Assessment of climate change impact and difference on the river runoff in four basins in China under 1.5 and 2.0&thinsp;°C global warming

Xu, Hongmei; Liu, Lüliu; Wang, Yong; Wang, Sheng; Hao, Ying; Ma, Jingjin; Jiang, Tong

doi:https://doi.org/10.5194/hess-23-4219-2019

Articles | Volume 23, issue 10

https://doi.org/10.5194/hess-23-4219-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/hess-23-4219-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 23, issue 10

Research article

|

21 Oct 2019

Research article |

| 21 Oct 2019

Assessment of climate change impact and difference on the river runoff in four basins in China under 1.5 and 2.0 °C global warming

Hongmei Xu, Lüliu Liu, Yong Wang, Sheng Wang, Ying Hao, Jingjin Ma, and Tong Jiang

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Final revised paper (published on 21 Oct 2019)
Supplement to the final revised paper
Preprint (discussion started on 27 Sep 2018)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review', Anonymous Referee #1, 28 Oct 2018
- AC1: 'response to reviewer1', Hongmei Xu, 28 Dec 2018
RC2: 'The approach taken is not suitable for estimating change in runoff due to climate change', David Post, 11 Nov 2018
- AC3: 'response to reviewer', Hongmei Xu, 28 Dec 2018
RC3: 'Assessment of climate change impact and difference on the river runoff in four basins in China under 1.5 °C and 2.0 °C global warming. Xu et al, HESS 2018-448', Anonymous Referee #3, 23 Nov 2018
- AC2: 'response to reviewer 3', Hongmei Xu, 28 Dec 2018

Peer-review completion

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

ED: Reconsider after major revisions (further review by editor and referees) (17 Jan 2019) by Alexander Gelfan

AR by Hongmei Xu on behalf of the Authors (07 Mar 2019) Manuscript

ED: Referee Nomination & Report Request started (24 Mar 2019) by Alexander Gelfan

RR by Anonymous Referee #4 (19 Jun 2019)

Suggestions for revision or reasons for rejection

The manuscript has significantly improved over the previous version. The new figures with hydrographs and flow duration curve are informative and adds to the paper. However, there seem to be a noticeable downgrade in writing quality in the added paragraphs. I have two additional main comments and a couple of minor comments, including some examples of spelling/wording errors in the text.

The authors should be more careful in using the word “cause” without proving the causation. For example, in P11L19 they use “precipitation change would cause a change in runoff”. Runoff change is the result of water balance change between key physical processes governing not only the change of precipitation but also the change of ET, groundwater, snowmelt etc. A proper discussion should investigate the change in water balances for the four basins studied and show that precipitation change is the dominating factor (if true). Note also some key processes are also missing from the model, fore example the effect of elevated CO2 concentration on vegetation growth stimulation and water use efficiency, therefore more caution should be applied before using the word “cause”. Later in P14L13 the authors also wrote ‘cause a “wet-get-wetter” and “dry-get-drier” response’. In genera, a more thorough explanation/analysis is needed to show, not tell about the causation between changes of hydrological variables.

Another comment concerns the metadata information of observation data used for comparison in this study. The authors added necessary comparison between WFD and meteorological observations in Table S1 and Fig. S1, however the new observations were not described. Metadata information such as data source, time period, temporal resolution and uncertainties is necessary to improve the transparency and credibility of this study to the readers. Similarly, it would help if the values of calibrated parameters are provided in addition to names of “identified sensitive parameters” in Table S4.

Minor comments:

1. In authors’ reply: 2P1. “In general, the model simulation is considered acceptable when the Ens values are greater than 0.5, R2 should exceed 0.6, and the Pbias less than 20%.” Is there a citation supporting this statement?
2. Figure 1. which years were used to generate the seasonal cycle? Suggest adding dots to indicate the location of gauges.
3. Figure 2. The meaning of the dots (ensemble mean or median) should be explained in the figure caption.
4. Figure 4. add a-d labels for the figure panels?
5. Table 3. What do you mean by “Uncertainty”
6. P2L27 “simulated water resource declined” -> “simulated water resource decrease”
7. P4L10 what do you mean by “reduced and intense droughts”?
8. P4L32 less -> “less than”
9. P5L18 “insistent well” -> “good”. Note the good agreement is by design: the GCMs are bias corrected against WFD data. The authors probably have done a bit too much showing their good agreement in climatology, which should come as a surprise to very few readers.
10. P11L16 “also coincided” -> “is also consistent”
11. P7L8 “underestimate” -> “underestimation”
12. P8L5 Is there an extra “s”?
13. P14L29 Is last sentence just repeating the first one in this paragraph? Suggest deletion.

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ED: Publish subject to minor revisions (review by editor) (25 Jul 2019) by Alexander Gelfan

AR by Hongmei Xu on behalf of the Authors (03 Aug 2019)

ED: Publish as is (30 Aug 2019) by Alexander Gelfan

AR by Hongmei Xu on behalf of the Authors (02 Sep 2019)

Short summary

1.5 and 2 °C have become targets in the discussion of climate change impacts. However, climate research is also challenged to provide more robust information on the impact of climate change at local and regional scales to assist the development of sound scientific adaptation and mitigation measures. This study assessed the impacts and differences of 1.5 and 2.0 °C global warming on basin-scale river runoff by examining four river basins covering a wide hydroclimatic setting in China.