glenglat: Global englacial temperature database

Open-access database of englacial temperature measurements compiled from published literature and submissions.

Data structure

The dataset adheres to the Frictionless Data Tabular Data Package specification. The metadata in datapackage.yaml describes, in detail, the contents of the tabular data files:

• data/source.csv: Description of each data source (either a direct contribution or the reference to a published study).
• data/borehole.csv: Description of each borehole (location, elevation, etc), linked to source.csv via source_id and less formally via source identifiers in notes.
• data/profile.csv: Description of each profile (date and time), linked to borehole.csv via borehole_id and to source.csv via source_id.
• data/measurement.csv: Description of each measurement (depth and temperature), linked to profile.csv via borehole_id and profile_id.

For boreholes with many profiles (e.g. from automated loggers), pairs of profile.csv and measurement.csv are stored separately in subfolders of data named {source.id}-{glacier}, where glacier is a simplified and kebab-cased version of the glacier name (e.g. flowers2022-little-kluane).

Supporting information

Folder sources contains subfolders (with names matching column source.id) with files that document how and from where the data was extracted. Files with a .png, .jpg, or .pdf extension are figures, tables, maps, or text from the publication. Pairs of files with .pgw and .{png|jpg}.aux.xml extensions georeference a .{png|jpg} image, and files with .geojson extension are the subsequently-extracted spatial coordinates. Files with an .xml extension document how numeric values were extracted from maps and figures using Plot Digitizer (https://plotdigitizer.sourceforge.net). Of these, digitized temperature profiles are named {borehole.id}_{profile.id}{suffix} where borehole.id and profile.id are either a single value or a hyphenated range (e.g. 1-8). Those without the optional suffix use temperature and depth as axis names. Those with a suffix are unusual cases which, for example, may be part of a series (e.g. _lower) or use a non-standard axis (e.g. _date).

How to contribute

To contribute data, send an email to jacquemart@vaw.baug.ethz.ch. Please structure your data as either comma-separated values (CSV) files (borehole.csv and measurement.csv) or as an Excel file (with sheets borehole and measurement). The required and optional columns for each table are described below and in the submission metadata: contribute/datapackage.yaml. Consider using our handy Excel template: contribute/template.xlsx!

Note: We also welcome submissions of data that have already been digitized, as they allow us to assess the accuracy of the digitization process.

borehole

name	description	type	constraints
id	Unique identifier.	integer	required: True unique: True minimum: 1
glacier_name	Glacier or ice cap name (as reported).	string	required: True pattern: [^\s]+( [^\s]+)*
glims_id	Global Land Ice Measurements from Space (GLIMS) glacier identifier.	string	pattern: G[0-9]{6}E[0-9]{5}[NS]
latitude	Latitude (EPSG 4326).	number [degree]	required: True minimum: -90 maximum: 90
longitude	Longitude (EPSG 4326).	number [degree]	required: True minimum: -180 maximum: 180
elevation	Elevation above sea level.	number [m]	required: True maximum: 9999.0
label	Borehole name (e.g. as labeled on a plot).	string
date_min	Begin date of drilling, or if not known precisely, the first possible date (e.g. 2019 → 2019-01-01).	date	format: %Y-%m-%d
date_max	End date of drilling, or if not known precisely, the last possible date (e.g. 2019 → 2019-12-31).	date	format: %Y-%m-%d
drill_method	Drilling method: - mechanical: Push, percussion, rotary, ... - thermal: Hot point, electrothermal, steam, ... - combined: Mechanical and thermal	string	enum: ['mechanical', 'thermal', 'combined']
ice_depth	Starting depth of ice. Infinity (INF) indicates that ice was not reached.	number [m]
depth	Total borehole depth (not including drilling in the underlying bed).	number [m]
to_bed	Whether the borehole reached the glacier bed.	boolean
temperature_accuracy	Thermistor accuracy or precision (as reported). Typically understood to represent one standard deviation.	number [°C]
notes	Additional remarks about the study site, the borehole, or the measurements therein. Literature references should be formatted as {url} or {author} {year} ({url}).	string	pattern: [^\s]+( [^\s]+)*

measurement

name	description	type	constraints
borehole_id	Borehole identifier.	integer	required: True
depth	Depth below the glacier surface.	number [m]	required: True
temperature	Temperature.	number [°C]	required: True
date_min	Measurement date, or if not known precisely, the first possible date (e.g. 2019 → 2019-01-01).	date	format: %Y-%m-%d
date_max	Measurement date, or if not known precisely, the last possible date (e.g. 2019 → 2019-12-31).	date	format: %Y-%m-%d required: True
time	Measurement time.	time	format: %H:%M:%S
utc_offset	Time offset relative to Coordinated Universal Time (UTC).	number [h]
equilibrated	Whether temperatures have equilibrated following drilling.	boolean

Validation

You can validate your CSV files (borehole.csv and measurement.csv) before submitting them using the frictionless Python package.

1. Clone this repository.

   git clone https://github.com/mjacqu/glenglat.git
   cd glenglat

2. Either install the glenglat-contribute Python environment (with conda):

   conda env create --file contribute/environment.yaml
   conda activate glenglat

   Or install frictionless into an existing environment (with pip):

   pip install "frictionless~=5.13"

3. Validate, fix any reported issues, and rejoice! (path/to/csvs is the folder containing your CSV files)

   python contribute/validate_submission.py path/to/csvs

Developer guide

Run tests

Follow the instructions below to run a full test of the data package.

1. Clone this repository.

   git clone https://github.com/mjacqu/glenglat.git
   cd glenglat

2. Install the glenglat Python environment (with conda):

   conda env create --file tests/environment.yaml
   conda activate glenglat

3. Run the basic (frictionless) tests.

   frictionless validate datapackage.yaml

4. Run the custom (pytest) tests.

   pytest tests

5. An optional test checks that borehole.glims_id is consistent with borehole coordinates. This requires a GeoParquet file of glacier outlines from the GLIMS dataset with columns geometry (glacier outline) and glac_id (glacier id). To run, first install geopandas and pyarrow, then set the GLIMS_PATH environment variable before calling pytest.

   conda install -c conda-forge geopandas=0.13 pyarrow
   GLIMS_PATH=/path/to/parquet pytest tests

Build generated files

The scripts directory contains Python scripts that update certain files:

• build_zenodo_json.py: Build .zenodo.json file (for Zenodo releases) from datapackage.yaml and data/source.csv.
• build_submission_yaml.py: Build contribute/datapackage.yaml from datapackage.yaml.
• build_submission_md.py: Updates tables in README.md from contribute/datapackage.yaml.
• build_submission_xlsx.py: Build contribute/template.xlsx from contribute/datapackage.yaml.

Assuming the glenglat Python environment is installed and activated (see above), they can be run as follows:

python scripts/build_zenodo_json.py
python scripts/build_submission_yaml.py
python scripts/build_submission_md.py
python scripts/build_submission_xlsx.py