=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 11-Jun-1991
Helgeroa            040/310 RLR(1966) is 8.3m below BM F38 N29
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 30-Mar-1995
Tide gauge network modernised, new equipment installed in 1987
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 28-Jan-2009
Following the input of revised data values station made Metric awaiting datum information.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 06-Apr-2009
2007/8 mean sea level values entered as METRIC only awaiting confirmation of a datum query.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 27-Oct-2009
The Norwegian Mapping Authority have revised their datasets. Whole dataset is now referred to TGBM F38 N29 which is 2.312m above TGZ. As a result RLR has been re-calculated year chosen was 1984 RLR value before 6.988.Revised RLR factor is now 6.088m
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 05-Sep-2012
For information on sea level rise along the Norwegian coast see paper "Contributions to sea level variability along the Norwegian coast for 1960-2010" by K. Richter, J.E.O. Nilsen and H. Drange.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 17-Nov-2015
The PSMSL has been notified by the Norwegian Authority that the tide gauge at Helgeroa is sinking. The rate of sinking has been confirmed as 0.22mm/year. With the supply of the 2014 sea level data a revised dataset beginning January 1988 has been supplied. Future data will be supplied with the correction applied.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 25-Jan-2018
Monthly mean value for December 1987 has been updated using values supplied by the Norwegian Mapping Authority.