Review Reports - The Interannual Fluctuations in Mass Changes and Hydrological Elasticity on the Tibetan Plateau from Geodetic Measurements

Round 1

Reviewer 1 Report

I am satisfied with the revisions and only have several minor comments. I'm sure the authors can handle these comments so no further review from my side is needed.

Fig2. The dashed curves are unexplained.

L214. The higher amplitudes in the southeastern TP are also a result of glacier change there.

L216. "the spatial patterns of the precipitation", precipitation brought by westerlies. It's a well-known cause.

L226. consistency -> consistent

Fig. 5a, two legends are "Filtered > 0.5 cpy", what's the difference?

Fig. 7. Explain in the caption that the locations are marked in Fig. 2.

Author Response

I am satisfied with the revisions and only have several minor comments. I'm sure the authors can handle these comments so no further review from my side is needed.

Response: Thanks for your significant suggestions in this round of review, which make our manuscript a great improvement. We have improved the manuscript as you suggested, please see in the revised version.

Fig2. The dashed curves are unexplained.

Response: The dashed pink and black curves are focus areas in this study. We have added the statement in the revised version, please see in the line 122-123.

L214. The higher amplitudes in the southeastern TP are also a result of glacier change there.

Response: We have improved the statement in the revised manuscript. Please see the lines 214-215. Thanks.

L216. "the spatial patterns of the precipitation", precipitation brought by westerlies. It's a well-known cause.

Response: We have improved the statement in the revised manuscript. Please see the line 218. Thanks.

L226. consistency -> consistent

Response: Have improved it, see line 228. Thanks.

Fig. 5a, two legends are "Filtered > 0.5 cpy", what's the difference?

Response: We have improved the two legends in Figure 5a with Filtered > 0.5 cpy. Please see the Figure 5a in revised manuscript.

Fig. 7. Explain in the caption that the locations are marked in Fig. 2.

Response: We have added the explain. Please see the lines 271-272.

Reviewer 2 Report

Review of “The interannual fluctuations in mass changes and hydrological elasticity on the Tibetan Plateau from geodetic measurements” by He et al.

The authors have improved this paper and I only have a few minor comments dealing mostly with the use of the word significant, which usually implies some sort of statistical test was completed. These minor comments are below.

Line 313: The word significant implies a statistical test was performed, but that is not the case here. Change particularly significant to the largest.

Line 315: Delete main and of.

Line 320: Remove significant.

Author Response

Review of “The interannual fluctuations in mass changes and hydrological elasticity on the Tibetan Plateau from geodetic measurements” by He et al.

Response: Thanks for your significant suggestions in this round of review, which make our manuscript a great improvement. We have improved the manuscript as you suggested, please see in the revised version.

Line 313: The word significant implies a statistical test was performed, but that is not the case here. Change particularly significant to the largest.

Response: We have changed it to the largest, please see in the line 316.

Line 315: Delete main and of.

Response: Have done it. Please see in the line 318. Thanks.

Line 320: Remove significant.

Response: Have removed it in line 322.

Author Response File: Author Response.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The manuscript used GRACE and GPS datasets to study mass changes in the Tibetan Plateau. It’s a popular topic and fits the scope of this journal. The content is well organized, but I would suggest adding some information about the characteristics of sub-region changes to make it more informative. The discussion part also needs to be rewritten. The detailed comments are given below.

L112. What are LC, PC, IONEX, IGRF12?

Section 2.1

Explain the data time span here.

L129, April 2002–December 2020 and from April 2002–December 2020, respectively

Odd sentence.

Section 2.3. The performance of global gridded precipitation and temperature datasets is doubtful here due to the lack of ground observations. I would suggest collecting ground data to validate them, or at least comparing several different datasets.

Fig. 4. The amplitude cannot be negative, and the phase spans from 0 to 360. The range of the color bars should be thus truncated. Besides, the phase result is too uniform. The authors may consider using a shorter color range to highlight the spatial difference.

L228. Three-monthly

The dash is unnecessary.

Fig. 6. Did you also detrend the GPS? If not, explain why you treated the results differently.

Show the locations in Fig. 1

L256. How large is the explained variance of the 1^st mode? Why only this mode is shown here?

PCA requires the time series have the same length. How did you treat series that have different time spans?

Fig. 8b. The series started in 2002, but many stations were set up after 2010. Did you only select stations beginning from 2002? If so, how many stations did you use?

L282, 283. Glacier quality

Should be glacier quantity?

L283. Transpiration

It happens only in plants.

L285, which correspond to the relatively stable temperature environment in the region.

I don’t get the point here.

L289, greater than

It cannot be concluded this way. First, the precipitation shows a positive trend there. Second, glacier mass balance has different sensitivities to temperature/precipitation, and you cannot tell it just from the absolute number of changes.

L307, are more scientific

It’s a very strong conclusion that cannot be drawn so easily. Besides, there are several methods to fill the data gaps in GRACE dataset.

Fig. 10a, how to explain the big discrepancy between GPS and GRACE around 2004?

Fig. 10b,d,f are not explained at all.

These results are very interesting, but the current version is not informative. As the whole region is so large that holds different signals sources, it is better to separate the whole region into several sub-regions, likely based on groundwater, glaciers, inner Tibet.

Fig. 11. It’s better to only use one (The comparison of MEI and IPO is irrelevant here and scientifically meaningless) and merge it into fig. 10.

