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What is the Permanent Service for Mean Sea Level?

Permanent Service for Mean Sea Level (PSMSL) is the world's main hub for monthly mean sea level data. It provides the international sea level community with essential data, a range of derived products, and expert advice.

PSMSL is based at the National Oceanography Centre's (NOC) site in Liverpool, and we're committed to supporting its vital work for the long term. NOC is an independent, self-governing organisation, a charitable company funded by UK Research and Innovation to carry out National Capability programmes.

Visit the PSMSL website for more information

What are PSMSL's main activities?

PSMSL doesn't work in a bubble. It draws on the wide range of expertise we have here at the NOC, like the deep technical knowledge of our engineering teams.

PSMSL's work focuses on a few key areas:

Providing Data

Offering free access to mean sea level and delayed-mode datasets online, along with all the supporting information you might need.

Training and Development

Creating training materials and run courses for tide gauge operators and the people who use their data.

Sharing Information

Responding to requests for information from a wide range of people, including national tide gauge agencies, decision-makers in government, the media, and the public.

What is PSMSL's role in the global community today? 

What is PSMSL's role in the global community today? 

PSMSL continues to be a vital part of the international scientific community. It's a permanent service of two of the IUGG's unions (for Oceanography and Geodesy) and serves as a key data centre for UNESCO's Intergovernmental Oceanographic Commission's (IOC) Global Sea Level Observing System (GLOSS). It is also a regular member of the World Data System (WDS).

The history of the PSMSL

The story of PSMSL goes all the way back to 1933, at the International Union of Geodesy and Geophysics (IUGG) General Assembly in Lisbon. It was there that Professor R. Witting highlighted the need for international cooperation, stating:

"For the study of the tides and the tidal currents, of other movements of the sea surface and of currents of different origin, continual observations of sea level are the sole or a most valuable basis. For the solution of a complex of geophysical problems, data regarding sea level and its changes are of great importance."

Following this call to action, Joseph Proudman, who became PSMSL's first director, was tasked with the important job of collecting and publishing mean sea level data from sites all around the world.

Podcasts

NOC's award-winning podcast, Into the Blue, takes listeners on a journey to discover some of the biggest topics and challenges the ocean faces today.

What Factors Are Increasing the Likelihood of Extreme Sea Levels?

What Factors Are Increasing the Likelihood of Extreme Sea Levels?

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Publications

Celebrating 80 years of the Permanent Service for Mean Sea Level (PSMSL)

Authors

Rickards, L.; Matthews, A. ORCID: https://orcid.org/0000-0001-5210-2453; Gordon, K.; Tamisiea, M; Jevrejeva, S. ORCID: https://orcid.org/0000-0001-9490-4665; Woodworth, P.; Bradshaw, E.. 2014 Celebrating 80 years of the Permanent Service for Mean Sea Level (PSMSL). In: Cudennec, C.; Kravchishina, M.; Lewandowski, J.; Rosbjerg, D.; Woodworth, P., (eds.) Complex interfaces under change: sea-river-groundwater-lake. Proceedings of HP2/HP3, IAHS-IAPSO-IASPEI Assembly, Gothenburg, Sweden, July 2013. Walllingford, IAHS Press, 11-15, 100pp. (IAHS Publication, 365).

Publication year

2014

Publication type

Book section

Mean sea level and tidal change in Ireland since 1842: a case study of Cork

Authors

Pugh, David T.; Bridge, Edmund; Edwards, Robin; Hogarth, Peter; Westbrook, Guy; Woodworth, Philip L. ORCID: https://orcid.org/0000-0002-6681-239X; McCarthy, Gerard D.. 2021 Mean sea level and tidal change in Ireland since 1842: a case study of Cork. Ocean Science, 17 (6). 1623-1637. 10.5194/os-17-1623-2021

Publication year

2021

Publication type

Article

Changes in mean sea level around Great Britain over the past 200 years

Authors

Hogarth, P.; Pugh, D.T.; Hughes, C.W. ORCID: https://orcid.org/0000-0002-9355-0233; Williams, S.D.P. ORCID: https://orcid.org/0000-0003-4123-4973. 2021 Changes in mean sea level around Great Britain over the past 200 years. Progress in Oceanography, 192, 102521. 10.1016/j.pocean.2021.102521

Publication year

2021

Publication type

Article

An ensemble approach to quantify global mean sea-level rise over the 20th century from tide gauge reconstructions

Authors

Palmer, M D; Domingues, C M ORCID: https://orcid.org/0000-0001-5100-4595; Slangen, A B A; Boeira Dias, F. 2021 An ensemble approach to quantify global mean sea-level rise over the 20th century from tide gauge reconstructions. Environmental Research Letters, 16 (4), 044043. 10.1088/1748-9326/abdaec

Publication year

2021

Publication type

Article

Get the Data

Looking for global sea level data or training on tide gauge operations? Visit the PSMSL website to explore datasets, find training resources, and see all the services supporting the international sea level community.