convection schemes of Grell (1993) …”

“…As a contribution to the COordinated Regional Downscaling EXperiment (CORDEX, Giorgi et al, 2009), a project aimed at producing large ensembles of regional model projections over regions worldwide, a set of 14 scenario projections was completed (extending from 1970 to 2100) for the Mediterranean CORDEX (Med-CORDEX) domain with the International Centre for Theoretical Physics (ICTP) regional climate model (RCM) RegCM4 (Giorgi et al, 2012). The projections employ different combinations of seven model physics configurations and two driving global climate models (GCMs), the HadGEM2-ES (HadGEM) and MPI-ES-MR (MPI).…”