Critical saturation ratio (at which condensation takes place) as a function of the wetting parameter in the numerical simulations reproducing Curtis et al. (2008) experiment. For both plots, the horizontal thick green line represents the observed critical saturation ratio and the green thin lines the upper and lower boundaries of the observed critical saturation due to standard deviation (Curtis et al. 2008). Left: results for methane are shown with the cases of linear isotherm used in Pruppacher & Klett (1997) (“PK”) and with the Langmuir isotherm (“LAN”). Right: results for ethane are shown with the linear isotherm (“PK”) and the BET isotherm (“BET”). For both plots, the label codes and model parameters are described in Table 2.