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Mean Sea Level Trends
360-001 Ponta Delgada, Portugal


The mean sea level trend is 2.58 millimeters/year with a 95% confidence
interval of +/- 1.01 mm/yr based on monthly mean sea level data from
1978 to 2007 which is equivalent to a change of 0.85 feet in 100 years.

[Metadata: Data for 1924-1977 are monthly mean tide level]

Source Data & Additional Metadata
GLOSS Station Information


The plot shows the monthly mean sea level without the regular seasonal fluctuations due to coastal ocean temperatures, salinities, winds, atmospheric pressures, and ocean currents. The long-term linear trend is also shown, including its 95% confidence interval. The plotted values are relative to the Revised Local Reference (RLR) datum as established by the Permanent Service for Mean Sea Level (PSMSL). The calculated trends for all stations are available as a table in millimeters/year and in feet/century (0.3 meters = 1 foot).

If present, solid vertical lines indicate times of any major earthquakes in the vicinity of the station and dashed vertical lines bracket any periods of questionable data or datum shifts. Source data and additional metadata are noted below the plot.


Revised: 10/15/2013
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services