Alpine Grassland Reviving Response to Seasonal Snow Cover on the Tibetan Plateau
Round 1
Reviewer 1 Report
This is a well-written paper that clearly shows the remote sensing associated with the study area. I have only a few comments that should be addressed before the publication of this paper.
line 40 and throughout the text: What is meant by °C/10a? Does this mean a change in temperature over a period of 10 years? Please provide additional context by adding a definition earlier in the document.
line 163: Despite or reference the signal processing associated with the noise removal step. Is this the signal processing described later in Section 3.1?
line 302: Why is the soil temperature listed in Kelvin here? Why not Celsius for context?
Author Response
Response to Reviewer #1
This is a well-written paper that clearly shows the remote sensing associated with the study area. I have only a few comments that should be addressed before the publication of this paper.
Response: Firstly, on behalf of all authors, we appreciate your affirmation of our work. Based on your comments, we have revised our manuscript and answered your questions on a point-by-point basis. Thank you so much.
1) line 40 and throughout the text: What is meant by °C/10a? Does this mean a change in temperature over a period of 10 years? Please provide additional context by adding a definition earlier in the document.
Response: Thank you for your suggestion. °C/10a means a change in temperature over a period of 10 years. The additional context was added to the manuscript. Please see the revision in line40-42: ‘The Tibetan Plateau (TP) warmed by approximately 0.4 °C/10a (°C/10a means a temperature change over 10 years) from 1981 to 2011.’
2) line 163: Despite or reference the signal processing associated with the noise removal step. Is this the signal processing described later in Section 3.1?
Response: Thanks for your comments. This sentence may be confusing to readers. We want to express that although MOD13Q1 is already a time series product generated every 16 days, residual fluctuations and noise still exist affecting the SOS extraction, which needs to be smooth by Savitzky–Golay filtering algorithm (S-G). The sentences were revised as (line169-170):
‘Although MOD13Q1 is already a time series product after the noise removal step and 16d synthesis process; residual fluctuations and noise still exist in these data due to the presence of clouds and atmospheric, sensor and surface reflectivity. Therefore, in this study, smooth NDVI variation curves were obtained using the Savitzky–Golay filtering algorithm (S-G) with a filter window size of 4 [42,43].’
3) line 302: Why is the soil temperature listed in Kelvin here? Why not Celsius for context?
Response: Thank you for the comments. Because the raw ST products are encoded as Kelvin, which is why we use the unit in our paper. And we think the larger range of Kelvin can better express the change of soil temperature in our study area.
Reviewer 2 Report
Alpine grassland reviving response to seasonal snow cover on the Tibetan Plateau
Ying Ma, Xiaodong Huang, Qisheng Feng and Tiangang Liang
Submitted to Remote Sensing, reference 1706145
General comments
The main theme of this paper (see lines 90-94 in the introduction, then L377-380 in the discussion, and finally lines 421-424) the statement according to which snow cover exerts an indirect effect on vegetation dynamics, through its impact on soil temperature and soil moisture.
While this conclusion is certainly correct, the papers suffers in my view several serious weaknesses.
- I have a problem with the data available. While NDVI and snow cover mapping from MODIS is basically well understood (although one would like to be sure that cloud free observations are frequent enough), the reader wonders about soil temperature and particularly soil moisture. I am unable to get any information about soil moisture measurements from the TPDC reference on line 138; concerning the text, when it claims a 5 km spatial resolution over the whole plateau I finds this claim unrealistic. Similarly, I am very doubtful about the 1 km spatial resolution claimed for precipitation on lines 155-160. Incidentally, I cannot read Chinese, therefore had no access to the (http://gre.geodata.cn) reference; keep in mind that many readers of the journal suffer similar limitations.
- The authors offer a lot of information about the trends over the 2000-2020 period. This may be of value for a reader interested in climate change, but what is the relevance for a better understanding of the impact of snow cover on vegetation? Moreover, I did not find in the paper any discussion or interpretation concerning these trend figures.
