A global network of commercial ships takes upper ocean thermal measurements (low density, 2-4 observations/day) using Expendable Bathythermographs (XBTs). These, together with observations by fishing and research vessels,form a global data set of temperature (and sometimes salinity) profiles in the top kilometer of the ocean. Some data are transmitted from the vessels by satellites and made available to users within 30 days of collection. Higher depth resolution profiles were submitted to the DAC and made available to users 1 year or more after collection. Additional profiles contributed from profiling floats and CTDs as well as instrumentation on moored and drifting buoys are also included.

Some XBT sections are occupied quarterly at a higher rate of spatial sampling. These High Density (one observation per 50km) sections can determine the mean, seasonal cycle, and eddy statistics of temperature andgeostrophic shear and transport fields, and obtain some measure of interannual variability.

The Upper Ocean Thermal DAC consisted of several centres which together provide a globally consistent data set as part of the Global
Temperature-Salinity Profile Project (GTSPP). There are two levels of quality control available to users; checks performed by national data centres (US National Oceanographic Data Center (NODC) and Marine Environmental Data Service (MEDS), Canada), and scientific quality controlon a profile-by-profile basis performed by 3 regional centres (AOML, Scripps, JAFOOS). The data collected during the WOCE period, and data collected since then, can be accessed from US NODC which acts as the GTSPP distribution facility.