Select a start year and end year from the date slider below to see a graph of annual Mean Sea Level (MSL) and it's associated annual rate of change. If a end year in the future is selected, i.e. beyond which there is available observed data, then the linear (black line) and polynomial (purple line) trendlines will show an estimate of MSL from the year which the observed data ends up to the year selected by the user.

The mean annual rate of Relative Sea Level (RSL) change for Tuvalu between and is approximately mm per year with a Standard Error of +/- mm per year.

Corrected for subsidence and Vertical Land Movement (VLM) of +/- mm per year, the mean annual rate of Absolute Sea Level (ASL) change for Tuvalu between and is approximately mm per year () with a Standard Error of +/- mm per year.

The mean Relative Sea Level acceleration for Tuvalu between and is approximately mm/year2.

Data represented by the blue line in the above graph is the mean observed annual Relative Sea Level (RSL) for the selected period. This is given as a height above RLR. The black line is the linear trendline for the selected period and indicates the overall direction of the data. It's gradient is the average annual rate of RSL change and is shown in the legend at the top right hand corner of the graph in the form of the straight line equation 'y = mx + c'. The purple line is the corresponding quadratic or second degree polynomial trendline which also gives the Relative Sea Level acceleration for the selected period.

Hover over the blue line to see individual annual MSL values in the tooltip. Hover over the legend at the top of the graph to see each trendline's equation and it's corresponding coefficient of determination, R2 value in the tooltip.

Please note that Mean Sea Level predicted from the facility to project the above trendlines into the future are estimates only.

I've created an R Shiny app which fits various degree (1-4) polynomials to the above data and also produces p-Values, R-Squared, F-Statistic and t-statistic error parameters which you can find here.

Station Documentation

Data for 1994 - 2020 retrieved May 2021 from Permanent Service for Mean Sea Level.