Gridded sea ice concentration, floe size distribution, and wave data from the ICESat-2 altimeter: October 2018-December 2024.

These data are produced using the ICESat‑2 analysis scheme of Horvat et al. (2025), then binned and gridded according ot the procedures outlined in the IS2‑Gridded‑Products code base. The files are self‑describing HDF5 outputs containing monthly spatially gridded summary metrics derived from along-track ICESat‑2 observations. These are: Linear Ice Fraction (LIF) The fraction of along-track path length classified as ice (versus open water or leads). This is computed from ICESat‑2 photon segment classifications (ice / water) following the algorithm in Horvat et al. (2025). LIFs built from other aspects of the surface classification (specular/dark leads) are also included. Floe Size Distribution (FSD) From sequences of “ice” segments bounded by leads (or water), floe chords (along-track projections of floes) are extracted and inverted through a Bayesian analysis to form moment statistics of the floe size distribution according to Horvat et al (2019). CAVEAT EMPTOR with this data - there are known issues with comparing chord lengths from ICESat-2 and Cryosat-2 and such data has not been ground-truthed. FSDs generated with other descriptions (e.g. specular/dark returns) are also included. Wave‑Affected Fraction Portions of ice cover influenced by propagating surface waves are identified using the algorithm of Horvat et al (2020) and further examined in Hell and Horvat (2024). Ancillary variables are included, including counts of input tracks or IS2 segments.