Code and collocated drifter-day samples for "Coriolis Amplification of SWOT Geostrophic Current Errors and a Coriolis-Weighted Blend With Conventional Altimetry"

This record contains the Python code and the collocated drifter-day samples used in the paper "Coriolis Amplification of SWOT Geostrophic Current Errors and a Coriolis-Weighted Blend With Conventional Altimetry" by Ban et al. The samples cover every drifter-day of the Global Drifter Program inside the SWOT swaths from 28 March 2023 to 1 May 2025 between 5° and 70° latitude (49,106 drogued and 71,232 undrogued drifter-days). For each drifter-day they give the daily-mean drifter position and velocity, the SWOT Level-3 (version 3.0) absolute geostrophic velocity, the DUACS geostrophic velocity from the Copernicus Marine MULTIOBS product, the MIOST Level-4 geostrophic velocity, the fitted ERA5-forced Ekman velocity, and the assignment of the drifter to the fitting or validation half. All scores in the paper are computed from these samples. The code covers the collocation of SWOT, MIOST, DUACS and ERA5 with the drifters, the cross-validated Ekman correction, the fit of the Coriolis-weighted blend k = sin²φ/(sin²φ + sin²φ₀), the drifter-bootstrap evaluation, the three-way error decomposition, and the figures and Supporting Information tables. The result files and Figures 1–3 of the paper are included. Files: swot_blend_deposit.zip (code, data, results and figures) and README.md (contents, column definitions, workflow, data sources and attribution). Licenses: data, results and figures under CC BY 4.0; code under the MIT License. The SWOT and MIOST values are adapted from AVISO data products under the AVISO License Agreement; see README.md for the source data and the required attribution.