- Coming to the central issue as I understand it (that is: effect of snow cover through its impact on soil temperature and moisture), the discussion is interesting; at the same time, it is frustrating, because (as the authors point out themselves) the situation is complicated by the interaction of several effects. As a consequence, the text is limited to qualitative considerations. The opinion if the present reviewer is that introducing a one-dimensional model might allow more definite and at least semiquantitative conclusions.
However, this ambition is obviously way beyond the scope of the present paper. I would however recommend to pay some attention to the earlier comments above.
In spite of some shortcomings, the quality of form and language is generally found good.
Specific comments
L038-040: the 0.6°C figure should be updated; as far as I know, it is estimated above 1°C by now.
L040-041: Assigning a trend to the "last 30 years" period is somewhat clumsy, inasmuch as you do not know the time at which the paper will be published. Moreover, your reference [10] was published in 2015 and therefore cannot report a trend over the 1992-2022 period! The wisest would be to spell out the definite period you have in mind, even if it is not the most recent.
L074-077: there is something wrong with this sentence.
L116: I assume that the plot on the left side of figure 1 means to describe topography; however, the colour code is not satisfactory at all. What do these 8253 and 85 figures mean?
On the right side, the "no grassland" category is enigmatic; if there is no vegetation at all, it would be clearer to spell it out. Moreover, the reader wonders what is described by the dark areas; although the answer is given on lines 149-150, it should be indicated in the legend.
L137-143: it is very surprizing that these data cover the full TP area with a 1 or 5km spatial resolution over the 2002-2018 period. One would like to learn about the way these data (soil temperature and soil moisture) were obtained.
L188-190: this sentence does not make much sense, as there is no "x" variable in equation (4)
L244-246: one would like to have these locations shown on a map, for example on figure 1. Same remarks for several other places in the text where geographical features or cities are quoted.
L256: Figure 4c does not help to demonstrate a correlation between SCD and elevation, since elevation is not shown on this map.
L282: it is disturbing that figure 3 comes after figure 4; figures (and the text accordingly) should preferentially be presented in increasing order.
L305-312: Are you sure that the accuracy and quality of the datasets supports ratios given down to the 2nd decimal place? This question may of course arise also in other parts of the paper.
L335 4.1. would that be subsection 4.3 rather than 4.1?
L421-423: this statement is not convincing, because the discussion about the influence of snow cover is purely qualitative. In the absence of any order of magnitude consideration, it might turn out that the effects suggested here are completely negligible.
L425-430: Rather than a conclusion, this paragraph describes, summarizes and quantifies main features of the dataset.
L431-440: same comment as above.
L441-445: unlike the former paragraphs, this is indeed a conclusion, and a valuable one, even though it is weakened by the purely qualitative nature of these repeated arguments.
Author Response
Response to Reviewer #2
General comments
The main theme of this paper (see lines 90-94 in the introduction, then L377-380 in the discussion, and finally lines 421-424) the statement according to which snow cover exerts an indirect effect on vegetation dynamics, through its impact on soil temperature and soil moisture.
While this conclusion is certainly correct, the papers suffer in my view several serious weaknesses. I have a problem with the data available. While NDVI and snow cover mapping from MODIS is basically well understood (although one would like to be sure that cloud free observations are frequent enough), the reader wonders about soil temperature and particularly soil moisture. I am unable to get any information about soil moisture measurements from the TPDC reference on line 138; concerning the text, when it claims a 5 km spatial resolution over the whole plateau I finds this claim unrealistic. Similarly, I am very doubtful about the 1 km spatial resolution claimed for precipitation on lines 155-160. Incidentally, I cannot read Chinese, therefore had no access to the (http://gre.geodata.cn) reference; keep in mind that many readers of the journal suffer similar limitations.
The authors offer a lot of information about the trends over the 2000-2020 period. This may be of value for a reader interested in climate change, but what is the relevance for a better understanding of the impact of snow cover on vegetation? Moreover, I did not find in the paper any discussion or interpretation concerning these trend figures.
