Turbulent convection in rapidly rotating spherical shells: A model for equatorial and high latitude jets on Jupiter and Saturn

On the Saturation and Temporal Variation of Mean Zonal Flows: An Implication for Equatorial Jets on Giant Planets

“…In numerical simulations of rotating spherical convection, Grote & Busse (2001) (see also Aurnou & Olson 2001) noted that the differential rotation tends to shear off the convection columns and results in a temporal intermittency. Recent simulations of convection in a relatively thin spherical shell (Heimpel et al 2005;Heimpel & Aurnou 2007) show strong prograde equatorial jets outside the tangent cylinder while multiple jets form in the northern and southern hemispheres inside the tangent cylinder, which are very similar to those observed in Jupiter and Saturn.…”

“…The zonal mean flow, partly powered by the internal heat of giant planets, may indicate deep convection taking place within the planets (see, for example, Busse 1970Busse , 1976Jones et al 2003;Heimpel et al 2005;Heimpel & Aurnou 2007). How convection in rotating spherical systems generates mean zonal flows has been studied for a very long time (see, for example, Busse 1970;Gilman & Glatzmaier 1981;Zhang 1992;Miesch et al 2000;Aurnou & Olson 2001;Christensen 2001;Jones et al 2003;Chan et al 2006;Heimpel & Aurnou 2007).…”

“…How convection in rotating spherical systems generates mean zonal flows has been studied for a very long time (see, for example, Busse 1970;Gilman & Glatzmaier 1981;Zhang 1992;Miesch et al 2000;Aurnou & Olson 2001;Christensen 2001;Jones et al 2003;Chan et al 2006;Heimpel & Aurnou 2007). In numerical simulations of rotating spherical convection, Grote & Busse (2001) (see also Aurnou & Olson 2001) noted that the differential rotation tends to shear off the convection columns and results in a temporal intermittency.…”

Saturn Atmospheric Structure and Dynamics

“…Although these early studies always produced a superrotating equatorial jet, a positive feature, there was a discouraging lack of resemblence between the simulated jet profiles and those observed on Jupiter and Saturn. Recently, however, Heimpel et al (2005) and Heimpel and Aurnou (2007) performed 3D simulations with much thinner shells (inner/outer radius ratios of 0.85 and 0.9). Like the earlier studies, these simulations are Boussinesq, meaning that they assume a basic-state density that is independent of radius, and have free-slip momentum boundary conditions at both the top and bottom.…”

“…The superrotating equatorial jet in the 3D Boussinesq simulations of Aurnou and Olson (2001), Christensen (2001, Heimpel et al (2005), and Heimpel and Aurnou (2007) results from the interaction of columnar convective rolls with the curving spherical planetary surface (Busse 2002;Vasavada and Showman 2005). This mechanism, which can be viewed as a ``topographic'' β effect, requires convective rolls that act as coherent Taylor columns (i.e., the convective rolls must remain coherent along their entire length from the northern to the southern boundary).…”