Merit:

The manuscript is concise and well written. I think the material would fit well in EGU Ocean Science and I anticipate it ultimately will be a nice contribution. While the figures and results are mostly convincing, I think there are a few weak points in the presentation and analysis, which I have mentioned below.

Major comments (see line-by-line comments for more details):

1. The findings are strongly based on two “showcase” days, and it is unclear whether they are necessarily reflective of what is typically observed in this region.
2. The spring-neap tide composite needs to be discussed in more detail with clearer physical context.
3. Several of the assumptions are not sufficiently justified and may be a source of uncertainty. These include a) exclusion of turbid waters when processing satellite data, b) assumption of stratification in ray tracing.
4. In several places, discussion is qualitative even though it appears that quantitative results could be deduced from the figures. I think that including additional quantitative results in the text would strengthen the findings.

Line-by-line comments and suggestions:

L8 – Perhaps it would be better to state that “chl was higher during neap tides”, etc. rather than the “chlorophyll differences” term which could be confusing (in the abstract only).

L11 – clarify what the composite means if you mention in the abstract

L19 – Clarify that this means chl max/min values occur 1-3 days after the tidal signal

L32 – I would recommend to add a bit more detail on how season conditions vary and how this modulates ISWs

L56 – “remote sensing”?

L71 – Do you mean “intra-annual” (or if not, please explain further)? As written it implies variability over many years, and I don’t understand how that would be impacted by tides.

L94 – Please explain why those two days were chosen. Were they objectively chosen? Are they representative of commonly observed conditions? I think it’s still probably ok if not, but in that case it should be more clear if these may not be typical of what’s usually observed.

L117 – I am concerned that such an exclusion will be seasonally dependent; i.e., discharge of the Amazon, and presumably turbidity as well, will vary seasonally. Thus, the excluded data will be disproportionally from a certain time of year. Please explain/quantify whether this is the case, and how this choice may have influenced later analysis and results.

L149 – I don’t understand exactly what S and N are. Are they the concentration of CHL corresponding to the center of the spring/neap time or something else?

L155 – What do you mean by “composite maps”? I don’t see any spatial term in Equation 3. From the equation it looks to me like the lagged dependence of chl on tidal cycles. Is this applied to different points in space? I am probably missing something here; please explain this in more detail.

Reading on, I can see the figures of this metric. I still think more explanation here would be helpful.

L163 – I do not think these stratification assumptions are valid in the region of study. Because of the Amazon plume, I suspect that the profile of N is highly variable and not gradual nor continuously varying (you seem to also mention this at L173). Are there any references that show how much N varies? I think some measure of uncertainty should be included and quantified.

Fig 2 – I would recommend to include in the caption or figure what “difference” specifically refers to.

Fig 2 a/b (and other figures) – I would suggest to change the color scale. Rainbow color scales are not perceptually uniform, and thus the magnitude of features such as fronts may be enhanced/biased by the scale. I would recommend to use “cmocean” or a similar perceptually uniform scale.

L213 – For clarity, the point here is that the mode 2 filtered signal is strongly correlated with the chlorophyll difference, correct? It might be helpful to quantify this correlation in some way.

L215/Fig 5 – There needs to be a physical explanation of what the result of the wavelet analysis is showing. It is just the spectral energy at a period of 15 days so an indicator of regions where spring/neap tides are strongest, correct? Or maybe I am missing a bit of it?

L252 – It would be helpful to quantify the coherence of the signals for each of the pathways. I agree with the findings visually, but having a quantitative comparison would make your argument stronger.

Fig 7 – This figure only shows lags up to 3 days. I would include days 4 and 5; otherwise it is unclear that there is not an even stronger signal with more time lag.

L321 – I’m still not quite convinced that aliasing does not significantly impact these results; I suspect there will be regional differences from the North Sea to the area of study. Are there other references that have looked at this in similar conditions (and found that the bias was between flood/ebb and not high/low)? In any case, I think more explanation beyond citing a single study would be helpful.

L350 – These factors would be expected vary seasonally. I would recommend to discuss in a bit more detail what conditions were present in the two showcase times. Regarding eddies and currents this could be verified with SSH.

L355-358 – The figures showed greater coherence with the mode 2 tides. Would that suggest those are more responsible?

