Tide gauge

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A tide gauge Tidal gauge dsc06189.jpg
A tide gauge
The tide gauge in Kronstadt, Russia Kronstadt tide gauge.JPG
The tide gauge in Kronstadt, Russia

A tide gauge is a device for measuring the change in sea level relative to a vertical datum.[ citation needed ] It is also known as a mareograph, [2] marigraph, [3] sea-level recorder [4] and limnimeter. [5] When applied to freshwater continental water bodies, the instrument may also be called a limnimeter. [6]



Sensors continuously record the height of the water level with respect to a height reference surface close to the geoid. Water enters the device by the bottom pipe (far end of the tube, see picture), and electronic sensors measure its height and send the data to a tiny computer.[ citation needed ]

Historical data are available for about 1,450 stations worldwide, of which about 950 have provided updates to the global data center since January 2010. [7] At some places records cover centuries, for example in Amsterdam where data dating back to 1700 is available. [8]

When it comes to estimating the greater ocean picture, new modern tide gauges can often be improved upon by using satellite data.[ citation needed ]

Tide gauges are used to measure tides and quantify the size of tsunamis. The measurements make it possible to derive the mean sea level. Using this method, sea level slopes up to several 0.1 m/1000 km and more have been detected.[ citation needed ]

A tsunami can be detected when the sea level begins to rise, although warnings from seismic activity can be more useful.[ citation needed ]


Sea-level measurements were made using simple measuring poles or "tide staffs" until around 1830, when self-recording gauges with mechanical floats and stilling wells were introduced. [9]

Tidal poles and float gauges were the primary means of sea-level measurement for over 150 years and continue to operate at some locations today. While still part of modern-day tide gauge instrumentation, these technologies have since been superseded by pressure gauges (similar to depth gauges), acoustic/ultrasonic gauges, and radar gauges.[ citation needed ]

The following types of tide gauges have been used historically: [10]

Common applications

Interior view of Cascais Tide Gauge showing data recording equipment CascaisTideGauge Interior.jpg
Interior view of Cascais Tide Gauge showing data recording equipment

Tide gauges have a practical application in the shipping and fishing industries where low or high tide levels can hinder or prohibit access to shallow bays or locations with bridges. An example is the Cascais tide gauge in Portugal, which was originally installed because of the sand bar in the River Tagus that causes difficulties for shipping entering Lisbon port. Because of similar problems many industries have installed private tide gauges in ports around the world, and also rely on government agencies (such as NOAA).

Data collected from tide gauges is also of interest to scientists measuring global weather patterns, the mean sea water level, and trends - notably those potentially associated with global warming.

Modern gauges

In recent years new technologies have developed allowing for real-time, remote tide information to be published online via a solar powered wireless connection to a tide sensor. Acoustic/ultrasonic sensors [11] have already been deployed to great effect and the data is regularly broadcast via Twitter and also displayed online. [12]

See also

Related Research Articles

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<span class="mw-page-title-main">Pressure measurement</span> Analysis of force applied by a fluid on a surface

Pressure measurement is the measurement of an applied force by a fluid on a surface. Pressure is typically measured in units of force per unit of surface area. Many techniques have been developed for the measurement of pressure and vacuum. Instruments used to measure and display pressure mechanically are called pressure gauges,vacuum gauges or compound gauges. The widely used Bourdon gauge is a mechanical device, which both measures and indicates and is probably the best known type of gauge.

<span class="mw-page-title-main">Tsunami</span> Series of water waves caused by the displacement of a large volume of a body of water

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<span class="mw-page-title-main">Sea level</span> Geographical reference point from which various heights are measured

Mean sea level is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datum – a standardised geodetic datum – that is used, for example, as a chart datum in cartography and marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to calibrate altitude and, consequently, aircraft flight levels. A common and relatively straightforward mean sea-level standard is instead the midpoint between a mean low and mean high tide at a particular location.

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<span class="mw-page-title-main">Storm surge</span> Rise of water associated with a low-pressure weather system

A storm surge, storm flood, tidal surge, or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as cyclones. It is measured as the rise in water level above the normal tidal level, and does not include waves.

<span class="mw-page-title-main">Bathymetry</span> Study of underwater depth of lake or ocean floors

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<span class="mw-page-title-main">Ultrasonic transducer</span> Acoustic sensor

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<span class="mw-page-title-main">Cascais tide gauge</span> First tide gauge installed in Portugal, also used to establish the countrys mean sea level

The Cascais tide gauge was the first tide gauge installed in Portugal and dates back to 1882. It is situated in Cascais Municipality, Lisbon District. It was one of the first systems of sea-level data collection installed on the coast of Europe and is still in use.

<span class="mw-page-title-main">Newlyn Tidal Observatory</span> British tidal observatory

Newlyn Tidal Observatory is a grade II listed tide gauge hut on the South Pier in Newlyn, Cornwall. Measurements of sea level taken at the observatory between 1915 and 1921 were used to define the reference level, Ordnance Datum Newlyn, for height measurement on the British mainland. The tide gauge has collected over 100 years of observations which has significantly contributed to studies in sea level science.


  1. "The Kronstadt sea-gauge". Your Guide in St Petersburg. Retrieved 26 April 2019. With explanatory diagram showing Lea-type float gauge and stilling-well.
  2. Torge, W.; Müller, J. (2012). Geodesy. De Gruyter Textbook. De Gruyter. p. 80. ISBN   978-3-11-025000-8 . Retrieved 2021-12-08.
  3. International Tsunami Information Center. "4. Tide, Mareograph, Sea Level". UNESCO. Archived from the original on 2018-07-24. Retrieved 2014-06-16.
  4. Ian Shennan; Antony J. Long; Benjamin P. Horton, eds. (2015). Handbook of Sea-Level Research. Wiley. p. 557. ISBN   978-1-118-45257-8.
  5. "Definition of LIMNIMETER". www.merriam-webster.com. Retrieved 2021-08-14.
  6. "Definition of LIMNIMETER". Merriam-Webster. 2022-10-07. Retrieved 2022-10-07.
  7. "Obtaining Tide Gauge Data". Permanent Service for Mean Sea Level. PSMSL. Retrieved 2016-03-07.
  8. "Other Long Records not in the PSMSL Data Set". PSMSL. Retrieved 2015-05-11.
  9. Tide gauge history UK National Oceanographic Centre Archived 2015-08-24 at the Wayback Machine
  10. "History of tide gauges". Tide Observation. Geospatial Information Authority of Japan. Archived from the original on 2013-01-05. Retrieved 2014-04-19.
  11. "Remote Monitoring a MaxSonar®". Archived from the original on 2012-09-03. Retrieved 2012-09-28.
  12. "ioBridge Apps - Ockway Bay Tide Levels".

Further reading