On the consistency of scale among experiments, theory, and simulation

McClure, James E.; Dye, Amanda L.; Miller, Cass T.; Gray, William G.

doi:https://doi.org/10.5194/hess-21-1063-2017

Articles | Volume 21, issue 2

https://doi.org/10.5194/hess-21-1063-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue:

Observations and modeling of land surface water and energy...

https://doi.org/10.5194/hess-21-1063-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 21, issue 2

Research article

|

20 Feb 2017

Research article |

| 20 Feb 2017

On the consistency of scale among experiments, theory, and simulation

James E. McClure, Amanda L. Dye, Cass T. Miller, and William G. Gray

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Final revised paper (published on 20 Feb 2017)
Preprint (discussion started on 15 Sep 2016)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Referee report', Anonymous Referee #1, 29 Sep 2016
- AC1: 'Response to Anonymous Reviewer #1', William Gray, 06 Nov 2016
RC2: 'Review of "on the consistency..." by J. McClure et al.', Anonymous Referee #2, 10 Oct 2016
- AC2: 'Response to Comments of Anonymous Reviewer #2', William Gray, 06 Nov 2016

Peer-review completion

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

ED: Reconsider after major revisions (further review by Editor and Referees) (20 Nov 2016) by Remko Uijlenhoet

Dear authors,

You have been served by two extensive review reports by colleagues that are much more knowledgeable on the subject matter of your work than I am. Both reviewers have raised a number of general issues (relevance to the broader hydrological community, link with Prof. Eric Wood's work, novelty with respect to previous work, definitions e.g. of macro-/micro-scale) as well as a number of technical issues.

You have provided detailed responses to all of the issues raised, for which I am thankful. On some counts you seem to agree with the points raised by the reviewers, on others you disagree. That is not a problem as such, as this seems to be part of a constructive debate among scientists.

Based on the review reports, your replies, as well as my own appreciation of the manuscript, I have decided to reconsider your manuscript after major revisions. The revised manuscript will be sent out for review again, in principle to the same reviewers that have commented on the first version of your manuscript.

Please provide, in addition to your replies to the issues raised by the reviewers, a detailed indication on how and where you have revised the formulation of your manuscript. In addition to the points raised by the reviewers, I would like to ask you to pay particular attention to the fact that HESS is a journal with a broad readership from the entire hydrological community (and beyond). It would therefore add to your manuscript if you would be able to reach out to that broader hydrological community (not necessarily experts in issues of soil physics and/or the physics of transport processes in porous media). This could be achieved, for instance, by better explaining the relevance of this work for the community of hydrological researchers dealing with hydrological processes at the scale of river catchments, large river basins, or even entire continents. That would really bridge the (scale) gap between your work and that of Prof. Wood and clarify the relevance of your work for researchers working on entirely different spatial and temporal scales. Along the way, you could take more room to explain your definitions of macro- vs. micro-scale as well as other issues raised by the reviewers.

Your replies to the reviewers' comments suggest that you have concrete ideas on how to revise your manuscript. Please go ahead and do so, bearing in mind the suggestions made above. I am looking forward to handling a thoroughly revised version of your manuscript and a point-by-point response to the issues raised by the reviewers. Thank you very much in advance.

Best regards,

Remko Uijlenhoet

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AR by Anna Mirena Feist-Polner on behalf of the Authors (30 Nov 2016) Author's response Manuscript

ED: Reconsider after major revisions (further review by Editor and Referees) (30 Nov 2016) by Remko Uijlenhoet

ED: Referee Nomination & Report Request started (04 Dec 2016) by Remko Uijlenhoet

RR by Anonymous Referee #1 (21 Dec 2016)

RR by Anonymous Referee #2 (22 Dec 2016)

