This proposal is aimed at mapping the Ra-228 distributions in the South Atlantic basin to upgrade circulation models and predict changes in ventilation. Approximately 1500 samples will be collected for Ra-228/Ra-226 ratios and Ra-226 values to obtain an accurate measure of Ra-228 from the product of these analyses. High sampling density requirements are required to resolve the low concentration gradients found in mid-basin areas. Only a portion of the sample set analyses will be supported until the need for greater detail is justified. Two campaigns to measure transient tracers in the Atlantic Ocean (TTO/NAS and TTO/Equatorial) were funded by NSF during the period from 1980 to 1985. A complete data base for modelling this ocean basin would include a South Atlantic Study to: 1.Determine CO2 transports and their influence on world climate, 2.Constrain models of major ocean currents in this area, and 3.Confirm an observed 5-fold increase in the addition rate of new carbon to the thermocline. Eight components of such a study (SAVE) will be performed by investigators from LDGO, Princeton, University of Washington, WHOI, and SIO. The track record of these scientists is well established by successful completion of previous studies in the Equatorial and North Atlantic. They will provide physical and chemical expertise which will be directed toward a cooperative effort to reach the goals of the geochemical study.
