Spatiotemporal Variability of Land Surface Albedo over the Tibet Plateau from 2001 to 2019

Round 1

Reviewer 1 Report

The manuscript is much clearer now.  There are a couple of places where the English isn't perfect but it no longer poses an obstacle to understanding what was done in this study or being able to understand the significance of the results.  Appreciate all of the hard work on improving the manuscript.

Author Response

Thank you very much for the constructive comments. They are valuable to improve this paper. This version of the manuscript has been revised according to the comments and suggestions from the reviewers and editors. This version has been carefully revised for the language issues by a native speaker. We wish we have made a clear expression. Except for the specific comments from the reviewers related to language issues have been responded in the corresponding comments later, other language revisions are listed in details in the later part of “Other modifications” like sentences rewriting for clear expression, grammar error corrections and et al.

Reviewer 2 Report

This is my fourth review of this manuscript. As was the case in each of my previous three reviews, a number of glaring English languages issues still remain in the text. It is difficult to understand why the authors have not invested the effort to resolve these issues before resubmitting the manuscript to the same journal. These issues begin in the first sentence of the abstract and persist throughout the body of the manuscript.

In addition, the authors have again ignored my comments on the the surface aspect figure (now Fig 2D) without justification. The authors have ignored my previous comment on the triviality of the conclusions (e.g., if the fraction of snow cover is decreasing, it is highly unsurprising that the land surface temperature is increasing. The very steep negative visible red to NIR spectral slope of snow will also obviously be strongly inversely related to NDVI).

The authors have clearly invested a substantial amount of time in writing and revising this manuscript. It is disheartening to come to this conclusion, but again, unfortunately, I cannot recommend this manuscript for publication without significant rewriting. I hope the authors will seriously consider much more comprehensive revisions before resubmission in this journal or elsewhere.

An incomplete list of line specific comments is given below.

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Lines 17-25: These sentences are difficult to follow. Are the authors claiming: a) that albedo impacts surface radiation budget and climate (sentence 1), b) that albedo changes are caused by changes in surface radiation budget and climate (sentence 2), or c) that variations in albedo will be used to infer regional climate change (sentence 4)? Is this inference being made based on the assumption that climate is causing the albedo change, or the assumption that the albedo change is causing climate change? If both, should we be thinking about the ice-albedo feedback here? This is unclear.

Lines 31 and 34: What is a “radiation force”? Do you mean “radiative forcing”?

Lines 41-45: “… land surface albedo and the parameters during its associated biophysical processes...” This sentence is incoherent.

Lines 55-57: “… which has been qualified by comparison with in situ measurements or the high-quality airborne observations”. What is the meaning of the word “qualified” here? Do you mean “validated”?

Figure 2. As I stated in my previous three reviews, the color scale on panel D here is not informative, unless the purpose is to show that all the aspects are nearly the same across the Tibetan plateau.

Line 61: What is a “variation trend”? Is this referring to heteroskedasticity? Or just a simple trend? Or something else?

Lines 65-57: “The sudden land cover change can cause a significant decrease of albedo, such as the example of significant albedo variation from 2001 to 2013, which occupied approximately 0.31% of the land surface in France”. This sentence is incoherent.

Lines 67-69: “These distinct conclusions demonstrated that the annual albedo has strong within-year seasonal characteristics [25,26], which increases in winter/spring and decreases during the growing season [27]”. This statement is at best vague and incoherent, and at worst factually incorrect and misleading. The authors appear to be making a global claim about albedo here. While this pattern may be observed in some places, and may be true when the entire northern hemisphere is integrated, this must be stated explicitly. The statement is not generally true about all land cover change from the perspective of satellite remote sensing. What about deserts? Urban areas? What about places where the “growing season” includes winter crops but not summer crops? Crops planted over black plastic tarps?

