TB – The fallacies in your argument have been detailed in the original SkyDragon thread, which makes clear why back radiation contributes more to ocean thermal energy than direct solar radiation. The fallacy of “non-penetration” is a fallacy regardless of the multiple mechanisms by which the absorbed surface IR is translated into an increase in thermal energy at depth – this involves the diurnal convective cycle, turbulent mixing, and inhibited conduction and convection in general. Some of these mechanisms involve physical bulk mixing (which we know is substantial from the shallow mixed layer gradient), and some do not, but they all contribute to the thermal energy within the entire mixed layer and below. This entails actual warming during the daytime (via combined solar/back radiation effects) and reduced net cooling at night, even though absorbed back radiation remains substantial at night. I’m not sure why a mechanism that has been so well discussed earlier, and well documented by the measured fluxes and gradients, needs to be regurgitated here, but anyone interested can see my own contributions to the discussion in the original thread by searching for my name, and can also find links to relevant references that I won’t repeat here..
In a general sense, this is a non-issue, although in theory, some discussion would be justified as to how close the substantial mixing of solar and IR effects comes to 100 percent.