CAS-TECRecon30: Global Ionospheric TEC Maps, 1999–2025, 30-min Cadence

CAS-TECRecon30 provides a complete and uniform global ionospheric total electron content (TEC) record derived from the Chinese Academy of Sciences Global Ionospheric Map archive. It covers every day from 1999 through 2025 at 30-minute cadence on the standard 2.5° × 5° latitude–longitude grid. Earlier 2-hourly days were reconstructed with the TECRecon deep-learning framework, while later days retain their native 30-minute sampling. The archive contains 9,862 daily IONEX 1.0 files with no temporal gaps. Each daily file contains 49 TEC maps from 00:00 to 24:00 UT at a 1,800-second interval on a 71 × 73 grid. Values use an exponent of −1 (0.1 TECU) and a 450 km single-layer shell. Independent validation against ground-GNSS slant TEC observations for 2013–2015 yields a mean STEC RMS of 2.67 TECU. The files are packaged by year. README.md documents the format and validation checks, and SHA256SUMS.txt provides integrity hashes. Methodology and validation are described in the accompanying manuscript, TECRecon: Reconstructing Global Ionospheric Maps for 1999–2025 at 30-Min Cadence Using Masked Autoencoders and a Spatiotemporal Transformer.