Data Checks and Processing Performed by CDIAC

An important part of the numeric data package (NDP) process at the Carbon Dioxide Information Analysis Center (CDIAC) involves the quality assurance (QA) of data before distribution. Data received at CDIAC are rarely in a condition that would permit immediate distribution, regardless of the source. To guarantee data of the highest possible quality, CDIAC conducts extensive QA reviews that involve examining the data for completeness, reasonableness, and accuracy. Although they have common objectives, these reviews are tailored to each data set and often require extensive programming efforts. In short, the QA process is a critical component in the value-added concept of supplying accurate, usable data for researchers.

The following information summarizes the data-processing and QA checks performed by CDIAC on the underway data obtained during the R/V Meteor Cruise 36/1 in the North Atlantic Ocean.

1. All data files were provided to CDIAC as 10 comma-separated files (9 for surface seawater underway measurements of fCO₂ and 1 for all marine air xCO₂ measurements) by Dr. Arne Koertzinger of IfMK. A FORTRAN 77 retrieval program was written and used to reformat the original files into uniform ASCII-formatted "water" and "air" data files.
2. All underway "water" data are presented as 9 daily data files. These files can be merged into a single data file by request.
3. All data were plotted to check for obvious outliers.
4. Dates and times were checked for bogus values (e.g., values of MONTH < or >6, DAY <8 or >16, YEAR < or >1996, TIME <0000 or >2400.
5. The cruise track was plotted using the coordinates presented in data files and compared with the maps and cruise information supplied by A. Koertzinger.