the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 31 Mar 2025
PortUrb: A Performance Portable, High-Order, Moist Atmospheric Large Eddy Simulation Model with Variable-Friction Immersed Boundaries
Abstract. This paper introduces "portUrb": a moist, compressible, non-hydrostatic atmospheric Large Eddy Simulation model that aims for portability, performance, accuracy, simplicity, readability, robustness, extensibility, and ensemble capabilities. Additionally, there is an emphasis on free-slip immersed boundaries with surface friction to account for urban building geometries. Coded in portable C++ with high-order Weighted Essentially Non-Oscilatory (WENO) numerics, this study investigates the behavior of portUrb under atmospheric boundary layer, supercell, and urban scenarios. PortUrb matches experimental observations and model comparisons closely under several test cases in mean and turbulent statistics. It also provides physically realizable flow through complex building geometries from a portion of Manhattan without needing to pre-process or smooth the building geometry.
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CEC1: 'Comment on egusphere-2025-1135 - No compliance with the policy of the journal', Juan Antonio Añel, 08 Apr 2025
Dear authors,
Unfortunately, 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.htmlIn the "Code and Data Availability" section of your manuscript you state "Simulation results will be made available publicly... if the manuscript is accepted." We can not accept this. Our policy clearly establishes that all the code and data must be published and available to anyone before submission of manuscripts in one of the suitable repositories listed in our policy.
Given this lack of compliance your manuscript should have not been accepted for publication in Discussions in our journal or sent out for review. Therefore, the current situation with your manuscript is irregular. We have to ask you to publish the data from the simulation results and reply to this comment with the relevant information for it: link and permanent identifier (e.g. DOI). In the meantime, I ask the Topical Editor of your manuscript to stop the peer-review process and stop inviting reviewers if it applies. We can not waste the time of reviewers and editors on reviewing a manuscript that we could have to reject due to no compliance with the policy of our journal.
After you have replied to this comment with the requested information, we will assess the compliance of your manuscript again, and will decide if to continue with the review process.
I have to note that if you do not fix this problem, we will have to reject your manuscript for publication in our journal.
Juan A. Añel
Geosci. Model Dev. Executive EditorCitation: https://doi.org/10.5194/egusphere-2025-1135-CEC1 -
AC1: 'Reply on CEC1', Matt Norman, 09 Apr 2025
Hi Juan,
We apologize for the miscommunication in our data statement. That statement was regarding solely the many Terabytes of full 3-D time snapshots of all variables of all netCDF data that goes beyond the code, analysis scripts, and Figures needed to support the discussion and conclusions in this manuscript. The full code itself as well as analysis scripts that produce the Figures are accessible publicly already via DOI through Zenodo (also referenced in the manuscript text and references) here: https://zenodo.org/records/15000787
What we have provided seems typical of other articles accepted in this journal, e.g.:
- https://gmd.copernicus.org/articles/17/3433/2024/#section6
- https://gmd.copernicus.org/articles/18/2137/2025/#section7
- https://gmd.copernicus.org/articles/18/1333/2025/#section13
- https://gmd.copernicus.org/articles/18/1357/2025/#section7
The two observation-based test cases we compare against do not have publicly available datasets beyond tables and figures published in other papers, which are referenced in the manuscript.
Again, we apologize for not making this more clear in the text. We want, upon successful review, to provide large resource above and beyond the direct analyses in this paper to other numerical model developers in Large Eddy Simulation fields in hopes that access to this larger dataset proves helpful for other model developers in the future. That is what the text was specifically referring to.
While we have sought to provide before the review process what seems to be common for GMD's accepted papers, we are, of course, more than happy to include a new DOI with extra data if it is believed that the full current code and analysis scripts used for this manuscript as well as the Figures provided in this manuscript are deemed insufficient for GMD. If that is the case, can the nature of the additional data requested be made more specific in order to reduce the size of permanently hosted data from Terabytes down to the order of perhaps Megabytes to Gigabytes?
Thanks,
-Matt
Citation: https://doi.org/10.5194/egusphere-2025-1135-AC1 -
CEC2: 'Reply on AC1', Juan Antonio Añel, 09 Apr 2025
Dear authors,
I do not think you have understood clearly my previous comment. I will try to explain it better. In your manuscript you present the result of simulations: you must publish the results of such simulations, which you use for your work, openly, without limitations, in a repository of the ones listed in our policy, which we expect authors read carefully and complied with before submitting their manuscripts. You make a mention to data sizes. If the data used in a submitted manuscript is too large (for example, several TeraBytes) we can make exceptions or request authors to publish only the few final variables that are used for a work, instead of data files containing full outputs from models. However, if it is your case, you need to reply to this comment clarifying the size of the outputs used in your work. Then we will study such case and will decide on how to proceed.
You mention in your comment previous works published in our journal. I want to make clear that what is relevant here is the policy. Comparison with previously published manuscripts for which you could not have all the information, or which could have been published without being fully compliant with our policy, does not grant any exception to your submission.
Therefore, please, publish all the data that you use in your manuscript in one of the suitable repositories, and if you feel that the dataset is too big to do it (for example more than 500 GB) then publish only the necessary fields or variables for the plots that you provide and the results you discuss.
