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Instrumentation, Moyens Analytiques, Observatoires en Géophysique et Océanographie


XBT Observation  Network


This 'Ship Of Opportunity Program' is internationally orga­nized in a data observation network, part of the World Meteorological Organization and the International Oceanographic Commision. For the last 30 years, the Institut de Recherche pour le Développement (IRD) has developed an Atlantic network, based in Brest and Le Havre (France), and a Pacific network based in Nouméa (New Caledonia).


Global XBT observation network



Participating vessels in March 2010 :

  • MN Colibri
  • Safmarine Nokwanda
  • Nuka Arctica



XBT (Expandable BathyThermograph) is an expandable and depth profiling system. It is typically comprised of an acquisition system onboard the ship, a launcher and an expandable temperature probe. Falling probe is linked to the acquisition system through a thin insulated conductive wire which is used to transmit the temperature data back to the acquisition system in real time. Depth is deduced from elapsed time using a well calibrated fall rate equation (about 6.5 m/s). Processed profile are transmitted in real-time through ARGOS satellites. Accuracy is normally better than 0.05°C for temperature.


Data are transmitted in real-time and made available to the oceanographic and meteorological communities for operational (assimilation in ocean models) and scientific purposes.
XBT probes are provided by NOAA (National Oceanographic and Atmospheric Administration)
  In 2009 , 606 XBT probes have been launched in by the Atlantic Network.




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