Determination of Discrete Sampling Locations Minimizing Both the Number of Samples and the Maximum Interpolation Error: Application to Measurements of Carbonate Chemistry in Surface Ocean

Over the past three decades, started extensive measurements of ocean properties at fixed stations throughout the water column, as well as in the surface ocean via oceanographic ships and via ships of opportunity. The later ones were particularly used to determine the air-sea CO2 fluxes from automated measurements of sea-surface temperature, salinity, and CO2 fugacity. These underway measurements, often recorded at a frequency of every minute, generate large data files that need to be quality controlled, stored and analyzed. Thus, for practical use, these data are often binned by 1degree latitude x 1degree longitude. Unfortunately, by doing so, there is loss of accuracy of these data sets.Here, using the original 2010 underway data sets of sea-surface temperature, sea-surface salinity, total alkalinity and total inorganic carbon, along the cruise track from Hobart (Tasmania) to Dumont DUrville (Antarctica), we show what would had been a more appropriate record pattern for each of these properties while still keeping the full accuracy of their measurements. Furthermore, we propose a general protocol to objectively determine appropriate locations of each property underway measurements according to their aimed accuracy. These results should greatly facilitate future cruise preparation and reduce cost of measurements, thus, our carbon imprint.