Author Response

1. As was the case in each of my previous three reviews, a number of glaring English languages issues still remain in the text. It is difficult to understand why the authors have not invested the effort to resolve these issues before resubmitting the manuscript to the same journal. These issues begin in the first sentence of the abstract and persist throughout the body of the manuscript.

Re: We are sorry for our poor English. It’s not easy to find a native English speaker familiar with our study. This version has been carefully revised for the language issues by a native speaker. We wish we have made a clear expression. Except for the specific comments from the reviewers related to language issues have been responded in the corresponding comments later, other language revisions are listed in detail in the later part of “Other modifications” like sentences rewriting for clear expression, grammar error corrections, and et al.

2. In addition, the authors have again ignored my comments on the surface aspect figure (now Fig 2D) without justification.

Re: We do agree with the reviewer’s comment on Fig.2 D of last manuscript. We have tried our best to adjust the figure color scale. But it’s hard to present the aspect details in the whole TP area due to the following two reasons. The aspects in a small region have randomly distributed in the range of [40°,360°], which can be seen from fig.2 E and fig.2 F as the following. Besides, details from such high spatial resolution (30 m) are suppressed when the whole TP area is shown. Unclear and dispersed textures formed by different colors are thus appeared randomly in TP (large range of aspect variation in local regions). Therefore, the whole image as the reviewer’s comment has mislead the reader that the entire TP has very similar aspect. To avoid this, we would like to follow the reviewer’s suggestion to give examples of local variations as fig.2E and fig.2 F. We also add the spatial scales in the new subfigures.

 A description of the TP aspect is added in the manuscript as “While for the aspect, more variations are revealed in local scales shown as dispersed and fusing textures in fig.2 D. Such textures are formed by wide range of aspect variation concentrated in a local region as fig.2 E and fig.2 F, but suppressed in the entire TP area.” (Line 122-124, in revised manuscript)

Fig.2 in last manuscript (Figure 2. The slope of the TP (A); Two subplots of the slope show the examples of the sites located at the top left (B) and lower right corner (C) of the TP; (D). The aspect of the TP; Two subplots of the aspect show the examples of the sites located at the top left (E) and lower right corner (F) of the TP.)

The revised figure is shown as the following.

Figure 2. the topographic features in TP. (A)the slope of the TP, (B) details of a subarea in (A), (C) the slope of a selected site and its surroundings; (D) the aspect of the TP, (E) details of a subarea in (D), (F) the aspect of a selected site and its surroundings.

3. The authors have ignored my previous comment on the triviality of the conclusions (e.g., if the fraction of snow cover is decreasing, it is highly unsurprising that the land surface temperature is increasing. The very steep negative visible red to NIR spectral slope of snow will also obviously be strongly inversely related to NDVI).

Re: We do agree with the reviewer’s opinion. The conclusions on the correlations between albedo and the other three parameters (NDVI, LST, and Snow cover) in TP quite agrees well with our general knowledge, which have already been proven from other researchers. Such conclusions are not novel discoveries, and indeed make little sense here as no new knowledge for readers. Besides, they are not the key points of our research. Therefore, we have deleted these conclusions in the revised manuscript. The corresponding places in the “Abstract”, “4.2 Albedo anomaly and the interrelation with ecological-meteorological parameters”, and “Conclusion” are rewritten or deleted as following.

