The data set comprises time series measurements from offshore pressure gauges mounted on the sea floor. The data holdings are approximately 250 observation months from 100 sites. The data have mainly been collected in the continental shelf seas around the British Isles. Data records contain date/time, total pressure and, occasionally, temperature. The sampling interval is typically 15 minutes or hourly, over deployment periods ranging from 1 to 6 months. Data were collected mainly by the Proudman Oceanographic Laboratory (POL), now the National Oceanography Centre (NOC) at Liverpool, and are managed by the British Oceanographic Data Centre (BODC).

The Joint North Sea Data Acquisition Project (JONSDAP) dataset comprises hydrographic and meteorological time series, including current velocities, water temperature (both at the sea surface and at depth), hydrographic pressure, air temperature, barometric pressure and wind velocities. The data were collected in the North Sea from March-June 1976. Automatically recording current meters (and usually temperature sensors), off-shore tide gauges, thermistor chains and meteorological data buoys were deployed at numerous locations around the study area for periods of a few days to several weeks. Data from 9 tide gauge, 4 meteorological data buoy, 10 thermistor chain and 81 current meter deployments are held at the British Oceanographic Data Centre (BODC). Additional hydrographic data were collected during JONSDAP 76 cruises, while over-flights with aircraft provided further measurements. However, these data are not stored at BODC. JONSDAP 76 consisted of two parts: FLEX, the Fladen Ground Experiment between 25 March and 15 June, and INOUT, the inflows of water of the whole North Sea as well as the internal movements from 15 March to 25 April. The data were collected by 13 laboratories in 8 countries.

This Met/Ocean data bank comprises wave, current, water temperature and surface meteorology (air temperature, humidity and wind) data collected at 11 off-shore sites on the UK continental shelf, between 1973 and 1988. Three hourly wave data (short term statistics) and hourly wind observations together with atmospheric pressure, air temperature and, occasionally, sea surface temperature were measured at weather ships (W.S.) Stevenson (61 20.0N, 000 00.0E from 1973 - 1976), Fitzroy (60 00.0N, 004 00.0W from 1973 - 1976) and Boyle (50 40.0N, 007 30.0W from 1974 - 1977). Moored current meter measurements were also made at 2 to 4 depths at each site. Three-hourly measurements of sea temperature, air temperature, barometric pressure, relative humidity, wind speed and wind direction were collected at the National Data Buoy DB/1 site (48 43.0N, 008 58.0W) between 1978 and 1982. Directional spectra of the wave field were also derived from measurements of heave, pitch and roll of the buoy, while surface currents were measured hourly. DB/1 was succeeded by DB/2 (located at 48 44.0N, 008 50.0W from 1984 - 1986 and at 58 59.0N, 007 13.0W from 1986 - 1988) and DB/3 (60 30.9N, 002 52.0W from 1984 - 1988). Met/Ocean data and directional wave spectra are available from these sites, comprising hourly recordings of wind speed and direction, maximum wind gust speed, air temperature, relative humidity, barometric pressure (and pressure trend over three hours), sea temperature, significant wave height and period, maximum wave height, swell wave height, period and direction, wind wave height and period, current speed and direction. The directional wave spectra consist of the 9 co- and quad- spectral densities for 51 frequency slots, plus derived height, period, direction and directional spread of all waves, wind waves, swell waves and spectral peak wave period. The UKOOA dataset also includes measurements from four platforms, with short term wave statistics, hourly wind observations, atmospheric pressure, air temperature and occasionally sea surface temperature data available from Forties (57 45.0N, 001 00.0E) between 1974 and 1980; Brent (61 04.0N, 001 43.0E) between 1975 and 1980; and Beryl/Frigg (59 35.0N, 001 40.0E) between 1979 and 1982. One dimensional wave spectra and meteorological data are available from Foula (60 08.0N, 002 59.0W) between 1977 and 1979. All data were collected by the UK Offshore Operators Association (UKOOA) and are stored at the British Oceanographic Data Centre (BODC).

