The expendable bathythermograph (XBT) sub-facility collects temperature profiles of the oceans surrounding Australia using high-resolution repeat lines samples collected by merchant ships equipped with a XBT. High-resolution temperature profiles are regularly collected along the 5 IMOS-funded sections (two of the three the Tasman Box lines, the Fremantle-Indonesia line, the line from Hobart to the French Antarctic Base – Dumont d’Urville – and the line within the Java/Banda Sea running from west to east). The XBT probes sample to approximately 800m and have a nominal accuracy of 0.15°C. The depth of the temperature profile for an individual probe is determined by a fall rate equation. These data are used in many studies to characterise the mean and time-varying properties of the major ocean currents around Australia.
Instrumentation and Data
The Expendable Bathythermograph (XBT) has been used by oceanographers for many years to obtain information on the temperature structure of the ocean to depths of up to 1800 meters. The XBT, shown in Figure 1, is a probe which is dropped from a ship and measures the temperature as it falls through the water. Two very small wires transmit the temperature data to the ship where it is recorded for later analysis. The probe is designed to fall at a constant rate, so that the depth of the probe can be inferred from the time since it was launched. By plotting temperature as a function of depth, the scientists can get a picture of the temperature profile of the water.
The Ships of Opportunity Publication Report - If you have any questions regarding the data, or corrections, or would like to add a publication or presentation that uses IMOS data please contact the IMOS office via email: publication(at)emii.org.au.
Dr Ann Thresher
SOOP Implementation Panel (SOOPIP)
Your access to IMOS Expendable Bathythermograph (XBT) data discovery and exploration is through the Australian Ocean Data Network (AODN) Portal.