Robustness of the structure of general atmospheric circulation under global cooling

Numerical simulations using an idealised laboratory-scale model were employed to study the transformation of the general circulation of the atmosphere under conditions of global cooling. The focus was on structural changes in the mean and fluctuating parts of general circulation as the temperature gradient decreased. It was found that the structure of the general circulation is very robust and practically does not change with decreased heating. Even with 20% of the initial heating power, the mean circulation consists of three cells: Hadley, Ferrel, and polar. However, the magnitudes of the main characteristics, such as maximum velocity and temperature difference, baroclinic wave amplitude significantly decrease with reduced heating. Specific aspects of baroclinic waves were identified. It was shown that blockings of baroclinic waves appear even with constant zonally symmetric boundary conditions. A significant time lag between temperature and radial velocity fluctuations was found. Fourier mode decomposition of baroclinic waves revealed remarkable similarities between the energy spectra and spatial energy distributions at the laboratory scale and those obtained in a full-scale idealised model of an Earth-like atmosphere.