The dataset comprises scanned images of historical analogue charts and data ledgers from eight tide gauge sites around the UK. The sites include: Sheerness, Belfast, and several sites around Liverpool managed by the Mersey Docks and Harbour Company namely, Eastham, Gladstone, Hilbre, Princes Pier, Tranmere and Waterloo. The Sheerness ledger data represents some of the earliest records of sea level data in the UK and cover the periods - January 1870 to December 1881, July 1882 to October 1894 and December 1929 to April 1941. Data availability for the other sites are: Belfast analogue charts - 27 November 1901 to 24 May 1902; Princes Pier ledgers: - 1941 to 1950, 1951 to 1960 and 1961 to 1970; Eastham, Gladstone, Hilbre, Princes Pier, Tranmere and Waterloo ledgers: - 1982 to 1988. The data recorded in some of the ledgers also describe meteorological measurements for example, air pressure, air temperature, wind speed and direction, and precipitation and evaporation. Funding to rescue these historical sea level data came from the Marine Environmental Data and Information Network (MEDIN) and the British Oceanographic Data Centre (BODC).These images have now been added to the National Oceanographic Database and are freely available to registered users (subject to licence agreement).

The World Ocean Circulation Experiment (WOCE) sea level data set comprises data collected from approximately 160 tide gauge sites distributed around the world. The data are usually hourly heights of sea surface elevation, although some were collected and supplied at higher frequencies (i.e. 6 or 15 minute intervals) or as pressure values rather than elevations. The data are primarily from 1990 to 1998 (the WOCE period), but the dataset also includes historical data as a number of the tide gauges had been operating for many years. The total volume of data held is 3550 site years. A few sites have data extending back over 50 years and many over 20 years. The British Oceanographic Data Centre (BODC) was responsible, as a WOCE Data Assembly Centre (DAC), for assembling, quality controlling and disseminating this comprehensive sea level data set. Data were supplied by Argentina, Australia, Canada, Chile, China, Cuba, Denmark, Ecuador, France, Iceland, Japan, New Zealand, Peru, Philippines, Portugal, Russia, South Africa, Spain, Ukraine, the UK and the USA. Data quality control was carried out with the aid of sophisticated screening software which allows rapid inspection of the data. The sea level data were tidally analyzed and the residuals inspected. Parameters other than sea level, for example atmospheric pressure and sea surface temperature, were also visually inspected. This quality control identified spikes and gaps in the data in addition to timing problems and datum shifts. Any problems identified were resolved with the data supplier. Qualifying information accompanying the data was also checked and data documentation assembled. The data can be downloaded from the BODC web site, or made available on CD-ROM.

The data set comprises continuous hourly recordings of electrical potential across the Dover Strait, which relate to the flux of water, over the period 1955-1965 and part of 1968-1969, together with parallel measurements of sea temperature and pressure. Voltages on telegraph cables were measured almost continuously by pen recording milliammeters installed at Dover since 1954. The d.c. potential between the inner conductor of the cable and its screen is measured through a 2.2 kohm resistor in series with a milliammeter, whose internal resistance was of order 1 kohm. The screen was earthed at both the English and French ends, and at the French end the conductor is also effectively earthed (through inductive elements) as far as low frequency voltage variations were concerned. Thus the voltage recorded at St. Margaret's Bay is effectively the difference in earth potentials between the particular coastal points in England and France. A 0.003F capacitance in parallel with the milliammeter shunted out voltage variations with time scales less than about half a minute. For calibration, a standard voltage cell was switched in place of the cable on occasions. For parallel measurements of sea temperature (related to conductivity) and local wind conditions, 6-hourly temperatures and barometric pressures from the Noord Hinder Light Vessel, the pressures from the Terschellinger Bank Light Vessel and the 6-hourly pressures from Gorlston (East Anglia) were used. Data for sea salinity at the Varne Light Vessel were extracted from International Council for the Exploration of the Sea (ICES) publications.

