This paper presents recent findings regarding surface horizontal kinetic energy (SHKE) levels in a series of high-resolution, realistic numerical simulations of the North and Equatorial Atlantic Oceans. These results are then compared with surface drifter data. This comparison uses simulated Lagrangian time series in the numerical simulations to provide an accurate comparison, as described by Zhang et al. (2024). The paper then explores the impact of various numerical parameters, including resolution, the presence of drag for internal waves, bathymetry resolution, and wind forcing frequency. The paper is clearly written and logically organised, providing results of interest to the ocean modelling community. However, I have a few remarks regarding the objectives of the paper – which I think could be clarified – and possible redundancies with previously published results, considering that the present paper is somewhat long.

Indeed, the main message of the paper is unclear to me. From the title, it sounds like it is about characterising the surface kinetics, which is actually discussed in Section 3. However, this has essentially been reported previously using very similar datasets and diagnostics in the referenced papers (Yu et al., 2019; Arbic et al., 2022; Zhang et al., 2024). Similarly, section 4.3 provides a lengthy comparison of Lagrangian estimates and Lagrangian vs. Eulerian spectra of SHKE, which seems redundant with previously published results. Section 5 then provides a discussion of the different numerical parameters, which corresponds best with the description provided in the abstract. This is probably the most interesting and novel part of the study. However, it is difficult to link these two sections (3 and 4 on the one hand, and 5 on the other). This is exemplified by the introductory paragraph at the beginning of Section 5, the logical path of which I could not understand (previous results -> motivations for next analysis). Therefore, I suggest that the authors provide clarifications on these points and perhaps take the opportunity to shorten the paper by using appendices for the detailed diagnostics that are not entirely novel, while retaining only the key messages relevant to the paper.

Finally, I think the authors could provide explanations for their results in numerous places to go beyond a mere description of their diagnostics. For instance, around lines 285–290, why is there such a bias? Likewise, I could not get the added value of the discussion in section 5.1, which discusses the differences between including only the M2 tidal component vs. all tidal components: what are the outcomes of this experiment, either in terms of model behaviour or ocean dynamics? At the end of section 5.2, why do you think a higher resolution reduces the diurnal HKE in nearshore domains? At line 493, why does semidiurnal energy increase in a closed sea with a higher wind frequency?

Minor comments and questions

• There are very few typos, and I am grateful for the authors for having been careful on this point
• l.45 and 46: I don’t understand what “significant vertical structure” means here
• l.142 ongoing: is this an offline advection of the numerical particles? What is the temporal scheme used, and what is the time resolution of the surface data? These details are lacking in this section.
• first paragraph in section 4: I was a bit surprised that you used undrogged drifter, although you provide some justification later on in this section. Indeed, I thought that undrogged drifters are more sensitive to wind effect, which can alter the resulting signal. Is this not important? Could the authors just mention whether it can be expected to have an impact or not (or maybe I am just completely wrong and this is merely negligible)?
• l. 262-264: I do not see the patterns described by the authors in the corresponding figure. In particular, it is said that low frequency HKE is higher in the center of the North Atlantic in the model, contrary to the observations, but there is a big blue patch there in the right panel. Could you please clarify?
• l.270: Once -> One
• l.336-339: sentence is repeated.
• l.554: insufficient horizontal resolution can enhance energy in the SD band by preventing scattering into the wave continuum (not promoting)

This study provides a comprehensive analysis of surface horizontal kinetic energy (KE) levels using high-resolution numerical simulations of the North and Equatorial Atlantic Oceans. They compared the results of numerical drifter experiments with surface drifter observations.  and further KE estimates in the Lagrangian versus Eulerian framework. The most distinguished part of this manuscript from previous published studies, is the sensitivity tests to explore the impacts of the forcings (tidal & winds) and model parameters on KE estimates by numerical simulations. Overall, this paper is well written and clearly organized, and the findings are of significant interest, offering valuable insights to the modelling community.

I highly recommend this paper for publication in Geoscientific Model Development after addressing the following major concerns about the objectives, results and reasons for the discrepancies between observations, different framework, and various numerical simulations. And some minor corrections are also required to be done.

This manuscript can benefit from improvements in several aspects before it is accepted. I have a couple of concerns and comments as below:

Major concerns

1. 1. Title Alignment: I think the title does not convey the motivation and key findings of this paper. In both abstract and most of the results section, the authors focus more on the numerical Lagrangian versus Eulerian analysis, as well as the sensitivity of the Eulerian simulation to the choices of parameters and forcings. The comparison between the surface drifter observations with numerical simulations seem not a central topic of this study. I suggest the authors carefully think about the title that can better summary their results, to avoid misleading the readers before they go through this paper.
2. Manuscript Structure and Visualization:The whole manuscript looks a bit long and difficult to follow. It would be easier to read if the authors try to find a better way to arrange their figures and texts. For example, the zonally averaged rotary sepctra plot can be combined with the KE maps for each subsection, right following the corresponding results and discussion on these figures. Then the readers will not be bothered by the mismatching of the texts and figures next to them. And the current figures are somewhat repetitive. The authors could consider using more diverse plots to present the results (e.g. figure 5 in Arbic et al., 2022, Figure 4 & Figure 5 d-f in Zhang et al., 2024). At present, most of the figures in this manuscript look highly similar and sometimes the maps may not a best or the only way to display your results.
3. Drifter Experiment Design: Even though the novel part of this munscript lies in the third part (i.e. sensitivity tests of parameter choices), the comparison between the surface drifter observations and the Ocean Parcel experiments based on NEATL simulations are important as well (despite previous studies like Yu et al. 2019, Arbic et al. 2022 and Zhang et al. 2024 have shown similar results). The authors need to provide more information and discussion on the design of their numerical drifter experiments (OP Seed 1/2 and OP Seed drifters). For this part I have a few questions: Why the authors choose observations from undrogued drifters for comparison? Why in Figure 1b the OP 1/2 have a very different coverage compared to the distribution of undrogued drifters in Figure 1c (I mean the less coverage of the northern part of the domain, say 50N and further north)? And the distribution of trajectories in Figure 1b and 1c looks highly different, in this case, does the comparison in section 4.1 (Figure 3-4) make sense? Why not using OP Seed drifters to directly compare with drifter observations instead? As such, may be section 4.2 and its figures are not necessary or at least could be moved to suppplementary materials. The length of the munuscript could be shorter then.
4. Depth of Discussion: Most of the results are about the basic description of plots and comparisons. I would like to see more discussion about the underlying resons or potential machnisms of these difference, then this paper would be more valuable for future studies. The summary is also too long and kind of repeating the information in previous sections. It will be a good idea to make this section brief, leaving key takeaway messages only, and perhaps to have a short paragraph in the end of Section 6 Summary, to provide some implications for using drifter observations and numerical Lagrangian vs Eulerian analysis for KE, and point out directions for future studies.

Minor comments

• Table 2 & 3: These show overlapping information. I suggest keeping only one in the main text, the other could be removed or placed in the supplementary materials.
• L243: this sentence refers to Yu et al. (2019)? Then Yu et al. 2019 should be put into the brackets.
• L266-267: repeating information” The bipolar pattern in the diurnal band, with more KE
• poleward of 30.N in the observations but equatorward in the model,” You have said this at the beginning of L265. Try to be concise when describing the results.
• L270: “Once can…”, Once -> One?
• There maight be some other typos and minor errors throughout the text, the authors should carefully check and correct them.