UK: The UK’s Permanent Service for Mean Sea Level (PSMSL) launched an interactive map that allows users to explore changes in sea level worldwide over five decades. The PSMSL, operated by the National Oceanography Centre under the auspices of the International Council for Science, is the global databank for sea-level change information. It was established in 1933.
The Anomalies Map, generated from a worldwide network of tide gauges, demonstrates how sea level varies from year to year when compared with the long-term average at a particular site, calculated over the period from 1960 to 1990. Moving a slider along the time line at the bottom of the map shows how, at some locations, sea level can vary by over 20 centimetres from year to year.
PSMSL’s Director, Dr Lesley Rickards, said, “This map lets users see how the estimate of a constant change in time or, in other words, a trend, for each tide gauge record depends upon the period of the data used in the calculation. Zooming out to show the world, it becomes clear that the vast majority of the sites are red, indicating a sea level rise.”
It is interesting to note the change in geographic coverage of the data over time. By choosing the entire time span available – from 1900 to 2010 – users can observe the lack of data covering this period in the Southern Hemisphere and western Pacific. More data is available if the start date is moved up to 1950, but unfortunately there is still a lack of geographic coverage in the Southern Hemisphere.