This dataset consists of high resolution tiff photographed images of tide gauge charts, from various historical tide gauges from the Grand Harbour (Port of Valletta), Malta. Due to the historical nature of these records, there is little associated metadata with the original charts. They come from various individual tide gauge locations around the Grand Harbour (Port of Valletta), Malta, and some are labelled with more specific locations, such as French Creek and Ricasoli Breakwater. General coordinates have been given for the geographic coverage: 14.49E to 14.53E, 35.87N to 35.9N. The earliest chart is from the 01/06/1871 and the latest is from 1926. There are gaps of several years in the dataset. In his 1878 paper, On the tides at Malta, G. B. Airy describes the gauge in operation in 1871: "The float was a copper vessel, nearly spherical, about 8 inches in diameter; a vertical rod attached to it passed freely through a guide, and was hinged to the end of a horizontal lever, of which the arms were so proportioned that each space marked on the tabular form between the horizontal lines [one-fourth of an inch. - G.B.A.] corresponded accurately to an inch rise or fall of the float." "The cylinder on which the paper was wrapped revolved once in 24 hours". It is not known how long this gauge was in operation for, but all of the tide gauges that produced the tide gauge charts in this dataset would have been float gauges. The original charts were collected by the Royal Navy as part of their surveying duties of the Grand Harbour. The United Kingdom Hydrographic Office (UKHO) had these charts in its archives, which were difficult to access and in need of conservation. The charts were conserved and photographed and made publically available as digital images to help preserve one of the longest and earliest temporal series of sea level data in the Mediterranean. The original data were collected by the Royal Navy and were placed in the archives of the Admiralty, now the UKHO. The conserved and photographed images were created by the United Kingdom Hydrographic Office Archives for the MALTESER, MediterrAnean Long TErm SEa level Rescue project and then deposited with the British Oceanographic Data Centre. This project was funded under the Central Government Breakthrough Fund, 2014. Reference: Airy, G. B. (1878). On the tides at Malta. Philosophical Transactions of the Royal Society of London, 169, 123-138.

The Global Sea Level Observing System (GLOSS) 'Delayed-mode' Data Assembly Centre at the British Oceanographic Data Centre (BODC) quality controls and archives high frequency (i.e. hourly or more frequent) global sea level data and any ancillary measurements (e.g. temperature, wind speed/direction, atmospheric pressure) that are included with the data. The tide gauges are situated on most coastlines, and data cover the Arctic to the Antarctic, and the Atlantic, Indian and Pacific oceans. The main component of GLOSS is the 'Global Core Network' (GCN) of 290 sea level stations around the world for long term climate change and oceanographic sea level monitoring. The Core Network is designed to provide an approximately evenly-distributed sampling. The GLOSS Long Term Trends (LTT) set of gauge sites (some, but not all, of which are in the GCN) are used for monitoring long term trends and accelerations in global sea level. The GLOSS altimeter calibration (ALT) set consists mostly of island stations, and provides a facility for mission intercalibrations. A GLOSS ocean circulation (OC) set, including in particular gauge pairs at straits and in polar area, complements altimetric coverage of the open deep ocean. Data exist from the mid 1800s up to the present day, with particularly long records from Newlyn, U.K.; Brest, France; Prince Rupert, Canada and Honolulu, San Diego and San Francisco, U.S.A.; Sea level has been measured by a variety of different instruments with the historical data mainly coming from mechanical float gauges. More recent technologies include acoustic, pressure, and radar instruments. GLOSS aims at the establishment of high quality global and regional sea level networks to create long‐term sea level records. These records, as well as being used in climate studies (sea level rise), are also used in oceanography (ocean currents, tides, surges), geodesy (national datum), geophysics and geology (coastal land movements) as well as various other disciplines. The programme became known as GLOSS as it provides data for deriving the 'Global Level of the Sea Surface'. GLOSS is an international programme conducted under the auspices of the Joint Technical Commission for Oceanography and Marine Meteorology (JCOMM) of the World Meteorological Organisation (WMO) and the Intergovernmental Oceanographic Commission (IOC). Data are collected by local agencies such as port authorities, universities and navies and sent to or downloaded by the data centre.