Newlyn Tidal Observatory is a

grade II listed In the United Kingdom, a listed building is a structure of particular architectural or historic interest deserving of special protection. Such buildings are placed on one of the four statutory lists maintained by Historic England in England, H ...

tide gauge A tide gauge is a device for measuring the change in sea level relative to a vertical datum. It is also known as a mareograph, marigraph, and sea-level recorder. When applied to freshwater continental water body, water bodies, the instrument may ...

hut on the South Pier in

Newlyn, Cornwall Newlyn () is a seaside town and fishing port in south-west Cornwall, England, United Kingdom.Ordnance Survey: Landranger map sheet 203 ''Land's End'' It is the largest fishing port in England. Newlyn lies on the shore of Mount's Bay and for ...

in England. Measurements of sea level taken at the observatory between 1915 and 1921 were used to define the reference level,

Ordnance Datum Newlyn Ordnance may refer to: Military and defense *Materiel in military logistics, including weapons, ammunition, vehicles, and maintenance tools and equipment *Artillery *Artillery shells *Aircraft ordnance, weapons carried by and used by an aircraft ...

, 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 Mean sea level (MSL, often shortened to sea level) is an mean, average surface level of one or more among Earth's coastal Body of water, bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical ...

science.

Building and location

The observatory is a building situated behind the lighthouse at the end of the South Pier in Newlyn, near Penzance, in Cornwall. Constructed of concrete, it has the appearance of a small hut and is painted in red and white stripes. Inside the building is an Ordnance Survey

benchmark Benchmark may refer to: Business and economics * Benchmarking, evaluating performance within organizations * Benchmark price * Benchmark (crude oil), oil-specific practices Science and technology * Experimental benchmarking, the act of defining a ...

, constituted of a brass bolt (OSBM SW 4676 2855), and a diameter stilling well set into the pier which has ocean access via an inlet.

History

The

Ordnance Survey The Ordnance Survey (OS) is the national mapping agency for Great Britain. The agency's name indicates its original military purpose (see Artillery, ordnance and surveying), which was to map Scotland in the wake of the Jacobite rising of ...

established the observatory in 1915 to contribute to the measurement of a national

vertical datum In geodesy, surveying, hydrography and navigation, vertical datum or altimetric datum is a reference coordinate surface used for vertical positions, such as the elevations of Earth-bound features (terrain, bathymetry, water level, and built stru ...

defined by

mean sea level A mean is a quantity representing the "center" of a collection of numbers and is intermediate to the extreme values of the set of numbers. There are several kinds of means (or "measures of central tendency") in mathematics, especially in statist ...

. The subsequent 6-year measurement campaign at the observatory, conducted from 1 May 1915 to 30 April 1921, determined the value of mean sea level as below the level of the brass bolt benchmark inside the hut. Due to the stable underlying granite bedrock, the proximity to the open ocean, and the absence of rivers, the observations at Newlyn were selected as the basis, or

ordnance datum An ordnance datum (OD) is a vertical datum used by an ordnance survey as the basis for deriving altitudes on maps. A spot height may be expressed as above ordnance datum (AOD). Usually mean sea level (MSL) at a particular place is used for the d ...

, for elevation measurements across Great Britain. To realise the reference

datum Data ( , ) are a collection of discrete or continuous value (semiotics), values that convey information, describing the quantity, qualitative property, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols t ...

across the country, in the early twentieth century spirit

levelling Levelling or leveling (American English; see spelling differences) is a branch of surveying, the object of which is to establish or verify or measure the height of specified points relative to a datum. It is widely used in geodesy and cartogra ...

techniques were used to measure a national network of circa 200 fundamental benchmarks, all referenced to the Newlyn brass bolt. From 1915 to 1983 the observatory measured sea level using a float in the stilling well, along with a gauge supplied by Cary and Porter. With advances in technology, an Aanderaa pressure gauge was installed in 1981 to operate alongside the well gauge. Since 1983 the primary sensor has been a bubbler pressure gauge. The Ordnance Survey operated the tide gauge until 1983, when the

Natural Environment Research Council The Natural Environment Research Council (NERC) is a British Research Councils UK, research council that supports research, training and knowledge transfer activities in the environmental sciences. History NERC began in 1965 when several envir ...

took over the management. The observatory was designated as

status by

Historic England Historic England (officially the Historic Buildings and Monuments Commission for England) is an executive non-departmental public body of the British Government sponsored by the Department for Culture, Media and Sport. It is tasked with prot ...

in December 2018. As of 2023 the observatory is operated by the

National Oceanography Centre The National Oceanography Centre (NOC) is a marine science research and technology institute based across two sites, one in Southampton and one in Liverpool, England. It is the UK’s largest institute for integrated sea level science, coastal ...

, and funding support is contributed by the UK

Environment Agency The Environment Agency (EA) is a non-departmental public body, established in 1996 and sponsored by the United Kingdom government's Department for Environment, Food and Rural Affairs, with responsibilities relating to the protection and enha ...

Impact

The 6 years of observations captured at the observatory up to 1921 continue to define the height reference system for Great Britain, with varied applications including flood planning, understanding air pollution, infrastructure design, and deliveries by

unmanned aerial vehicles An unmanned aerial vehicle (UAV) or unmanned aircraft system (UAS), commonly known as a drone, is an aircraft with no human pilot, crew, or passengers onboard, but rather is controlled remotely or is autonomous.De Gruyter Handbook of Dron ...

. In 2016 Bradshaw et al. published an article to commemorate 100 years of sea level measurements at the Newlyn observatory, in particular highlighting how the collected data had "played a fundamental role in UK geodesy and oceanography", and in 2021 the impact of the data on ocean and climate change studies was noted.

Building and location

History

Impact

See also

References

Further reading