Juan A. Añel
Geosci. Model Dev. Executive Editor
Citation: https://doi.org/10.5194/egusphere-2025-1135-CEC2 -
AC2: 'Reply on CEC2', Matt Norman, 17 Apr 2025
Hi Juan,
All gridded data used in the plots and discussed in the manuscript is now available here: https://doi.org/10.5281/zenodo.15232629
Best,-MattCitation: https://doi.org/10.5194/egusphere-2025-1135-AC2 -
AC3: 'Reply on CEC2', Matt Norman, 22 Apr 2025
Hi Juan, could you update us on the status of the review process now that the requested data has been added? Thanks,
-Matt
Citation: https://doi.org/10.5194/egusphere-2025-1135-AC3 -
AC4: 'Reply on CEC2', Matt Norman, 01 May 2025
Hi Juan, do you have an ETA on when we'll be notified of when review will resume? Thanks,
-Matt
Citation: https://doi.org/10.5194/egusphere-2025-1135-AC4 -
CEC3: 'Reply on AC4', Juan Antonio Añel, 05 May 2025
Dear authors,
Many thanks for making available a new dataset containing the information necessary to replicate the results presented in the manuscript. We can consider the current version of your manuscript in compliance with our code and data policy, and therefore the review process can continue. Please, remember to remove the statement on making the data available only after acceptance from the Code and Data Availability section of your manuscript.
Juan A. Añel
Geosci. Model Dev. Executive Editor
Citation: https://doi.org/10.5194/egusphere-2025-1135-CEC3 -
AC5: 'Reply on CEC3', Matt Norman, 06 May 2025
Thanks Juan, we will be sure to update the data statement appropriately. Best,
-Matt
Citation: https://doi.org/10.5194/egusphere-2025-1135-AC5
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AC5: 'Reply on CEC3', Matt Norman, 06 May 2025
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CEC3: 'Reply on AC4', Juan Antonio Añel, 05 May 2025
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AC2: 'Reply on CEC2', Matt Norman, 17 Apr 2025
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AC1: 'Reply on CEC1', Matt Norman, 09 Apr 2025
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RC1: 'Comment on egusphere-2025-1135', Anonymous Referee #1, 21 Jul 2025
Title: PortUrb: A Performance Portable, High-Order, Moist Atmospheric Large Eddy Simulation Model with Variable-Friction Immersed Boundaries
In this paper, the PortUrb code is introduced. This code is designed for moist atmospheric LES with a focus on urban environments, emphasizing portability, performance, accuracy and clarity. It leverages portable C++ libraries and GPU-friendly numerical methods like WENO schemes to ensure high performance and robustness across various hardware platforms. Numerical experiments validate its accuracy and robustness across multiple test cases, including atmospheric boundary layers, urban flow around buildings, and realistic geometries, demonstrating reliable, physically accurate performance without numerical artifacts. The topic is important, and the manuscript is generally well-written and streamlined. The scientific merit of the study deserves publication. Yet, I recommend minor revision of the manuscript before its acceptance. This recommendation is based on the comments and remarks listed below:
- In lines 55–58, the authors note that a series of numerical discretization studies led to their choice of discretization schemes. To enhance the manuscript's clarity and value to readers, it would be helpful if the authors briefly discussed the rationale behind selecting these particular schemes in the introduction. What specific advantages or limitations influenced their decision? Including this context—such as trade-offs in accuracy, stability, or computational cost—would strengthen the motivation and transparency of their methodological choices.
- While the introduction emphasizes the portability of the model, it is unclear how this is demonstrated in the manuscript. Could the authors clarify what specific aspects of the code design or implementation contribute to its portability across architectures? Additionally, it would be helpful to include performance metrics—such as total runtime or computational resources used—for the Neutral Atmospheric and Dry Convective Boundary Layer test cases. This information would give readers a better understanding of the model’s efficiency and scalability.
- It is not clear how geostrophic forcing enters Equation 1. Could the authors explicitly state how this term is incorporated into the governing equations? Additionally, in line 297, the statement that “Equation 18 is applied using the average column” is ambiguous. What does “average column” refer to?
- The manuscript contains several references to figures in other studies when comparing results. For instance, in line 310, the authors state that “these profiles closely match Figure 3 in Sauer and Muñoz-Esparza (2020),” which requires readers to consult external sources while reading. To improve readability and make the manuscript more self-contained, I recommend including the relevant figures from these referenced studies alongside the corresponding figures in this manuscript (e.g., overlaying Figure 3 from Sauer and Muñoz-Esparza (2020) with Figure 3 here). This approach would allow readers to directly assess the comparison without referring to external documents. A similar suggestion applies to Figure 2 and other instances where visual comparisons are made.
- In line 306, the authors mentioned that “the smoothing of the second temperature discontinuity is lower in portUrb than seen in FastEddy”. The author did not provide any evidence to support this statement.
Citation: https://doi.org/10.5194/egusphere-2025-1135-RC1 - RC2: 'Comment on egusphere-2025-1135', Anonymous Referee #2, 08 Sep 2025
Model code and software
portUrb Matthew Norman https://zenodo.org/records/15000787
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