Argo world 

Why is Argo data novel?

As a worldwide array of 3200 floats, Argo data is unique for several reasons:

  • The distribution of data throughout the oceans is uniform rather than dependent on shipping lines.
  • There is a of lack of seasonal bias since the floats operate year round.
  • The efficient data management network that provides free automatic quality controlled data within 24 hours and scientifically quality controlled, delayed mode data within a year.
  • Multi-national collaboration to deploy, monitor and analyze floats and their data.
The following table summarizes some novel parts of Argo's data set:

Observation type
Number per year
Max Depth
Geographical restriction
Ship-based temperature and salinity
T + S
5000 (to 1000m)
Full water depth
• Limited by ship endurance
(100 per month)
• Few at high latitude in winter
• Typically along lines
Expendable XBT from merchant ships
• Along shipping routes
• Avoid high latitude in winter
• Many areas unsampled
T + S
42,000 (May 2004)
100,000+ (2013)
• Ice free areas deeper than 2000m

Argo Floats

apex_launch density map
Global coverage at the target of 3° x 3° density achieved near the end of 2007.

World Ocean Database 2009

The World Ocean Database contains 500,000+ profiles deeper than 1000m from the 20th century onwards.
Argo has 100,000+ profiles per year since 2012.

Ship Based CTDs during WOCE

ctd-oceanus-s WOCE-O-T
In 8 years the WOCE Hydrographic survey collected data from about 30,000 CTD stations mostly along the sections shown here.

Ship based XBTs

XBT ship XBT auto launcher XBT countries
Positions of XBT temperature profiles from merchant ships in 2002. Note poor coverage in southern hemisphere.