Sampling and Analytical Methodology:
\nDIC and TA samples: Sampling from the Niskin followed standard CLIVAR-CO2, GEOTRACES and GO-ship protocols.\u00a0 Samples were collected in ~500 ml Pyrex bottles that were poisoned with 100 \u03bcl Hg2Cl, sealed and stored in the dark before analysis back in the laboratory at BIOS. DIC was determined using a high precision (0.05%CV) coulometer based instrument (VINDTA 3C)(Bates et al., 2012).\u00a0 TA was determined by a high- precision (<0.05%CV) potentiometric technique using a VINDTA 2S (Marianda, Germany). Replicate samples were also analyzed at BIOS.\u00a0 Both DIC and TA instruments were routinely calibrated using seawater Certified Reference Material (CRM) from A.G. Dickson, Scripps Institute of Oceanography, and the accuracy of samples compared to CRM\u2019s was less than 0.1% (2 \u03bcmoles kg-1).
Data Processing:
\nDIC and TA data have been corrected to CRM values. Quality flags here include:
\n
\n- 2: good data
\n- 5: questionable data
\n- 6: bad data (denoted in data column by -999)
\n- 9: no data
\n
\n
BCO-DMO Processing Notes:
\n
Original file submission on 2012.12.21.\u00a0 Corrected file submitted on 2013.01.30.
\n
Edits:
\n-Parameter names were modified to conform with BCO-DMO conventions.
\n-Completed metadata parameters for missing fields of duplicate bottles from station 20 bottles 4, 6, 8.
\n-Removed reference to cruise KN199-05 and cruise parts A and B for cruise KN204-01 in header comments.
\n
Note: bad data values of -999, submitted by the PI, were retained in the data.
\n
Additional GEOTRACES Processing: After the data were submitted to the International Data Management Office, BODC, the office noticed that important identifying information was missing in many datasets. With the agreement of BODC and the US GEOTRACES lead PIs, BCO-DMO added standard US GEOTRACES information, such as the US GEOTRACES event number, to each submitted dataset lacking this information. To accomplish this, BCO-DMO compiled a 'master' dataset composed of the following parameters: station_GEOTRC, cast_GEOTRC (bottle and pump data only), event_GEOTRC, sample_GEOTRC, sample_bottle_GEOTRC (bottle data only), bottle_GEOTRC (bottle data only), depth_GEOTRC_CTD (bottle data only), depth_GEOTRC_CTD_rounded (bottle data only), BTL_ISO_DateTime_UTC (bottle data only), and GeoFish_id (GeoFish data only). This added information will facilitate subsequent analysis and inter comparison of the datasets.
\n
Bottle parameters in the master file were taken from the GT-C_Bottle_GT10, GT-C_Bottle_GT11, ODF_Bottle_GT10, and ODF_Bottle_GT11 datasets. Non-bottle parameters, including those from GeoFish tows, Aerosol sampling, and McLane Pumps, were taken from the Event_Log_GT10 and Event_Log_GT11 datasets. McLane pump cast numbers missing in event logs were taken from the Particulate Th-234 dataset submitted by Ken Buesseler.
\n
A standardized BCO-DMO method (called \u201cjoin\u201d) was then used to merge the missing parameters to each US GEOTRACES dataset, most often by matching on sample_GEOTRC or on some unique combination of other parameters.
\n
If the master parameters were included in the original data file and the values did not differ from the master file, the original data columns were retained and the name of the parameters were changed from the PI-submitted names to the standardized master names. If there were differences between the PI-supplied parameter values and those in the master file, both columns were retained. If the original data submission included all of the master parameters, no additional columns were added, but parameter names were modified to match the naming conventions of the master file.
\n
See the dataset parameters documentation for a description of which parameters were supplied by the PI and which were added via the join method.