Coming to the central issue as I understand it (that is: effect of snow cover through its impact on soil temperature and moisture), the discussion is interesting; at the same time, it is frustrating, because (as the authors point out themselves) the situation is complicated by the interaction of several effects. As a consequence, the text is limited to qualitative considerations. The opinion if the present reviewer is that introducing a one-dimensional model might allow more definite and at least semiquantitative conclusions.
However, this ambition is obviously way beyond the scope of the present paper. I would however recommend to pay some attention to the earlier comments above. In spite of some shortcomings, the quality of form and language is generally found good.
Response: Firstly, on behalf of all authors, we appreciate your great help and suggestions for this manuscript. Based on your comments, we have revised our manuscript and answered your questions on a point-by-point basis. In addition, the whole manuscript was checked by use a professional English editing service of American Journal Experts. Please see the following replies and the revised manuscript for your comments.
The answers as followed for the overall comments above:
- For your dataset concerns. We changed to the English website of the ST and SM dataset (TPDC; http://data.tpdc.ac.cn/en), and a brief description of the data production was added in the paper (line141-145, line148-155). The references for the two products were also updated. The precipitation data is not used in the article finally, thus, the data description have been deleted in the revised manuscript. Sorry for our carelessness.
- We think it is necessary to examine the variation and trends of snow cover and vegetation in intro- and intra-annual, in order to better understand the impact of snow cover on alpine grassland phenology. Through the trend analysis, we found that there was good consistency among the changes in snow cover, ST and SM as well as the intra-annual changes in vegetation. The regions with delayed SEDs and increased SCDs on TP, the SOS have earlier trend. In contrast, SOS tended to delay in areas where the SEDs advanced and SCD decreased. The discussion or interpretation concerning these trend figures were added and revised in line 232-236, line 303-305, line 321-324, and line 335-341. Thank you for your advice.
- Base on your suggestion. We made a line fitting model between snow cover, SOS and soil temperature and moisture. (figure 1). The results further indicated that seasonal snow cover plays an important role in SOS by affecting ST and SM in TP. It is consistent with our results in snow cover effect the alpine grassland SOS in our study. However, affected by the uncertainty of ST and SM products, the results of quantitative analysis are not credible enough, thus, the quantitative analysis result is not shown in this paper this time. In future, more accurate soil temperature and moisture products will be obtained to carry out quantitative analysis of alpine grassland SOS alteration caused by snow cover. Thank you very much for your great suggestion.
Figure 1. Panels (a)~ (h) represent the one-dimensional model of ST and SM with SED and SCD, ST, SM, SED and SCD with SOS. The red line presents the linear fit trend line.
Specific comments
1) L038-040: the 0.6°C figure should be updated; as far as I know, it is estimated above 1°C by now.
Response: Thank you for the comment. Did as suggested. Please see the revision in line38-40: ‘Since 1860, the global average temperature has reportedly increased by nearly 1.0 °C [8,9], and this trend is more pronounced in high-latitude and high-elevation areas.’
2) L040-041: Assigning a trend to the "last 30 years" period is somewhat clumsy, inasmuch as you do not know the time at which the paper will be published. Moreover, your reference [10] was published in 2015 and therefore cannot report a trend over the 1992-2022 period! The wisest would be to spell out the definite period you have in mind, even if it is not the most recent.
Response: Did as suggested. We using definite period “from 1981 to 2011” instead ‘last 30 years’. Thank you for the comments.
3) L074-077: there is something wrong with this sentence.
Response: Sorry for this wrong expression. We revised this sentence as (line74-76): ‘The thermal insulation and moisture retention effects of snow cover can create optimal microbial living environments which benefit the soil organic matter convert to nutrient efficiently.’
4) L116: I assume that the plot on the left side of figure 1 means to describe topography; however, the colour code is not satisfactory at all. What do these 8253 and 85 figures mean?
Response: Thanks for the comments. We renewed the color code and revised the “Legend” to “Elevation (m)”. And the vegetation types for no grassland were also added in the figure. Please see the revision maps on Figure 1.
