Variability in snow cover phenology in China from 1952 to 2010

Ke, Chang-Qing; Li, Xiu-Cang; Xie, Hongjie; Ma, Dong-Hui; Liu, Xun; Kou, Cheng

doi:https://doi.org/10.5194/hess-20-755-2016

Articles | Volume 20, issue 2

https://doi.org/10.5194/hess-20-755-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/hess-20-755-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 20, issue 2

Research article

|

19 Feb 2016

Research article |

| 19 Feb 2016

Variability in snow cover phenology in China from 1952 to 2010

Chang-Qing Ke, Xiu-Cang Li, Hongjie Xie, Dong-Hui Ma, Xun Liu, and Cheng Kou

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Final revised paper (published on 19 Feb 2016)
Preprint (discussion started on 30 Apr 2015)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC C1588: 'Valuable results, some clarifications needed', Anonymous Referee #1, 18 May 2015
- AC C1745: 'Replies to the comments of Anonymous Referee #1', Chang-Qing Ke, 25 May 2015
RC C1746: 'Review of the manuscript hess-2015-49', Anonymous Referee #2, 25 May 2015
- AC C1853: 'Replies to the comments of Anonymous Referee #2', Chang-Qing Ke, 29 May 2015
RC C2000: 'Referee comment', Anonymous Referee #3, 07 Jun 2015
- AC C2049: 'Replies to the comments of Anonymous Referee #3', Chang-Qing Ke, 12 Jun 2015

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (08 Jul 2015) by Harrie-Jan Hendricks Franssen

AR by Chang-Qing Ke on behalf of the Authors (16 Aug 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (18 Aug 2015) by Harrie-Jan Hendricks Franssen

RR by Anonymous Referee #3 (07 Sep 2015)

RR by Anonymous Referee #2 (08 Sep 2015)

Suggestions for revision or reasons for rejection

This manuscript, although revised somewhat, is basically the same as the previous version. It still suffers from the main problems raised by previous reviewer #2. Authors almost denied all comments and suggestions by reviewer #2. They only accepted to change the concepts of “heavy-snow year” and “light-snow year”. Even for this change, they made it only after reviewer #3 raised the same problem. In the initial version of the replies to reviewer #2 on the HESS web site, they claimed their definitions were right. As they did not give reasonable reasons for their defense, I would retain previous comments. In addition, I have some other comments.

1. Thin SCDs should be separated from “non-thin SCDs” (snowcover existing for a long time, e.g. 10 days). As previously pointed out, the snow cover observations are commonly conducted at 8:00 (Beijing time) in the morning, and most of the thin snow covers correspond to the snowing events in which snow exists only several hours. Suppose two sites: one site with 30 thin SCDs and the other site with 30 “non-thin SCDs”, both of them belong to the same group of 30 SCDs and are of the same climatic significance according to their study. However, in reality they could be quite different in meteorology and climatology. This makes their results of climatic analysis questionable. Actually, this issue is not a new one. Authors should refer to the existing statistical methods of snowcover, such as those in Japan.
2. Consistensy of the data. This is also raised in the previous comments. For the Specifications for Surface Meteorological Observations of China, there have been several versions. There are some differences in the criteria between the versions (e.g. minimum snow depth of 0.5 cm in the 2003 version, whereas it is 1.0 cm in the previous versions). This is actually not a matter of version, but relates to the reliability of their results. Obviously, the criteria change of minimum snow depth would bring more SCDs for a same snowcover with no climate change. Again, they did not address this issue, which also makes their results questionable.
3. Presentation is confusing. They initially define the “snow year” (Lines 149-151, author reponse-version3, the same below). However, in the subsequent parts, they did not use it, but use the calendar year. For example, the 2008 SCDs (Lines 350-359) should belong to the 2009 snow year according to their definition. Readers don’t know which are snow years and which are calendar years. In addition, in the Results section, there are many statements which are not directly related to their results (e.g. Lines 329-340; Lines 343-347; Lines 356-360) and thus bring confusions to readers.
4. Key words or terms problems. Some key words or terms are very difficult to understand. For example, “Areas with SCDs of 10–60 are called unstable snow areas with annual periodicity (there is definitely snow in every winter)” (Lines 258-259). Are the stable/unstable snow areas determined according to the number of SCDs? If so, I don’t think it is a good classification. And annual periodicity means there is definitely snow in every winter??? Also, it is unclear with the concept of “year with a positive/negtive SCD anomaly”. Why 70% and 30% (Lines 318-321)? Could “30%” be “the other 30%”(line 319)?
5. English should be improved. For example, “We define a snow year as the period from 1 September of the previous year to 31 August of the current year (Lines 150-151).” Is this sentence correct?

