Comparative terrestrial atmospheric circulation regimes in simplified global circulation models: I. from cyclostrophic super-rotation to geostrophic turbulence. (arXiv:1906.07561v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Wang_Y/0/1/0/all/0/1">Yixiong Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Read_P/0/1/0/all/0/1">Peter Read</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tabataba_Vakili_F/0/1/0/all/0/1">Fachreddin Tabataba-Vakili</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Young_R/0/1/0/all/0/1">Roland Young</a>
The regimes of possible global atmospheric circulation patterns in an
Earth-like 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 equator-to-pole 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 eddy-related 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.
The regimes of possible global atmospheric circulation patterns in an
Earth-like 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 equator-to-pole 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 eddy-related 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.
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