The following activities were carried out on S4P 2011:

• Samples were collected for S, O₂, nutrients (NO₃, NO₂, PO₄, SiO₃), CFCs (F11, F12, SF6), DIC, ALK, pH, DOC, CDOM, helium, tritium, and 14C
• At every second station, there was a one-hour trace metal rosette cast
• One daily 30-minute hand-lowered optical profile
• Four mooring recoveries and one mooring deployment
• Aerosol/precipitation collection
• Solar radiation data collection

The program is driven by the need to monitor the changing patterns of carbon dioxide (CO₂) in the ocean and provide the necessary data to support continuing model development that will lead to improved forecasting skill for oceans and global climate. The WOCE/JGOFS survey during the 1990s has provided a full depth, baseline data set against which to measure future changes. By integrating the scientific needs in the following five areas, major synergies and cost savings will be achieved. These areas are of importance both for upcoming research programs, such as CLIVAR and the U.S. GCRP Carbon Cycle Science Program (CCSP), and for operational activities suchas GOOS and GCOS. In this regard, consensus was reached at the First International Conference on Global Observations for Climate, held in St. Raphael, France in October 1999, that one component of a global observing system for the physical climate/CO₂ system should include periodic observations of hydrographic variables, CO₂ system parameters and other tracers (Smith and Koblinsky, 2000). The large scale observation component of the CCSP has also clearly defined a need for systematic observations of the invasion of anthropogenic carbon in the ocean superimposed on a variable natural background.