Sea level

Sea level data for the PLOCAN test bed come from the tide gauge located in the port of Las Palmas, 10km to the north of the test bed. The report on the historical set of the port of Las Palmas, available on the State Ports Authority web site, is used as a reference. The State Ports Authority has a network of tide gauges installed in ports under its management.

The following table and photo describe the two tide gauges used to build the historical series.

Station Sensor Latitude Longitude Period of operation
LasP Acoustic (SRD) 28º 8' 48.12"N 15º 24' 27.32"W Jul/1992 - Nov/2010
Las2 Radar (Miros) 28º 8' 26.02"N 15º 24' 42.52"W Jan/2009 - to date

Reference level

Port zero is defined by the port itself and normally coincides with the lowest low tide. On the other hand, the REDMAR zero is the reference level of the tide gauge measurements, and is usually made to coincide with the port zero, as shown in the figure below.

High and low tide statistics

An analysis of the complete set from 1992 to 2014 gives the following table of statistics, where “Med” is the mean value and “D.E.” is the standard deviation. This table shows that with respect to the REDMAR zero:

  • The mean value of the tide is 159.5 cm.
  • The minimum value is 0 cm.
  • The maximum value is 319 cm.

The difference between observed data and the astronomical tide is defined as the residue or meteorological tide, and it is basically associated with the action of wind and air pressure.

Historical record of extreme values observed

The graph below shows the time series of the annual extreme values of the sea level observed in the port of Las Palmas.

In blue: maximum (blue dotted line) and 95 percentile (p95, solid blue line). In red: minimum (red dotted line) and 5 percentile 5 (p5, solid red line).

 

Mean monthly values and trends

The graph below shows the time series of the mean monthly sea level for the port of Las Palmas in centimetres. The green straight line represents the trend of the series, calculated as 0.494cm with an uncertainty of ± 0.046 cm. Event “A” marks the changeover to data from the new station Las2.