the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 16 Jan 2024
A simple approach to represent precipitation-derived freshwater fluxes into nearshore ocean models: an FVCOM4.1 case study
Abstract. High-resolution numerical ocean models can be used to help interpret sparse observations in the nearshore as well as to help understand the impacts of climate change and extreme events on these dynamically complex coastal areas. However, these high-resolution ocean models require inputs with comparably high resolution, which is particularly difficult to achieve for freshwater discharge. Here, we explored a simple rain-based hydrological model as inputs into a high-resolution (≳13 m) model of Quatsino Sound – a fjord system located on the northwest coast of Vancouver Island, British Columbia, Canada. Through a series of sensitivity tests using an application of the Finite Volume Community Ocean Model (FVCOM version 4.1), we found that model performance was hindered by the lack of knowledge of ungauged rivers and streams. In this case study, including the only major gauged river implied ignoring 538 other watersheds of various sizes and accounted for only about a quarter of the total estimated freshwater discharge. We found that including at least 60 % and ideally closer to 75–80 % of total freshwater fluxes gave similar model performance to including all possible 539 freshwater sources; in our model simulations, this percentage of freshwater flux meant including rivers with watersheds greater than 20–50 km2, or 7–19 total rivers. Further sensitivity tests also indicated that knowing the main outpour locations into the nearshore ocean is an important factor, but not as important as the total freshwater discharge included. Overall, this study illustrates the complexities of studying the land-ocean connection and offers a simple and accessible tool to help address a common problem in nearshore modelling.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
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CEC1: 'Comment on egusphere-2023-3064', Juan Antonio Añel, 26 Jan 2024
After checking your manuscript, it has come to our attention that it does not comply with our Code and Data Policy.
https://www.geoscientific-model-development.net/policies/code_and_data_policy.html
You have archived your code and data in repositories that does not comply with our trustable permanent archival policy (waterproperties.ca and GitHub). Therefore, you must store your code and data in one of the appropriate repositories according to our policy. Also, we can not accept embargoes such as "upon acceptance". All the assets used in the manuscript must be available at the submission of the manuscript.In this way, you must reply to this comment with the link to the new repository used in your manuscript, with its DOI. The reply and the repository should be available as soon as possible, and before the Discussions stage is closed, to be sure that anyone has access to it for review purposes. I should note that, actually, your manuscript should not have been accepted in Discussions, given this lack of compliance with our policy. Therefore, the current situation with your manuscript is irregular.
Also, you must include in a potential reviewed version of your manuscript the modified 'Code and Data Availability' section and the DOI of the code. Also, remember that for your code you must include a licence. If you do not include a license, the code continues to be your property and can not be used by others, despite any statement on being free to use. Therefore, when uploading the model's code to the repository, you could want to choose a free software/open-source (FLOSS) license. We recommend the GPLv3. You only need to include the file 'https://www.gnu.org/licenses/gpl-3.0.txt' as LICENSE.txt with your code. Also, you can choose other options that Zenodo provides: GPLv2, Apache License, MIT License, etc.Please, reply as soon as possible to this comment with the link for it so that it is available for the peer-review process, as it should be.
Be aware that failing to comply promptly with this request could result in rejecting your manuscript for publication.Juan A. Añel
Geosci. Model Dev. Executive EditorCitation: https://doi.org/10.5194/egusphere-2023-3064-CEC1 -
AC1: 'Reply on CEC1', Krysten Rutherford, 26 Jan 2024
Dear Chief Editor,
Thank you for bringing this to our attention. We are working on making the model code and data available as soon as possible through an appropriate repository. We will reply with the DOI and an updated Code and Data Availability statement as soon as it is available.
Sincerely,
Krysten Rutherford on behalf of all coauthors
Citation: https://doi.org/10.5194/egusphere-2023-3064-AC1 -
AC2: 'Reply on CEC1', Krysten Rutherford, 01 Feb 2024
Dear Chief Editor,
Please find an updated Code and Data Availability statement below that includes DOIs to two repositories with the code and data used in this study:
FVCOM code is developed by the Marine Ecosystem Dynamics Modeling Laboratory (MEDM-Lab) at the University of Massachusetts and is publicly available by their developers at https://github.com/FVCOM-GitHub/FVCOM under the MIT/X license; a fixed version of the code and input files used in this case study can be found at https://doi.org/10.5281/zenodo.10602542 (Rutherford et al. 2024a). Observational and model datasets used in this manuscript are available at https://doi.org/10.5281/zenodo.10602511 (Rutherford et al. 2024b).
