Nong et al. 
Argo Data 1999-2019 
REGIONAL /GLOBAL 
PRODUCTS 
ARGO REGIONAL 
DATA CENTERS 
g 
Final corrected 
data available 
at DACs-GDACs 
within 12 months 
Pis AND REGIONAL 
DATA FXPERTS 
SCIENTIFIC USERS 
OPERATIONAL 
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Information 
Delayed mode 
data stream 
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RT DATA QUALITY CONTROL 
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FIGURE 4 | Components of the Argo data system and their interactions. [Source: Euro-Argo ERIC]. 
synchronized once per day. The two GDACSs are access points for 
all Argo data. 
At the GDACSs, data from each float are stored in 4 types 
of files: 
» a metadata file that holds the float’s specifications and sampling 
configurations, which can vary in time for Iridium floats; 
» a technical data file that stores transmitted 
engineering information; 
» a trajectory data file that stores positions, cycle timing, surface 
data, and park-phase data; and 
a profile data file for each float cycle that stores vertical profile 
data from that cycle. (For floats equipped with biogeochemical 
sensors, vertical profile data are stored in two separate profile 
data files. See section Extension of the Argo Data System.) 
A file checker operated at the GDACs checks the format and 
content consistency of these data files before they are admitted 
into the global data holdings (Ignaszewski, 2018). Moreover, for 
rontiers in Marine Science | www.frontiersin.ore 
each float, the GDACs concatenate the single-cycle profile files 
together to make a multi-cycle profile file for each float, for users 
who require all profiles from each float in one file. 
Vertical profile data and trajectory data are subjected to a 
common set of quality control procedures (Wong et al., 2020) 
and are available via two pathways: real-time and the slower but 
more accurate delayed-mode. 
Real-Time 
Jata are received via satellite transmission, decoded and 
assembled at national DACs. These DACs apply a set of 
automatic quality tests to the data, and quality flags are assigned 
accordingly. These flags warn users about grossly bad data 
that may result from corrupted data transmission or sensor 
malfunction. Data may be adjusted automatically in real-time 
in a preliminary manner, based on information from the float 
or results from the delayed-mode procedures described below. 
In such cases both the raw and real-time adjusted data are 
Qanteambear 2020 1 Valııme 7 | Article Z01