Operational use of continuous surface fluorescence measurements offshore Rimini to validate satellite-derived chlorophyll observations

Continuous chlorophyll (Chl) measurements derived from lab-validated in situ fluorometry in the coastal Adriatic Sea are used as a matchup database to validate MODerate resolution Imaging Spectroradiometer MODIS/AQUA Chl. Daytime quenching reduces fluorescence with respect to the higher values measured in the samples taken to the lab which are well correlated with the maximum measurements recorded within the preceding 12 h. Comparison between remotely-sensed and in situ Chl indicates that the 27% of the matchups within 35% of the in situ data have a 0.97 correlation while the discrepancy of the remaining 63% is not linked to remotely-sensed data-quality flags.