Sea Level Data Haiti

On this page we show the cumulative sea level record from telemetered sites installed in March 2010. For general installation informations see this link.

Differences

The data below represent the difference in sea level between the two tide gauges that measure sea level directly:Gonave, or GONA, our reference station, and PARA, near Grande Guave close to where most aftershocks have occurred. The trend in the month below suggests that PARA is sinking at 0.8 mm/week - 4 cm/yr -relative to Gonave.

Subsequent data reveal that linear fits to monthly spans of data are aliased by long term oscillations in sea-level slope. In this last plot below we difference three months of smoothed data to reveal relative sea level changes at two weekly periods with amplitudes of 1-2 cm, and towards the end sea-level at Para rising 6 cm relative to Jack only 5 km to the west. These variations are unexpectedly large and are likely the result of near-shore currents, wind stress, salinity and temperature variations. They suggest that sea-level is an unsuitable datum for monitoring vertical crustal motions at periods of months in the Bay of Gonave.

The rise at Para relative to both Jack and Gona starting in June 2010 is most easily explained by subsidence of the pressure sensor at Para, however the sensor is bolted to concrete block set on a coral foreshore, selected for its apparent stability.

Piezometric sites

Three sites measure hydrostatic pressure on beaches where no convenient piers for direct sea level measurement are available. To various degrees the measurement of sea level at these locations is contaminated by rainfall. The most purturbed is Beloc, which is installed approximately 4 m inland from the high water tide level on a promontory adjoining a straight undrained hinterland. Jack appears to be least influenced by rainfall.