Numerical Study on the Expansion and Variation of Changjiang Diluted Water in Summer and Autumn

Round 1

Reviewer 1 Report

This is a revised version of a manuscript that I previously reviewed.

The authors have addressed most of my comments. Compared to the original version the language has been also edited. Overall, the language could be still improved but one can follow the meaning. 

Note that some sections in the submitted version are colored text, which needs to be removed in the final version. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript titled "Numerical Study of the Expansion and Variation of Changjiang Diluted Water in Summer and Fall" is interesting, but may interest only "local" readers.

In order overcome this shortcoming, authors are encouraged to change the Abstract and Introduction by framing the work in a different way and expand the Reference. For example, they could compare similar case studies in other parts of the world and/or mentioning where Finite Volume Community Ocean Model (FVCOM) has been previously applied.

Authors should better emphasize the measured data that were used to validate the model. They could add the information about measured data in paragraph “3.1. Model Validation” or better describe the measured data which were used for validation in the beginning of paragraphs “3.1.1. Verification of Tidal Level”, “3.1.2. Verification of Tidal Current” and “3.1.3 Verification of salinity”.

It is more correct to use the word Validation than Verification (i.e., “3.1.1. Verification of Tidal Level”, “3.1.2. Verification of Tidal Current” and “3.1.3 Verification of salinity”).

Moreover, authors should pay more attention to the text and figures. In the text, there are some typos (e.g., lines 18, 41, 69-70-71, 87, 91, 122, 183, 186, 199, 219 and 245). All figures should be self-explanatory (e.g., the figure 3 lacks the legend) and their captions should offer their full explanation (e.g., the figures 5, 6, 12, 13 and 14 should be described in its entirety).

Why text is written in different colors (e.g., lines 18, 164-173, 179, 182, 183, 186, 191, 196, 199, 216-221, 224, 241, 243, 245, 247, 251, 264, 270, 272, 279, 280, 287, 296, 298-301, 303, 308, 311, 316, 322-324 and 332-334)?

Lines 26 and 29: the acronym should be explained the first time it is cited.

Line 95: why was select this area?

Line 102: the acronym should be explained.

Line 122: Why was this time frame selected?

Author Response

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Author Response File: Author Response.pdf

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 manuscript is written on expansion and variation of CDW based on FVCOM, NCEP winds, and typhoons. Understanding of CDW behaviors is necessary for several reasons. The authors have compared the results of surface salinity with/without winds in summer and autumn. However, some points mentioned below are not clear enough, thus suggested for clarification before publishing:

• More deep explanation on how winds affect CDW expansions from June to November quantitatively
• Please give wind speed index clearly in Fig. 7.
• As shown in Fig. 6, wind speeds in summer are less than 5 or 6 m/s. To talk about the wind effect, duration should be considered. Thus monthly average wind fields in summer are expected to be too low compared to other months in Fig. 7.
• Wind speed scales should be the same through Jun to Nov.
• Please show the maximum extends of a certain salinity in each month in Fig. 8. Temporal variations of CDW here are necessary.
• Not possible to find a clue or evidence for the conclusion “When the monsoon wind direction is the same as the typhoon wind direction, the continuous typhoon transit accelerates the path turning of the CDW”.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

In this study Hou et al developed a three-dimensional model to study expansion and directional changes of Yangtze River water during dilution with seawater in the rivers’ estuary and beyond into the sea and along the adjacent shoreline. The study focuses on summer and autumn conditions, including consideration of the influence wind directions and typhoons. Overall, the study is fairly well presented, while I cannot comment on the novelty as this is slightly outside my field of expertise. The language is occasionally bumpy, while the overall message of the comes across.  

1. First sentence in abstract split in two sentences and start with second part “a three-dimensional hydrodynamic model of the Yangtze River Estuary and its adjacent waters was established based on …”
2. First sentence introduction: “Bulletin of China Marine Environmental Status” - add reference or link to website in references”
3. Line 53/54: Add a sentence here that clearly states the aim of this study: The aim of this study was to ….
4. Line 54: “Considering the dispute on the expansion of the CDW caused by runoff or wind, this study selects summer and autumn with great difference in wind and runoff.” Unclear what you are trying to say here: You mean you modelled both summer and autumn conditions using a wide range of different wind speeds (or directions) and runoff volumes? Clarify sentence as this one is important.
5. As a general comment on the introduction: You should try to better elaborate what the actual issue is you are trying to solve with your research. In the current stage this is quite vague, better describe why it is important to understand expansion patterns, describe more clearly what the influencing patterns are, and what research has been done, then define the research gap and name the aim of your study clearly, perhaps followed by a hypothesis, before giving a brief summary of what you have done (see also comment 6). The described structure is sort-off there, but you need to shape this better out.
6. Line 62: Here add a very brief 1 or 2 sentences summary what was done in the study, this increases text flow and readability.
7. Line 71: Replace “internationally” with what the method is used for instead. “most commonly used models for … finding out x or modelling y or determining z”.
8. Geophysical Data Center (http://www.ngdc.noaa.gov/mgg/global/), you may move link into references so it will be easier to find by readers.
9. Ocean Model (HYCOM) data: no reference needed here, or is included in next reference? Check
10. Shanghai Water Conservancy Commission (http://www.cjw.gov.cn/), , you may move link into references so it will be easier to find by readers. Do same also for all following weblinks e.g. line 122, which I do not comment on from here.
11. Figure 3: The differences of T1 and T2 (tidal stations to appear briefly in Figure caption. A figure should work standalone.
12. Table 1: O1, K1, K2, S2 to be briefly explained in table caption.
13. Line 277 “, while enriching the research content and providing scientific basis and reference.” This is a very generic statement. Can you be more 

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors made a revision of the manuscript. But those modifications are not enough to clear up the doubts about the expansion and variation of CDW. And some comments are as follows:

1. CDW expansion: For the investigation, coverage should be extended to 128E as in Fig. 11. And surface salinity lines of 31, 32, 33, and 34 are necessary with surface/bottom salinity difference.
2. There could be a response time of CDW behaviors to winds. Therefore it is not easy to understand CDW explanations through Fig. 11

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The authors have addressed my comments and I have no further remarks. 

Many thanks 

Author Response

Thanks for your carefully advice for my article, wish you a happy life！

Round 3

Reviewer 1 Report

For verification of the CDW model, you can compare it with in-situ data as in a paper (Journal of Oceanography, Vol. 65, pp. 129 to 135, 2009). And when it comes to hourly or daily data, it is expected to reveal detailed variations.

From Figures 11-12, we could not get to a conclusion as follows:

“When the monsoon wind direction is the same as the typhoon wind direction, the continuous typhoon transit accelerates the path turning of the CDW”.

When a typhoon is moving northward, its wind fields are changed so much, not simply matched as in Figure 11.