Why are there two ocean profile databases at NODC?

NODC maintains two ocean profile databases. The first is the Global Temperature-Salinity Profile Program (GTSPP) and the second is the World Ocean Database (WOD). Having two related databases may seem unnecessary and redundant but both of these databases serve critical and complementary roles.

The GTSPP database is comprised of real-time data transmitted over the Global Telecommunication System (GTS) and delayed-mode data from national oceanographic data centers which participate in the International Oceanographic Data and Information Exchange (IODE) system of the Intergovernmental Oceanographic Commission (IOC). Most profiles contain temperature and salinity as a function of depth. The GTSPP focuses on managing data collected after 1990. At the request of the oceanographic community, each GTSPP profile has an associated history file that contains information about any changes made to the profiles or their associated metadata for errors that were discovered during processing. GTSPP is updated on a daily basis and serves the needs of the real-time oceanic and atmospheric forecasting communities.

NODC also supports the World Ocean Database (WOD), which is the world's largest collection of ocean vertical profile data. The WOD contains profiles dating back to the 19th century and includes data from over 20 variables such as temperature, oxygen, nutrients, plankton, and tracers. Every three months, the WOD includes data from GTSPP by applying additional quality control procedures to the latest GTSPP collection. Errors or problems discovered through the WOD quality control processes are reported back to GTSPP for inclusion in that database and its methods, if applicable. The WOD also includes historical data recovered as part of the IOC/IODE Global Oceanographic Data Archaeology and Rescue project. Substantial amounts of additional data received at NODC and its collocated World Data Center for Oceanography, are also included in the WOD. The WOD contains more detailed quality control flags than GTSPP does. The WOD is widely used for ocean climate diagnostic analyses, for long-term ocean data assimilations in numerical models, and for comparisons with satellite data.

Efforts are underway to improve the synchronization between the GTSPP and WOD databases so users can visit the NODC website, and with one selection, acquire all data from both databases with no duplication. Both projects work closely together to mutually improve their databases and processes, which will better serve NODC's user communities.