Surface velocity of the ice sheets from satellite observations, remapped onto the grids of the domains. Velocity is a thematic dataset made by remapping (see Gridded data): its products are defined in Velocity/remap.toml.
Products
Product
Source
Fields
Domains
Velocity-Joughin2018
Joughin et al. (2018): MEaSUREs multi-year Greenland velocity mosaic 1995-2015, 250 m (NSIDC-0670 v1), doi:10.5067/QUA5Q9SVMSJG
The velocity components are remapped conservatively as eastward and northward components and then rotated to the axes of each grid. The speed uxy_srf is the remapped speed of the source (the mean speed in each cell, not the speed of the mean velocity). The errors are those of the source along the axes of its projection, which is that of the grids. Each file also has f_valid, the fraction of each cell covered by the source.
In Velocity-Mouginot2019, the gaps of the source over the ice are filled on each grid: the cells with ice in TOPO-BedMachine-v4 (H_ice > 0) but no data (f_valid = 0) get ux_srf, uy_srf by harmonic (Laplace) interpolation of the cells around them, and uxy_srf is their magnitude there; the errors stay missing. These cells have mask_fill = 1.
Precision
The float fields are rounded on output to a tolerance by kind (see Precision and file sizes): the velocities and their errors to 1% or 1 m yr-1, the larger; f_valid to 0.001. mask_fill is exact.
Licences
Source
Licence
Joughin et al. (2018)
NASA Earth science data (NSIDC), no restrictions on use; cite the data set and article
Rignot et al. (2011)
NASA Earth science data (NSIDC), no restrictions on use; cite the data set and articles
Mouginot et al. (2019)
NASA Earth science data (NSIDC), no restrictions on use; cite the data set and article
Making the dataset
julia-t 8 fesmdata.jl remap Velocity
Downloads
Download the files with fesmdata.jl into $FESMDATA_PRODUCTS/<Domain>/<GRID>/ (see Download), or one by one from the links below. All released datasets are listed under Products.
Antarctica
Version 2.3.1 (2026-10-16, packages). 14 files, 531.0 MB.
julia fesmdata.jl fetch Velocity Antarctica # all grids
julia fesmdata.jl fetch Velocity ANT-32KM # one grid
These nests and crops get products of Velocity by cropping those of the domain (or crop) that contains them: fetch downloads these and cuts them (see Nests and crops), e.g. julia fesmdata.jl fetch Velocity Amery.
