Thermistor String

NIOZ Thermistor String: Internal Wave Data

The ocean interior is constantly in motion due to "internal" waves that are supported by the stable vertical density stratification. These waves are much slower than waves at the surface. Their typical periods range between 10 minutes and 1 day. However, their vertical amplitudes are typically 10 m and can grow over 100 m!

Using new detailed deep-ocean measurements we can show constantly varying but fairly smooth internal waves (video 1 & 2).

These data are from the open ocean Canary Basin (North-Atlantic Ocean) between 1390 and 1520 m. Video 1 (above) contains 3 panels: 24 hours span, 8 hours and 2 h 40 min. Video 2 (below) is the middle panel.

Great Meteor Seamount

Similar measurements at 550 m near the top of an underwater volcano, Great Meteor Seamount, in the same area show large breaking waves up to 50 m above the bottom and passing within a minute (video 3 below).

These waves are so turbulent that they sweep up sediment 1000 times better than tidal currents in the area. Also, very small-scale turbulence is seen throughout the rest of the wave period.

The above data are collected using a novel set of 110 independent temperature sensors developed at NIOZ. Together these sensors constitute "NIOZ3", the most recent successor of NIOZ thermistor strings (NIOZ1 - download as document [PDF]; NIOZ2 download as document [PDF]). In contrast with the former models, NIOZ3 has no cables between the sensors and communicates via an inductive link with a programming and synchronizing device. It can measure 1.5 years at a rate of 1 Hz and still resolve temperature better than 0.0001�C.