by Nick Brown, NSERC PermafrostNet Data Scientist
Students in NSERC PermafrostNet’s Theme 1, led by postdocs Michel Paquette and Samuel Gagnon, have digitized 2 historic reports (Hodgson, 1982 and Hodgson, & Nixon 1998) containing profile data from more than 250 boreholes in polar desert environments. Information on ground ice content, ground ice descriptions, soil type, grain size and more, is now available for re-use in a variety of formats using the PermafrostNet ERDDAP data server. Data can be accessed and searched from a single borehole, or from the entire report. Both the data and metadata can be downloaded as a csv.
These data take advantage of the new additions to the CF standard name list to make the data more interoperable and reuseable. Nick Brown has also documented a set of standardized variable names and their associated CF Names – Standardized permafrost variable names and equivalent CF Names. This technical note document describes the variables that are on the NSERC PermafrostNet ERDDAP and their associated metadata. It can also be used as a guide to connect commonly-used permafrost variables to the recommended CF standard_name.
One of the steps involved in redistributing these data on the ERDDAP server is converting them into the NetCDF data format. This is a way of distributing scientific data that is gaining popularity because it is self-documenting and uses a several well-established community-built standards to increase data interoperability. These include the CF conventions and the Attribute Convention for Data Discovery (ACDD). There are a number of data distribution platforms (ERDDAP, THREDDS, HYRAX) that can be used to easily distribute NetCDF files using a standardized API and web interface. NSERC PermafrostNet uses ERDDAP as a data distribution platform for these reasons and because it offers a graphical web interface for those who want to access data interactively. It also makes it possible to adopt the associated data standards as one way to increase the interoperability of permafrost data generated by and used within the network.
The NetCDF format and associated standards were originally developed for atmospheric, oceanographic and climatic data, so there are few examples of these files being used to represent observed soil profiles or geotechnical borehole data, and the CF standard_name table lacks many variables that are relevant to permafrost science. A new technical document – Representing geotechnical borehole profile data with netCDF and ERDDAP provides considerations and recommendations for structuring observed borehole profile data in a way that complies with existing standards, is distributable on ERDDAP, and useable by permafrost scientists.
These new documents are available on the PermafrosNet Data Standard Recommendations page.
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