L54: Not sure if "appropriate" is the right word here. Each model center has chosen the model resolution appropriately, according to their needs and computational resources.

Zhou W., L.R. Leung, J. Lu, (2022): Linking large-scale double-ITCZ bias to local-scale drizzling bias in climate models. Journal of Climate 35 (24), 4365-4379.

The novel contribution of this paper is to use the diagnostic framework of Emanuel (2019) to help understand the physical reasons for the differences among a set of 4 experiments using an aquachannel model with prescribed, zonally symmetric sea surface temperature. The 4 experiments differ only in whether or not they use a parameterization of deep convection or one of two parameterizations of shallow convection. The horizontal grid spacing is 13 km, so deep convection is poorly resolved and shallow convection is not really resolved at all. Even so, understanding why the results differ, even if the results are seriously compromised relative to nature, is a step forward, so I am in favor of seeing some version of the paper published with this strong caveat.

The Emanuel framework consists of diagnostic equations for cumulus updraft mass flux, large-scale vertical motion, and a single predictive equation for the mass-weighted vertically integral of the moist static energy. In the original paper, it was used as a tool for very basic understanding of tropical circulations.  Here it is being used instead to help diagnose and understand complex simulations, albeit in a simple aquachannel framework with steady, zonally symmetric SSTs.

Of the three equations in the original framework, the current authors use only one. It would be useful if they could explain why they chose only a single diagnostic. The most important criticism I have is that it is not made clear what is being specified and what is being calculated from this framework. I gather from a mediated, anonymous exchange with the authors that the models’ precipitation, surface heat fluxes, radiative cooling, dry static stability, and difference between boundary layer and lower tropospheric moist static energy are being fed into the framework, and precipitation efficiency and updraft mass flux are being diagnosed. Whatever the case, the inputs and output(s) must be clearly stated. The sentence “In our diagnostics, M_u and epsilon_p are not obtained directly from vertical motion but indirectly using other consistent quantities” is far too vague. Perhaps just state that these quantities are diagnosed using (1) and (2) with inputs from the simulations.

One clear difference among the simulations is that the parameterization of deep convection tends to weaken the Hadley circulation. The diagnostic framework does not really help us understand why. Since the output is precipitation efficiency and mass flux and everything else is fed in from the simulations themselves, one would suppose that the focus would be in the predicted quantities. To imply that the Hadley circulations in the simulations with no parameterization of deep convection are stronger because the wind-driven fluxes are stronger seems tautological. When the stronger fluxes are fed into the framework, it dutifully diagnoses a stronger convective mass flux in the ITCZ; not sure what we have learned. I think the authors are up against the age-old problem of inferring causality in a steady system. One might also point out that the specification of SST means that surface energy balance is not enforced; if a slab ocean were coupled it would not be able to sustain the large differences in turbulent heat fluxes observed among the experiments.

One result that is fascinating is the constancy, across experiments, of the precipitation efficiency in the ITCZ region. It would be great if the authors could address this result.

Another improvement that very much help with the understanding of the diagnostic is to plot, either as part of Figure 4 or as a separate figure, the actual terms in (1); namely, the ratio of the surface heat flux to the moist static energy difference, and the ratio of the radiative cooling to the dry static stability.

One other question I have is why the authors chose the diagnostic equation for the cumulus updraft mass flux rather than the one for the large-scale vertical velocity. Is it because the latter is difficult to sample in the simulations? More difficult than sampling rainfall?

A few specific points:

Figure 1:  As the authors note, the model does not seem to have settled down into a steady state by the end of the integration. It might be worth it to extend one of the 4 simulations beyond this ending time.

Line 199:  “We speculate that extreme rainfalls….”

Line 210-211:  It is not necessarily true that the steady state must be equatorially symmetric.  There can be spontaneous symmetry breaking.

Equation 2:  I would have though that the water vapor concentration that appears here should be evaluated at cloud base rather that taking a vertical average.

Section 5.1.1: I understand the breakdown between wind and delta enthalpy, but why is it important to distinguish sensible from latent fluxes here?

Line 633-634:  If radiative cooling is shut off, there can be no latent heating that, over the whole domain, must balance the cooling. The system would shut down.