Simulation of present-day climate, its variability, and historical changes with the ARTS-ESM-M Earth system model

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We describe the key features of the All-Range Time Scales Earth System Model with medium spatial resolution (ARTS-ESM-M) and evaluate the results of the CMIP7 DECK experiments against observations, reanalyses, and the CMIP6 multi‑model ensemble. This model is the successor to the INMCM (INM RAS climate model) generation of models and, like its predecessors, has been developed largely independently of other models, which makes it a valuable contributor to the CMIP ensemble. ARTS-ESM-M is the first INM RAS model with near 100 km atmospheric resolution to take part in CMIP, and is designed to simulate processes ranging from seasonal to centennial timescales. The model introduces notable improvements to the physical parameterizations in the atmosphere and land surface sub-models, and updates to the ocean, aerosol, and sea ice components. ARTS-ESM-M has an equilibrium climate sensitivity of about 3.45 K and a transient climate response of 1.8 K, both close to the CMIP6 ensemble mean. The model simulates the mean state of the present-day climate, its historical changes, and climate extreme events well. Compared with the previous model version INMCM5, the root-mean-square error of the lower-tropospheric temperature is more than halved, and the interannual sea surface temperature variability, nearly absent in the equatorial Pacific and the Southern Ocean before, now falls within the CMIP6 ensemble spread. ARTS-ESM-M reproduces observed stratospheric variability, including the quasi-biennial oscillation with a period near 29 months, and the formation and evolution of El Niño.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.