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.