The data set comprises time series of sea level data from coastal tide gauges. The data holdings include over 1000 site years of data from about 200 sites comprising about 10 million records. About 75 per cent of the data are from some 100 sites around the British Isles - the remaining data are from coastal sites and islands scattered across the globe. Data are primarily hourly values. Recording periods vary from one month at some sites to over several years.There are three short series from around the Irish coast which were collected in 1842.

The data set comprises time series measurements from offshore pressure gauges mounted on the sea floor. The data holdings are approximately 100 observation months from 30 sites. The data are mainly from trans-ocean sections in the North Atlantic. Data records contain date/time, total pressure (or relative 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 Mediterranean-Alpine Experiment (MEDALPEX) data set comprises over 200,000 hourly sea level measurements. Data are included from 28 sites around the northern coast of the Mediterranean and one in the Atlantic at Cadiz. Measurements were collected from December 1981 and September 1982, with a special observing period (SOP) between 15 February and 30 April 1982. Twenty eight coastal sites were instrumented with conventional stilling wells, while one offshore site off Corsica used a bottom pressure recorder. The data are stored, together with benchmark information, as time series at each site with hourly values of sea surface elevation recorded to the nearest millimetre. The aim of the MEDALPEX Experiment was to study the role of atmospheric forcing on the dynamics of the Western Mediterranean. Data were supplied by laboratories in Belgium, France, Monaco, Italy, Spain, UK and former Yugoslavia. Responsibility for assembling, quality controlling and analyzing the sea level data collected during MEDALPEX was vested in the British Oceanographic Data Centre (BODC).

The dataset consists of 2580 tiff images of tide gauge charts from Bowling, River Clyde. The images were taken from annual bound volumes of tide gauge charts (~1 page per week, 52 pages per volume). A typical volume measures 37 x 34 x 3.5 cm and pages are single sided. The ledgers for Bowling begin in 1888 and end in 1952, but under this project, only the charts up until 04/01/1939 were photographed. The trace on the original charts was generated by a float tide gauge. The float inside a stilling-well was connected by a wire run over pulleys to a pen that moved up and down as the tide rose and fell. The images were generated by a commercial scanning organisation (TownsWeb Archiving Ltd) using a planetary overhead book scanner. In July 2016 The Peel Group Ltd. (Glasgow) approached BODC to donate their tidal archive, due to office redevelopment. The archive consists of ledgers of tide gauge charts (345 annual bound volumes) and handwritten ledgers (91 bound books) from several locations along the Clyde, with the earliest record beginning in 1841 from Glasgow Harbour. Later that year BODC received a grant from the Marine Environmental Data and Information Network (MEDIN) to photograph a selection of the ledgers. MEDIN released these funds to support small Data Archiving Projects that increase access to industry marine data. Ledgers also exist for Broomielaw, Dalmuir, Gourock, Govan Wharf, Greenock, Partick Wharf Glasgow, Queen's Dock Entrance Glasgow and Rothesay Dock. Most begin in the late 19th Century and run to the mid-20th century. It is hoped that these will be digitised in the future, subject to funding.

A large number of charts (originals and copies) together with tabulations of data are also available, some of which date back to the 1850s. A more detailed description of these will be available once they have been systematically catalogued and archived.

This dataset contains tabulations of the heights and times of tidal high and low water at St. Helena from 1 October 1826 to 31 October 1827. The tide was recorded by an instrument designed by Manuel Johnson, a future President of the Royal Astronomical Society, while waiting for an observatory to be built. The tabulations in this dataset were obtained by inspection of photographs of Johnson's tabulation sheets that are held in the archive RGO 6/500 in the Royal Greenwich Observatory collection at Cambridge University Library. It is an important record in the history of tidal science, as the only previous measurements at St. Helena had been those made by Nevil Maskelyne in 1761, and there were to be no other systematic measurements until the late 20th century. Johnson’s tide gauge, of a curious but unique design, recorded efficiently the height of every tidal high and low water for at least 13 months, in spite of requiring frequent re-setting. These heights compare very reasonably with a modern tidal synthesis based on present-day tide gauge measurements from the same site. Johnson’s method of timing is unknown, but his calculations of lunar phases suggest that his tidal measurements were recorded in Local Apparent Time. Unfortunately, the recorded times are found to be seriously and variably lagged by many minutes. Johnson’s data have never been fully published, but his manuscripts have been safely archived and are available for inspection at Cambridge University. His data have been converted to computer files as part of this study for the benefit of future researchers. This dataset supports the paper “Cartwright, D.E.; Woodworth, P.L.; Ray, R.D.. 2017 Manuel Johnson's tide record at St. Helena. History of Geo- and Space Sciences”. Richard Ray (National Aeronautics and Space Administration) and Philip Woodworth (National Oceanography Centre) modified and added figures to David E. Cartwright’s original draft paper and sections of text have been updated, but otherwise the paper is as he intended it. This work was undertaken when Philip Woodworth was an Honorary Research Fellow at the National Oceanography Centre in Liverpool in receipt of an Emeritus Fellowship from the Leverhulme Trust. Part of this work was funded by UK Natural Environment Research Council National Capability funding.