References
Rutherford, K., Bianucci, L., & Floyd, W. (2024a). Code and input files for the manuscript "A simple approach to represent precipitation-derived freshwater fluxes into nearshore ocean models: an FVCOM4.1 case study" [Data set]. Zenodo. https://doi.org/10.5281/zenodo.10602542.
Rutherford, K., Bianucci, L., & Floyd, W. (2024b). Observations and model data used in the analysis of the manuscript "A simple approach to represent precipitation-derived freshwater fluxes into nearshore ocean models: an FVCOM4.1 case study" [Data set]. Zenodo. https://doi.org/10.5281/zenodo.10602511.
Citation: https://doi.org/10.5194/egusphere-2023-3064-AC2
-
AC1: 'Reply on CEC1', Krysten Rutherford, 26 Jan 2024
-
RC1: 'Comment on egusphere-2023-3064', Anonymous Referee #1, 14 Feb 2024
Review of “A simple approach to represent precipitation-derived freshwater fluxes into nearshore ocean models: an FVCOM4.1 case study” by Rutherford et al.
General comments:
This manuscript studies an important technical issue of how to represent freshwater fluxes accurately and efficiently in high-resolution nearshore ocean models. For coarse-resolution models, freshwater inputs are normally incorporated by aggregating individual contributions from various watersheds into one source and specifying it at one or two model grid points. This approach is definitely undesirable for high-resolution models in which explicit depiction of disparate spatial scales is at high priority. Using Quatsino Sound as a case study site and employing a relatively simple rain-based hydrological model, the authors perform a series of sensitivity tests to answer the two research questions they proposed. The topic is interesting and scientifically important within the geoscientific model development. The results derived here can be extended to other coastal areas and, thus, are worthy of publication. However, I would suggest the authors to clarify certain points and make some statements in the text more accurate.
Specific comments:
1) I would suggest that the title of the paper be changed to “A simple approach to represent precipitation-derived freshwater fluxes into nearshore ocean models: a case study of Quatsino Sound, British Columbia”.
This method is not unique to FVCOM. If you change to another coastal ocean circulation model, the proposed rain-based hydrological model can still be used. In the meantime, the conclusions of the paper, such as those listed in the Abstract, is only valid for Quatsino Sound.
2) This paper only considers the very simple rain-based hydrological model. Actually, within the framework of FVCOM, a more accurate way to estimate the effect of precipitation-derived freshwater fluxes on fjord salinity dynamics can be done. In this approach, nearshore ocean model domain will be enlarged to encompass all the watersheds in the study area. Then using FVCOM's wetting and drying capability to simulate over land flow due to rain events using FVCOM’s precipitation and evaporation forcing. Have the authors tried this approach? Of course, it requires a lot more computational time.
Do the authors consider evaporation or evapotranspiration, in addition to precipitation?
3) Lines 170-173, do you consider the freshwater falling on the surface of the numerical domain (i.e., the fjord system)? If not, the simulated salinity field will be biased.
4) Lines 228-249, the authors should give a definition of “mean” or “average” in the paragraphs here. Otherwise, it will take the readers a lot of time to try to figure that out.
5) Lines 297-298, “All other sensitivity tests had metrics in between those of the Marble River Only and All Rivers simulations”. This is definitely a wrong statement, which is not consistent with the numbers (e.g., Willmott Score) quoted in the text. Fig. 9 is another source to check with.
6) Lines 310-313, to make sure this statement is correct, you can either use the general vertical coordinate in FVCOM simulation, and/or greatly increase the number of the vertical layers. Have you tried these?
Technical corrections:
1) Line 128, add “on” before October 14th, 2021
2) Line 131, add “on” before October 14th, or (it would be better) add “at 00:00 am on October 14th”
3) Line 162, delete “in each watershed”
4) Line 169, Equation (3). Should it be AHRDPS,j the denominator and AWS,j the numerator?
5) Line 319, add “as” after “as long”
6) Figure 4 caption, “in equation 2” or in equation 3?
7) Figure 6, for right-hand side panels I would suggest to change the color scale to blue color only because, I guess, no positive difference in surface salinity exists in the result.
8) Figure 7 caption, is this called a histogram? I can understand that Figure 8 is called a histogram, but not this one.
