Global Land Ice Velocity Extraction from Landsat 8 (GoLIVE), Version 2

This data set is a compilation of ice velocity mappings for all terrestrial permanent ice larger than 5 km squared within the latitude range 82°S to 82°N, generated from pairs of Landsat 8 panchromatic images acquired between May 2013 and May 2021. The data are updated monthly with new Landsat 8 images that are paired with older images acquired within 400 days of the new acquisition for the Antarctic ice sheet; 112 days for the Greenland ice sheet; and 96 days for all other glacierized areas. The data are generated with an image correlation algorithm that produces grids of ice displacement referenced to in-image rock outcrops, slow moving ice, or lacking that, the satellite's geo-positioning (accurate to +/- 5 m). Velocity vector grids are generated at a sample spacing of 300 m from small sub-images that are either 300 m or 600 m on a side, depending on the region. For example, ice sheet areas are mapped with 600 m x 600 m sub-images, and mountain glaciers are mapped with 300 m x 300 m sub-images. Accuracy of the velocity data varies depending on the time separation between the images, ranging between ~1 m/d per day to 0.02 m/d per day. NOTE: A reprocessed version of these data is available from the ITS_LIVE project (https://nsidc.org/apps/itslive/), which uses additional imagery and a more robust algorithm to produce global ice velocities for all areas of permanent ice larger than 5 square km, from 1984 to present. GoLive data are stored on the University of Colorado Boulder Research Computing FTP site. To access these files, go to NSIDC's <a href="https://nsidc.org/data/user-resources/help-center/how-access-nsidc-data-using-ftp-client-command-line-wget-or-python">"How to access NSIDC data using an FTP client, command line, wget, or Python"</a> webpage. Under the heading "How to find a data set's FTP address on NSIDC servers," GoLive's FTP data locations can be found under "Data sets hosted on dtn.rc.colorado.edu."