These are the values they use in their studies of the global carbon cycle to calculate long-term trends and interannual and seasonal variations. This numeric data package provides 57 data files containing monthly CO 2 mixing ratios derived from individual flask measurements. The data for the shipboard measurements have been grouped into 5-degree latitude intervals. The next two digits specify the 5-degree latitude band. The equator is specified by 000 .
All data files have the same format with one line for each monthly value.
The codes and the stations or ocean cruises they denote are shown on pages 32-33. YYYY is the year. The monthly means were calculated from a smooth curve obtained by a combination of curve fitting and digital filtering based on the methods of Thoning et al. The value -999.99 denotes months where there was not sufficient data to calculate a monthly mean.