The charts come from various locations around Grand Harbour (Port of Valletta) including French Creek and Ricasoli Breakwater.

Sea level; Air pressure; Other meteorological measurements; Air temperature; Wind strength and direction

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.

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