5) On the right side, the "no grassland" category is enigmatic; if there is no alpine grassland at all, it would be clearer to spell it out. Moreover, the reader wonders what is described by the dark areas; although the answer is given on lines 149-150, it should be indicated in the legend.
Response: Thank you for your comments. The figure 1b was re-drew and added the categories for those no grassland.
6) L137-143: it is very surprizing that these data cover the full TP area with a 1 or 5km spatial resolution over the 2002-2018 period. One would like to learn about the way these data (soil temperature and soil moisture) were obtained.
Response: Thank you for your comments. We changed to the English website of the ST and SM dataset (TPDC; http://data.tpdc.ac.cn/en). And brief descriptions of the data production were added (line141-145, line148-154) in the paper. The DOI number of data reference were also added for better understanding the data source information.
7) L188-190: this sentence does not make much sense, as there is no "x" variable in equation (4)
Response: Sorry for this wrong expression, we deleted it in the paper. Thanks.
8) L244-246: one would like to have these locations shown on a map, for example on figure 1. Same remarks for several other places in the text where geographical features or cities are quoted.
Response: Thank you for your suggestions. Geographical features have been showed in figure 1a, and the typical cities of Ngari, Lhasa and Aba were marked in figure1a.
9) L256: Figure 4c does not help to demonstrate a correlation between SCD and elevation, since elevation is not shown on this map.
Response: Thanks for your advice. We revised this sentence as followed (line261-262): ‘With the combined the spatial distribution of elevation (Fig. 1a), the SCD showed an increasing trend with increasing elevation on TP (Fig. 3c)’.
10) L282: it is disturbing that figure 3 comes after figure 4; figures (and the text accordingly) should preferentially be presented in increasing order.
Response: Sorry for this wrong figure number, figures have been renumbered according to the order when appeared in this paper. Thank you for your comments.
11) L305-312: Are you sure that the accuracy and quality of the datasets supports ratios given down to the 2nd decimal place? This question may of course arise also in other parts of the paper.
Response: Thank you for the comments. Did as suggestion. In addition, because the SM data is too small, so 2nd decimal place was given down, others give down to 1st decimal place in the paper.
12) L335: 4.1. would that be subsection 4.3 rather than 4.1?
Response: Sorry for this wrong subsection number, figures have been renumbered according to the order when appeared in this paper. Thanks.
13) L421-423: this statement is not convincing, because the discussion about the influence of snow cover is purely qualitative. In the absence of any order of magnitude consideration, it might turn out that the effects suggested here are completely negligible.
Response: Thank you for the comments. We revised this statement as (line435-438): ‘By analyzing the effect of the seasonal snow cover on the soil hydrothermal conditions in spring, we clarified that there is a certain relationship between seasonal snow cover and SOS of alpine grassland, and the snow cover affects the SOS by affecting the soil temperature and moisture in spring’.
14) L425-430: Rather than a conclusion, this paragraph describes, summarizes and quantifies main features of the dataset.
Response: Thank you for your comments. We revised the conclusion as (line440-442): ‘1) There was both a significant negative correlation between the SOS with ST and SM in TP (P < 0.001), indicating that alpine grassland would revival and growth earlier in warmer and wetter soil environment in spring.’
15) L431-440: same comment as above.
Response: Thank you for your comments. We also revised two conclusions as followed (line443-448):
2) In TP, the SCD was significantly positively correlated with the SM, and significantly negatively correlated with the ST, suggesting that increased SCD can lead to spring soil temperature decrease and moisture increase in spring.
3) The SED was both significantly negatively correlated with the ST and SM. It indicated that the end of snow season is earlier, the spring soil would be warmer and wetter in TP.
16) L441-445: unlike the former paragraphs, this is indeed a conclusion, and a valuable one, even though it is weakened by the purely qualitative nature of these repeated arguments.
Response: Thank you for your comments. We revised this conclusion and added a brief summarize and perspective for our overall conclusion (line449-459):
4) Both the delayed SED and the increased SCD contributed to the advanced SOS, and the reduction of snow cover and the advance of melting will lead to the delay of SOS.
