Monthly Means (W5) 
Station -- Unique seven character identifier for the station 
Year -- Year of data 
Mo -- Month of data 
MHHW -- Mean Higher-High Water 
MHW -- Mean High Water 
DTL -- Mean of MHHW and MLLW 
MTL -- Mean of MHW and MLW 
MSL -- Mean Sea Level 
MLW -- Mean Low Water 
MLLW -- Mean Lower-Low Water 
GT -- Difference between MHHW and MLLW 
MN -- Difference between MHW and MLW 
DHQ -- Difference between MHHW and MHW 
DLQ -- Difference between MLW and MLLW 
HWI -- Greenwich Mean High Water Interval in Hours 
LWI -- Greenwich Mean Low Water Interval in Hours 
Data are in Meters above MLLW Times are on UTC (GMT)