CLIMATE AND CLIMATE-CHANGE IN WESTERN CANADA AS SIMULATED BY THE CANADIAN REGIONAL CLIMATE MODEL

A first climate simulation performed with the novel Canadian Regional Climate Model (CRCM) is presented The CRCM is based on fully elastic n on-hydrostatic field equations, which are solved with an efficient sem i-implicit semi-Lagrangian (SISL) marching algorithm, and on the param etrization package of subgrid-scale physical effects of the second-gen eration Canadian Global Climate Model (GCMII). Two 5-year integrations of the CRCM nested with GCMII simulated data as lateral boundary cond itions are made for conditions corresponding to current and doubled CO 2 scenarios. For these simulations the CRCM used a grid size of 45 inn on a polar-stereographic projection, 20 scaled-height levels and a ti me step of 15 min; the nesting GCMII has a spectral truncation of T32, IO hybrid-pressure levels and a time step of 20 min. These simulation s serve to document: (1) the suitability of the SISL numerical scheme for regional climate modelling, (2) the use of GCMII physics at much h igher resolution than in the nesting model, (3) the ability of the CRC M to add realistic regional-scale climate information to global model simulations, and (4) the climate of the CRCM compared to that of GCMII under two greenhouse gases (GHG) scenarios.