There is no doubt that the raised ST and increased SM in spring will lead to an earlier SOS. However, the spatial trends showed the SM increased in the whole TP. It indicated that although the decreased SCD and delayed SED limited the increased SM, it is still replenished probably from by the permafrost thawing or liquid precipitation. In addition, the snow cover in TP is not continuous and melts very rapidly, which increases the complexity of analyzing the effect mechanism of how the changes of SOS of alpine grassland effected by snow cover. In order to clarify the contribution of SED to the SOS of alpine grasslands, further analysis should be made in combination with spring precipitation and temperature changes in alpine grassland over the Tibetan Plateau.
Author Response File: 
Author Response.pdf
Reviewer 3 Report
Dear Authors,
The study is devoted to an important and urgent problem - the impact of climate change on vegetation. The authors consider the change in the duration of snow cover and the date of its end on the Tibetan plateau, and also consider the temperature of the soil and moisture content of the soil and the dates of the start of growth over the past two decades. The amount of data analyzed is astonishing.
The relevance and scientific novelty of the study are beyond doubt.
At the same time, the analysis of the obtained data confused me a little. I got the feeling that in some places of the text words were used that are directly opposite to those that should be used, following the logic (see file).
I would like to wish the authors to carefully review the text and correct obvious inaccuracies. I would also like the authors to give a more detailed rationale for the relationships between (1) the duration of the snow period and the dates of its end, (2) temperature and soil moisture, and (3) the beginning of the growing season. At the moment, having read the manuscript, I still do not understand the reasons why:
1) the lengthening of the snow period and the delayed end date of the snow period in most of the plateau leads to an earlier start of the growth period,
2) the earlier end of the snow period contributes to a decrease in soil temperature.
I would recommend a second review.
Comments for author File: Comments.pdf
Author Response
Response to Reviewer #3
The study is devoted to an important and urgent problem - the impact of climate change on vegetation. The authors consider the change in the duration of snow cover and the date of its end on the Tibetan plateau, and also consider the temperature of the soil and moisture content of the soil and the dates of the start of growth over the past two decades. The amount of data analyzed is astonishing. The relevance and scientific novelty of the study are beyond doubt. At the same time, the analysis of the obtained data confused me a little. I got the feeling that in some places of the text words were used that are directly opposite to those that should be used, following the logic (see file). I would like to wish the authors to carefully review the text and correct obvious inaccuracies. I would also like the authors to give a more detailed rationale for the relationships between (1) the duration of the snow period and the dates of its end, (2) temperature and soil moisture, and (3) the beginning of the growing season. At the moment, having read the manuscript, I still do not understand the reasons why:
1) the lengthening of the snow period and the delayed end date of the snow period in most of the plateau leads to an earlier start of the growth period,
2) the earlier end of the snow period contributes to a decrease in soil temperature.
I would recommend a second review.
Response: Firstly, on behalf of all authors, we appreciate your great comments and also you carefully review. In this paper, we found that there is a certain relationship between seasonal snow cover and SOS of alpine grassland, and the snow cover affects the SOS by affecting the soil temperature and moisture in spring. Based on your comments, we have revised our manuscript and answered your questions on a point-by-point basis.
For your central concerns, we carefully analyzed the results, re-summarized the results and conclusions in the revised manuscript, which can better clarify the interaction between snow cover, soil temperature and moisture, and grassland greenness. The main conclusions are re-summarized as follows, and a brief summarize and perspective were also added for our overall conclusion:
In this paper, the dynamics of vegetation revival, snow cover, SM and ST in alpine grasslands in TP were examined from 2000 to 2020. By analyzing the effect of the seasonal snow cover on the soil hydrothermal conditions in spring, we clarified that there is a certain relationship between seasonal snow cover and SOS of alpine grassland, and the snow cover affects the SOS by affecting the soil temperature and moisture in spring. The main conclusions are summarized as follows:
1) There was both a significant negative correlation between the SOS with ST and SM in TP (P < 0.001), indicating that alpine grassland would revival and growth earlier in warmer and wetter soil environment in spring.
