The paper reconstructed a century-scale sea level rise at tide gauges, using a data assimilation approach that has been proposed by previous studies, but I saw some modifications or improvements, e.g., introducing a random process. The data assimilation is indeed driven by physical mechanisms, and therefore the reconstruction, or essentially the interpolation or extrapolation are physically interpretable. Authors considered 35 CMIP6 model output and, consequently, they gave 35 reconstructions, this ensemble obviously offers some useful statistical assessments, and this is really convenient, users can compute a desirable uncertainty estimate. Authors compared their reconstructions to observations from satellite altimetry, and other sea level reconstructions that are widely accepted by the community. The comparisons were performed on both global and local scales, and the results seems promising, although some differences were still seen, especially at the sites of tide gauges. The new global mean sea level reconstruction can serve as an independent estimate, users can get a better ensemble for average and spread. Overall, I think the dataset can be potentially applied to sea level studies, and the community would benefit from it. However, I have several comments, and I hope authors can address them before I see the paper published.

(1) In the method section, authors used the HP filter to compute the instantaneous rate for SDSL changes. My question is how the authors determine the parameter lambda (i.e., equation 14)? As a filter, HP might be sensitive to the changes of lambda. Based on my own understanding, the filtered or smoothed SDSL is perhaps related to the smoothed sea level curves seen in, e.g., Figure 6. Another reason that might explain the smoothed curves is that authors used the Kalman filter and smoother for the sea level fingerprints, so the total sea level would be much smooth. Authors need to prove how the curves would vary with parameter lambda.

(2) There might be confusing explanation in Table 3. Treu et al. (2024) used the low-frequency sea level reconstruction from Dangendorf et al. (2019), who employed a hybrid reconstruction. This hybrid reconstruction combined traditional EOF reconstruction and the data assimilation, the former provided sea level variability, the latter provided long-term trends. But why authors claimed that ‘Differences are possible between reconstructions and raw records’, is this because they observed apparent discrepancies in Figure 10 when they compared with Treu et al. (2024). If so, I think there might be another reason, that is Treu et al. (2024) considered different selection of tide gauges. Anyway, authors should add some more wording to clarify.

(3) In Figure 9, authors compared many GMSL reconstructions to justify theirs. I saw some differences in the overall rates. Authors attributed the differences to reconstruction methods and selections of tide gauges, this is true, and I agree. But authors overlooked another fact, that is, the GMSL curves represent the relative sea level or absolute sea level? This is of course highly related to the reconstruction methods, but I think author should add some comments to this point, and the paper Dangendorf et al. (2017) might be helpful (https://doi.org/10.1073/pnas.1616007114).

(4) In section 4, authors pointed out some limitations in their reconstructions, this is very important and useful. Authors claimed that some abrupt changes are not removed from the raw records, and those changes are induced by earthquakes, but have no significant effect on sea level reconstruction, this is understandable, as they account for only a small portion. I could agree to this. However, authors should elaborate a little bit more on the second limitation. The refined trends could be informative for long-term changes, despite we did not know how ‘long’ it is. The community usually employs a 30-year window for computing GMSL rise, so why not compare all the GMSL curves for the 30-year-rate curves, I would expect some differences, even significant ones, readers can glean some useful knowledge, and it would be better if authors add more wordings.

Minor suggestions:

Line 13, period over 1900 to 2022 -> period from 1900 to 2022

Line 17, assessment -> assessments

Line 18, GMSL rise -> GMSL rate

Line 22, observed sea level rise at -> observations from

Line 27, collection -> collected

Line 27, add the reference Holgate et al. (2013) after the website

Lines 33 and 35, reference Calafat et al. (2022) was not shown in the reference list, correct it

Line 43, cause ->causes

Line 62, at tide gauges ->at the sites of tide gauges

Line 69, physical -> physically

Line 75, error in citation of Calafat et al. (2022) as shown before

Line 76, Since -> since

Lint 97, at tide gauges -> at the sites of tide gauges

Line 113, raw tide gauge records -> raw records of tide gauges

Line 132, include -> includes

Line 176, its -> their

Line 189, Instantaneous -> instantaneous

Line 190, variation -> variations

Line 215, sea-level -> sea level, you should be consistent about the writing

Line 226, to address the ‘a zero global mean’, you add ocean mass increase, what about the global mean of thermosteric sea level, how you exactly treat this term?

Line 230, figure 3 was not even cited, you might want to add some more wordings to describe the changes shown in figure 3

Line 235, error in caption of figure 4, e.g., panel (e) was missing

Line 240, rises -> rise

Line 249, remove ‘for this’

Line 300, AVISO sea level observations -> AVISO sea level products

Line 316, assessment -> assessments

Line 333, influence of sea level observations in -> influence of sea level observations on

Line 355, ensemble of subset -> subsets

Line 379, the GMSL -> the GMSL curves

Line 401, The resulting GMSL curve with raw records exhibits -> The resulting GMSL curves with raw records exhibit

Line 425, figure 11, add a panel showing the difference between 95th and 5th percentiles

Line 429, sea level rate -> sea level rates

Line 440, T2024 who provide -> T2024 who provided or provides

Line 458, 3.3 Statistical assessment -> 3.3 Statistical assessments, this correction applies to others, e.g., line 459

Line 505, add a plot showing the 30-year rates for all GMSL reconstructions

Thank you for including me as a reviewer for this manuscript.

Please find my detailed comments attached.