QUALITY ASSESSMENT POLICY
The quality assessment is mostly based on the residuals (observed data minus predicted tides) of the hourly data. This assessment also applies to the daily and monthly data since they were derived from the quality-controlled hourly data.
The following abbreviations are used in the assessment:
JASL - Joint Archive for Sea Level; GLOSS - Global Sea Level
Observing System; TOGA - Tropical Ocean Global
Atmosphere research program; NODC - National Oceanographic Data Center;
Instrmnt - instrument; Digitzd Intvl - digitized interval;
Gaps > 1 mon - missing data in a span greater than one month;
Refernce - reference.
The following corrections are made to the hourly data prior to this assessment:
1) Gaps or obviously wrong data points in a span less than 25 hours are filled by the predicted tide method*.
2) Timing errors of exact increments of an hour are corrected by shifting the data.
3) Reference level shifts are only corrected after information from tide staff readings or comparative readings with a fixed bench mark are checked to verify that the shift was not a natural event. If comparative readings are missing or incomplete, comparisons of the data with nearby stations may warrant the adjustment of some obvious shifts.
4) Data with unresolved datum shifts are not disseminated. However, if sufficient time spans of data are available before or after the year(s) with the unresolved shift(s), a subset of quality assured data is made available.