Volume 40, Issue 2

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.

The validation of the Voeikov Main Geophysical Observatory (MGO) Regional Climate Model (RCM) is conducted using a new land surface model (LSM). A brief description of the new LSM is provided highlighting its differences from the previously used (control) version. The simulated climate variables obtained with the RCM are compared against observational data. Analysis of the results of simulations indicates that the new LSM enhances the accuracy of snow cover evolution, precipitation, and surface temperature calculations compared to the control version. The CaMa-Flood model is employed for river discharge calculations using RCM-simulated outputs as input data. The computed river discharge is evaluated against river gauge observations. The results demonstrate that the modified RCM provides more accurate river discharge estimates compared to those obtained with the control version.

It is expected that atmospheric models with kilometer-scale horizontal resolution will become accessible for use in climate research in the near future. Such high-resolution models require efficient, accurate and conservative numerical solvers for the non-hydrostatic atmospheric dynamics equations on quasi-uniform spherical meshes. In this article, we address this problem by presenting a novel high-order accurate, energy-conserving spatial approximation for non-hydrostatic dynamics equations on the cubed-sphere mesh. The key novel feature of our work is the application of the Summation-By-Parts Finite-Difference (SBP-FD) method for horizontal approximation. SBP-FD enables high-order accurate and stable approximations on logically rectangular multiblock meshes, such as the cubed-sphere. The horizontal gradient and divergence operators constructed using SBP-FD satisfy the discrete analogue of the Ostrogradsky–Gauss theorem, which is essential for energy conservation. As compared to previous works, we explicitly present expressions for discrete vertical mass and entropy fluxes in height-based vertical coordinates, ensuring the compensation potential and thermodynamics energy tendencies with energy contributions from pressure gradient and gravity forces. The proposed spatial approximation is verified using a suite of widely accepted idealized test cases, the results are in good agreement with reference solutions. The robustness of presented spatial approximation is confirmed with the stability in long-term Held–Suarez experiment.

Weather regimes, i.e., recurrent and persistent large-scale structures of atmospheric circulation, is the dominant manifestation of the low-frequency variability of the mid-latitude atmosphere on subseasonal time scales. Here we suggest a method for studying reproducibility of these structures in the Earth system model simulations, including ensemble experiments. The method is based on the identification of the metastable structures in the state space of the system by means of the hidden Markov model approach. Constructing a Markov evolution operator from data allows us to detect statistically significant communities of the system states with abnormally long lifetimes. Capabilities of the approach are demonstrated on the analysis of data obtained in historical and preindustrial experiments with INMCM Earth system model. The set of the detected regimes is presented and compared with the regimes extracted from reanalysis data. Structures of atmospheric anomalies of geopotential heights, surface air temperatures and precipitations in the obtained regimes are presented.

The aim of the paper is to obtain a high-precision solution in a given area of the electromagnetic device of the experimental facility for studying ROT effects in heavy nuclear fission. The simulation of magnetic field is based on the well-known formulation of the magnetostatics problem for two scalar potentials. Taking into account specific configuration features of this device and the requirements to the level of homogeneity of the magnetic field, the discretization of the continuous problem using the continuous Galerkin method leads to systems whose dimensions reach 1.7 · 107. The solution of such systems is carried out with the help of a new economical variant of the matrix-free preconditioned gradient method with partitioning of the calculation domain into subdomains, which is efficient for multicore computations. As the result, the required homogeneity of the magnetic field is obtained at the level of 10 −4 in the volume of location of the 3 He spin filter.