Continuous optical chlorophyll-a and turbidity data along R/V SONNE cruise SO293

Underway optical chlorophyll-a and turbidity data were collected along the cruise track with Sea-Bird Scientific ECO FLNTU sensors installed within two autonomous measurement systems, called self-cleaning monitoring boxes (SMBs). The SMBs measure alternatingly. While one box is measuring, the other one is being cleaned. The boxes switched generally every 24 hours. The water inlet for the SMBs is at about 4 m depth. The data were quality controlled and the chlorophyll-a data were additionally calibrated by comparison with satellite matchups using the GlobColour CHL1 product. Calibration is based on satellite data, because no discrete water samples were collected on this expedition as reference. We note that a calibration with satellite data is not as accurate due to temporal and spatial mismatch between the underway and satellite data and due to uncertainty of the satellite product. The chlorophyll-a time series shows effects of non-photochemical quenching which was not corrected. The user may only want to use night-time data unaffected by non-photochemical quenching. Details on all quality control steps and the calibration plus discussion can be found in the data processing report. The resulting data set contains the original data and corresponding quality flags and, in case of chlorophyll-a, additionally the calibrated data plus quality flag. The data source is given through the name of the active SMB. The data set contains data during transect and station. We recommend to use ship's speed to filter for only transect data.