< Funding applications open
13.02.2013 02:13 Age: 5 yrs
Category: ANFOG, WA-IMOS

Glider deployments extended to Northern Western Australia

Since December 2011, ANFOG has deployed 7 Slocum gliders in the ocean off the Kimberley and the Pilbara regions.

Figure 1. The WAIMOS northern observation array

Figure 2. Glider’s trajectory of the July 2012 Kimberly mission (colour indicates date, in days since the glider’s launch). The loops evidence strong periodic currents due to the tide, deviating the glider from its planned straight trajectory.

Figure 3. Data from the Kimberly Glider mission of May-June 2012: salinity (top panel, in PSU), backscattering (middle panel, in m-1sr-1) and corresponding time series of the bottom velocity at the 100m deep Kimberly mooring. The patterns in the backscattering data seem to be linked to the tidal current, with high suspended particulate concentrations associated with strong eastward velocities induced by the tides.

This effort is part of the Western Australian node of the Integrated Marine Observing System (WAIMOS), partly funded by the WA Government which is providing $6 million over three years to extend the national observing infrastructure into the Pilbara and Kimberley coast.

Together with measurements collected by moorings and buoys (Fig 1.), glider data from both the four Kimberly missions and the three Pilbara missions to date will help with monitoring and understanding of the major boundary currents, continental shelf processes and ecosystem responses in this region of strong tidal environment, which has the largest tidal range (> 10 m) for an open coastline (Fig 2.).

In the Pilbara region, the Ningaloo current is characterised by relatively colder, upwelled water. Thus, having Temperature-Salinity data along the Pilbara line, together with Sea Surface Temperature (SST) images will allow the documentation of the northern extent of the current.

Preliminary assessment of chlorophyll a from satellite data in Western Australian waters suggests a strong cross-shelf gradient with influence from tropical rivers and a range of offshore features. Relationships between light penetration, tidal mixing, suspended particulate material and primary production need to be investigated, and the biological parameters measured by the gliders deployed in the region provide an invaluable input to these investigations (Fig 3.).