Implementation of the CMIP6 Forcing Data in the IPSL-CM6A-LR Model

Abstract

The implementation of boundary conditions is a key aspect of climate simulations. We describe here how the Climate Model Intercomparison Project Phase 6 (CMIP6) forcing data sets have been processed and implemented in Version 6 of the Institut Pierre-Simon Laplace (IPSL) climate model (IPSL-CM6A-LR) as used for CMIP6. Details peculiar to some of the Model Intercomparison Projects are also described. IPSL-CM6A-LR is run without interactive chemistry; thus, tropospheric and stratospheric aerosols as well as ozone have to be prescribed. We improved the aerosol interpolation procedure and highlight a new methodology to adjust the ozone vertical profile in a way that is consistent with the model dynamical state at the time step level. The corresponding instantaneous and effective radiative forcings have been estimated and are being presented where possible.