the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 27 Jan 2025
age_flow_line-1.0: a fast and accurate numerical age model for a pseudo-steady flow tube of an ice sheet
Abstract. Numerical age models are useful tools for investigating the age of the ice in an ice sheet. They can be used to date ice cores or to interpret isochronal horizons which are observed by radar instruments. Here, we present a new numerical age model for a flow line of an ice sheet. The assumption here is that the geometry of the flow line and the velocity shape functions are steady (i.e. constant in time). A time-varying factor can only be applied to the surface accumulation rates and basal melting rates. Our model uses an innovative coordinate system (𝜋,𝜃), previously published, which is suitable for solving transport equations. Using this coordinate system, solving the age equation is simple, fast and accurate, because the trajectories of ice particles pass exactly through the nodes of the grid. Our numerical scheme, called Eulerian-Lagrangian, therefore combines the advantages of Eulerian and Lagrangian schemes. We present an application of this model to the flow line going from Dome C to Little Dome C and show that horizontal flow is a non-negligible factor which should be considered when modelling the age-depth relationship of the Beyond EPICA ice core. The code we developed for age modelling along a flow tube is named age_flow_line-1.0 and is freely available under an open-source license.
-
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.
-
Preprint
(6303 KB)
-
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(6303 KB) - Metadata XML
- BibTeX
- EndNote
- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2024-3411', Anonymous Referee #1, 05 Mar 2025
-
AC1: 'Reply on RC1', Frédéric Parrenin, 14 May 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2024-3411/egusphere-2024-3411-AC1-supplement.pdf
-
AC1: 'Reply on RC1', Frédéric Parrenin, 14 May 2025
-
RC2: 'Comment on egusphere-2024-3411', Anonymous Referee #2, 23 Mar 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2024-3411/egusphere-2024-3411-RC2-supplement.pdf
-
AC2: 'Reply on RC2', Frédéric Parrenin, 14 May 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2024-3411/egusphere-2024-3411-AC2-supplement.pdf
-
AC2: 'Reply on RC2', Frédéric Parrenin, 14 May 2025
-
EC1: 'Comment on egusphere-2024-3411', Andy Wickert, 14 May 2025
Dear Frédéric Parrenin and co-authors;
Based on the two constructive referee comments, I invite you to prepare and submit a revised manuscript.Best,
Andy Wickert
Citation: https://doi.org/10.5194/egusphere-2024-3411-EC1
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2024-3411', Anonymous Referee #1, 05 Mar 2025
Parrenin et al. report a 2.5D "flowtube" model that utilizes a coordinate transformation that greatly improves the numerical efficiency. This coordinate transformation was developed in previous publications roughly a decade ago, so the primary new aspect of this work is providing the model code so that others can more easily use the model. This paper is well suited for Geophysical Model Development.
The manuscript is clearly written and the primary equations and assumptions are well described and justified. The figures are informative, and are mostly auto-generated from the code. There is no particular scientific conclusion to the paper, which is ok since that is not the primary purpose. The application to EDC-BELDC is appropriate and demonstrates the model capabilities.
I have used this model before and found it useful, functional, and well documented.
I have only a few suggestions given below:
- The conclusion is missing text and should be expanded upon.
- In the abstract, intro, and conclusion, the coordinate transformation should be described with an additional sentence. What is the gist of the coordinate transformation?
- L21 - change "most important" to "largest" since "most important" is an opinion
- L22-25 - give references for each of these points and separate with semicolons rather than commas
- L26 - make "type" plural
- L50 - make "scheme" plural
- L234 - change "in front of" to "compared to"
- L256 - change ">15km" to ">20km" to be consistent with other locations in the paper
- Figure 1. I don't understand the labeling of "Q(x)" beneath the ice sheet, should it be m(x)? The caption could also use more description of what the symbols represent.
- Figure 5. Can you describe why the red dashed lines in the top panel for the core sites don't reach the bottom of the graph? I think this is because the model domain gets to older ages than is actually found at the ice core sites, but it isn't clear.
- Figure 6 - I think added subpanels with the horizontal flux shape function plotted for each core site would make the figure more interpretable
- Figure 9 - mention in Figure 9 caption that the vertical thinning functions at EDC and BELDC are shown in Figure 10
Citation: https://doi.org/10.5194/egusphere-2024-3411-RC1 -
AC1: 'Reply on RC1', Frédéric Parrenin, 14 May 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2024-3411/egusphere-2024-3411-AC1-supplement.pdf
-
AC1: 'Reply on RC1', Frédéric Parrenin, 14 May 2025
-
RC2: 'Comment on egusphere-2024-3411', Anonymous Referee #2, 23 Mar 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2024-3411/egusphere-2024-3411-RC2-supplement.pdf
-
AC2: 'Reply on RC2', Frédéric Parrenin, 14 May 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2024-3411/egusphere-2024-3411-AC2-supplement.pdf
-
AC2: 'Reply on RC2', Frédéric Parrenin, 14 May 2025
-
EC1: 'Comment on egusphere-2024-3411', Andy Wickert, 14 May 2025
Dear Frédéric Parrenin and co-authors;
Based on the two constructive referee comments, I invite you to prepare and submit a revised manuscript.Best,
Andy Wickert
Citation: https://doi.org/10.5194/egusphere-2024-3411-EC1
Peer review completion
Journal article(s) based on this preprint
Viewed
| HTML | XML | Total | BibTeX | EndNote | |
|---|---|---|---|---|---|
| 701 | 69 | 25 | 795 | 32 | 57 |
- HTML: 701
- PDF: 69
- XML: 25
- Total: 795
- BibTeX: 32
- EndNote: 57
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1
Cited
1 citations as recorded by crossref.
Frédéric Parrenin
Ailsa Chung
Carlos Martín
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(6303 KB) - Metadata XML
Parrenin et al. report a 2.5D "flowtube" model that utilizes a coordinate transformation that greatly improves the numerical efficiency. This coordinate transformation was developed in previous publications roughly a decade ago, so the primary new aspect of this work is providing the model code so that others can more easily use the model. This paper is well suited for Geophysical Model Development.
The manuscript is clearly written and the primary equations and assumptions are well described and justified. The figures are informative, and are mostly auto-generated from the code. There is no particular scientific conclusion to the paper, which is ok since that is not the primary purpose. The application to EDC-BELDC is appropriate and demonstrates the model capabilities.
I have used this model before and found it useful, functional, and well documented.
I have only a few suggestions given below:
- The conclusion is missing text and should be expanded upon.
- In the abstract, intro, and conclusion, the coordinate transformation should be described with an additional sentence. What is the gist of the coordinate transformation?
- L21 - change "most important" to "largest" since "most important" is an opinion
- L22-25 - give references for each of these points and separate with semicolons rather than commas
- L26 - make "type" plural
- L50 - make "scheme" plural
- L234 - change "in front of" to "compared to"
- L256 - change ">15km" to ">20km" to be consistent with other locations in the paper
- Figure 1. I don't understand the labeling of "Q(x)" beneath the ice sheet, should it be m(x)? The caption could also use more description of what the symbols represent.
- Figure 5. Can you describe why the red dashed lines in the top panel for the core sites don't reach the bottom of the graph? I think this is because the model domain gets to older ages than is actually found at the ice core sites, but it isn't clear.
- Figure 6 - I think added subpanels with the horizontal flux shape function plotted for each core site would make the figure more interpretable
- Figure 9 - mention in Figure 9 caption that the vertical thinning functions at EDC and BELDC are shown in Figure 10