Coordinated Global and Regional Climate Modelling

A new approach of coordinated global and regional climate modelling is presented. It is applied to the Canadian Centre for Climate Modelling and Analysis regional climate model, CanRCM4, and its parent global climate model CanESM2.  CanRCM4 was developed specifically to downscale climate predictions and climate projections made by its parent global model.  The close association of a regional climate model, RCM, with a parent global model, GCM, offers novel avenues of model development and application, which are not typically available to independent regional climate modelling centres.  For example, when CanRCM4 is driven by its parent model, driving information for all of its prognostic variables is available (including aerosols and chemical species), significantly improving the quality of their simulation.  Additionally, CanRCM4 can be driven by its parent model for all downscaling applications by employing a spectral nudging procedure in CanESM2 designed to constrain its evolution to follow any large-scale driving data. Finally, coordinating regional and global modelling efforts helps to highlight the importance of assessing RCM ``value added'' relative to their driving global models.  As a first step in this direction, a framework for identifying ``appreciable differences'' in RCM vs. GCM climate change results is proposed and applied to CanRCM4 and CanESM2.

Bio: Dr. John Scinocca is the Head of Model Development at the Canadian Centre for Climate Modelling and Analysis, Environment and Climate Change Canada. His research interests include global and regional climate modelling, climate dynamics, middle-atmosphere dynamics, internal gravity wave dynamics, stratified shear instability and geophysical fluid dynamics.