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Isla da Pascua-E (Chile) Site History

History Summary

Reference Level

The data have been linked to tide staff zero which is leveled to fixed benchmarks. These benchmarks are not linked to the benchmarks used by other data sets for Easter Island; thus, this data record is independent. A reference level shift has been identified in the analog rolls by the originators and an adjustment was applied:

The period after the long gap in 1991 appears to have a lower mean level although data received via satellite also show this feature. It is not clear if a reference shift occurred during the gap.

Benchmarks

Quality Assessment by the UH Sea Level Center

Comment

Some questionable fluctuations of nearly a one-day duration during the winter months are related to weather events. The daily and monthly means reveal no apparent changes in the reference level. However, in comparison with the satellite-received data at the University of Hawaii, the difference plot of daily means shows a possible shift around 27 August 1986 (+7 cm). This difference plot also shows some other subtle shifts. The originators have checked the tide staff observation sheets and the analog rolls and found no problems.

The gaps filled below flagged '*' used redundant satellite-received data that were decimated to hourly with a spot sample technique. '$' below denotes that the PRS series was filled with BUB data.