2) In TP, the SCD was significantly positively correlated with the SM, and significantly negatively correlated with the ST, suggesting that increased SCD can lead to spring soil temperature decrease and moisture increase in spring.
3) The SED was both significantly negatively correlated with the ST and SM. It indicated that the end of snow season is earlier, the spring soil would be warmer and wetter in TP.
4) Both the delayed SED and the increased SCD contributed to the advanced SOS, and the reduction of snow cover and the advance of melting will lead to the delay of SOS.
There is no doubt that the raised ST and increased SM in spring will lead to an earlier SOS. However, the spatial trends showed the SM increased in the whole TP. It indicated that although the decreased SCD and delayed SED limited the increased SM, it is still replenished probably from by the permafrost thawing or liquid precipitation. In addition, the snow cover in TP is not continuous and melts very rapidly, which increases the complexity of analyzing the effect mechanism of how the changes of SOS of alpine grassland effected by snow cover. In order to clarify the contribution of SED to the SOS of alpine grasslands, further analysis should be made in combination with spring precipitation and temperature changes in alpine grassland over the Tibetan Plateau.
Specific comments:
1) Lines 269-270 mention two scenarios for measuring the duration of the snow period and the end date of the snow period, and describe the areas in which these two scenarios develop. It would be very good to link areas with an accelerated start of growth with areas where the snow situation develops according to two different scenarios.
Response: Thank you for your comments. Did as suggestion. We added a sentence to link two scenarios with where SOS changed as followed in line 232-236. Thank you for your suggestion.
‘Moreover, compared to the two different scenarios of SED and SCD, the regions with delayed SEDs and increased SCD, where the SOS showed an advanced tendency in alpine grassland. In contrast, SOS tended to delay in areas where the SEDs advanced and SCD decreased.’
2) It is not quite clear why in the territories where the end of the snow period is postponed (Fig. 4, b) and the duration of the snow period is increased (Fig. 4, d), an earlier start of the growth period is observed (Fig. 3, b). I can't understand what could cause an earlier start of the growth period in 65% of the territory (line 292), while the end of the snow period is delayed in 59% of the same territory (line 265). It turns out that the delay in the snow period contributes to an earlier start of growth?
Line 265: The SCD in 59.0% of the study area showed an increasing trend
Line 292: Among the 65.4% of TP that exhibited advancing SOS trend.
Do I understand correctly that the growth period begins when the snow period has not yet ended? Or is there a gap between the end of the snow period and the start of growth?
It is also not clear why with increasing days with snow (lines 262-263) and a later end date of the snow period (lines 246-247), the growth period begins earlier (lines 296-297).
Lines 246-247: The SED was delayed by 1.22 d/10a on average 246 over 21 years on the TP.
Lines 262-263: SCD increased by 2.2 d/10a from 2000 to 262 2020 on the TP.
Lines 296-297: Overall, the average SOS over the TP advanced by 2.1 d/10a from 2000 to 2020
Response: Thank you for carefully review and great comments. The mean annual snow end date on March 27, and the annual average SOS on the 127th day (early May) of the Julian year from 2000 to 2020 in TP. Thus, there is no gap between the end of the snow period and the alpine grassland start of growing season in most areas except in those mountainous with higher elevation. We made a careful analysis of our results, we are sure that the delayed snow period and increased snow-covered days contributes to an earlier start of vegetation growth, however, the situation is complicated by the interaction of several effects in our study. We carefully analyzed the results, re-summarized the results and conclusions in the revised manuscript, which can better clarify the interaction between snow cover, soil temperature and moisture, and grassland greenness. We found that more snow and the delay of melting time will inhibit the rise of ST, but can provide enough SM to promote the alpine grassland to turn green in advance.
5) It is not clear why the soil temperature decreased in areas where the duration of the snow cover decreased and the dates of the end of the snow cover were earlier (lines 314-315). Logic tells me that in these areas the temperature of the soil should rise. Perhaps you didn't mean "decreased" but "increased"?
