Analysis of forced response and internal climate variability in the INMCM Earth system model

Abstract We perform a comparative analysis of the mode composition of forced and internal variability of the INMCM Earth system model for various single realization and ensemble experiments within CMIP5 and CMIP6 projects. For this purpose, we apply Linear Dynamical Mode (LDM) method of data decomposition and its forced/ensemble modifications to surface air temperature data with the main attention paid to the analysis of climate dynamics on interannual, decadal and multidecadal time scales. We compare the results with the mode composition of reanalysis data obtained by the same LDM method. Our main findings classify the representation of the forced response, El Niño – Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation in different versions of the INMCM model, as well as possible contributions of the effects of limited statistics and dynamical forced response.