Discussion part.

It is no discussion but like a detailed conclusion. In this part, it is supposed to discuss the potential limitation in the study, deep implication of the results, other connections with others’ studies, and so on.

Reviewer 2 Report

The authors examine the interannual fluctuations in glacial mass balance, precipitation, and temperature over the Tibetan Plateau to assess the influence of climate on the fluctuations in mass balance. This paper is nicely written, but I do have one major comment that could impact the results. I do not think it will take the authors long to address this potential issue though.

Major Comment:

My main concern is the uncritical use of ERA5 for the precipitation data. Herbach et al. (2020) note spatial variability in the correlations between ERA5 and NASA’s TRMM Multi-satellite Precipitation Analysis product with lower correlations observed over the Tibetan Plateau region. Moreover, Fallah et al. (2020) show that due to this spatial variability, other products can do a better job capturing precipitation variability at regional scales. The authors do cite Lei et al. (2021) elsewhere in the manuscript, and it would be good to bring it up here too, since the results there are encouraging. However, Lei et al. (2021) focused on precipitation-evaporation and not variability and trends in precipitation, which can have large spatial variability. ERA5 should be compared against some sort of real precipitation product for Tibetan Plateau region (e.g., one of the Global Precipitation Climatology Centre datasets). The authors would not really need to add much here. Just a simple mention that ERA5 precipitation data were compared to a real precipitation product and did not impact the results would minimize concerns readers may have about the quality of precipitation reanalysis in ERA5 and make this a stronger paper.

Minor Comments:

Line 67: GIA not defined.

Figure 2 cited before Figure 1.

Additional References Mentioned in Review:

Fallah, A., G.R. Rakhshandehroo, P. Berg, S. O, R. Orth, 2020: Evaluation of precipitation datasets against local observations in southwestern Iran. International Journal of Climatology, 40, 4102-4116.

Hersbach, H. B. Bell, P. Berrisford, S. Hirahara, A. Horanyi, J. Muñoz-Sabater, J. Nicolas, C. Peubey, R. Radu, D. Schepers, A. Simmons, C. Soci, S. Abdalla, X., Abellan, G. Balsamo, P. Bechtold, G. Biavati, J. Bidlot, M. Bonavita, G. De Chiara, P. Dahlgren, D. Dee, M. Diamantakis, R. Dragani, J. Flemming, R. Forbes, M. Fuentes, A. Geer, L. Haimberger, S. Healy, R.J. Hogan, E. Holm, M. Janiskova, S. Keeley, P. Laloyaux, P. Lopez, C. Lupu, G. Radnoti, P. de Rosnay, I. Rozum, F. Vamborg, S. Villaume, J-N Thepaut, 2020: The ERA5 global reanalysis. Quarterly Journal of the Royal Meteorological Society, 146, 1999-2049.

Reviewer 3 Report

Title: Interannual fluctuations in mass changes and hydrological elasticity on the Tibetan Plateau from geodetic measurements.

The authors present a study of hydrological changes of Tibetan Plateau using GPS and GRACE/GRACE-FO observations. This subject has been largely studied and after reading this manuscript, I think that this paper doesn’t bring new insights. So, I suggest to reject this manuscript.

I could reconsider my decision if the authors show new results or conclusions.

Next, I will justify my decision:

- Zao et al 2016 https://doi.org/10.1016/j.jseaes.2016.11.010 have already used GRACE and GPS observations to study the Tibetan plateau. One of their conclusions is “ The vertical components of more than 78% of the total number of GPS stations exhibit correlations of more than 0.8 with respect to the corresponding GRACE components” then good correlations have already demonstrated (conclusion in line 369).

- Common Mode Component proposed by Pan et al 2019 (and cited in the manuscript) is used to analyse the Global Positioning System (GPS) time series in the Eastern Tibetan Plateau. Principal component analysis (PCA) and wavelet time-frequency spectra are also used. The authors have used the same methodology. In addition, we notice that Figure 7 of Pan et al. 2019 is very similar to figure 8 of He et al. paper. After a completed analysis of their results, Pan et al. 2019 concluded :

“we tend to believe that the mantle-inner core gravity coupling (MICG)suggested by Ding and Chao (2018b) [42] is the mechanism for the ~6 yr signal in the CMC” . Then, other conclusion of the paper (line 372) has been already demonstrated.

- Another conclusion of Pan et al. 2019 is “some ~2–5 yr signals are also present in the wavelet spectrum in Figure 7f (especially the time span denoted by the dashed ellipse) that are likely caused by El Niño-Southern Oscillation (ENSO) meteorological oscillations “. Conclusion in line 374 has already demonstrated.

- ENSO effect has been already studied by Pan et al. 2019 , they concluded “ ”We further discovered that the GRACE-derived elastic loading displacements present similar patterns represented by the quasi-periodic oscillation of La Niña (El Niño) phenomena that may reflect responses to global climate change.“ Conclusion in line 379 has been largely demonstrated. Please see also:

https://doi.org/10.1029/2019JD031384

https://doi.org/10.3390/w12102862

- Authors don’t show the contribution of GRACE FO observations to their study.

- Different GRACE solutions give similar results. This comparison is not really useful.

- Zou et al. 2019 (https://doi.org/10.3390/rs11091103) have used temperature and precipitation datasets to better understand mechanisms controlling water storage variations.