A Ship of Opportunity Observation Network for the Oceans aroundAustralia

Ridgway Ken1, Helen Beggs2, Miles Furnas3, Ann Gronell1, Graham Hosie4, Randall Lee7, Anthony Richardson5, Eric Schulz2, Bronte Tilbrook5,6.

Aims

We present results from a major new ship of opportunity (SOOP) program observing the ocean waters around Australia. The SOOP Facility encompasses both the open ocean and coastal waters, in support of short time-scales associated with ocean prediction and the longer term scales of climate research. The aim of the SOOP Facility is to implement an integrated observing system in Australian regional seas that link physical, chemical and biological oceanography. Our ships of opportunity include both commercial vessels on regular routes and research vessels covering more varied routes. The SOOP Facility forms part of the Integrated Marine Observing System (IMOS) which is a new science infrastructure initiative funded by the Australian Government.

The target regions are the boundary current systems off Eastern and Western Australia, the Southern Ocean, the shelf seas across northern Australia, and the Great Barrier Reef. This is achieved by the following specific goals:

  1. Implement vessels on suitable routes with an integrated system of measurements including physical and biogeochemical parameters
  2. Monitor the major boundary currents systems around Australia.
  3. Monitor both local processes and the interactions of the boundary currents on the continental shelf

2. Provide in situ input and/or validation to model and data analyses covering the waters around Australia (SST, Air-Sea flux, BLUElink, POAMA etc).

Figure 1. The main current systems around Australia.

Monitoring Platforms

High-density XBT Sections - Five major (HRX) high-resolution XBT lines provide boundary to boundary profiling, closely spaced sampling to resolve mesoscale eddies, fronts and boundary currents. The lines are repeated 4 times per year with an on-board technician. The routes sample each major boundary current system using available commercial vessel traffic. All of the transects transmit data in real-time.

Biogeochemical Program - uses the RV Southern Surveyor and the l'Astrolabe which sample the critical regions of the Southern Ocean and Australian waters, which have a major impact on CO2 uptake by the ocean and are regions where biogeochemical cycling is predicted to be sensitive to changing climate. Southern Surveyor has a wide spatial coverage and each year covers tropical to sub-polar waters.

The Astrolabe line, is one of the most significant repeat sampling lines for the ocean and samples all major Southern Ocean water masses. Observations of carbon, nutrients, pigments, phytoplankton species and bio-optical properties of organic matter cover the spring through late summer period when the region is most active biologically.

AusCPR - To monitor plankton we use the Continuous Plankton Recorder (CPR), the only platform that can assess plankton species and be towed behind ships of opportunity. Species-level data are vital to examine mesoscale productivity, biodiversity, and climate impacts on marine ecosystems. Two seasonal routes are operated, in the Southern Ocean, and the East Australian Current

Sensors on Tropical Research Vessels – Fixed sensor sets maintained on the 2 tropical research vessels (RVCapeFerguson and RV Solander). The instruments obtain underway observations of temperature, salinity, chlorophyll, fluorescence, light absorption, and irradiance. Data are collected in both the Great Barrier Reef waters, the western Coral Sea, and Arafura Sea within repeated transects and individual voyage tracks. The actual location of data collected depends on the operational schedules of both vessels.

SST Sensors – Implemented on Australian Volunteer Observing Fleet (AVOF) vessels and several passenger ferries. Hull-mounted sensors supply high-quality bulk SST data fed into existing data management systems and broadcast via satellite back to Australia every one to three hours. Radiometers on ferries supply high-quality skin SST data in near real-time.

Research Vessel Real-time Air-Sea Fluxes - Research vessels have been equipped with "climate quality" met. systems, providing high quality air-sea flux measurements and delivered in near real-time. A full set of air-sea fluxes essential for climate studies requires: wind, air and sea temp., humidity, pressure, precip., long- and short-wave radiation. Data are broadcast via satellite back to Australia daily.

All of the data are freely and as far as possible, immediately available to all Australian and international researchers. Research in climate science, physical oceanography, ocean forecasting, coastal ocean dynamics and ecosystem and fisheries benefit from these regular, high-quality, timely observations of the ocean state. Results from each of the components will be presented.

Figure 2. The components of the IMOS Ship of Opportunity Facility