The long-term Relative Sea Level change (RSL) change at five tide gauges in New Zealand (Auckland, Taranaki, Wellington, Lyttelton and Dunedin) has been estimated using data through to 2013. The relative rates of vertical crustal motion between these four sites using up to 15 years of GPS data have also been determined to provide and estimate of the stability of each tide gauge site. Three of the four sites are found to be stable relative to each other within an estimated 0.5 mm/yr accuracy of the GPS vertical rate estimates, while the fourth site, Wellington, shows variable tectonic motion at a level that makes the Wellington RSL data unreliable for studies of global sea level change. Excluding this site, our best estimate of “absolute” sea level change around New Zealand is +1.6 ± 0.15 mm/yr.
This project has been undertaken in collaboration with GNS Science