1. Abstract:

“As an Essential Climate Variable (ECV), land surface albedo plays an important role in the Earth surface radiation budget and regional or global climate change. Tibetan Plateau (TP) is a sensitive environment to climate change, understanding its albedo seasonal and inter-annual variations is thus important to help capture the climate change rules. In this paper, we analyzed the large-scale spatial patterns, temporal trends, and seasonal variability of land surface albedo overall the TP, based on the Moderate Resolution Imaging Spectroradiometer (MODIS) MCD43 albedo products from 2001 to 2019. Specifically, we assessed the correlations between the albedo anomaly and the anomalies of normalized difference vegetation index (NDVI), the fraction of snow cover (Snow Cover), and land surface temperature (LST). The results show that the larger albedo variations distributed in the mountainous terrain of the TP. Approximately, 10.06% of the land surface is identified to have been influenced by the significant albedo variation from the year 2001 to 2019. The yearly averaged albedo was decreased significantly at a rate of 0.0007 (Sen’s slope) over the TP. Also, the yearly averaged snow cover was decreased at a rate of 0.0756. However, the yearly averaged NDVI and LST were increased with slopes of 0.0004 and 0.0253 over the TP, respectively. The relative radiative forcing (RRF) caused by the land cover change (LCC) is larger than that caused by gradual albedo variation in steady land cover types. Overall, the RRF due to gradual albedo variation varied from 0.0005 to 0.0170 W/m2, and the RRF due to LCC variation varied from 0.0037 to 0.0243 W/m2 during the year 2001 to 2019. The positive RRF caused by gradual albedo variation or the LCC can strengthen the warming effects in the TP. Thought, the impact of the gradual albedo variations occurring in the steady land cover types was very low between 2001 and 2019 because the time series was short, it cannot be neglected when examining radiative forcing for a long time series regarding climate change.” (Line 15-36, in revised manuscript)

2. 2 Albedo anomaly and the interrelation with ecological-meteorological parameters

“The evolution of average monthly albedo variation demonstrated that the albedo anomalies 242 were distributed over the range of -0.02 to 0.056, with a large albedo anomaly of 0.04 in February of 243 2008 (Fig.5A). The quality of albedo products showed a larger uncertainty in spring and winter 244 seasons, with more than 50% of the data having lower qualities (Fig.5B). Specifically, more than 70% 245 of pixels had a large uncertainty in Oct. and Nov. In contrast, less than 20% of the albedo products 246 had low-quality over the summer season (Fig.5B). The land surface temperature anomalies varied 247 from -4 to 2 °C and did not show the obvious seasonal changes from 2001 to 2015 (Fig.5C).” is deleted in revised manuscript (Line 242-248 in last manuscript)

3. Conclusions:

“The Tibetan Plateau (TP) is very vulnerable to climate change and plays an important role in regional weather and climate researches in East and South Asia [46,71,72]. The land surface albedo, LST, NDVI, fraction of snow cover, and the radiative forcing over the mountainous terrain of the TP were selected to understand the regional radiation transfer and the climate change.

(1) The mountainous terrain was more sensitive to albedo variation than the places with gentle slopes, which can be identified as the significant albedo anomaly occurred at the mountainous terrain with larger topographic slopes over the years 2001 to 2019 (Fig.3C and D). The land surface albedo and albedo anomaly exhibited the spatial and seasonal variability at the Tibetan Plateau. The larger yearly albedo was distributed in the southwest of the Hindu Kush, the western and central Himalayas, and the central Kunlun mountainous range, where many permanent glaciers are distributed and were suffering from rapid retreating during the observed time period (Fig.3).

(2) The topographic slope has a larger influence on the surface albedo than the topographic aspect, with the decreasing trend of albedo following the increase of mean slope. However, the topographic aspects did not show obvious difference in the albedo variation when comparing to the albedo at the south-facing slope to north-facing slope.

(3) The yearly albedo and the fraction of snow cover have a significant decreasing trend from 2001 to 2019. However, the yearly LST and NDVI showed an increasing trend during this period (Fig.6). The slow albedo variations impacts on RF. The RF due to LCC was shown to be larger than that due to gradual albedo variation in steady land cover types. Overall, the positive RF due to gradual albedo variation in steady land cover types, which were detected to not land cover changes during the years from 2001 to 2019, can reach to 0.0005 ~ 0.4408 W/m2. The RF due to LCC can reach to 5.0712 W/m2 during these years. Weighed against the surface area of the study area, approximately 10.06% of the area suffered from significant albedo variation over the whole TP due to the gradual albedo variation. Though, the magnitude of RRF due to gradual albedo variation decreased by 90% than that the magnitude of RF, and still has the warming effects from the year 2001 to 2019. The LCC also led to a positive RF over the TP since the land cover was primarily changed from barren and soil to savanna, shrubland, and the water bodies, which have the smaller albedos than the barren and soil. The RRF due to LCC were varied about 0.0037 to 0.0243 W/m2, when using the BSA shift, and 0.0043 to 0.0239 W/m2 using the WSA shift.

