(general comments)

This paper is the first well-organized study on the validation of ATLID using ground-based lidar, and it serves as an extremely valuable report for both ATLID users and algorithm developers. It evaluates ATLID products using reliable ground-based lidar systems at locations scattered around the world for various types of aerosols. The text is clear and easy to read, and the figures are of high quality. While I believe this paper is nearly ready for publication, some technical corrections and few additional explanations are needed, so I consider minor revisions to be necessary.

(specific comments)

• Please clarify whether, for all selected cases, the profile closest to the ground site was used, or whether, in some cases, the profiles were averaged. For example, line 89 states “all but one within 20 km,” which I interpreted to mean that all profiles within 20 km were used; however, as noted in line 357, Fig. 9 states that the closest product was used.
• Regarding lines 416–417, it states, “Dedicated investigations have shown...”; if there is a reference, please include it.

(technical corrections)

• Line 254: It says 14.4 N, but based on Fig. 3, isn’t 14.1 N correct?
• Line 278: Regarding “100 km vertical smoothing,” isn’t this a typo for “horizontal”?
• Line 399: Since “ore” is a proper noun, it should be written as “Ore.”
• Line 573: “)” is missing in “(see Fig. 19”.

This paper provides a detailed discussion of the results of ground-based/ship-borne validation of the ESA aerosol product derived from EarthCARE satellite-borne lidar data. The validation process demonstrates meticulous and sophisticated planning, including the selection of datasets that account for the horizontal heterogeneity of the target aerosols and the incorporation of various aerosol scenarios. Furthermore, the paper not only demonstrates the validity of the product but also discusses remaining challenges, providing valuable information and insights for aerosol science using EarthCARE data. The writing is extremely thorough and clear, the figures and tables are appropriate, and it is a well-written paper. For the reasons stated above, this reviewer recommends the publication of this paper in AMT. While no major revisions are required, I would like the authors to revise the paper taking into account the points listed below.

1. Although the text is written in a clear manner, I feel that the key points of this paper—such as its findings—become less clear as I read on. This paper selects seven aerosol cases. For each case, it describes the atmospheric and aerosol conditions, the differences in optical properties between satellite and ground-based data, findings, suggestions, and conclusion. The underlying issue may be not only the large number of cases—seven in total—but also the substantial amount of information provided for each one (and the writing may be somewhat redundant). Furthermore, it may be difficult to recall the details of a previous case while reading about a new one. Therefore, it would be very helpful to have a table summarizing the key points (observation area and period, what type of aerosol case it is, whether the optical properties between satellite and ground observations are consistent, what findings were identified—e.g., edge effects) corresponding to Section 3 for the seven cases.
2. Conclusion: It would be very helpful if you could emphasize the description of the findings. For example, you could elaborate on the findings, stating something like, “The findings of this paper are as follows.”
3. While many descriptions of the differences in optical properties between satellites and ground-based measurements tend to “overestimate” or “underestimate” these differences, it would be helpful if the actual magnitude of the difference (relative or absolute error) were specified in specific instances.
4. P6 L163: AM-COL (Haarig et al., 2023), ACM-CAP (Mason et al., 2023) : A brief explanation of the synergy with which sensor (MSI?, CPR?, both?) would aid the reader's understanding.
5. P10 L279: 100 km vertical smoothing => 100km horizontal smoothing?
6. P13 Fig5: No description on NR
7. P23 L443: Above the aerosol layers, ice clouds were observed at around 7.5 and 11.5 km: Is the 11.5 km layer a cloud? It appears to have a very high lider ratio (~80sr ?). Could it be an aerosol in some areas?
8. P33 L565: hardly revealing the horizontally heterogeneous atmospheric state.: At this point, I think a bit more explanation is needed as to why this is stated in this way. Some persons may suggest that while high-resolution products (right figure) are indeed noisier than low-resolution products (left figure), their horizontal structure appears to be similar to that of low-resolution products.