9) Figure 9, a Table may be a better choice than a Figure
Citation: https://doi.org/10.5194/egusphere-2023-3064-RC1 -
AC3: 'Reply on RC1', Krysten Rutherford, 19 Mar 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2023-3064/egusphere-2023-3064-AC3-supplement.pdf
- AC5: 'Reply on RC1', Krysten Rutherford, 19 Apr 2024
-
AC3: 'Reply on RC1', Krysten Rutherford, 19 Mar 2024
-
RC2: 'Comment on egusphere-2023-3064', Nicolas Lambert, 11 Apr 2024
General comments:
The paper, “A Simple Approach to represent precipitation-derived Freshwater Fluxes into Nearshore Ocean Models: an FVCOM4.1 Case Study,” presents a straightforward solution that significantly improves the representation of hydrological influence in ocean circulation models. The authors demonstrate a keen understanding of the simplicity of this solution that would be beneficial to oceanographers when improving the results of their model. For example, the decision to utilize the grid of the atmospheric model HRDPS aligned well with this principle. While not perfect, this approach eliminates the need for remapping operations and mitigates other potential sources of error, such as water conservation.
Furthermore, the authors explore various gaps in the knowledge of the river network, including the watershed area and river mouth location. They provide valuable insights into where efforts should be concentrated to enhance the efficiency of coastal circulation models. Despite these strengths, the authors remain cognizant of the existing gaps in their rivers model.
Specific comments:
- The river proxy currently relies solely on precipitation data. Incorporating evaporation data (P-E) could enhance the proxy’s accuracy in predicting the volume of water in the river system.
- The frequency of the river proxy used in the FVCOM model is unclear. While some analyses were conducted at a high frequency (as shown in Figure 4), others were done on a monthly basis (Figure 5). Clarification on the frequency of these inputs implemented in the model would be beneficial.
- Insufficient time was dedicated to validating the CIOPS-W model in the region under study. This raises concerns about whether the CIOPS-W model itself could be a source of errors from the initial states and the boundary conditions used in their coastal circulation model.
- The paper frequently mentions that the river proxy is rain-based and does not account for snow coverage. Conducting a climatological overview of the region, particularly regarding winter snow coverage or snowfall, could help assess the extent of this limitation in the current model.
- Validation of the properties of deeper water should be considered. While the 0-50m depth is directly affected by river flow, this could also influence the content of deeper water through estuarine circulation.
- The modelling of water storage will primarily delay and temper peak precipitation, rather than limit the total volume of water flowing into the river system (line 176).
- A comparison with the Marble River at a higher time resolution than monthly could provide more detailed insights (line 196). One suggestion could be to combine Figures 4 and 5 for this purpose.
- The paper states that the All Rivers configuration performs better, but then suggests that only 60-75% of the total freshwater source is necessary (line 324). An explanation of this apparent contradiction would be helpful.
Citation: https://doi.org/10.5194/egusphere-2023-3064-RC2 -
AC4: 'Reply on RC2', Krysten Rutherford, 19 Apr 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2023-3064/egusphere-2023-3064-AC4-supplement.pdf
Interactive discussion
Status: closed
-
CEC1: 'Comment on egusphere-2023-3064', Juan Antonio Añel, 26 Jan 2024
After checking your manuscript, it has come to our attention that it does not comply with our Code and Data Policy.
https://www.geoscientific-model-development.net/policies/code_and_data_policy.html
You have archived your code and data in repositories that does not comply with our trustable permanent archival policy (waterproperties.ca and GitHub). Therefore, you must store your code and data in one of the appropriate repositories according to our policy. Also, we can not accept embargoes such as "upon acceptance". All the assets used in the manuscript must be available at the submission of the manuscript.In this way, you must reply to this comment with the link to the new repository used in your manuscript, with its DOI. The reply and the repository should be available as soon as possible, and before the Discussions stage is closed, to be sure that anyone has access to it for review purposes. I should note that, actually, your manuscript should not have been accepted in Discussions, given this lack of compliance with our policy. Therefore, the current situation with your manuscript is irregular.
Also, you must include in a potential reviewed version of your manuscript the modified 'Code and Data Availability' section and the DOI of the code. Also, remember that for your code you must include a licence. If you do not include a license, the code continues to be your property and can not be used by others, despite any statement on being free to use. Therefore, when uploading the model's code to the repository, you could want to choose a free software/open-source (FLOSS) license. We recommend the GPLv3. You only need to include the file 'https://www.gnu.org/licenses/gpl-3.0.txt' as LICENSE.txt with your code. Also, you can choose other options that Zenodo provides: GPLv2, Apache License, MIT License, etc.Please, reply as soon as possible to this comment with the link for it so that it is available for the peer-review process, as it should be.
