Atlantic Meridional Transect cruise AMT27 (DY084/DY085) calibrated and corrected chlorophyll concentrations from the fluorometer on the CTD rosette between September and November 2017.

These are the corrected and calibrated chlorophyll concentrations estimated from the fluorometric profiles collected during the 78 CTD casts conducted along the Atlantic Meridional Transect programme cruise 27 (AMT27, DY084, DY085) between 23rd September 2017 and 5th November 2017. The cruise track between UK and Falkland Islands, via South Georgia, passed through both north and south Atlantic gyres. Corrections applied to the fluorometer measurements include subtracting a dark value using deep data and removing the influence of non-photochemical quenching following standard Biogeochemical-Argo QC procedures. These data are available under the most recent version of the NERC Open Government Licence.