Convective Heat Transfer and the Pattern of Thermal Emission on the Gas Giants
Abstract
Jupiter and Saturn emit nearly twice the thermal energy they receive from the Sun. Although insolation decreases toward the poles, the large-scale outward heat flux is nearly uniform, with smaller-scale latitudinal undulations that correlate with the zonal jet streams. Here we present numerical models of rapidly rotating, turbulent three-dimensional convection in geometrically thin, uniformly-forced layers of Boussinesq fluid that approximate the deep convection zones of Jupiter and Saturn. In previous studies we have demonstrated that such models generate zonal flows comparable to those observed on the gas giants. By analyzing the simulated patterns of convective heat transfer, we show that deep convection in the gas giants can explain the anomalously uniform large-scale thermal emissions as well as the jet-scale variations. In particular, we find that convective heat transfer by quasi-geostrophic thermal plumes in relatively thin spherical shell geometries generates an outward heat flow pattern with a broad equatorial minimum and peaks at the poles. The results suggest an alternative to the longstanding hypothesis that insolation controls the large-scale patterns of heat flux and zonal flow on the gas giants. Instead, we propose that the large-scale thermal and zonal flow fields can originate deep within the planets' molecular envelopes.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.P11B1277A
- Keywords:
-
- 3314 Convective processes;
- 3346 Planetary meteorology (5445;
- 5739);
- 5704 Atmospheres (0343;
- 1060);
- 5724 Interiors (8147);
- 6207 Comparative planetology