The National Tidal Centre (NTC) specialises in sea level monitoring and analysis for the purpose of deriving trends in absolute sea level and producing national tide predictions, tide streams and related information.
The services provided by the NTC are an important element of the Bureau's new Oceanographic Services Program, complementing its aim of supporting Australia's social, economic, cultural and environmental goals in the public interest. More particularly, NTC's services support climate monitoring, defence, navigation, public safety and ship operations in Australian and nearby waters, and assist persons and authorities engaged in recreation, tourism, marine resource related industries, land and hydrographic mapping, coastal development, trade and commerce.
Commencing operation in January 2004, the NTC within the Bureau brings into the public domain many of the functions of the former National Tidal Facility of Australia (NTFA) operated by Flinders University of South Australia until December 2003.
The NTC is the primary source of tide tables, tidal streams and tidal constituents provided to the Australian Hydrographic Service. The NTC also manages the national data archive for sea levels and tides.
For a glossary of terms, please see the NTC glossary
The NTC is located within the South Australian Regional Office in Adelaide. Contact details are:
National Tidal Centre
Australian Bureau of Meteorology
PO Box 421
Kent Town SA 5071
Email: firstname.lastname@example.org (Remove the'.nospam' part to use this address)
Telephone: (08) 8366 2730 (9am-4pm SA Time, Monday to Friday)
Facsimile: (08) 8366 2651
NTC produces a range of products involving tidal and sea level processes that include:
While the moon's gravitational force is recognised as the primary influence on tides, there are more than 100 scientifically recognised constituents (called harmonic constants) that affect the timing and height of tides. NTC balances the impact of these specific constituents with analysis of regional factors, such as coastally-trapped waves, to prepare tide predictions for port and harbour authorities, the Royal Australian Navy, and persons and authorities engaged in recreation, tourism, marine resource related industries, coastal development, trade and commerce.
Sea level monitoring
NTC's high-precision tide gauges collect sea level data to assess long term variability related to global warming, and short term changes related to climate e.g. ENSO, and other forcings.
NTC undertakes a wide range of tidal and sea level data acquisition, quality control analysis and archiving, including satellite retrieval of data and automated checking and computer archiving. Data from Australia and its territories, Antarctica, and sites in New Zealand and the southwestern Pacific Ocean is collected. The continuous analysis of tide data provides NTC with updated material for improving the official tide predictions for Australian locations.
NTC is engaged by government agencies to interpret the data with respect to trends in absolute sea level and sea level response to other climatic and oceanographic phenomena. Additionally, NTC is engaged by port operators to produce a high standard of tide predictions suited to critical port operations.
The Association of Australian Port and Marine Authorities
The NTC is engaged by state port authorities and private port operators, through AAPMA, to provide tide products for up to 80 primary ports. These include tide predictions and tide streams, as required for the Australian National Tide Tables (ANTT), published by the Royal Australian Navy as the official tide predictions. Other products in the package assist in the safeoperation and optimal loading of shipping, particularly where the under keel clearance of ships is critical.
The Hydrographer, Royal Australian Navy
Hydrographic charts rely on a marriage of tides, datums and depths for navigation purposes. NTC provides the Hydrographer with computational, modelling and advisory services relating to tides and mean sea level. The information is used by the Hydrographer in the annual production of the ANTT.
Incorrectly known as Tidal Waves, a Tsunami (Harbour Wave) is generated by seismic activity and detected via sea level signals. Capable of travelling for thousands of kilometres across oceans, tsunamis can cause severe damage to coastal environments. Access to real time sea level data enables NTC to contribute information to the Australian Tsunami Alert system. Advance warning can be issued to coastal communities at risk from tsunamis.
Barely discernible in the open ocean, the amplitude of Tsunamis may increase to several metres in the shallow coastal regions. Tsunamis are most common in the Pacific. Similar technology enables the risks posed by storm surges at high tide to be advised to coastal development planners.
Antarctic tide gauge network
Recognising the significance of the Southern Ocean in world scale circulation and its links with issues of climate change, the NTC with the support of the Australian Antarctic Division obtains high quality, geodetically controlled sea level data from the region, to:
- Support oceanographic, geodetic and geographic research for national and international programs (including GLOSS, GCOS and GOOS projects and initiatives sponsored by the SCAR Working Group on Geodesy and Geographical Information).
- Collect sea level measurements as indicators of ocean dynamics and in the context of climate change
- Assist in datum control for mapping and charting
- Supply tidal predictions for shipping and operational needs.