Lines 314-315: In contrast, STs tended to decrease in areas where the SEDs occurred earlier and the SCD decreased.
Response: Thank you for your suggestion. Yes, you are right, we did a wrong statement here. Soil temperature will tend to decrease in areas where the SED occurred earlier and the SCD decreased. We revised it (line 321-324).
‘Comparing the spatial and temporal changes in SED and SCD, regions with delayed SEDs and increased SCDs on the TP were found to have had lower STs (Fig. 5b). In contrast, STs tended to increase in areas where the SEDs occurred earlier and the SCD decreased.’
6) Also, I do not understand the logic of the reasoning in the first paragraph of the "Discussion" section, lines 364-369.
Response: Thank you for your suggestion. We revised these sentences as (line381-383): ‘Previous studies revealed that the increased SCD and delayed SEDs contributed to earlier SOSs, while the decreased SCD on the western TP promoted the delay of the SOS [50-52]. Those conclusions are consistent with the founding of this paper.’
Minor comments:
There are also many inaccuracies in the figures, in the legend (perhaps in Fig. 5a), in the captions, and in the mention of figures in the text.
- The panels of Figure 2 (lines 231-232) do not show (a) - (d).
Response: Thank you for your reminder. We added panels (a) - (d) in Figure 2.
- I suspect that the numbers of figures 3 and 4 in the captions are mixed up. There is also some confusion with references to these figures in the text. That is, Fig. 4 (lines 274-275) is referenced on line 240 as figure 3, and figure 3 (lines 297-298) is referenced on line 282 as figure 3 too. Line 256 refers to panel (c) of the same Figure 3, but here it is referred to as Figure 4c. It is required to check all references to figures 3 and 4 in the text to avoid confusion.
Response: Sorry for this mistake. We revised it in the whole paper. Thank you for your comments.
- In Figure 4 (lines 274-275), panels (b) and (d) show the trend of two parameters, the legend shows the characteristics of these trends (significantly advanced, Increased, etc.), but it is not clear how many days these characteristics correspond. Wouldn't it be better to give trend values in days? Same for Figure 5 (b) and (d).
Response: Did as suggestion. We revised the figure 3(b, d),4(b) and 5(b, d) to give trend values in days and *, which denotes a significant trend. And we added explanation information of * in caption to figures. Thank you for your comments.
- In the caption to Figure 4 (lines 276-277), panels (a) and (b) are mentioned twice, and panels (c) and (d) are not mentioned. Same problem is for Figure 5 caption (lines 332-333).
Response: Thank you for your comments. We revised the caption of panels (a) and (b) to Figure 3 and Figure 5.
- In Figure 3a (lines 297-298), the legend shows the change in the "SOS" parameter from 80 to 192, are these days from the beginning of the year, that is, from January 1? Perhaps you should indicate this in the caption?
Response: Thanks for your suggestions. We added an explanation of the time as “the Julian year” in the caption of Figure 4.
- There are inaccuracies in the caption to figure 5: line 332 mentions SM twice, but ST is not mentioned. The legend for panel (a) in Figure 5 shows the temperature range from 137 to 296 K. If I'm not mistaken, 137 K corresponds to -136 degrees Celsius. Perhaps the lower limit of the range is 237 K (-36 degrees Celsius)?
Response: Sorry for this mistake. We revised it in Figure 5. Thanks for your comments.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
The authors substantially revised the manuscript, making the logic of reasoning clearer. Also corrected typos. I recommend the manuscript for publication in its current form.
Best,
Galina Zdorovennova
Author Response
Response to referee3:
The authors substantially revised the manuscript, making the logic of reasoning clearer. Also corrected typos. I recommend the manuscript for publication in its current form.
Response: Dear Dr. Galina, thank you for your recognition of our paper, and paying the time to review it. Thank you again for the great suggestions and comments that were very helpful in revising the manuscript. In the future, your great comments will be taken into account in the design of the further study.
