Improved and extended tide gauge records for the British Isles leading to more consistent estimates of sea level rise and acceleration since 1958



Hogarth, P, Hughes, CW ORCID: 0000-0002-9355-0233, Williams, SDP and Wilson, C
(2020) Improved and extended tide gauge records for the British Isles leading to more consistent estimates of sea level rise and acceleration since 1958. PROGRESS IN OCEANOGRAPHY, 184. p. 102333.

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Abstract

This paper describes methods of obtaining improved estimates of long-term sea level trends for the British Isles. This is achieved by lengthening the sea level records where possible, then removing known sources of variability, and then further adjusting for datum errors that are revealed by the previous processes after verification using metadata from archived sources. Local sea level variability is accounted for using a tide and surge model. Far field variability is accounted for using a “common mode”. This combination reduces the residual variability seen at tide gauges around the coast of the British Isles to the point that a number of previously unrecognised steps in individual records become apparent, permitting a higher level of quality control to be applied. A comprehensive data archaeology exercise was carried out which showed that these step-like errors are mostly coincident with recorded site-specific changes in instrumentation, and that in many cases the periodic tide gauge calibration records can be used to quantify these steps. A smaller number of steps are confirmed by “buddy-checking” against neighbouring tide gauges. After accounting for the observed steps, using levelling information where possible and an empirical fit otherwise, the records become significantly more consistent. The steps are not found to make a large difference to the trend and acceleration observed in UK sea level overall, but their correction results in much more consistent estimates of first order (Sea Level Rise) and second order (Sea Level Acceleration) trends over this 60-year period. We find a mean rate of sea level rise of 2.39 ± 0.27 mm yr−1, and an acceleration of 0.058 ± 0.030 mm yr−2 between Jan. 1958 and Dec. 2018. The cleaner dataset also permits us to show more clearly that the variability other than that derived from local meteorology is indeed consistent around the UK, and relates to sea level changes along the eastern boundary of the North Atlantic.

Item Type: Article
Uncontrolled Keywords: Sea level rise, Sea level acceleration, Mean sea level, Tide gauge, Time series analysis
Depositing User: Symplectic Admin
Date Deposited: 14 May 2020 10:43
Last Modified: 18 Jan 2023 23:52
DOI: 10.1016/j.pocean.2020.102333
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3087220