Horizontal Electrometer Pressure Inverted Echosounder V17

HPIES About to Drop 2900 meters
HPIES pin removal

Removing the pins holding the descent weights onto the HPIES platform at Axial Base.

Photo Credit: NSF-OOI/UW/CSSF, Dive 1739, V14

The Horizontal Electrometer-Pressure-Inverted Echosounder (HPIES) is an instrument that utilizes a bottom pressure sensor, a 12-kHz inverted echosounder and a horizontal electrometer to measure the horizontal electrical field, the bottom pressure, and the vertical acoustic travel time from the sea floor to the sea surface. These properties provide insights into the vertical structure of current fields and water properties including temperature, salinity, and specific volume anomaly, separation of sea surface height variation and temperature, and near-bottom water currents.

During VISIONS '14, two HPIES were installed, one at Axial Base (LJ03A) and one at Slope Base (LJ01A).