In conclusion, the albedo variation needs to be taken into account in radiative forcing research for long duration climate change studies, whatever the causes of the albedo trends. The investigation of the NDVI, albedo, snow cover, and LST gradual variation reveals that the gradual decreases in the snow cover had a positive impact on RF via the decreasing of the albedo, which might lead to warming effects. However, the gradual increase in the NDVI showed a slight increase in forest cover and gave rise to additional evapotranspiration and surface roughness, which feedback to climate cooling. The gradual increases of LST reveal that the decrease of snow cover has a more significant influence than other parameters on climate change. However, the mechanisms linking the surface relative parameters and climate change are very complex at temperate latitudes, and therefore more relative parameters (e.g., evapotranspiration and surface roughness) need to be measured and analyzed to support the climate change research.” (Line 416-455, in revised manuscript)

An incomplete list of line specific comments is given below.

4. Lines 17-25: These sentences are difficult to follow. Are the authors claiming: a) that albedo impacts surface radiation budget and climate (sentence 1), b) that albedo changes are caused by changes in surface radiation budget and climate (sentence 2), or c) that variations in albedo will be used to infer regional climate change (sentence 4)? Is this inference being made based on the assumption that climate is causing the albedo change, or the assumption that the albedo change is causing climate change? If both, should we be thinking about the ice-albedo feedback here? This is unclear.

Re: These sentences make readers fusing. There exists a feedback between the ice and albedo. To make expressions clear, we have rewritten the sentences as “As an Essential Climate Variable (ECV), land surface albedo plays an important role in the earth’s surface radiation budget and the local climate change. Tibetan Plateau (TP) is a sensitive environment to climate change, understanding its albedo seasonal and inter-annual variations is thus important to help to capture the climate change rules. In this paper, the large-scale spatial patterns, temporal trends, and seasonal variability of land surface albedo are analyzed overall the TP, based on the Moderate Resolution Imaging Spectroradiometer (MODIS) MCD43 albedo products from 2001 to 2019. The correlations between the albedo anomaly and the anomalies of normalized difference vegetation index (NDVI), the fraction of snow cover (Snow Cover), and land surface temperature (LST) were assessed to explain the nature of albedo variations over the TP.”

5. Lines 31 and 34: What is a “radiation force”? Do you mean “radiative forcing”?

Re: Yes, we mean “radiative forcing”. “radiation force” has been changed to “radiative forcing” throughout this manuscript.

6. Lines 41-45: “… land surface albedo and the parameters during its associated biophysical processes...” This sentence is incoherent.

Re: This sentence has been changed to ‘Land surface albedo is an essential climate variable and its variations have significant impacts on climate change, in particular for the snow-covered land surfaces at mid-latitudes and high latitudes in the Northern Hemisphere’.

7. Lines 55-57: “… which has been qualified by comparison with in situ measurements or the high-quality airborne observations”. What is the meaning of the word “qualified” here? Do you mean “validated”?

Re: These sentences are to express that the MODIS albedo product has been assessed to have great performances by comparison with in situ measurements or the high-quality airborne observations. “qualified” here means the product is validated to be of good quality. The word ‘qualified’ is a mistake here. In revised manuscript, the sentence “which has been qualified by comparison with in situ measurements or the high-quality airborne 56 observations” has been deleted.

8. Figure 2. As I stated in my previous three reviews, the color scale on panel D here is not informative, unless the purpose is to show that all the aspects are nearly the same across the Tibetan plateau.