L384 (and in other places) – This study does not directly show that there is mixing due to tides. It is inferred based on surface measurements. This should be explicitly clear somewhere.

L389 – “less turbid”

L395 – Might be helpful to refer to these pathways by longitude here as well

L425 – Run-on sentence. Please reword.

L428 – Do not directly state what your future work is. I think a reworded version of the previous sentence could be used to motivate it without saying it directly.

The manuscript (MS) makes a comprehensive and detailed analysis to connect wave-like signal in chlrophyll-a satelitte images to internal tide dynamics off the Amazon continental shelf. Although the title and abstract suggest a focu on baroclinic tides, the MS also presents ideas connecting observed patterns to barotropic tides. The results are interesting and certainly relevant, but the MS requires extensive reorganization for the main message to come through clearly. The knowledge gap is not well-defined, and in several parts of the document, the arguments are largely speculative and not sufficiently supported by evidence. I recommend major revision. If the speculative aspects are clarified, supported by evidence, or removed, and the MS is restructured, it could make a strong contribution to the literature.

MAJOR CONCERNS

My major concerns relate primarily to structure and terminology:

1. Structure of Introduction and Conclusion:

The introduction reads almost like a discussion. Although the last paragraph mentions the topic of the MS, the knowledge gap or main question is uncluear.

Similarly, the conclusion reads like a dicussion and is repetitive compared to Section 4.3. I sugget renaming it Summary and Conclusions.

2. Terminology:

The use of showcase seems inappropriate in this context. Consider using case study or illustrative case.

Sunglint should not be used as an adjective.

Although I think I understand the reason behind the two study cases, the MS should clarify why they are used. It should explicit that they are intended to demonstrate the existence of internal tides in the area, which justifies exptrapolating to a time series of chlorophyll images from Globcolour and MODIS-Aqua.

Avoid using coloquial terms like “sandwich”; I recommend “to be flanked” instead.

The term “spring-neap tide” is confusing; I believe you mean “spring-neap tidal cycle”. Clarify or define this early in the MS.

Please correct the spelling of “MODIS-Aqua” consistently throughout the MS.

SPECIFIC COMMENTS (line numbers are referenced)

51: the availability of PAR.

53: Define interfacial ITs.

55: Use deep or subsurface chlorophyll maximum

61-62: “to two combined effects”

72: Indonesian Seas (there are several of them) or Indonesian Throughflow

117:  Suggestion: more than 20% of the time series.

129: Define what is a showcase day.

163: Is this assumption valid for this region? The freshwater inflow could have drastic effects on local stratification, likely preventing gradual and continuous profiles. How might this assumltion affect your analysis? You should demonstrate the valifity of your asumption specially becasue you are looking into a surface signature of these waves.

173: N (or M – the lateral buoyancy gradient) will certainly exhibit lateral variability due to riverine input and submesoscale/mesoscale stirring.

Figure 2: Points A and B are barely visible. The magenta font over red/orange background lacks contrast. Also, clarify which quantity is shown in panel D? In addition, having the coastline would improve visualization, orientation and highlight the relevant features. ISW signatures do not stand out, significant zooming is needed to see them.

189, 192: References for the typical waelengths are needed.

205: Clarify whether the average is temporal only (one value) or also considers spatial differences (2D map).

Figure 4: Consider adding arrows to highlight peaks.

216: statistically significant.

249: Difference relative to what? Please clarify.

337-341: Here and later on. How would the DCM be visible from remote sensing? Does IT-induced mixing bring chlorophyll from the DCM to the surface?

379: The MS focuses on internal tide signatures in surface chlorophyll; clarify why barotropic tides are also discussed.

386-389: These statements are speculative. Explain more clearly how the time series analysis supports these conclusions.

389: Clarify “lower turbid”?

392-393: “as they propagate offshore the open ocean”, likely a typo; please check.

402: […] beam signal is attenuated after 300-400 km […]

404: more effective TO OBSERVE.

417: How is stratification a “background circulation feature”?

421-422: This statement is clearer than Lines 386-389.

423-424: Could the difference between tracers simply be because chlorophyll is biologically reactive while temperature is a physical tracer? The current explanation is overly complicated. I do not agree with your argument.