ERA5 137-Level Atmospheric Refraction Coefficient Recomputation (ERA5-Land Surface Anchor) for the OERK/Riyadh Levelling Corridor (RCD_PLO Campaign, June–August 2012)

Nine-date atmospheric refraction coefficient (kappa) values computed from the ERA5 137-level profile with an ERA5-Land surface anchor, for the RCD_PLO Riyadh levelling corridor (OERK), covering the June-August 2012 campaign dates. Computed via the KAPPA Arc V4 backend using Smith-Weintraub refractivity and OLS regression on a composite ERA5-Land near-surface / ERA5 L137 profile. Mean kappa 0.19342; deviation from the campaign-mean ERA5-derived value 0.1977 (mean 2.2%, range 0.4-3.4%). This is a reproducibility check, not a comparison with field data: no per-date field kappa is published. This dataset backs Table 4 of the corresponding Geodesy and Geodynamics manuscript. The file includes full computational provenance (endpoint, backend version, run date, and cache-status confirmation). Version 2 (3 November 2026) corrects the labelling: the value 0.1977 was previously described as a field-measured value and attributed to Al-Kherayef et al. (2018) (RCD_PLO project, FIG Congress Istanbul, Paper 9488). It is the campaign mean of the nine ERA5-derived kappa values in the companion deposit 10.5281/zenodo.21931557.