ALL DUTCH METRIC DATA ARE MEASURED TO NAP (NORMAAL AMSTERDAMSCH PEIL) PRIOR TO 1936 VALUES BASED ON HIGH AND LOW WATERS OR ON 4 OR 8 READINGS/DAY
Documentation added 2011-02-08
Following information received from Douwe Dillingh giving values for NAP up to 2005 and the re-levelled value from 2005 onwards RLR can now be calculated for the Dutch stations. Harlingen is now an RLR station. RLR factors up to 2005 6.907m. From 2005 onwards 6.914m.
Documentation added 2016-01-22
The note above stating that periods of the data are MTL is misleading. Sections of the original data were MTL. However, Pub. Sci. 5 states “For these periods a shallow water correction has been added to the mean heights of high and low water in order to give a mean height of sea-level comparable with those otherwise calculated for other periods.” Thus, a correction to MSL has already been applied.
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