He could even say, use a static model «balancing»
isothermal boundaries or envelopes considering, radiantless, mixed or radiant only transfer.
If he defines his «envelope» or
isothermal boundaries properly, the type of transfer doesn't matter, just the total.
Exactly, since there is
no isothermal boundary that is common to both the liquid and gas phases that includes the estimated effective radiant layer of CO2, you have two models, water and air, moist model and then a dry air radiant model.
Not exact matches
Constant entropy will only prevail within the adiabatic
boundary after conduction within the systems ceases (ie after thermal equilibrium is achieved ie the system becomes
isothermal).
Thermal radiative equilibrium for his black
boundaries is
isothermal, and if the gas has a different thermal equilibrium then the system perpetually violates the second law with a radiative - gravitaional «heat fountain» that runs without work being done, precisely as my silver wire example does.