Treatment of overlapping gaseous absorption with the correlated-k method in hot Jupiter and brown dwarf atmosphere models

摘要: The correlated- k method is frequently used to speed up radiation calculations in both one-dimensional and three-dimensional atmosphere models. An inherent difficulty with this how treat overlapping absorption, i.e. absorption by more than one gas a given spectral region. We have evaluated the applicability of three different methods hot Jupiter brown dwarf models, all which been previously applied within models literature: (i) random overlap, without resorting rebinning, (ii) equivalent extinction (iii) pre-mixing opacities, where combine -coefficients for gases obtain mixture gases, while calculates from corresponding mixed line-by-line opacities. find that overlap most accurate flexible these treatments, fast enough be rebinning. In such as global circulation (GCMs) it too slow, however, can provide speed-up at least factor only minor loss accuracy same time retaining flexibility gained combining computed each individually. Pre-mixed opacities are significantly less flexible, we also particular care must taken when using order adequately resolve steep variations composition important chemical equilibrium boundaries. use rebinning our model GCM, allows us e.g. consistently feedback non-equilibrium chemistry on total opacity therefore calculated P – T profiles