Indicator: CO-04 Sea surface temperature variability

Data

The Australian Navy’s Meteorological and Oceanic Services reports the range of sea surface temperature recorded at towns around Australia.

Annual range of temperatures in coastal waters at selected towns
Coastal Town Annual change in temperature
Adelaide 4.7
Albany 3.8
Bateman's Bay 6.4
Broome 5.2
Cairns 4.3
Darwin 3.8
Dunk Island 4.3
Hobart 4.6
Macquarie Island 2.8
Melbourne 5.4
Perth 3.4
Sydney 5.8
Townsville 4.5

Source: National Oceanographic Data Center 1999, World Ocean Atlas 1998 - Coastal Sea Surface Temperatures, viewed 8 Jun 2006, http://www.metoc.gov.au/products/data/aussst.html,

CSIRO Marine also uses remote sensing to monitor sea surface temperature. Data are available on their website back to 1993:

The following figure is a sea surface temperature satellite image from March 1995, showing strong cold water upwelling along the Bonney Coast, and cool water near Eyre Peninsula, Kangaroo Island, and eastern Victoria

Sea surface temperature satellite image from March 1995, showing strong cold water upwelling along the Bonney Coast, and cool water near Eyre Peninsula, Kangaroo Island, and eastern Victoria

Sea surface temperature satellite image from March 1995, showing strong cold water upwelling along the Bonney Coast, and cool water near Eyre Peninsula, Kangaroo Island, and eastern Victoria

Source: CSIRO Marine Laboratories Remote Sensing Facility

Trends in sea surface temperature for the Australian region, 1950-2002 and 1970-2002 (C/ 10 yrs)

Trends in sea surface temperature for the Australian region, 1950-2002 and 1970-2002 (C/ 10 yrs)

Source: Bureau of Meteorology 2006, Trends in annual total rainfall for three time periods, viewed 26 Oct 2006, http://www.bom.gov.au/cgi-bin/silo/reg/cli_chg/trendmaps.cgi.

The Bureau of Meteorology also publishes sea surface temperature data on its website

What the data mean

The data show that sea surface temperatures vary considerably, throughout the year and around the coast. The data give no indication of whether average or extreme sea surface temperatures are changing. The patterns of variability in Australia’s upwellings, and their relationship with large-scale climate features, such as currents and wind patterns, are unclear. It is likely that changes in climate and ocean currents will affect the location, extent and duration of up wellings, and this has direct implications for biodiversity conservation and fisheries production in Australian waters.

Data Limitations

The Royal Navy analysis, which is presented in a readily accessible, user friendly form, is based on historical data as at 1998. The CSIRO and Australian Government Bureau of Meteorology (BoM) data are raw and have not been analysed to reveal trends. To monitor in any systemic way whether sea surface temperatures are changing, these data would need to be analysed and updated on an annual basis.

Issues for which this is an indicator and why

Coasts and Oceans — Condition of the ocean and coastal waters - Climatic and carbon dioxide factors 

Changes in sea surface temperature patterns may be indicative of changes in ocean climate, affecting marine organisms over potentially vast areas. Ultimately, changes in ocean climate could lead to changes in ocean currents, affecting all marine ecosystems and potentially also affecting terrestrial ecosystems.

Other indicators for this issue:

Coasts and Oceans — Contributions and pressures between the coasts and oceans and the atmosphere - Climate and carbon dioxide 

Changes in sea surface temperature patterns may occur as a consequence of climate change and are therefore an indicator of pressures from the atmosphere, particularly from greenhouse gas concentrations, on the ocean. Changes in ocean currents, resulting from changes in ocean temperature, could, in turn, lead to changes in atmospheric temperatures.

Other indicators for this issue:

Biodiversity — Pressures on biodiversity - Climate variability 

Changes in sea surface temperature are likely to result from changes in global climate and are therefore an indirect indicator for these changes.

Other indicators for this issue:

Atmosphere — Climate variability and change - Greenhouse 

Changes in sea temperature may be indicative of anthropogenic climate change due to the emission of greenhouse gases and the loss of greenhouse sinks.

Other indicators for this issue: