Overall this manuscript provides an important contribution to the remote sensing of GHGs from space. I recommend that it be published after a number of minor revisions given in the attached marked-up PDF.

The updated FOCAL retrieval (v3) is presented in this paper. It can process GOSAT and GOSAT-2 data. It has improved capabilities, mostly bigger spatial coverage than its predecesors, new molecular species measured and new processing. It can measure CO2, CH4, H2O, HDO, CO and N2O.

The paper is well written and well presented, and, as such, deserves publsihing. Some minor comments would improve the readability of the paper.

Unfortunately, it has been written in a manner that serves solely as a reference, since most of the content are references to previous papers. It is therefore very dull to read and has very little "information" appart from some uncertainty figures, sepcially for someone outside of the field . Since the style of the paper cannot be modified substantitally because this would mean a huge effort, I suggest to include the following additions:

- It should be stated, in the abstract, the beggining and in section "3.2 Processing" whether the uncertainties of the retrievals are determined. A great emphasis is placed on the amounts derived, but very little in the uncertainties. Are the uncertainties for each individual "pixel" determined? Or can a global uncertainty figure be derived?

- In line with the previous statement, include a sentence or two describing, in general, the algorithm used for pre-processing, processing and post-processing. Is it something similar to a linear regression? Non-linear regression? Machine learning? Optimal estimation? Please include some phrases such that the reader does not need to read one or two other papers to understand in general terms how the retrieval works.

- In the conclusion, for a reader outside from this field, it is not known whether these retrievals will make a difference in the community or not. Do they satisfy the requirements to geographycally locate the sources and sinks of CO2? CH4? Do they satisfy some requirements that can be useful to the communitty? Can they be assimilated in an AC numerical model? If not, which requirements would be needed in future instruments? In summary, a paragraph to show that this work is useful for humanity and not just for the machines that are being fed the numbers.

This paper presents a new retrieval (FOCAL 3.0) for XCO2, XCH4, XH2O, XCO, HDO, and XN2O from GOSAT and GOSAT-2. It is exciting to see retrievals from GOSAT-2. The retrievals are validated following standard protocols. I was very interested by the scatter and temporal bias metrics relative to TCCON – they are not usually shown but I found them very instructive. I recommend publication in AMT but suggest that the authors consider the following comments:

1. The Introduction advertises that comparisons with previous satellite products will be shown but I could not find these comparisons in the text.
2. Equation (1) suggests that methane must be retrieved by the full-physics algorithm in order to derive a proxy estimate but that would erase much of the benefit of the proxy method in enabling successful retrievals when the full-physics method can’t.
3. Gradients in Figures 2 and 3 are so washed out as to make the Figures useless.
4. Line 390: ‘the data sets…are available from the authors’. That’s OK at the submission stage but won’t do at the publication stage. The data sets should be publicly posted.

This paper describes the new v3.0 FOCAL retrievals for GOSAT and GOSAT-2, used to retrieve XCO2, XCH4, XCO, XNO2, XH2O, and the relative ratio of semi-heavy water to water vapour. The paper describes the methods used in the retrievals and validates the new dataset against the TCCON network. Overall, the paper clearly describes the retrieval methods and demonstrates the value of the new data products. Therefore, I recommend publication, with several minor revisions based on the comments below.

Specific comments

• Title: Should the title list the species being retrieved? 
• Abstract: Are the new FOCAL v3.0 datasets publicly available?
• Line 10: I found this paragraph a bit difficult to follow. For lines 10-11, do you mean something like this? "For XCO2, the new FOCAL retrieval (v3.0) significantly increases the number of valid XCO2 data compared with the previous FOCAL retrieval version (v1) by 50% for GOSAT and about a factor of two for GOSAT-2." Are "All FOCAL data products" in line 11 referring to all v3.0 data products?
• Line 165: For the filtering procedure -  how do you ensure that real variability isn't accidently filtered out from the dataset?
• Line 216: Could you add a brief definition of the full physics vs proxy datasets for CH4 and explain why there are more data for the proxy products? Are the full physics and proxy comparable or do they have different applications/uncertainties?
• Line 252: Add a brief description of the CO2 timeseries to the text since this is also shown in the figure? Is the timeseries qualitatively in line with other versions of the CO2 retrieval? Other monitoring?
• Line 263: Is there also no temporal trend in delta_D? Is it expected that year-to-year variations for delta_D be larger?
• Line 287: Please add a bit more detail about the comparison quantities being calculated. Perhaps including formulae would be helpful. For example, how is the seasonal variation of the difference at each station being calculated?
• Figure 1: This figure takes a bit of effort to read. Is there a reason that the full timeseries is shown instead of, e.g., a summary of the count during the measurement period with all available datasets? If so, describe the timeseries more in the text. Perhaps it would be easier to read if colours were used consistently across figure panels and if the FOCAL data product was somehow distinguished from the other products (e.g., with a distinct colour choice, cross-hatching or something else?). In panel (d), could the FOCAL v1.0 and focal v3.0 XCO2 be put next to each other so that they can be more easily compared?
• Figures 6-10 are barely described in the text. Can these be moved into an appendix or the supplementary material? Also, please make font sizes bigger.
• Tables: There are a lot of tables included in the paper. Some of these are not referenced from anywhere in the text (Table 2, 4, 5). Are all tables needed in the main body of the text - if so add descriptive text. (Otherwise, could move to appendix or supplement)

Technical comments

• Line 266: Rephrase so that it is clear what XCO is similar to. E.g., "Across different latitudes, GOSAT-2 XCO shows similar values and seasonal variations, except in the southern hemisphere…"