Abstract:
This dataset contains ice surface velocity values for 102 lake- and land-terminating Greenland Ice Sheet outlet glaciers, years 2000 and 2015 to 2019, including the flowlines and sampling boxes used for data production. The dataset is provided in two folders: (i) Shapefiles and (ii) Velocity_Data.
Funding was provided by the NERC standard grant NE/S007458/1.
Keywords:
Greenland Ice Sheet, Ice sheets, Lake-terminating, Outlet glaciers, Velocity
Harpur, C., Smith, M., Carrivick, J., Quincey, D., & Taylor, L. (2026). Ice surface velocity of lake- and land-terminating Greenland Ice Sheet outlet glaciers, 2000 and 2015 to 2019 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/fa7887ea-5c4e-4d7a-b39f-456792f34b37
| Access Constraints: | None. |
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| Use Constraints: | This data is governed by the NERC data policy (http://www.nerc.ac.uk/research/sites/data/policy/) and supplied under Open Government Licence v.3 (http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/). |
| Creation Date: | 2026-02-11 |
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| Dataset Progress: | Complete |
| Dataset Language: | English |
| ISO Topic Categories: |
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| Parameters: |
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| Personnel: | |
| Name | UK Polar Data Centre |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Connie M Harpur |
| Role(s) | Technical Contact, Investigator |
| Organisation | University of Leeds |
| Name | Mark W Smith |
| Role(s) | Investigator |
| Organisation | University of Leeds |
| Name | Jonathan L Carrivick |
| Role(s) | Investigator |
| Organisation | University of Leeds |
| Name | Duncan J Quincey |
| Role(s) | Investigator |
| Organisation | University of Leeds |
| Name | Liam S Taylor |
| Role(s) | Investigator |
| Organisation | University of Leeds |
| Parent Dataset: | N/A |
| Reference: | Harpur et al. (2026) Commun Earth Environ [in prep] Gardner, A. S., Fahnestock, M. A. & Scambos, T. A. (2019) ITS_LIVE regional glacier and ice sheet surface velocities (Version 1). NSIDC. https://doi.org/10.5067/6II6VW8LLWJ7 How, P., Messerli, A., Mätzler, E., Santoro, M., Wiesmann, A., Caduff, R., Langley, K., Bojesen, M. H., Paul, F., Kääb, A., & Carrivick, J. L. (2021). Greenland-wide inventory of ice marginal lakes using a multi-method approach. Scientific Reports, 11(1), Article 4481. https://doi.org/10.1038/s41598-021-83509-1 |
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| Quality: | Errors associated with each velocity value, extracted from the relevant ITS_LIVE annual velocity mosaic (Gardner et al., 2019), are presented in files LakeBoxError.csv and LandBoxError.csv. Note all shapefiles produced in QGIS under coordinate system WGS 84 NSIDC Sea Ice Polar Stereographic North EPSG: 3413 Missing values are indicated by NaN. |
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| Lineage/Methodology: | Shapefiles were produced in QGIS 3.40. Flowlines were manually digitised to follow the line of fastest flow at each lake- and land-terminating outlet glacier as seen in the ITS_LIVE 2017 velocity mosaic. Each flowline extends inland from the glacier terminus until the head of the glacier trunk is reached, or for a maximum of 10 km. To determine sampling locations, points were placed at 1500 m intervals between 500 m and 9500 m up-ice of the terminus. A 500 x 500 m box was then centred on each point to produce a chain of up to seven sampling boxes along each glacier flowline, depending on flowline length. ITS_LIVE annually averaged regional velocity mosaics (and associated error mosaics; Gardner et al., 2019) with a pixel resolution of 120 m x 120 m were sampled as the average pixel value within each sampling box. Velocity and associated error are both presented in metres per year. For a full methodology, please refer to Harpur et al. (2026). | |
| Temporal Coverage: | |
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| Start Date | 2000-01-01 |
| End Date | 2019-12-31 |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | 60.8 |
| Northernmost | 82.2 |
| Longitude | |
| Westernmost | -69.1 |
| Easternmost | -22.5 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | N/A |
| Depth | |
| Min Depth | N/A |
| Max Depth | N/A |
| Location: | |
| Location | Greenland |
| Detailed Location | N/A |
| Data Storage: | This dataset is organised into two folders: (1) Shapefiles Contains glacier flowlines and sample boxes used to produce the velocity dataset. Each subfolder contains a .shp file with its associated file formats. Files ending '2000' relate to shapefiles used to produce the year 2000 data only. All other files relate to shapefiles used to produce data for years 2015 - 2019. (2) Velocity_Data Contains box-sampled velocity data and associated error values derived from ITS_LIVE Version 2 annual velocity magnitude mosaics (Gardner et al., 2019), years 2000 and 2015 - 2019. Velocity and error values are reported in metres per year (m/a). Attributes are as follows: LakeBoxVelocity.csv and LandBoxVelocity.csv: lake_glac_id = Lake-terminating glacier id land_glac_id = Land-terminating glacier id drainage_basin = drainage basin distance = distance from terminus along flowline (m) count = number of sampled pixels mean = mean of sampled pixel values stdev = standard deviation of sampled pixel values lake_id = lake ID, as in How et al. (2021) lake_area = lake area (m2), as in How et al. (2021) LakeBoxVelocityError.csv and LandBoxVelocityError.csv: year_err_count = number of sampled error pixels year_err_mean = mean of sampled error pixel values year_err_median = median of sampled error pixel values etc. |
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