***** Change log *****

v1.1
Quick summary of issues addressed in CTD DOI Update
- Resolved discrepancies between upcast and downcast MLD estimates
- ‘Bad’ datapoints in file dACE201601_002_ct1.csv which were not flagged with ‘4’ Bad measurement
- CTDFLUOR1, CTDFLUOR1Q, CTDFLUOR2, CTDFLUOR2Q ‘dark’ correction was not applied consistently in first processing and should have been applied to all fluorescence variables
- CTDFLUOR1Q, CTDFLUOR2Q quenching correction needed to be recalculated and reapplied after update to MLD and dark correction
- Limit the number of decimal places for fluorescence, PAR and backscattering variables according to the instrument sensitivity limits (which is 4 decimal places except for backscattering which is 6)
- Changed file names described in data_file_header.txt

Additional details on ‘Issues’ and resolutions
Mixed layer depth estimates
- Large discrepancy in MLD estimates from upcast and downcasts at the same station was due to differences in the ‘reference’ depth i.e. depth other than 10 m was used when there were no datapoints at 10 m. 
- Note: influence of time between casts was also checked and was not the driver of the discrepancies.
- Issue was resolved by setting the MLD for any cast where the reference depth was not 10 m to NaN.

Bad data flagging
- 22 ‘bad’ datapoints for variables salinity, density, temperature and sound at the end of the downcast file dACE201601_002_ct1 were missed during the visual inspection of the first CTD processing and hence were not flagged as bad.
- The bad datapoints are now flagged as ‘4’ bad measurement

Fluorescence
- In the first processing, dark correction was only applied to the files where quenching correction was needed, and only to the quenched corrected fluorescence variable, but should have been applied to all fluorescence variables in all files. This has been corrected
- In the first processing, the upcast MLD was used as the MLD estimate in quenching correction for both the upcast and downcast file. This has been changed so that the MLD from the same cast is used i.e. downcast estimate for the downcast file and upcast estimate for the upcasts file, unless the MLD estimate is NaN (because the reference depth was not 10 m), in that case the either the downcast or upcast estimate is used - whichever exists.

Decimal places
- The number of decimal places for the fluorescence, PAR and backscattering variables far exceeded the sensitivity limits of the respective sensors - for the fluorescence and backscattering variables this was due to the additional calculations and corrections applied. For the PAR variable it was the output from the Seabird processing.

Updated files list
The following files have been updated:
Folder: ace_bottle_BOTTLE20200406CURRSGCMR (all files within)
Folder: ace_ctd_CTD20200406CURRSGCMR (all files within)
ace_ctd_mld_CURRSSRGCMR20200405.csv
ace_ctd_visual_inspection_v2.csv
README.txt
data_file_header.txt
ace_physical_biogeochemical_oceanography_ctd_change_log.txt (new file)

v1.0 - Initial release of physical and biogeochemical oceanography data set.