The structure of the Uranus atmosphere

A series of radiative/connvective models is presented for the Uranus atmosphere for various methane-to-hydrogen mixing ratios and internal heat fluxes. The variation of flux through the atmosphere, which is largely defined by absorption of sunlight in methane bands, the partial pressure of methane, which is taken to be limited by saturated vapor pressure, and the temperature structure are all constrained to be self-consistent. From model spectra calculated for the visible, thermal infrared, and microwave regions, it is concluded that the methane-to-hydrogen mixing ratio is greater than 0.01 and probably less than 0.10. The lower limit to the internal heat flux is nonzero but less than ～1/2000th of the total flux. In addition, the specific heat of the molecular hydrogen is found to be very close that that for normal hydrogen, as suggested previously by Trafton. Peculiarities in thermal structure are found to be of no help in understanding the microwave spectrum, but H₂S-to-NH₃ mixing ratios somewhat greater than unity are almostt as good in explaining the spectrum as the precisely unity case ey S. Gulkis, M. A. Janssen and E. T. Olsen (1978, Icarus34, 10–19).