Be aware that failing to comply promptly with this request could result in rejecting your manuscript for publication.Juan A. Añel
Geosci. Model Dev. Executive EditorCitation: https://doi.org/10.5194/egusphere-2023-3064-CEC1 -
AC1: 'Reply on CEC1', Krysten Rutherford, 26 Jan 2024
Dear Chief Editor,
Thank you for bringing this to our attention. We are working on making the model code and data available as soon as possible through an appropriate repository. We will reply with the DOI and an updated Code and Data Availability statement as soon as it is available.
Sincerely,
Krysten Rutherford on behalf of all coauthors
Citation: https://doi.org/10.5194/egusphere-2023-3064-AC1 -
AC2: 'Reply on CEC1', Krysten Rutherford, 01 Feb 2024
Dear Chief Editor,
Please find an updated Code and Data Availability statement below that includes DOIs to two repositories with the code and data used in this study:
FVCOM code is developed by the Marine Ecosystem Dynamics Modeling Laboratory (MEDM-Lab) at the University of Massachusetts and is publicly available by their developers at https://github.com/FVCOM-GitHub/FVCOM under the MIT/X license; a fixed version of the code and input files used in this case study can be found at https://doi.org/10.5281/zenodo.10602542 (Rutherford et al. 2024a). Observational and model datasets used in this manuscript are available at https://doi.org/10.5281/zenodo.10602511 (Rutherford et al. 2024b).
References
Rutherford, K., Bianucci, L., & Floyd, W. (2024a). Code and input files for the manuscript "A simple approach to represent precipitation-derived freshwater fluxes into nearshore ocean models: an FVCOM4.1 case study" [Data set]. Zenodo. https://doi.org/10.5281/zenodo.10602542.
Rutherford, K., Bianucci, L., & Floyd, W. (2024b). Observations and model data used in the analysis of the manuscript "A simple approach to represent precipitation-derived freshwater fluxes into nearshore ocean models: an FVCOM4.1 case study" [Data set]. Zenodo. https://doi.org/10.5281/zenodo.10602511.
Citation: https://doi.org/10.5194/egusphere-2023-3064-AC2
-
AC1: 'Reply on CEC1', Krysten Rutherford, 26 Jan 2024
-
RC1: 'Comment on egusphere-2023-3064', Anonymous Referee #1, 14 Feb 2024
Review of “A simple approach to represent precipitation-derived freshwater fluxes into nearshore ocean models: an FVCOM4.1 case study” by Rutherford et al.
General comments:
This manuscript studies an important technical issue of how to represent freshwater fluxes accurately and efficiently in high-resolution nearshore ocean models. For coarse-resolution models, freshwater inputs are normally incorporated by aggregating individual contributions from various watersheds into one source and specifying it at one or two model grid points. This approach is definitely undesirable for high-resolution models in which explicit depiction of disparate spatial scales is at high priority. Using Quatsino Sound as a case study site and employing a relatively simple rain-based hydrological model, the authors perform a series of sensitivity tests to answer the two research questions they proposed. The topic is interesting and scientifically important within the geoscientific model development. The results derived here can be extended to other coastal areas and, thus, are worthy of publication. However, I would suggest the authors to clarify certain points and make some statements in the text more accurate.
Specific comments:
1) I would suggest that the title of the paper be changed to “A simple approach to represent precipitation-derived freshwater fluxes into nearshore ocean models: a case study of Quatsino Sound, British Columbia”.
This method is not unique to FVCOM. If you change to another coastal ocean circulation model, the proposed rain-based hydrological model can still be used. In the meantime, the conclusions of the paper, such as those listed in the Abstract, is only valid for Quatsino Sound.
2) This paper only considers the very simple rain-based hydrological model. Actually, within the framework of FVCOM, a more accurate way to estimate the effect of precipitation-derived freshwater fluxes on fjord salinity dynamics can be done. In this approach, nearshore ocean model domain will be enlarged to encompass all the watersheds in the study area. Then using FVCOM's wetting and drying capability to simulate over land flow due to rain events using FVCOM’s precipitation and evaporation forcing. Have the authors tried this approach? Of course, it requires a lot more computational time.
Do the authors consider evaporation or evapotranspiration, in addition to precipitation?
3) Lines 170-173, do you consider the freshwater falling on the surface of the numerical domain (i.e., the fjord system)? If not, the simulated salinity field will be biased.