Suggestions for revision or reasons for rejection

I have mentioned earlier on the extensive objectives, background, and quite basic eqs (1-19), which I think are basically definitions. The authors refer to the broader context in honor of Prof Wood, that their manuscript may be the only one on porous media, and therefore reasonable to connect with other approaches.
This reviewer has of course no objection that Prof. Wood is honored by a special issue (presumably with an editorial to highlight Prof. Wood’s great achievements). But this manuscript is a normal paper, not an editorial and not a review. Therefore, I read it as a paper and I find ‘this connection’ far from convincing. Instead, to me it reads as an artificial attempt to broaden the perspective of this paper. That this paper may be the only one on porous media is completely irrelevant, as I see it. The manuscript is not a chapter of a book that intends completeness to some degree, I see no reason why the special issue should pretend that. Again: this is a normal paper, and such papers should be to the point. I can extend this point to the abstract. An abstract is a short description of the main points of the manuscript, with primary findings. A short editorial on Prof. Wood (though sympathetic) as well as insightful comments that are not basic to this paper should be omitted. Though the response considers that upscaling techniques are the same, whatever scale and context, maybe appropriate for a review article, but is beside the point in a research article, for the same reason as the response argues for being to the point in its response of averaging references: “...the averages computed in this work”. I have indicated the lines that I think are obsolete in the abstract of this submission in the first round.
I also still find that six bullets in the objectives section are overdoing it. To me it looks as if every breath has to be announced. I would suggest that they are following the suggestion of the author himself regarding possible overlap with the much cited McClure et al paper: “A sentence or two can be inserted to clearly assert what is the new contribution...”. Please go ahead (despite that you need three points to highlight the most significant differences with the PRE paper) and do the same with the objectives.
On my remark on how it is checked that equilibrium is reached, the author states the willingness to add an apparently necessary experimental methods section (if really needed!). I find it quite remarkable, that to convince the readership of this equilibrium, apparently an entire section is needed, that apparently was considered obsolete in the first submission, and apparently is not yet sufficiently described in the McClure et al. or other papers. I am also somewhat confused by this response: is the content of such a section not part of another paper (hence, should be presented here), why is it then still not needed, and is the provided statement on this issue in the response sufficient or not?
In my earlier comments, I mentioned that the equations in section 4.1 are basically definitions. In response, I get the pun that apparently I lack the appropriate background. I would think that such a set of definitions can be found in handbooks, other articles and are therefore obsolete in this manuscript, as they are definitions. For this manuscript, this section can be shortened to what matters. In that case, it may be less painful, if the authors use notations of cited or not cited references, without explaining it.
The response on Figure 1 is fine, but I suggest that for instance the caption explicitly mentions the black circles to be pure solid.
It is still not completely clear to me, if R2 in the ‘depth’ direction is 2.2 micro-meter, and the black circles differ in size (horizontal plane): these black volumes are therefore not pure spheres? You might mention so, as Figure 1 could be interpreted differently.
I am glad to hear that the experimental work is new. However, I asked about the instrument also.
Thank you for your response to issue 8. I understand from your answer, that if interfacial area is included, all possible microstates collapse into one relationship, thus eliminating ‘history’.

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ED: Publish subject to revisions (further review by Editor and Referees) (10 Jan 2017) by Remko Uijlenhoet

AR by William Gray on behalf of the Authors (12 Jan 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (12 Jan 2017) by Remko Uijlenhoet

RR by Anonymous Referee #1 (12 Jan 2017)

Suggestions for revision or reasons for rejection

No significant changes were made. I read the replies and cannot escape the impression that in the communication between the authors and this reviewer both sides appear to have some difficulties to grasp what the other side means to convey. I have made progress there and gained a better understanding, but the rather tort response from the authors shows that this is not mutual. As a case in point, my reference to MODFLOW was an attempt to try to get one of my points across a bit differently, and certainly not an invitation to build a TCAT version of it. A full paragraph discussing the limitations of MODFLOW would not have been necessary.

I have some background in the area the authors are covering, but after providing extensive detailed comments to help the authors identify parts of the paper that are hard to follow or otherwise would benefit from modification am being informed that my limitations undermine my ability to understand the contribution of the paper. I am rather pessimistic in fearing that the vast majority of the HESS readership will be burdened by similar if not larger limitations.

To see the contribution of the paper it helps to be aware that most hydrological problems manifest themselves and need solutions at the megascale. Hydrology is moving in the direction of modeling megascale problems with macroscale models through the use of brutal computing power for running models with a very large number of nodes and sophisticated parameter optimization techniques. In the revision the authors do a better job of highlighting the limitations of these models, but most hydrologists are aware of that, although usually not with the thermodynamical rigour that I ascribe to the authors.

At the megascale, hydrologsts face massive issues with heterogeneity, spatial and temporal dynamics in porous medium properties caused by such factors as swelling and shrinkage, bioturbation, tillage, land use changes, and what not. The scientifically elegant and physically imperative approach advocated in this work is not generally considered the biggest fish to fry.

For the work to make a significant contribution, some expansion is still required, as per my earlier suggestions and those put forward by the authors.

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RR by Anonymous Referee #2 (16 Jan 2017)

