1956 values based on readings of high and low waters
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 04-Aug-1994
For a discussion of interannual variability of sea level along the coasts of Pakistan and India, see Clarke and Liu, Journal of Physical Oceanography, 24, 1224, 1994.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 06-Dec-2002
SMRC Newsletter Jul-Dec 2001 reports high E coast correlation with SOI and MSL. MSL is much higher during La Nina tropical cyclones than during El Nino.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 26-Jan-2016
A value of MTL-MSL=-39 mm has been derived using a historic databank of harmonic tidal constants gathered by the International Hydrographic Organization (IHO).  Care must be taken when using these IHO constants, though, as there are many known errors in tidal amplitudes and phases. As the correction is only applied to RLR data and the data from 1956 is metric, it is not used in the data set.  Should this period become metric in future, however, it would be used.