Re: Yes, this figure is to show that more than 70% of the slopes face toward the sun, with the aspects distributed at the range of 135° to 225°. And the range of color bar also had been revised to the range of 45° to 330° in the second round of review. Though, it is not very clear, we can also find the topographic aspect change (the lower aspect (e.g. smaller than 45°) marked with green bar in Ulan county, the larger aspect (e.g., larger than 315°) marked with red bar in western Himalayas). Also, for clearly displayed the topographic aspect of the selected sites, two subplots (Fig.2E and F) also have been added in the revised manuscript.

9. Line 61: What is a “variation trend”? Is this referring to heteroskedasticity? Or just a simple trend? Or something else?

Re: The words “variation trend” just refer to ‘trend’ in this paper. It has been revised to ‘trend’ in revised manuscript.

10. Lines 65-57: “The sudden land cover change can cause a significant decrease of albedo, such as the example of significant albedo variation from 2001 to 2013, which occupied approximately 0.31% of the land surface in France”. This sentence is incoherent.

Re: This sentence has been rewritten as “Land cover change can lead to a significant change in albedo, like a decrease of 0.31% in albedo is reported due to the land cover change in France from 2001 to 2013.” (Line 65-68, in revised manuscript)

11. Lines 67-69: “These distinct conclusions demonstrated that the annual albedo has strong within-year seasonal characteristics [25,26], which increases in winter/spring and decreases during the growing season [27]”. This statement is at best vague and incoherent, and at worst factually incorrect and misleading. The authors appear to be making a global claim about albedo here. While this pattern may be observed in some places, and may be true when the entire northern hemisphere is integrated, this must be stated explicitly. The statement is not generally true about all land cover change from the perspective of satellite remote sensing. What about deserts? Urban areas? What about places where the “growing season” includes winter crops but not summer crops? Crops planted over black plastic tarps?

Re: Thank you for your advice. There is a misunderstanding in these sentences. Therefore, it has been rewritten as “These conclusions demonstrate that the land surface albedo has strong within-year seasonal characteristics [29,30], and are affected by land cover change [31].” (Line 67-68, in revised manuscript).

Author Response File: Author Response.docx

Reviewer 3 Report

The article ‘Spatiotemporal variability of land surface albedo products over the Tibet Plateau from 2001 to 2015’ provides a comprehensive look at the changes in albedo and the controlling factors within the Tibetan Plateau. The methods are good, and the results are well presented. The discussion is framed within the existing literature and discusses important implications for climate change in the region. There are a few comments/changes that could be made to improve clarity in certain areas, see comments below.

Line 17-18: “the local ecosystem’s climate change”, should be changed to “local climate change”

Line 52: This is the first mention of MODIS, make sure the full acronym is provided (Moderate Resolution Imaging Spectroradiometer).

Line 62: “the albedo” can be changed to just “albedo”.

Line 63-64: “over the summers from 2001 to 2016” can be changed to “during the summers of 2001 to 2016”.

Line 65-67: What was the significant change in albedo? Please clarify the exact change.

Line 67: “demonstrated” should be changed to “demonstrate”

Line 99-103: Please provide a table that clarifies how many sites fell into each of the different types and the criteria for each type. Were samples equally split between the three types? Although a random sample is good, it is also important to properly represent the study area. There also appears to be a lack of sites in the central northern area of the TP, is this due to a lack of variation in slope, aspect, and land cover? Please provide some rationale for this.

Section 2.2.1: Providing a table in this section would be good to outline the MODIS remote sensing products and metadata that were used for this study.

Line 129: Why was only data from 2001 to 2015 selected? There would now be 4 additional years of data to add to the time series, would it be logistically possible to add these data as this would provide further validity to the trends investigated.

Line 139: Beyond the reference provided, was any investigation conducted on how resampling the 90m SRTM DEM to 1000m affected the results? The reference provided show slopes will decrease, is this true for all areas and is there any possibility that this will have an effect on the results found in this paper?

