Angular Spectrum of Acoustic Pulses at Long Ranges
Round 1
Reviewer 1 Report
This paper report a method for analysis of acoustic pulses by angular spectrum. It may be interesting for the reader who works in ocean field. I would like to suggest this paper to be published after following question answered:
1. What’s the meaning of Ze? Is the diameter of eddy core or the distance of the eddy from source?
2. What’s the tanx in figure 2? I hope the author describe the detail clearly.
3. When ∆z changed from 10m to 30m, what is the difference between figure 2 and 3? I suggest author figure out a parameter to describe this change, (from data but not theoretical ∆p). Such as correlation coefficient or error.
Author Response
Response to Reviewer 1 Comments
We are thankful to the Reviewer for the comments indicating unclear points in the manuscript.
Point 1: What’s the meaning of Ze? Is the diameter of eddy core or the distance of the eddy from source??
Response 1: ze is the depth of the eddy core (center of the core). The corresponding clarification is added after Eq. (22) in the revised version.
Point 2: What’s the tanx in figure 2? I hope the author describe the detail clearly.
Response 2: It is not “tanx”, it is tan Χ (chi), i.e. tangent of the arrival angle. We’ve added the detailed description into the figure caption. Also, the formula describing the link between ray variable p and arrival angle \chi is moved to a separate line (Eq. (6) in the revised version).
Point 3: When ∆z changed from 10m to 30m, what is the difference between figure 2 and 3? I suggest author figure out a parameter to describe this change, (from data but not theoretical ∆p). Such as correlation coefficient or error.
Response 3: We agree that the case of Δz = 30 m is poorly described in the manuscript. This parameter is linked to the array length and plays the decisive role for angular resolution. Therefore, we significantly extended description of this data in the last paragraph of Section 4.
Reviewer 2 Report
The article presents the problem of acoustic pulse propagation at long ranges in the environment of deep water.
The methods presented are an implementation of previously published theoretical solutions.
In the reviewer's opinion, the paper should clearly indicate the novelty of the work in the field of research covered.
The language style should be improved, including the overused personal forms.
Figures should be located as close as possible to their descriptions in the text of the article.
Yours Sincerely,
Reviewer.
Author Response
Response to Reviewer 2 Comments
We are thankful to the Reviewer for the comments indicating unclear points in the manuscript.
Point 1: In the reviewer's opinion, the paper should clearly indicate the novelty of the work in the field of research covered.
Response 1: We focus attention on influence of internal waves on angular spectrum. We represent a simplified version of the Husimi transform for calculation of arrival structure, but this is rather an auxiliary result. In our opinion, the most important observation is separation of arrivals with opposite angles as the array length increases. It facilitates ray-based interpretation of an arrival pattern that can be helpful for identification of propagation geometry. This inspires optimism from the viewpoint of various practical applications like hydroacoustical tomography. In the revised version we have underlined this circumstance in the Abstract, Discussion, and Conclusion.
Point 2: The language style should be improved, including the overused personal forms.
Response 2: We have significantly rewritten the text and reduced the usage of personal forms.
Point 3: Figures should be located as close as possible to their descriptions in the text of the article.
Response 3: This manuscript is made using LaTeX, therefore locations of figures are not fully controlled. Usually such things are corrected in course of final preparation by the publisher.
Reviewer 3 Report
The authors present a numerical model for the underwater noise propagation prediction.
Below the following questions and comments:
1. the authors should include a comparison with some exprimental data in order to demonstrate the validity of the model;
2. the sea data seem to be missing (depth, salinity, etc.);
3. the list of references is suggested to be extrended. For example some papers:
Ocean Ambient Noise, Measurement and Theory;
Increases in deep-ocean ambient noise in the Northeast Pacific west of San Nicholas Island
Bidimensional Ray Tracing Model for the Underwater Noise Propagation Prediction.
4. the first person should be avoided.
Author Response
Response to Reviewer 3 Comments
We are thankful to the Reviewer for the comments indicating unclear points in the manuscript.
Cited from the Referee’s report: The authors present a numerical model for the underwater noise propagation prediction.
Response: It is not quite correct. We study properties of angular spectrum of a wavefield formed by a coherent pulse source. Noise propagation is a different thing, because noise should be rather considered as a stochastic field created by random superposition of sources. Of course, noise-induced sound fields also can exhibit some regular features like modal spatial structure, but basically it is a different phenomenon.
Point 1: The authors should include a comparison with some exprimental data in order to demonstrate the validity of the model;
Response 1: Unfortunately, there are no experiments of this kind. Something similar is reported in Ref. 9, but that paper considers sound propagation in the Baltic shelf where influence of internal waves is qualitatively different as compared to the deep ocean.
Point 2: The sea data seem to be missing (depth, salinity, etc.).
Response 2: It is not the case, all necessary information is given in the section 3. Effect of salinity is taken into account in the corresponding buoyancy frequency profile that is calculated according to experimental data (the database [28]). This procedure is described in detail in Ref. 4, here we can only repeat that description.
Point 3: The list of references is suggested to be extrended. For example some papers:
Ocean Ambient Noise, Measurement and Theory;
Increases in deep-ocean ambient noise in the Northeast Pacific west of San Nicholas Island
Bidimensional Ray Tracing Model for the Underwater Noise Propagation Prediction.
Response 3: We’ve added references [34-36].
Point 4: The first person should be avoided.
Response 4: We have significantly rewritten the text and reduced the usage of personal forms.
Round 2
Reviewer 2 Report
Since my comments and questions have been clarified, in my opinion the article can be published in JMSE.
Yours Sincerely,
Reviewer.
Reviewer 3 Report
Dear authors,
you have done a good work. By my side, the paper is ready for a publication.
Thanks for the answers to my comments.
Regards.
