The authors present the new simple model LADDIE that can be used (1) as a high-resolution parameterisation to link hydrographic properties in front of an ice shelf and melt at its base and (2) as a method to use information from coarse ocean models resolving the circulation in ice-shelf cavities to simulate high-resolution basal melt patterns. The authors present the model and its tuning (done on the Crosson-Dotson ice shelf) and then evaluate it on two ice shelves with different characteristics: Crosson-Dotson and Filchner-Ronne.

This model is an advancement compared to “classic” parameterisations in the sense that it includes 2D effects like the Coriolis force and provides the possibility to include fine-scale bathymetric characteristics in the resulting melt patterns. The topic is timely as the representation of basal melt in models remains a large source of uncertainty for future Antarctic ice-sheet projections. In particular, LADDIE enables the resolution of fine-scale channels and regions near the grounding line, where high melt occurs, and which are therefore crucial when forcing ice-sheet models. Its application therefore has the potential to improve the forcing of ice-sheet simulations.

The manuscript is pleasant to read and the procedure to set up and evaluate the model is thoroughly described. I am curious to see how the application of LADDIE will change the behaviour of ice-sheet simulations when it will be ready for a more widespread use! 

Before publication, however, I think that a few points need to be addressed to clarify this manuscript and make it more robust, especially concerning the evaluation procedure. I hope it is only a matter of restructuring and reformulating and does not involve redoing a major part of the analysis. I realise there are a lot of remarks but they come from sincere interest in the study. I hope that the authors can use them constructively and am looking forward to reading a clearer revised manuscript!

My comments are enclosed in the attached pdf.

This paper introduces LADDIE, a 2D model that implements the depth-averaged navier stokes equations for ocean physics over a mixed layer thickness. The equations have been implemented before (e.g. Holland and Feltham 2006), but there are new modifications (for instance avoidig a hard constraint on minimum thickness), and moreover it is written in the form of an open source python code intended for wide use (though I have not tried it, and am not clear on how easy it is to port to another domain!) The model results are carefully compared against available observations for select ice shelves with high quality modelling and satellite observations of ice ocean interactions. 

I have very few issues with this paper. The model itself is a step forward, and the reasons for it being a step forward are explained thoroughly, legibly, and carefully within the introduction, results and methods sections. The paper does make a very good point that there is a limit to how useful 3D ocean models can be due to cost and resolution required -- but is very clear on what LADDIE is *not* able to do ie model deep cavity dynamics -- and i found the discussion of its limitations (and possible extensions) to be very thougtful. As a scientific paper i feel adequate attention is given to the extensive literature on modelling and observing ice ocean interactions. I would recommend publication following the address of a few minor comments, which i feel will be quite easy.

two general but still minor comments are on the Dotson/Crosson results section:

a) there have been other studies with 3D ocean models run at higher resolution e.g. 1km, I wonder why you did not want to compare to these?

b) Given the emphasis on the channelised melt, I think it is worth mentioning that a recent coupled modelling study (Goldberg and Holland 2022) saw this channel melt completely through within 50 years (in line with the extrapolation of Gourmelen 2017), and the ice-dynamic impact was minimal, somewhat downgrading its importance. The same is not true for the internal shear margin and grounding line of course!

line 34: "presumed stagnant" -- this is an assumption of LADDIE, not the physics of entrainment into the actual ML, which is how this reads.

line 44: at-->over

eqs 1-5: it would be nice to state whether these differ from the PDEs solved in Gladish et al 2012, and how if so. Also, this is for the author to decide, but an appendix showing how to do the integration that arises in the pressure terms (1st 2 terms on the LHS of (2) and (3)) would actually be quite helpful -- because im not sure i've ever seen clearly how these come about, or how to do the layer integration and with which boundary conditions. For your consideration.

eqs 1, 8-10, and 14. Can you state that m_dot>0 indicates melt (if this is true). I don't think you do. (1) indicates it is, and i can reason this is consistent with (8) without referring to other papers. But i have not seen (14) before -- my simple understanding of it is that entrainment is enabled by positive TKE production, and (where there is freezing) by negative buoyancy flux. All seems consistent but it would be nice to be sure.

L192: i don't understand what a weighted average between free and no slip is. are you solving the model twice at each time step with different boundary conditions? would showing an equation help?

L213: "one can interpret"... i think this is only true if the 3D model is isopycnal.

L215: i like this rather than a hard constraint.

L224-5: "to ensure continuity" -- by you, or the satellite analysts?

L339: just to point out that these values for Ah are not huge but bigger, for instance, than that suggested by the MISOMIP protocol. What happens when you have Ah=5, do things change then? or is LADDIE unstable?

L400: "near-zero due to the lack of simulated barotropic flow" -- you don't show any evidence of this, or of it being the cause of low melt rates. My recollection is that the column here is quite a bit bigger than at the Smith and Pope grounding line. On the other hand the Naughten model has pretty coarse vertical resolution at this depth and so the resolution of near-ice variation is particularly poor.. could this be a another potential reason? 

Figure 6: could you show profiles from the 3D model as well?

line 444: what do you mean by the remote sensing not showing conclusive evidence? of channelised melt? or of specific features mentioned above? Im also not sure what you highlight in 3a -- there is very little detail here.

L 458: it is possible that channelisation can lead to enhanced stresses and damage, but a reference would be nice here.

L495 -- where does this warm water come from? surface-warmed or other?

L534: propose-->suggest

L608: a good point about subgl outflow. Is it not in fact trivial to add this?

L620-623 -- a really good point about thin columns. Should note though this assumes detailed knowledge of bathymetry, which i think can only be this good if there is drilling, no?

references:

Goldberg, D. N., and P. R. Holland. "The Relative Impacts of Initialization and Climate Forcing in Coupled Ice Sheet‐Ocean Modeling: Application to Pope, Smith, and Kohler Glaciers." Journal of Geophysical Research: Earth Surface 127.5 (2022): e2021JF006570.