Sea Surface Temperature

Thermal imagery from the AVHRR sensors on the NOAA polar-orbiting environmental satellites are processed by the IMOS Satellite Remote Sensing Facility and published at the SRS thredds server at CSIRO. The high-resolution shown here use the national-coverage GHRSST-format L3U files, while the larger-domain images use the L3S both, both produced by the Bureau of Meteorology for IMOS. All these IMOS SST products are significantly more data-rich than global-coverage datasets derived from the on-board-subsampled Global Area Coverage (GAC) data. This is because the IMOS products are based on the High Resolution Picture Transmission (HRPT) data downlinked since ~1982 from the NOAA satellites by Australian ground stations in Perth (WASTAC), Darwin and Melbourne (BoM), Hobart (CSIRO) and Townsville (AIMS). The entire archive was re-processed in 2014 so we have re-generated our small-region graphics (also with more of the other IMOS in-situ data included).

We monitor the availability and region-specific coverage using our [SST data monitoring] system. The analysis is repeated three times a day. In the upper panel, red indicates high data density while blue can mean either cloudy conditions, or lack of data from the satellites. The lower panel shows the availability of data from individual NOAA satellites.

Ocean Colour

Ocean colour imagery from the MODIS sensor on NASA's Terra and Aqua satellites is processed by the IMOS Satellite Remote Sensing Facility. We obtain the 1-day composite chlorophyll-a estimates (which are essentially unaveraged over time because most of the ocean is only seen once a day) from the SRS thredds server and show it here in two forms: daily data in the small-region maps, and latest-data composite for the whole Australasian region. In March 2015, the SRS released a new version of the entire dataset so we have re-generated all our graphics (also with more of the other IMOS in-situ data included).

Sea Surface Height

Satellite observations of sea surface height are available along the ground-tracks of several satellite altimeter missions. We use the [last 10 day's data] from [Jason-2], [Cryosat-2], [SARAL], [HY2-A] and [Jason-1 (until July 2013)], [Envisat (until April 2012)] along with tide gauges to make maps of sea surface height anomaly for the Australasian region. We publish these at the IMOS thredds server along with the gestrophic surface current velocity we derive from them and shown here on many of our maps.

The along-track altimetry data are obtained from the NOAA Laboratory for Satellite Altimetry via the Radar Altimeter Database System (RADS), except for HY2 data, which are obtained from AVISO. In the plots linked above, some data points (sometimes whole tracks) are outlined in magenta, signifying that they have been rejected by our automatic quality control. At present this includes the very-most-recent days' data from some satellites because a sufficiently-accurate estimate of the satellite's orbit is not available.

Tide gauge data are provided by the agencies responsible for the Australian tide gauge network: National Tidal Centre, Queensland EPA, Manly Hydraulics Laboratory, and the WA Department of Transport. Inclusion of these coastal sea surface height observations improves our satellite-based maps of the sea surface because sea level varies too rapidly with time over the continental shelf to be adequately sampled by the satellites. The continuous sampling by the gauges also makes the removal of tides more complete, so the derived estimates of surface currents based on the geostrophic approximation have fewer spurious values over the shelf, compared with global altimetry products that do not include the Australian tide gauges.

Ocean current velocity and temperature - IMOS current meters

Current meters are deployed and operated by three IMOS facilities. The Australian National Moorings Network (ANMN) is responsible for the shelf array and the coastal National Reference Station (NRS) array. The Australian Bluewater Observing System (ABOS) is responsible for moorings in deeper (off-shelf) water. There are also a few current meters deployed as part of the Satellite Remote Sensing altimetry calibration sub-facility. Links to the respective sections of the IMOS thredds server are provided on our current meters page. For detailed information about the Northern Australian shelf moorings, see the IMOS sub-facility page at AIMS.

Ocean surface current velocity - IMOS HF radars

The IMOS Australian Coastal Ocean Radar Network (ACORN) facility operates six pairs of High-Frequency (HF) radar antennas in four regions: off Perth, the SA gulfs, Coff's Harbour and the Capricorn-Bunker group of the Southern Great Barrier Reef. These data are available close to real-time at the IMOS thredds server so we include it, where possible, in our daily-updating maps of satellite data. When those maps are re-generated to include the other IMOS data that are not available in real-time, we use the delayed-mode, quality-controlled versions of the radar data, if available. Further information.

Temperature, salinity, fluorescence and oxygen to 200 or 1000m - IMOS gliders

The IMOS Australian National Facility for Ocean Gliders (ANFOG) operates two sorts of gliders: Slocum and Seaglider. A subset of the profile data is available in near-real time from the IMOS thredds server and we update our detailed plots of the glider trajectories and profile data every two hours on our gliders page. The spatial context of those observations (e.g. in relation to ocean eddies or coastal fronts) can be seen by finding the glider on the appropriate regional map of satellite (SST or Ocean Colour) and other data. As the delayed-mode data become available, it is periodically added to our gliders page and regional maps. For additional information about the IMOS gliders see the ANFOG site at UWA.

Temperature and salinity to 2000m - Argo

The IMOS Argo facility is Australia's contribution to the international Argo project. Argo Australia data are available at the IMOS thredds server. Our Argo page shows data from the global array, downloaded daily from the ARGO GDAC FTP site. See also:
[Australian Argo real-time processing]
[Argo Australia delayed-mode processing]
[Argo Information Centre]

Surface current velocity and temperature - the drifting buoy program

Trajectories of surface drifters, showing derived estimates of the surface velocity as well as the observed temperature, are shown on many of our maps. These data are updated several times per day from the international Drifting Buoy Data Assembly Center.