=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 01-Dec-1998
values for March 1997 to January 1998 were revised in November 1998
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 18-Nov-1999
Original POL 'B gauge' installed May 1993 which ran until June
1998, then replaced with new 'B gauge' in March 1999.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 26-Apr-2000
Ascension           402/001 RLR(1993) is 10.184m below BM POL13
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 10-Sep-2002
Ascension gauge failed March 2001.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 30-Jun-2014
The datum history at Ascension is complicated. Half-tide ref. 1993-1998 and 2006-2007 was used for the data June 1993-June 1998 and again for data Jan. 2006-Dec 2007. Half-tide datum Apr. 1999-Mar. 2001 was used specifically for that period. Half-tide ref. Ascension B datum Sept. 2005 was used for Nov. and Dec data 2005 and also data for Jan.2008- May 2010. Full tide datum B gauge 870mm below the original datum for 1993-1998 and 2006-2007 was used for data Dec. 2010 onwards.

