Comparative terrestrial atmospheric circulation regimes in simplified global circulation models. Part I: From cyclostrophic superrotation to geostrophic turbulence
Abstract
The regimes of possible global atmospheric circulation patterns in an Earthlike atmosphere are explored using a simplified GCM based on the University of Hamburg's Portable University Model for the Atmosphere with simplified (linear) boundary layer friction, a Newtonian cooling scheme and dry convective adjustment. A series of controlled experiments are conducted by varying planetary rotation rate and imposed equatortopole temperature difference. These defining parameters are cast into dimensionless forms to establish a parameter space, in which different circulation regimes are mapped and classified. Clear trends are found when varying planetary rotation rate and frictional and thermal relaxation timescales. The sequence of circulation regimes as a function of planetary rotation rate strongly resembles that obtained in laboratory experiments on rotating, stratified flows, especially if a topographic $\beta$effect is included in those experiments to emulate the planetary vorticity gradients induced by the spherical curvature of the planet. A regular baroclinic wave regime is also obtained at intermediate values of thermal Rossby number and its characteristics and dominant zonal wavenumber depend strongly on the strength of radiative and frictional damping. These regular waves exhibit some strong similarities to baroclinic storms observed on Mars under some conditions. Multiple jets are found at the highest rotation rates, when the Rossby deformation radius and other eddyrelated length scales are much smaller than the radius of the planet. These exhibit some similarity to the multiple zonal jets observed on gas giant planets. Jets form on a scale comparable to the most energetic eddies and the Rhines scale poleward of the supercritical latitude. The balance of heat transport varies strongly with {\Omega}* between eddies and zonally symmetric flows, becoming weak with fast rotation.
 Publication:

Quarterly Journal of the Royal Meteorological Society
 Pub Date:
 October 2018
 DOI:
 10.1002/qj.3350
 arXiv:
 arXiv:1906.07561
 Bibcode:
 2018QJRMS.144.2537W
 Keywords:

 Astrophysics  Earth and Planetary Astrophysics;
 Nonlinear Sciences  Chaotic Dynamics;
 8502
 EPrint:
 18 pages (21 pages as published), 11 figures