Volume 39, Issue 6

The paper considers the results of climate change modelling for 1850–2100 using the INM-CM6M climate model of the Marchuk Institute of Numerical Mathematics of the Russian Academy of Sciences. The calculations were performed according to the CMIP6 protocol for modelling the present-day climate for the period from 1850 to 2014 and the IPCC scenarios SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5 of anthropogenic forcing changes in 2015–2100. We analyse changes in such characteristics of the climate system as global mean near-surface temperature, spatial distributions of near-surface temperature, precipitation, sea level pressure, and radiative forcing characteristics in comparison with observational data and results obtained with the previous (INM-CM5) version of the model. We conclude that the new version of the model is superior to the previous one in terms of the quality of simulation of the observed climate and its changes in 1960–2022. The amplitude of global warming predicted by the INM-CM6M for moderate IPCC scenarios is close to the average value of the CMIP6 model ensemble, and for severe scenarios it is closer to the upper limit of its range. For the SSP3-7.0 and SSP5-8.5 scenarios, INM-CM6M predicts a complete loss of Arctic sea ice in summer. As the rate of global warming increases, so does the amplitude and duration of extreme weather and climate events.

The paper reviews the planetary boundary layer parameterizations in the current generation of the INMCM Earth system model. We discuss some of the challenges and improvements necessary to correctly reproduce the essential non-linear interactions of physical processes common to the boundary-layer physics. Overview of some of the improvements implemented in the PBL single-column version of the INMCM model is presented. These include the hierarchy of turbulence closures of different computational complexity suited for modelling a thin stable boundary layer. The closures are based on a consistent definition of the first-order, single- and two-equation approaches and inclusion of stability functions in the surface layer parameterizations tailored for strong static stability of the atmosphere.

The description of the new version of the INM–RSHU chemistry–climate model, created on the basis of the climate model INMCM6.0 is presented. A special feature of the new version of the chemistry–climate model is the complete unification of the model structure with the basic core of the INMCM6.0 climate model. The transport of chemically active species in the atmosphere is performed on the same grid and by the same methods as the transport of meteorological parameters and aerosol. Chemical transformations are added as local processes at each grid point of the model, correcting the changes in tropospheric and stratospheric concentrations of chemically active species caused by dynamical processes. The model was tested using the results of calculations of changes in the chemical composition of the atmosphere over the last 20 years of the 20th century, performed with a version of the model with a resolution of 4 × 5 degrees in latitude and longitude.

This paper presents the INM RAS–MSU land surface scheme, extracted from the INM RAS Earth system model into an independent software complex and supplemented with several modules to reproduce new components and processes of the Earth system. The resulting software product is referred to as TerM (Terrestrial Model). The physical and mathematical foundations of the model, the main features of the software implementation, and examples of applications in reproducing components of the terrestrial hydrological and carbon cycles are briefly outlined. Separating the land surface block into a standalone software complex significantly saves computational resources when assessing the impact of global and regional climate changes on natural resources (including hydrological ones), ecosystem dynamics, and emissions of climate-relevant substances with high spatial detalization. Within the TerM modelling complex, the development, validation, and calibration of new parameterizations of physical and biogeochemical processes are being conducted in an autonomous mode for subsequent implementation into the full INM RAS Earth system model.

In this paper, we present the current stage of development of the INM-CM Earth system model family by the Marchuk Institute of Numerical Mathematics of the Russian Academy of Sciences. The major change from the previous model version INM-CM5 is a new computational platform for the Earth System modelling. We describe the main parts of this digital platform, such as ocean-atmosphere coupling, version control, compilation/configuration, and automated testing subsystems. We also discuss major modifications of the physical parts of the climate model whereby the model simulations of observed climate were significantly improved as well as the model computational performance.