An idealized protocol to assess the nesting procedure in regional climate modelling.

Summary Nesting an RCM (regional climate model) into a GCM (global climate model) is generally realized through a relaxation applied at boundaries of the RCM. This procedure of using GCM as a driver to nudge RCM may produce climate deteriorations and biases. The present work elaborates an idealized protocol to assess the uncertainty and performance of the nesting procedure for both long-term mean climate (illustrated here for seasonal-mean T2m drifts) and concomitance of synoptic sequences between the RCM and GCM.