Section 2.2.2: What specific variables were downloaded for the ERA data? Did the authors consider using the new ERA5 or ERA5-Land dataset?

Line 183: Are there areas of the study areas that were not considered rugged? I think the subscript here should be changed to Total instead as it is using the entire study area unless there were some criteria used to decide between different areas.

Line 195-196: “at the four seasons” can be changed to “during the four seasons”.

Line 196: “at the grassland” can be changed to “of the grassland”.

Line 202: Does figure 3B show the variation or trend in albedo, if it is showing trends in albedo the wording of this line needs to be changed, “did not show clear trends”?

Figure 3: This figure needs to be adjusted, the y-axes are not equal and overlapping between the two columns and the label for the Gongzha glacier overlaps the bounding box.

Line 252: I believe that Pearson’s coefficient should be lower-case r, not capital. Was any investigation done on the distribution of the data? The relationships seem linear, however, non-parametric tests (Spearman’s Rho or Kendall’s Tau) should be considered if the data is not normally distributed. Significance values should also be provided for the correlation tests.

Figure 5: The month label is covered for plot C and the NDVI Anomaly label overlaps the y-axis.

Line 283: The paper states that 0.05 is being used as the significance level, however, the NDVI trends show a p-value of 0.03 and is stated as being insignificant. Although the trend is slight it is still significant. Additionally, the previous sentences said that the albedo had a p-value that allowed for rejection of the null hypothesis and it is higher than the value obtained for NDVI. Please clarify these values and ensure the correct phrasing is used.

Line 294: Were the triangles only in grassland areas? Please clarify this in the earlier section.

Figure 8: This figure needs to be corrected, the lines for the different years do not match with each other and some overlap.

Line 382: “suffered” is not an appropriate word, “experienced”?

Line 393-404: Supporting some of the conclusions made here with statistics would be beneficial. What was the quantitative relationship between these changes in land cover and the albedo values? Correlation between changes in the variables or just mean change for the associated regions would be good to show.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors have clearly invested a substantial amount of work in improving the manuscript. I am happy to recommend the manuscript be published.

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 authors revised their manuscript following the recommendations of reviewers. Hence the manuscript can be published in the journal Remote Sensing.

Reviewer 2 Report

Review of revised paper “Spatiotemporal variability of land surface albedo products of the Tibet Plateau Mountains from 2001-2015.”  I appreciate the changes that have been made in the manuscript in response to the earlier reviews, however, the English in this paper is still very poor and makes the paper very difficult to read.  Rather than list every instance of poor English, I have chosen some of the worse examples to highlight below.

Starting with the Abstract, line 18 would read better as: “Land surface albedo has significant…”

I think that it makes more sense to use present tense – e.g., variations are analyzed (line 22) and “Results show” (line 26.

Line 27 refers to the rate of change…is this over the entire time period? Or evaluated over a sub-interval.

Line 31 the sentence “Generally,…” makes no sense as written.  Didn’t your research reveal that roughly 10.5% of the surface is significantly influenced by albedo variations??

Line 34: The sentence “Results show that the radiation forcing …”  Is very unclear and incomplete.  You are referring to the gradual albedo change and I think mean to be saying that the radiative forcing produced by the gradual albedo change cannot be neglected when examining the radiative forcing associated with other long time-series measurements.

Line 45:  Perhaps saying “Deforestation in tropical areas increases the surface albedo and…”

Line 55:  …are available and “provided the efficiently used approaches”. Makes no sense.  The point is that the data that you are analyzing are widely available and of sufficient quality to allow the investigation of spatiotemporal changes in surface albedo.

Line 74 would be clearer as:  “decades, little effort has been expended to identify the underlying”

Line 79-81: makes no sense. What do you mean by “has made it complex”

Line 97 ‘Known as the ‘three poles” ….is incorrect and a poor restatement of Line 71”The Tibetan Plateau (TP), which is also the so-called third pole…”

Line 101, “41” should be spelled out, i.e., “Forty one…”

Line 178… “can be got”  Do you mean that you downloaded these quantities directly from the ERA-Interim daily downward surface solar radiation and the TOA incident solar radiation products or that you have derived them from quantities in those data sets?