Historic sea level data from 6 sites on the South coast of England, recovered as part of a PhD on sea level trends in the English Channel. Devonport: 1961-1986, 1988-1990 Newhaven: 1942-1948, 1950-1951, 1953-1957, 1964-1965, 1973, 1988 Portsmouth: 1961-1990 Southampton: 1935-1979, 1982-1990 St. Marys: 1968-1969, 1973, 1975, 1977-1978, 1987-1989 Weymouth: 1967-1971, 1983-1987 There are raw data files and cleaned data files. The cleaned files have been corrected for datum changes which are recorded in the readme files for each site.

This dataset contains high and low water values manually digitised from historic hand-written tabulated ledgers, from the Port of London Authority (PLA). The dataset contains 463 years of data, from across 15 tide gauge sites along the Thames Estuary (bounding box = -0.3159W, 51.3914N, 1.3797E, 51.8428N), for the period 1911 to 1995. When these historic records are combined with digital records available from the PLA since 1995, the new sea level time-series spans the 109-year period from 1911 to 2019. London is one of the world’s most important coastal cities and is located around the Thames Estuary. Quantifying changes in sea levels in the Thames Estuary over the 20th century and early part of the 21st century is vital to inform future management of flood risk in London. This dataset is of importance for ongoing monitoring of mean sea-level rise, and changes in tidal range and extreme sea levels in the Thames Estuary. The project was led by the Ocean and Earth Science, University of Southampton and the Environment Agency, with contributions from the Leibniz Institute for Baltic Sea Research Warnemunde and the National Oceanography Centre. The study contributes to the objectives of UK National Environment Research Council (NERC) project E-Rise: Earliest detection of sea-level rise accelerations to inform lead time to upgrade/replace coastal flood defence infrastructure (NE/P009069/1; I.D.H.).

A set of historical tide gauge sea level records from Alicante (Spanish Mediterranean coast) have been recovered from logbooks stored at the Spanish National Geographical Institute (IGN). Sea level measurements have been digitised, quality-controlled and merged into two consistent sea level time series. Vertical references among instruments benchmarks have been derived from high precision vertical levelling surveys. Earlier observations are daily averages and more recent data are hourly values. The observations are from 7 different tide gauge records in Alicante outer harbour (Alicante I) and five tide gauge series in Alicante inner harbour (Alicante II). The sea level record in Alicante starts in 1870 with daily averaged values until the 1920s and hourly afterwards, and is still in operation, thus representing the longest tide gauge sea level time series in the Mediterranean Sea. The sea level at Alicante I has been measured by tide pole, floating gauge, mechanical recorder, digital recorder and since 2014 by radar gauge. The sea level at Alicante II has been measured by floating gauge, digital recorder and from 2014 onwards by radar gauge. This scarcity of long-term sea-level observations, as well as their uneven geographical distribution is a major challenge for climate studies that address, for example, the quantification of mean sea-level rise at centennial time scales, the accurate assessment of sea-level acceleration or the long-term changes in sea-level extremes that are vital for coastal risk assessments. This dataset represents an additional effort of sea-level data archaeology and aims at preserving the historical scientific heritage that has been up to now stored in old archives in non-electronic format. The research was partially funded by the Spanish Ministry of Science, Innovation and Universities. A further series was rescued from Santander under the same initiative.