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ED: Reconsider after major revisions (15 Sep 2015) by Harrie-Jan Hendricks Franssen

AR by Chang-Qing Ke on behalf of the Authors (09 Nov 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (10 Nov 2015) by Harrie-Jan Hendricks Franssen

RR by Anonymous Referee #2 (14 Dec 2015)

ED: Publish subject to minor revisions (Editor review) (28 Dec 2015) by Harrie-Jan Hendricks Franssen

Dear Dr Ke,

Your manuscript “Variability in snow cover phenology of China from 1952 to 2010” was subjected again to review by one of the original reviewers. This reviewer recommended rejection of the manuscript.

Given the in general positive evaluation by two of the original reviewers and one unfavorable review, I went through the manuscript. As you handled in subsequent revisions a large part of earlier comments, I think that the paper can be accepted after additional revisions. However, I found that the text still needs to be improved and that there is still some doubt on part of the methodology you used. The paper needs therefore additional moderate revision.

Detailed comments:
L22: As you worked only with the 296 stations I think this text part can be condensed.
L44-L45: I suggest to include China as keyword, replace "trend" with "temporal trend" and skip "spatiotemporal variation".
L94: skip "the" before Western Europe
L115-L116: rephrase.
L160: rephrase.
L205: skip "only". Before you also mentioned 95% but here only 90%. Please be consistent. I feel it would be more meaningful to document only trends with 95% significance.
L210-L214: This explanation can be skipped as it is basic knowledge.
L215: skip "only". Change to: "are considered significant (...)".
L217: It was not indicated that this is a cross-validation.
L220: What do you mean? Did you use universal cokriging? Was altitude included as a covariable for generating the map?
L221-L226: This is a result and does not belong in this section.
L243: include everywhere in the paper the units for SCD (per year).
L243: Change to: "Areas with SCDs of 10-60 per year are called unstable (...)"
L246: Change to: "(..) regions north of the (...)".
L247: Change to: Areas with SCDs of 1-10 per year are called unstable snow regions (...)"
L278: Change to: "(...) show large fluctuations (...)".
L283: Change to: "(...) also have large SCD fluctuations (...)"
L294: Change to -7.7 degrees Celsius and 7.9 mm.
L309-L313/314-L336-L340-L352-L359: not scientific language or imprecise statements, please modify.
L309-L321: Is this needed and relevant for the paper?
L344-L347: reformulate sentence.
L349: skip "there".
L457: As you worked only with the 296 stations I think this text part can be condensed.
Caption Table 4: Rewrite, this is unclear. Do you mean significant trends and significant relations?
caption Figure 6: Significance of trends according Mann-Kendall test of annual mean SCDs (...)

In your answer to the main points and detailed comments, please indicate how comments have been handled exactly, indicating also whether text has been deleted and what the position of newly included text blocks is. Please add a version of the paper which highlights all the changes made. I am looking forward to the new version of the paper.

Best regards,

Harrie-Jan Hendricks Franssen - editor -
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AR by Chang-Qing Ke on behalf of the Authors (11 Jan 2016) Author's response Manuscript

ED: Publish subject to technical corrections (03 Feb 2016) by Harrie-Jan Hendricks Franssen

AR by Chang-Qing Ke on behalf of the Authors (05 Feb 2016) Author's response Manuscript

Short summary

The heavy snow years in China include 1955, 1957, 1964, and 2010, and light snow years include 1953, 1965, 1999, 2002, and 2009. The reduction in number of days with temperature below 0 °C and increase in mean air temperature are the main reasons for the delay of snow cover onset date and advance of snow cover end date. This explains why only 15 % of the stations show significant shortening of snow cover days and differ with the overall shortening of the snow period in the Northern Hemisphere.