Data

Break of drought conditions in Port Phillip Bay with overturning of bay salinity and coincident plankton bloom extension through the bay. Figure from Lee et al., 2011.
Break of drought conditions in Port Phillip Bay with overturning of bay salinity and coincident plankton bloom extension through the bay. Figure from Lee et al., 2011.

Your access to IMOS Sensors on Temperate Merchant Vessels data discovery and exploration is through the Australian Ocean Data Network (AODN) Portal.

Underway data collected by this facility include salinity, temperature, turbidity and chlorophyll. EPA and IMOS have developed standardised protocols for SOOP sampling platforms to ensure all data is quality controlled and assured prior to release. These code developments have flowed on to benefit a range of internal EPA clients. Validated data is released by EPA to the IMOS data warehouse on a 3-6 monthly basis.

Data from the Temperate Merchant Vessel sub-facility has been used to detect a strong low salinity signature and initial high turbidity “pulse” at the onset of a flood event in Port Philip Bay (predominantly from the Yarra River). Plankton responses have been seen in tandem with the southward dispersion of floodwaters, similarly prevailing for several weeks.

The figure below shows the breaking of the drought in PPB as defined in late 2010 with an overturning of bay salinity (to fresher than ocean conditions) and subsequent prolonged plankton activity. 

The full record for the northern section (Port Phillip Bay and upper Bass Strait) shown for Temperature, Salinity, Chl-a fluorescence and turbidity.
The full record for the northern section (Port Phillip Bay and upper Bass Strait) shown for Temperature, Salinity, Chl-a fluorescence and turbidity.

The contoured sensor data is typically presented as shiptrack distance in Port Phillip Bay and Bass Strait against date.  For example a six month plot represents data from ~180 Bass Strait crossings, with 10 second records representing a 100m average that accumulates to over 4400 “samples” per crossing.

The figure below shows the conditions in 2008 and 2009 for the entire ship track. The vast dataset is being used to quantify satellite images, interpolate traditional monthly site-specific sampling and integrate into operational models to assess system responses (e.g. plankton blooms, dredging, oils spills, fish kills, climate change).

IMOS turbidity measurements from September 2008 – June 2009. Note the high (red) turbidity readings at the top (Melbourne) and in the centre (south Port Phillip Bay).
IMOS turbidity measurements from September 2008 – June 2009. Note the high (red) turbidity readings at the top (Melbourne) and in the centre (south Port Phillip Bay).