Earth Observation to Investigate Occurrence, Characteristics and Changes of Glaciers, Glacial Lakes and Rock Glaciers in the Poiqu River Basin (Central Himalaya)

Round 1

Reviewer 1 Report

The authors provide a detailed assessment of glacier change in the Poiqu Basin.  The methods are well described. There are several places where greater detail is needed:

• On the number of observed and reported GLOF’s or overflows.
• Delineation of the difference in the timing of seasonal runoff in the basins.
• The difference in elevation and location of rock glaciers from other glaciers.
• Size distribution of the lakes both now and one other key moment in time.
• The impact of increased winter ablation in the region that has been reported already.

This added detail will move the overall merit to High.

45: “serious”

47: “..permafrost environments, that contain a significant…”

61: “This commonly used approach, is a geodetic method that has been widely applied…”

92: “..occurring in the summer, which makes the glacier in the basin summer accumulation glaciers.” Worth specifying this particular nature.

94: What is the summer 0 C isotherm? Should be close to 56000 m.

137: Instead of saying several, why not specify a number.

157:  This is a very small lake indeed.  I agree they are worth noting because they might grow, but the volume is too small to be relevant.

171: Must point out that because of the summer monsoon, peak glacier runoff overlaps with peak precipitation and rain generated runoff, which is unique to HMA. 

“In the Himalayas, the main accumulation season for snow on glaciers is during the summer

monsoon, coinciding with the main ablation season on glaciers as well. As a result peak runoff

from glaciers is similar in timing to peak runoff from pluvial segments (Thayyen and Gergen, 2010).

The summer monsoon month also experience the highest solar insolation and temperature, which leads to the greatest glacier ablation and snowpack melt (Thayyen and Gergen, 2010).

261: “including”

265: “landforms”

292: How many of the lakes are greater than 0.02 km2?

297: How many have drained via GLOR or overflow?

309 and 324 and 390: The time period 1974-2000 and 1974-2004 are both used in this section.  Why not use the same time intervals? Also in discussion since the millennium is used.

346: Is this velocity difference true near the ELA and in the accumulation zone?

368: How does the compare to mean glacier elevation?

407:  Should not the likely impact of extended ablation seasons in the region extending into mid-winter as indicated by rising snow lines in recent years from October-January near Mount Everest (Pelto et al, 2021). These winter warmer post monsoon and early winter periods can lead to significant sublimation as well (Potocki et al, 2022).

427:  The lack of contrast for debris cover has been noted previously, move this into the introduction which explains why you did not consider this separately. Did your study show the same?

434: “..that dynamic thinning plays an important role..”

436: “basal”

Pelto, M.; Panday, P.; Matthews, T.; Maurer, J.; Perry, L.B. Observations of Winter Ablation on Glaciers in the Mount Everest Region in 2020–2021. Remote Sens. 2021, 13, 2692. https://doi.org/10.3390/rs13142692.

Potocki, M., Mayewski, P.A., Matthews, T. et al. Mt. Everest’s highest glacier is a sentinel for accelerating ice loss. Nat. Clim Atmos Sci, 2022, 5, 7. https://doi.org/10.1038/s41612-022-00230-0.

Thayyen, R. J. and Gergan, 1. T. Role of glaciers in watershed hydrology: a preliminary study of a Himalayan catchment". The Cryasphere, 2010, 4, 115-128,2010. doi: 1O.5194/tc-4-115-2010.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Dear authors,

I have read the (cited) paper you already published ZHANG, G., BOLCH, T., ALLEN, S., LINSBAUER, A., CHEN, W., & WANG, W. (2019). Glacial lake evolution and glacier–lake interactions in the Poiqu River basin, central Himalaya, 1964–2017. Journal of Glaciology, 65(251), 347-365. doi:10.1017/jog.2019.13.

In my opinion, compared to this paper, the submitted manuscript does not contain additional information, except for the rock glacier part. Figures 4, 5 and 6 show data taken from other studies, so I wonder what did you do innovative?

I do not support the publication of this manuscript and inform the editor of potential self-plagiarism.

Best regards

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Dear editor and authors,

This paper clearly shows the last trends in the cryosphere of a basin in the Himalaya region using a wide range of Remote Sensing methods. To me, the paper has a very high quality, as all methods are explained, their potential errors addressed and the final results justified. 

Just some minor comments which I will divide in three parts: 

1. Section 2.1 shows the initial intention and how it changed into the final project that was finally developed. I think this is somehow misleading and I suggest just showing the undergone subprojects and the team involved.
2. I spotted some minor spelling errors which areall clustered in the final part of the paper: 

• Line 436. The last word should be "basal" instead of "basel".
• Line 437. "elsewhere" is misspelled.
• Line 440: "emphasis" is missing its h and "hase" should be "has".
• Line 442. "account" instead of "accound".
• Line 444. Should be "extent" instead of "extend". 

3. I would recommend removing the prominent "Shishapangma" label in figures 4 and 5 at least, because it hides some interesting glacier mass balance and velocity information underneath. Also, the inset graph in figure 5 is not the best option to me: line graphs are commonly used for temporal trends, in which case X axis is time. This does not seem to be the case here, as axis X is either accumulated number of glaciers or pixels (it is not clear to me and the figure caption is not clear either). 

Once these suggestions are addressed, I would recommend straight paper publication.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear authors,

I still do not support the publication of your manuscript since your answer did not convince me, for these reasons:

1) it is not stated anywhere that the aim of the manuscript is to "critically compare and discuss results from different studies", as you wrote in your letter.

2) A critical comparison and/or discussion with previous studies is not present. You just mentioned that the results of your research, which are already published, agree with other studies. But this is not sufficient for being your study innovative.

3) The glacier mass change reported in the current manuscript (-0.33±0.12) is different from that of Zhang et al (2019) (-0.39±0.13), which is cited as a reference.

4) I see that the figures of this manuscript are new, but they all report the same data of other figures already published.

5) I do not see the "project report" option in the admissible types of publication listed in the instructions for authors panel of the journal website.