The Permanent Service for Mean Sea Level (PSMSL)

Established in 1933, the Permanent Service for Mean Sea Level (PSMSL) is responsible for the collection, publi­cation, analysis and interpretation of sea level data from the global network of tide gauges. It is based at the National Oceanography Centre (NOC), Liverpool, and is supported by NERC and the Intergovernmental Oceanographic Commission (IOC). The PSMSL operates under the auspices of the International Council for Science (ICSU) and is working towards membership of the new ICSU World Data System.

Aside from its central role of operation of the global sea level data bank, the PSMSL provides advice to tide gauge operators and analysts. It occupies a central management role in the development of the Global Sea Level Observing System (GLOSS) and hosts important international study groups and meetings on relevant themes.

Visit the PSMSL website →

Explore the PSMSL data set

A suite of interactive maps allow users to explore changes in sea level worldwide using the data from tide gauges held in PSMSL’s global sea level data bank.

  • PSMSL data set on Google Earth

    Using Google Earth

    Detailed information about the tide gauge sites together with the datum controlled monthly mean values of sea level and time series plots can be accessed with the Google Earth viewer software; this can also be used to give detailed views of the areas around PSMSL datum controlled tide gauges.

    View the tide gauge information and data with Google Earth →

  • Sea level anomalies map

    Sea level anomalies

    Annual mean sea level can vary considerably from year to year in response to a variety of meteorological and oceanographic forcing. The Mean Sea Level Anomalies Map demonstrates how sea level varies from year to year when compared with the long-term average at a particular site.

    Browse sea level anomalies →

  • Sea level trends

    Sea level trends

    The Trend Explorer map allows interactive investigation of relative mean sea level trends since 1900. The map allows users to see how the estimate of a trend for each tide gauge record depends upon the period of the data used in the calculation.  Viewing the whole world, it becomes clear that the vast majority indicate a rise in sea level.

    Browse relative sea level trends →


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