A Repository of 100+ Years of Measured Soil Freezing Characteristic Curves
- 1McGill University, Earth and Planetary Sciences, Montréal, Canada
- 2Carleton University, Geography and Environmental Studies, Ottawa, Canada
- 1McGill University, Earth and Planetary Sciences, Montréal, Canada
- 2Carleton University, Geography and Environmental Studies, Ottawa, Canada
Abstract. Soil freeze-thaw processes play a fundamental role in the hydrology, geomorphology, ecology, thermodynamics and soil chemistry of a cold-regions landscape. In understanding these processes, the temperature of the soil is used as a proxy to represent the soil ice content through a soil freezing characteristic curve (SFCC). This mathematical construct relates the soil ice content to a specific temperature for a particular soil. SFCCs depend on many factors including soil properties (e.g., porosity, composition, etc.), soil pore water pressure, dissolved salts, (hysteresis in) freezing/thawing point depression, and degree of saturation, all of which can be site-specific and time varying. SFCCs have been measured using various methods for diverse soils since 1921, and to date this data has not been broadly compared, in part because it has not previously been compiled in a single data set. The dataset presented in this publication includes SFCC data digitized or received from authors, and includes both historic and modern studies. The data is stored in an open-source repository, and an R package is available to facilitate its use. Aggregating the data has pointed out some data gaps, namely that there are few studies of coarse soils, and comparably few in-situ measurements of SFCCs in mountainous environments. It is hoped that this dataset will aid in the development of SFCC theory, and improve SFCC approximations in soil freeze-thaw modelling activities.
Élise G. Devoie et al.
Status: final response (author comments only)
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RC1: 'Comment on essd-2022-61', Anonymous Referee #1, 29 Mar 2022
The manuscript «A Repository of 100+ Years of Measured Soil Freezing Characteristic Curves» by Devoie et al. describes a new data base pooling published and unpublished measurements of soil freezing characteristic curves, while also providing a repository to report such measurements in the future. I very much like and support this effort and recommend publication after a number of comments and weaknesses are addressed.
Major comments:
- The critical point on data uncertainty is left to an accompanying paper, Devoie et al., 2022b, in prep., which is not available at this point? As a potential user of the database, having some quality assessment of the different data sets in the data base (or even data uncertainty in the best of worlds) is critical. As an example, if one wants to look into the freezing point depression and a measurement at -0.09 degree C is reported, it is important to know if the temperature sensor has an accuracy of 0.01 K or 0.1 K. I assume that such information is extremely hard to come by in most cases, but outsourcing this uncertainty part to an external manuscript (which is not even available yet) is not a good solution. So ideally, the authors should include uncertainties or quality assessments in the database wherever possible, and discuss this briefly in the manuscript. If such data quality assessment cannot be provided for any of the data, this should at least be mentioned, as it is a highly important limitation for some applications. On a general note, the ESSD paper should contain all aspects related to data use, and uncertainty is a rather important aspect. This still offers the possibility for a companion paper on the measurement techniques and related uncertainties.
- The csv file for metadata contains doi’s and author + year, but not the full reference. Are all published studies also referenced in the main paper, so that the citation can be found there? If yes, it would be good to mention this somewhere, so that the authors of the original studies can receive due credit if their data are downloaded from the database and used. It could be mentioned e.g. under “data availability” that you encourage to additionally refer to the original publication whenever possible. If no, it would be good to provide a list of the references of all published studies somewhere so that it can be linked to the data in the database. Potentially related to this, in SFCCMetadata.csv I am not sure about the last column “file”. Are these pdf’s available as a collection somewhere, or is this only an internal file path? In case of the latter, consider replacing it with the full citation!?
- Add a section on how new entries to the database will be quality-controlled in the future. Otherwise, measurements of questionable quality may be added in the future and weaken the usability of the database. See Minor comments.
- l.184: I can’t access https://github.com/egdevoie/SFCCRepository , this gives an error for me. It may be a problem on my end, but worth checking.
Minor:
I am unsure about the title. Is the fact that 100 year old measurements are included really that important? As a user, I would mostly care about having the best possible measurements, no matter how old they are. A measurement conducted 100 years ago should have yielded the same result for the same soil as a measurement conducted today, so unlike quantities that do change over time (e.g. climate-related data), the “length of the time series” does not play a role here. But I leave this point up to the preference of the authors.
l. 3: very minor point: “the soil ice content” is also determined by the water content before onset of freezing (i.e. water plus ice content). So something like “partitioning of soil water and ice” would be more precise.
l. 54: it would be good to add a sentence on dissolved ions and other molecules in the soil water which depress the freezing point and can concentrate in the brine upon freezing, leading to further depression of the freezing point of the brine.
l.61: add year in reference
l.150: I do not agree with the causality. If the last water to freeze is also the last water in drying soils, this only means that the low-temperature end of the SFCC can be approximated by looking at drying soils. For the rest of the SFCC range, this is not necessarily true, and it is in fact contested by some studies (e.g. overview in Karra and Painter, 2014).
l.170: are you sure about 1, and not rather “can exceed the porosity of the dry soil”?
Appendix B: it would be good to add a field on “known errors/uncertainties”, e.g. if authors are not sure whether the position of the temperature and soil water sensors may have shifted during measurements. This could be essential to quality-control new entries to the database, see Major comments.
References
Painter, S. L., & Karra, S. (2014). Constitutive model for unfrozen water content in subfreezing unsaturated soils. Vadose Zone Journal, 13(4).
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RC2: 'Comment on essd-2022-61', Anonymous Referee #2, 02 May 2022
Comments on “A repository of 100+ years of measured soil freezing characteristic curves” by Devoie et al.
The authors described a repository for some measured soil freezing characteristic data, which are helpful for the community. The current manuscript is too coarse for publication, a lot of information is missing, and the logic is unclear, although it is a data paper. I would like the have the authors add more details to make a complete paper before considering it for publication in ESSD.
The introduction is short, why the SFCC is important for the community. A short paragraph with a soft touch on the soil freeze-thaw model is insufficient. Some background here for the SFCC and its implication for the community is valuable, and the knowledge gaps (or data gaps) should be provided.
The background section does include an example of SFCC, a typical SFCC curve. I suggest it should be included in the dataset section. It can be used as a case study to show what has been done in the current repository. If the authors would like to keep it as it is as a background for the SFCC, I would suggest the authors put out some data from your current repository and compare them with this figure to show better present the data and confirm the SFCC introduced in the early section of the paper.
If the data contain lab/long for data points. I would say the coverage of the data points is missing. Although some data are extracted from lab experiments, as the soil type is available, it is possible to put those data on a global map for a geographic location.
The size of the dataset, the primary format of the data, storage, and accessibility are missing; if possible, I would like to see a few robust patterns based on the data, but all of them are missing.
It is good to see the R package is included in the repository; the authors should provide more detailed information about the R scripts, the essential functions, and the organization of those functions. Some examples of the analysis should be provided.
Some writing problems stand out and should be addressed. I just listed a few; authors should be more serious about this issue.
Line 23, an example of SFCC
The 100+ years is not appropriate, as you compiled data of >100 years apart; I originally thought you had data for 100 years duration.
Line 155, this package contains the repository. I thought you mentioned your repository contains the R package, but you stated the R packages contain the repository. I guess you meant your R package contains the function to call for the data repository and can directly access the dataset.
Élise G. Devoie et al.
Data sets
A Repository of 100+ Years of Measured Soil Freezing Characteristic Curves Élise Devoie, Stephan Gruber, Jeffrey McKenzie https://doi.org/10.5281/zenodo.5592825
Élise G. Devoie et al.
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