Tangaroa during dry dock. (Photo: Brett Grant, NIWA)
Display of current speed through Cook Strait region as measured by the new ADCP.
The recent Tangaroa dry-dock at Devonport Naval Base in Auckland provided the ideal opportunity to install a new Acoustic Doppler Current Profiler (ADCP) - one of the most important tools on NIWA’s iconic research vessel.
ADCPs provide three dimensional current data from beneath the ship by measuring the frequencyshift (or Doppler shift) in echoes reflected from free-floating particles or plankton. Tangaroa’s original ADCP was installed in 1996, but this new piece of US designed technology has many refinements, including the ability to operate at far greater depths – up to 850 m compared with the original 250 m. We have already measured the strong tidal currents of Cook Strait, flowing at up to 1.8 metres per second: the first complete sectional measurements of currents to these depths taken in Cook Strait.
The ADCP will be run on many future voyages to extend our understanding of currents around New Zealand and surrounding waters and to add context to many of the other measurements made during our voyages.