The article examines the variability across calibration laboratories can impact the consistency of ocean color data; this study reports about a spectral irradiance and radiance comparison calibrations, where the consistency across six international laboratories was tested in the years 2022–2023. Each participant determined the responsivity for four transfer radiometers using their own SI-traceable radiometric standards and calibration procedures. The main objective was to verify that the calibration laboratories can fulfill the updated International Ocean Color Coordination Group protocols to perform calibrations with a standard uncertainty of 1%. The differences between the participants varied from ±(1–2)% up to ±5% but after uniform data processing, the metrological compatibility between the participants was reached within ±3%.
The cover of the journal illustrates how calibration uncertainty propagates across the ocean color observing community — visually highlighting the importance of harmonized radiometric standards.
