Numerical simulations of jets on giant planets: effects of large-scale latent heating

Our previous numerical simulations of the atmospheric flow on giant planets showed that shallow thermal forcing confined to pressures near the cloud tops can produce deep winds from the tropopause all the way down to the bottom of the atmosphere. These deep winds are 25% to 100% as strong as the winds within the cloud layer. Under some circumstances, we also reproduced the stable equatorial superrotation with wind speed greater than 100 m/sec and banded multiple zonal jets similar to those observed on Jupiter. These jets can violate the traditional barotropic stability criterion, as observed on Jupiter. Nevertheless, the forcing in these models was simplified: latitudinal differences in temperature were imposed, which crudely represented heating contrasts associated with solar-energy absorption or latent heating associated with condensation of water. Here, we describe updates that substantially improve the realism of the model. Rather than simply imposing an ad hoc thermal forcing, we explicitly include the advection of water vapor and calculate the latent heating expected when the relative humidity exceeds 100%. This allows the locations of heating to evolve with the flow in a way that was not possible in our older models. Absorption of solar radiation is also treated more realistically. The goal is to determine whether multiple Jupiter-like zonal jets form, including a superrorating equatorial flow, and whether these jets penetrate deeply into the interior. Here we describe our new schemes and present preliminary results from the new model.