GTS data stream (for operational center use)
Data that go out on the GTS are subject to a number of quality checks in national data assembly centers and only those measurements within a profile that pass all tests (see real time quality control tests) are inserted onto the GTS. The checks are also used to set quality flags in the data that go on to enter other data streams detailed below.
Currently only temperature, salinity and pressure data are sent in BUFR format with quality flags. Temperature and salinity data are truncated to two decimal places. The vertical co-ordinate is depth not pressure (as measured). No corrections are made to salinities in the GTS data stream. Oxygen data is being tested in its BUFR format and should be available by the end of 2020. Other biogeochemical parameters will follow.
An Argo Grey list of floats is maintained at the GDACs ( here and here). Floats on the Grey list may have problems with one or more sensors, but their data is sent onto the GTS with quality flags indicating the possible bad data (usually with a flag of ‘3’ or a ‘4’).