4) Lines 228-249, the authors should give a definition of “mean” or “average” in the paragraphs here. Otherwise, it will take the readers a lot of time to try to figure that out.
5) Lines 297-298, “All other sensitivity tests had metrics in between those of the Marble River Only and All Rivers simulations”. This is definitely a wrong statement, which is not consistent with the numbers (e.g., Willmott Score) quoted in the text. Fig. 9 is another source to check with.
6) Lines 310-313, to make sure this statement is correct, you can either use the general vertical coordinate in FVCOM simulation, and/or greatly increase the number of the vertical layers. Have you tried these?
Technical corrections:
1) Line 128, add “on” before October 14th, 2021
2) Line 131, add “on” before October 14th, or (it would be better) add “at 00:00 am on October 14th”
3) Line 162, delete “in each watershed”
4) Line 169, Equation (3). Should it be AHRDPS,j the denominator and AWS,j the numerator?
5) Line 319, add “as” after “as long”
6) Figure 4 caption, “in equation 2” or in equation 3?
7) Figure 6, for right-hand side panels I would suggest to change the color scale to blue color only because, I guess, no positive difference in surface salinity exists in the result.
8) Figure 7 caption, is this called a histogram? I can understand that Figure 8 is called a histogram, but not this one.
9) Figure 9, a Table may be a better choice than a Figure
Citation: https://doi.org/10.5194/egusphere-2023-3064-RC1 -
AC3: 'Reply on RC1', Krysten Rutherford, 19 Mar 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2023-3064/egusphere-2023-3064-AC3-supplement.pdf
- AC5: 'Reply on RC1', Krysten Rutherford, 19 Apr 2024
-
AC3: 'Reply on RC1', Krysten Rutherford, 19 Mar 2024
-
RC2: 'Comment on egusphere-2023-3064', Nicolas Lambert, 11 Apr 2024
General comments:
The paper, “A Simple Approach to represent precipitation-derived Freshwater Fluxes into Nearshore Ocean Models: an FVCOM4.1 Case Study,” presents a straightforward solution that significantly improves the representation of hydrological influence in ocean circulation models. The authors demonstrate a keen understanding of the simplicity of this solution that would be beneficial to oceanographers when improving the results of their model. For example, the decision to utilize the grid of the atmospheric model HRDPS aligned well with this principle. While not perfect, this approach eliminates the need for remapping operations and mitigates other potential sources of error, such as water conservation.
Furthermore, the authors explore various gaps in the knowledge of the river network, including the watershed area and river mouth location. They provide valuable insights into where efforts should be concentrated to enhance the efficiency of coastal circulation models. Despite these strengths, the authors remain cognizant of the existing gaps in their rivers model.
Specific comments:
- The river proxy currently relies solely on precipitation data. Incorporating evaporation data (P-E) could enhance the proxy’s accuracy in predicting the volume of water in the river system.
- The frequency of the river proxy used in the FVCOM model is unclear. While some analyses were conducted at a high frequency (as shown in Figure 4), others were done on a monthly basis (Figure 5). Clarification on the frequency of these inputs implemented in the model would be beneficial.
- Insufficient time was dedicated to validating the CIOPS-W model in the region under study. This raises concerns about whether the CIOPS-W model itself could be a source of errors from the initial states and the boundary conditions used in their coastal circulation model.
- The paper frequently mentions that the river proxy is rain-based and does not account for snow coverage. Conducting a climatological overview of the region, particularly regarding winter snow coverage or snowfall, could help assess the extent of this limitation in the current model.
- Validation of the properties of deeper water should be considered. While the 0-50m depth is directly affected by river flow, this could also influence the content of deeper water through estuarine circulation.
- The modelling of water storage will primarily delay and temper peak precipitation, rather than limit the total volume of water flowing into the river system (line 176).
- A comparison with the Marble River at a higher time resolution than monthly could provide more detailed insights (line 196). One suggestion could be to combine Figures 4 and 5 for this purpose.
- The paper states that the All Rivers configuration performs better, but then suggests that only 60-75% of the total freshwater source is necessary (line 324). An explanation of this apparent contradiction would be helpful.
Citation: https://doi.org/10.5194/egusphere-2023-3064-RC2 -
AC4: 'Reply on RC2', Krysten Rutherford, 19 Apr 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2023-3064/egusphere-2023-3064-AC4-supplement.pdf
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Cited
Krysten Rutherford
Laura Bianucci
William Floyd
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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