Line 188 (and elsewhere) you refer to values being “exhibited”, I think “shown” would be better.

Line 247 “distributed at the range” do you mean “distributed over the range?”

Line 259 and Line 268 “corrections” do you mean “correlations”?

Line 263:  Again you have “at the range” when I think that you mean “over the range”

Line 270 “showed” should be shown

Line 272 “negative correlation was existed” do you mean ‘negative correlation was found”

Figure 5G which shows the relationship between LST and Land Surface Albedo and Figure 5H which shows the relationship between NDVI and Land surface albedo raise to me more questions than they answer.  The data points corresponding to lowest values of land surface albedo have a very different relationship to LST, NDVI and snow cover than higher land surface albedo values and appear to be independent of LST, NDVI and Snow cover….what do they correspond to and why are they different?  The spread in the LST data is interesting and suggests a least 4 different relationships between LST and land surface albedo (i.e., for a land surface albedo value of 0.2 the LST data cluster at 0, 4, 6,and 12) due to what?  Similarly, the relationship between NDVI and Land surface albedo appears to have distinct clusters with different behaviors…care to comment on that?

Line 316 should read “(shown as triangles…”

317 should read “the results show that the largest albedo occurred in the …

Line 345 not sure what you are trying to say

Similarly I’m not sure what you are trying to say on  lines 376-378.

Line 399 not sure what you are trying to say. DO you mean land surface albedo and albedo anomaly exhibit obvious spatial and seasonal variability?

 Line 416 need a space after the parenthesis and it should be topographic slopes "have a" rather than "has the"

Sadly, I think that this paper needs additional revision before it is acceptable for publication.

Reviewer 3 Report

Again, the authors have clearly invested a substantial amount of time in revising this manuscript. However, as before, several passages of the text are still uninterpretable or must be reread several times because their meaning is unclear. This renders interpretation of the results challenging at best. It is disheartening to see this lack of clarity in a manuscript in its third revision.

The color scale on the figure showing land surface aspect remains uninformative. Two of the conclusions are obvious and do not contribute to our knowledge of the system. Again, I cannot recommend this manuscript for publication without significant rewriting. An incomplete list of line specific comments is given below.

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Lines 18 and 20: The addition of the definite article “the” to these sentences renders them grammatically incorrect and detracts from readability.

Lines 28-29: “Also them showed...” This sentence is grammatically incorrect.

Lines 34-35: “Results show that the radiation forcing caused by gradual albedo cannot be neglected when evaluated radiation forcing for long time series climate change regardless of the causes of albedo trends”. This sentence is incoherent.

Lines 55-56: “… are available and provided the efficiently approaches for the analysis of albedo variation”. This statement is incoherent.

Lines 79-82: “These situations are mainly because that the rugged mountainous environment has made it complex to reveal the feedback mechanism of albedo and resulted in very limit in situ albedo observations...” This statement is incoherent.

Figure 2. The aspect color scale remains uninformative.

Lines 399-415: More importantly than the numerous grammatical issues that still remain with this text, these results are neither surprising nor do they contribute substantially to the state of our knowledge. Obviously albedo varies seasonally at high elevations due to snowpack; Tibetan glacier retreat has been well documented by previous studies (e.g. [1]); obviously albedo has a strong positive correlation with snow cover fraction; obviously albedo has a strong negative correlation with NDVI and LST.

[1] Maurer, Joshua M., Summer B. Rupper, and Joerg M. Schaefer. "Quantifying ice loss in the eastern Himalayas since 1974 using declassified spy satellite imagery." The Cryosphere 10.5 (2016): 2203-2215

Comments for author File: Comments.pdf