DEVELOPMENT OF IMPROVED SPACE SAMPLING STRATEGIES FOR OCEAN CHEMICAL-PROPERTIES - TOTAL CARBON-DIOXIDE AND DISSOLVED NITRATE

Large-scale ocean observing programs such as the Joint Global Ocean Fl ux Study (JGOFS) and the World Ocean Circulation Experiment (WOCE) tod ay, must face the problem of designing an adequate sampling strategy. For ocean chemical variables, the goals and observing technologies are quite different from ocean physical variables (temperature, salinity, pressure). We have recently acquired data on the ocean CO2 properties on WOCE cruises P16c and P17c that are sufficiently dense to test for sampling redundancy. We use linear and quadratic interpolation method s on the sampled field to investigate what is the minimum number of sa mples required to define the deep ocean total inorganic carbon (TCO2) field within the limits of experimental accuracy (+/- 4 mu mol/kg). Wi thin the limits of current measurements, these lines were oversampled in the deep ocean. Should the precision of the measurement be improved , then a denser sampling pattern may be desirable in the future. This approach rationalizes the efficient use of resources for field work an d for estimating gridded TCO2 fields needed to constrain geochemical m odels.