Technology



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The basic configuration of the IOEB consists of a surface apex and 110 m of suspended mooring instrumentation. The apex provides flotation for the mooring, and houses the surface electronics and batteries. The underwater mooring system is electronically and mechanically attached to the surface package by standard three-conductor mooring cable. Below the deepest instrument, an anchor provides tension on the mooring to reduce sailing of the underwater system. Generally, the IOEBs produced so far are configured nearly identically (as described below), with a few minor instrument changes. However, the system is designed to be adaptable to a variety of scientific configurations.

The surface electronics consist of dual ARGOS antennae, platform transmit terminals (PTTs), and network microcontrollers, and modules to acquire data from external meteorological and ice sensors. Due to the extreme cold temperatures that the apex is expected to encounter, high energy density lithium batteries are used. The microcontrollers acquire data from all the surface and underwaster instrumentation and feed the compressed datastream to the PTTs. The meteorological sensors consist of a wind monitor, air temperature sensor, barometer, magnetic compass, and mechanical tilt sensor. The ice sensors consist of 3 internal ice stress sensors, 33 ice-profiling thermistors, and an upward-pointed echo sounder to accurately detect the icefloe bottom.

Below the apex are three conductivity/temperature recorders at different depths, an Acoustic Doppler Current Profiler (either 150 or 75 kHz) near the surface pointed downward, one or two fluorometers, a transmissometer, a microfiltering water transfer system, a particle collecting sediment trap, and an electromagnetic current meter. A complete description of the technology of the IOEB is available in Woods Hole Oceanographic Institution Technical Report WHOI-93-45 (Krishfield et al., 1993).

Last updated: March 18, 2009