Trend and Anomalies Maps Updated

23 Feb 2016

The web pages illustrating the trends in the tide gauge data set, as well as yearly variation of sea level with respect to an average (the sea level anomalies), were updated with the 02 Feb 2016 release of the data set. The release date is displayed on both pages in line with our referencing recommendation.

Note that these trends now account for periods where monthly data has been based on mean tide level measurements. For further information, see our previous news item on changes to MSL time series with some MTL values. Also, the table of long term trends now contains an estimate of the number of years necessary at each site to obtain a trend with uncertainties of 1.0mm/yr, 0.5mm/yr and 0.1mm/yr.

Each year, the Permanent Service for Mean Sea Level (PSMSL) starts anew to gather as much data as possible from the previous year to update the tide gauge time series. For example, during 2015 we tried to update all time series from active stations with the 2014 data. Other changes also occur to the data set over the course of a year. In some cases, the yearly effort includes the addition of new time series. Occasionally, data suppliers provide a replacement time series for an existing record. Thus, changes to the data set frequently reflect more than an addition of 12 monthly means. This update marks an internal milestone as we start a new year and provides the best opportunity to update our products.