The Formulation of the André Robert MC²(Mesoscale Compressible Community) Model

Abstract

ABSTRA~ A description of the numerical formulation of the dynamics module of the Mesoscale Compressible Commun@ (MC') mode1 is presented. This mode1 is based on the fülly elastic, semi-implicit semi-Lagrangian mode1 developed by Tanguay et al. (1990). This version was extended to incorporate topography by Denis (1990), and later variable vertical resolution was added as an option. This article is a condensed version of an extensive report by Bergeron et al. (1994) that documents a11 the numerical aspects of the tUC2 model. The performance of the mode1 is illustrated through a sample of results obtained on a wide range of physical problems.RÉSUMÉ Cet article présente une description de la formulation numérique du module de la dynamique du modèle de mésoéchelle compressible communautaire (Mê). Ce modèle est basé sur les équations pleinement élastiques qui sont solutionnées par les schémas semiimplicite et semi-lagrangien comme dans Tanguay et al. (1990). La présente version incorpore la topographie comme dans Denis (1990), et elle permet l'utilisation d'un étirement de la maille verticale. Cet article constitue un condensé du volumineux rapport de Bergeron et al. (1994) qui décrit tous les divers aspects numériques du modèle MC'. La performance du modèle est illustrée avec un échantillon de résultats obtenus sur une grande variété de problemes physiques.

Testing the downscaling ability of a one-way nested regional climate model in regions of complex topography

“…The Canadian regional climate model (CRCM) used in these experiments is a limited-area model based on fully elastic nonhydrostatic equations, solved with a semiLagrangian and semi-implicit time-marching scheme (see Bergeron et al 1994;Laprise et al 1997). Horizontal representation of the fields uses an Arakawa C-grid on a polar-stereographic projection; in the vertical, Gal-Chen scaled-height terrain-following coordinates are used.…”

“…The affordable fine resolution over a limited area allows better representation of the surface forcings such as topography, coastlines, inland water or land-surface characteristics, which are the main source of fine-scale features (e.g. Jones et al 1995;Leung and Ghan 1998;Laprise et al 1997). Hydrodynamic instabilities and nonlinear processes such as stretching, folding and stirring by meanders in atmospheric circulation are also better represented on the high-resolution gridmesh and can develop fine-scale structures even in the absence of fine-scale surface forcings.…”

“…With the one-way nesting, the downscaling is achieved over a selected region by nesting a highresolution atmospheric regional-climate model (RCM) within a global GCM, or within global analyses of atmospheric observations e.g. Jones et al 1995;Walsh and McGregor 1995; Laprise et al (1997Laprise et al ( , 2000; Takle et al 1999;Hong and Leetmaa 1999;Leung et al 1999;de Elı´a et al 2001.…”

Coupled runoff simulations as validation tools for atmospheric models at the regional scale

“…The MC2 Canadian atmospheric prediction research model has been developed by the Atmospheric Environment Service (Environment Canada, Dorval). It is a three dimensional (3D) fully compressible non-hydrostatic LAM, that employs a semiimplicit, semi-Lagrangian time scheme and a terrain-following coordinate system (Tanguay et al 1990;Laprise 1995;Benoit et al 1997). The parametrization of physical processes is realized by using the fully uni ed RPN (Recherche en Prévision Numérique) physics package (see also Benoit et al 2000Benoit et al , 2002Willemse et al 2002).…”

Development of a model-based high-resolution extreme surface wind climatology for Switzerland

“…The model used in this study is the Canadian RCM whose principal characteristics is an efficient semi-Lagrangian, and semi-implicit marching scheme (Tanguay et al 1990;Laprise et al 1997), applicable to a wide range of atmospheric motions, coupled with the physical parameterizations of the second generation GCM of the Canadian Centre for Climate modelling and analysis (GCMII; McFarlane et al 1992). This combination is applicable to both short-and long-term simulations (Caya and Laprise 1999;Laprise et al 1998).…”