NZG - Offshore Tongatapu Tonga
DARTAbout NDBC buoy 5401003
NDBC station 5401003 (Offshore Tongatapu Tonga) is a moored - deep ocean DART tsunami-detection station at 23.352°S 173.402°W, operated by New Zealand National Emergency Management Agency by Te Pu Ao GNS Science and NIWA Taihoro Nukurangi. PierMonkey reads its observations straight from the NOAA National Data Buoy Center and republishes them free, with no account required to see current conditions.
It reports water-column height, the measurement tsunami detection depends on.
DART stations sit on the seafloor and measure the height of the water column above them, which is how tsunamis are detected in open ocean long before they reach a coast. The readings are far more sensitive than surface wave measurements and are reported in metres of water column rather than wave height.