Gap-Free Arctic Sea Ice Albedo Dataset (2000–2025; Daily, May–September), Version 2

The dataset provides daily Arctic sea ice albedo for the melt season (May–September, annually) from 2000 to 2024 at 12.5 km spatial resolution, covering regions north of 60° N, referenced to the Polar Stereographic North projection (EPSG:3413, WGS84) and distributed as GeoTIFF format. Data records are organized into annual directories, with files named Sea_Ice_Albedo_YYYYMMDD_Daily_12.5km.tif. 

The gap-free dataset is reconstructed by combining Moderate Resolution Imaging Spectroradiometer (MODIS) Terra observations with passive microwave brightness temperatures (Tb) through a radiative transfer model-based machine learning approach that accounts for sea ice anisotropy and melt-pond effects, yielding a spatiotemporally continuous Arctic sea-ice albedo record for 2000–2025 (May–September each year).

Daily sea ice extent is delineated using the industry-standard sea ice concentration (SIC) threshold of >15%, using concentration inputs from the National Snow and Ice Data Center (NSIDC) Distributed Active Archive Center (DAAC) to ensure temporal continuity: Version 2 Sea Ice Concentrations from Nimbus‑7 SMMR and DMSP SSM/I‑SSMIS (NSIDC‑0051) data (covering the period from 2000 to July 2025) and the near‑real‑time DMSP SSMIS daily polar gridded sea ice concentrations (NSIDC‑0081) data from July 2025 onward.