Biogeochemical Ocean Flux Study (BOFS) North Atlantic data set CDROM

Whilst every effort was made to ensure that the original release of the BOFS North Atlantic data set CDROM was as error free as possible a small number of errors have been reported. In addition, feedback on the quality of the data set has also been actively encouraged from users.

Discovery 182 nitrate data

Work using TCO₂ and nitrate (expressed as nitrate+nitrite) data from the 1989 North Atlantic Bloom Experiment has revealed two problems.

1. The difference between the UK data and the American data was too large to be explained by the change in TCO₂.

2. The UK data contained an internal inconsistency between the surface underway and CTD water bottle data sets.

Subsequent investigation has revealed that the CTD water bottle data set had not been corrected for nitrite in the mixed standard. Consequently, all Discovery 182 CTD water bottle nitrate values (a subset of the data in file dbkit\botnet\nutri.csv) need to be multiplied by a correction factor of 1.1.

This correction made the internal discrepancy between the Discovery 182 underway and CTD water bottle data sets worse. Extensive investigations revealed a bug in a processing program which resulted in the underway data being divided by 1.1 instead of being multiplied by 1.1. Consequently, the Discovery 182 underway nitrate+nitrite data (in file underway\di182.bmm) need to be multiplied by a correction factor of 1.21.

Discovery 183 mesozooplankton biomass data

The mesozooplankton biomass data (in file dbkit\botnet\mesomass.csv) for Discovery 183 contain a significant number of errors. A corrected replacement data set has been supplied by the data originator. This can be supplied on request from BODC. Contact the BODC Enquiries Officer for further information. Note that only this one cruise is affected. The rest of the data in mesomass.csv have no known problems.

Data file syntax errors

The header record in file dbkit\botnet\nutri.csv on the CDROM contains no spaces between some of the field names and the delimiting commas. It has been discovered that this causes problems when using the DBMERGE program.

The file dbkit\botnet\cn.csv has a period instead of a comma as the delimiter between the POC and TPC fields. This will cause problems when using the data file with the DBMERGE program and when importing the data into commercial software.

Units for pCO₂

In the CDROM manual and the data documentation on the disc, the units 'ppm' and 'micro-atmospheres' have been used interchangeably for pCO₂. It has been pointed out that, strictly speaking, these units are different — 'ppm' infers that the data have not been corrected from ambient atmospheric pressure to one bar.

In all cases the pCO₂ data on the BOFS CDROM have been corrected to an atmospheric pressure of one bar and all references to 'ppm' should be read as 'micro-atmospheres'.

Table C14DAT

On page 93 of the manual the units for fields PPMIC, PPNAN, PPPIC and PPTOT of table C14DAT are incorrectly stated as mg C/m²/day. These should read mg C/m³/day.

The error has been carried over to file PARADESC.DAT that is used by the DBMERGE utility in the DOS software interface.

BOFS North Atlantic data set CDROM software interface

The CDROM includes DOS based interface software. This is now obsolete. A web based delivery mechanism for project data is now under development.