Suggestions for revision or reasons for rejection

I have mentioned earlier on the extensive objectives, background, and quite basic eqs (1-19), which I think are basically definitions. The authors refer to the broader context in honor of Prof Wood, that their manuscript may be the only one on porous media, and therefore reasonable to connect with other approaches.
This reviewer has of course no objection that Prof. Wood is honored by a special issue (presumably with an editorial to highlight Prof. Wood’s great achievements). But this manuscript is a normal paper, not an editorial and not a review. Therefore, I read it as a paper and I find ‘this connection’ far from convincing. Instead, to me it reads as an artificial attempt to broaden the perspective of this paper. That this paper may be the only one on porous media is completely irrelevant, as I see it. The manuscript is not a chapter of a book that intends completeness to some degree, I see no reason why the special issue should pretend that. Again: this is a normal paper, and such papers should be to the point. I can extend this point to the abstract. An abstract is a short description of the main points of the manuscript, with primary findings. A short editorial on Prof. Wood (though sympathetic) as well as insightful comments that are not basic to this paper should be omitted. Though the response considers that upscaling techniques are the same, whatever scale and context, maybe appropriate for a review article, but is beside the point in a research article, for the same reason as the response argues for being to the point in its response of averaging references: “...the averages computed in this work”. I have indicated the lines that I think are obsolete in the abstract of this submission in the first round.
I also still find that six bullets in the objectives section are overdoing it. To me it looks as if every breath has to be announced. I would suggest that they are following the suggestion of the author himself regarding possible overlap with the much cited McClure et al paper: “A sentence or two can be inserted to clearly assert what is the new contribution...”. Please go ahead (despite that you need three points to highlight the most significant differences with the PRE paper) and do the same with the objectives.
On my remark on how it is checked that equilibrium is reached, the author states the willingness to add an apparently necessary experimental methods section (if really needed!). I find it quite remarkable, that to convince the readership of this equilibrium, apparently an entire section is needed, that apparently was considered obsolete in the first submission, and apparently is not yet sufficiently described in the McClure et al. or other papers. I am also somewhat confused by this response: is the content of such a section not part of another paper (hence, should be presented here), why is it then still not needed, and is the provided statement on this issue in the response sufficient or not?
In my earlier comments, I mentioned that the equations in section 4.1 are basically definitions. In response, I get the pun that apparently I lack the appropriate background. I would think that such a set of definitions can be found in handbooks, other articles and are therefore obsolete in this manuscript, as they are definitions. For this manuscript, this section can be shortened to what matters. In that case, it may be less painful, if the authors use notations of cited or not cited references, without explaining it.
The response on Figure 1 is fine, but I suggest that for instance the caption explicitly mentions the black circles to be pure solid.
It is still not completely clear to me, if R2 in the ‘depth’ direction is 2.2 micro-meter, and the black circles differ in size (horizontal plane): these black volumes are therefore not pure spheres? You might mention so, as Figure 1 could be interpreted differently.
I am glad to hear that the experimental work is new. However, I asked about the instrument also.
Thank you for your response to issue 8. I understand from your answer, that if interfacial area is included, all possible microstates collapse into one relationship, thus eliminating ‘history’.

Hide

ED: Publish subject to minor revisions (further review by Editor) (16 Jan 2017) by Remko Uijlenhoet

Dear authors,

Thank you very much for submitting your replies to the issues raised by the reviewers and for submitting the revised version of your paper.

As you can see, reviewer #1 still feels the paper will probably not easily fit into the scope of the other papers to be published as part of the Special Issue of HESS honoring Prof. Eric Wood. The main point of this reviewer is that the spatial scale at which you deal with the topic of scale consistency among experiments, theory and simulation (namely that of soil as a porous medium) is likely going to be quite disparate from the spatial scales at which Prof. Wood and many of his colleagues have been and are working (namely that of landscapes, catchments, river basins, and continents). The reviewer is therefore not convinced that your work is going to provide new perspectives for hydrologists trying to model the world at such larger scales. That may be true, but at the same time the reviewer does not seem to have major concerns with the technical details of your work. Therefore, I am inclined to leave the discussion about the value of your work from a broader hydrological perspective to the readers of the pages of HESS and other scientific journals rather than to the reviewers of your manuscript alone.

Reviewer #2 also seems to have no major issues with the technical content of your revised manuscript. This reviewer still finds the way in which you present your work, including your reference to Prof. Wood's work, not appropriate for a regular paper that is submitted to become part of a special issue. Although I am sympathetic with this reviewer's perspective, I feel that the presentation style is merely a matter of taste.

In conclusion, I recommend to accept your manuscript subject to minor revisions. As far as I am concerned, the paper will not be sent out for review again. I would appreciate it very much if you could give it one last try to accommodate some of the issues raised by the referees. Thank you very much in advance. I look forward to handling the revised version of your manuscript.

Best regards,

Remko Uijlenhoet

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AR by William Gray on behalf of the Authors (17 Jan 2017) Author's response Manuscript

ED: Publish as is (20 Jan 2017) by Remko Uijlenhoet

Short summary

A complicating factor in describing the flow of two immiscible fluids in a porous medium is ensuring that experiments, theory, and simulation are all formulated at the same length scale. We have quantitatively analyzed the internal structure of a two-fluid system including the distribution of phases and the location of interfaces between phases. The data we have obtained allow for a clearer definition of capillary pressure at the averaged scale as a state function that describes the system.