The A13.5 cruise is in the southeastern Atlantic Ocean and was previously occupied in 1984, 1995, and 2010. Scientists from NOAA and academic institutions will collect full water column CTD rosette casts along the A13.5 section at 30 nautical mile (54km) spacing, with closer spacing at the basin boundaries. Measurements taken from the instrument package include temperature, salinity, oxygen, currents (LADCP), and particles (transmissometer). Discrete samples were collected on these casts and analyzed for a variety of parameters including salinity, dissolved oxygen, nutrients, chlorofluorocarbons (CFCs), SF6 , dissolved inorganic carbon (DIC), alkalinity, pCO2, pH, and dissolved organic carbon (DOC). Underway data collection included upper-ocean current measurements from the shipboard ADCP, surface oceanographic (temperature, salinity, and CO2 ) and measurements from the ship’s scientific seawater supply, meteorological parameters, bathymetric data and atmospheric measurements of CO2, CFCs, and SF6.