Day 3: Triaxus observations for ocean forecasting

By: Christie Evans

Launched off the stern of the Investigator, the Triaxus glides from 10m to 240m behind the ship collecting data on the condition of the ocean. Armed with sensors, cameras and probes this apparatus measures conductivity, temperature, depth, oxygen and chlorophyll and takes video. This data is used to interpret the condition of the ocean and its currents. Monitoring the chlorophyll in the ocean indicates the presence of life at the surface of the water which then in turn gives scientists an idea of biological health.

Whilst interesting, this is not the main objective of this investigation. CSIRO are working in partnership with the Royal Australian Navy (RAN) and the Bureau of Meteorology to develop an effective way of forecasting ocean currents (called Bluelink). Presently, satellite images give indications of ocean surface temperature but they give a sparse representation. Readings from space are interrupted by clouds and so the temperature can be inaccurate in spots. By running technology such as the Triaxus, accurate readings are taken both from the surface and deep below giving a more accurate representation of the ocean in terms of temperature and currents.

So why is this important? All three Bluelink collaborators are interested in improving ocean forecasts to support defence applications. Lieutenant Commander Annalise Pearson, RAN oceanographer and meteorologist, said the RAN take advantage of ocean currents to travel efficiently and successfully complete naval operations. For example, in areas of high nutrient cold water pushing upward there tends to be high concentrations of marine animals which create sound, interfering with the operation of the sonar systems. Forecasting areas of high and low density and currents is useful for the RAN, fishers, ocean surveying and other ocean users.

The data collected by the RV Investigator will be further analysed by CSIRO Scientists back in Hobart after the voyage.