The Horizontal Electric Field, Pressure and Inverted Echo Sounder (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.

(text and images courtesy of Interactive Oceans)

Data Products

This instrument measures the following data products. Select a data product's name to learn more.

Data Product Code DPS
Vertically Averaged Horizontal Water Velocity (VAHWV) IESAHWV
Water Column Heat Content IESHEAT
Bottom Pressure IESPRES
Roundtrip Acoustic Travel Time (RATT) IESRATT
Horizontal Electric Fields IES_HEF
Water Property Profile Time Series IES_WPP

Instrument Models & Deployed Locations

The OOI includes the following instrument makes and models for this instrument type. Follow the links below to find out where in the OOI this instrument has been deployed. You'll also find quick links for each instrument to Data portal, where you can plot and access data.

Class-Series Make Model
HPIESA Sanford, UW cabled HPIES

Reference Information

John Dunlap, the instrument engineer and subject matter expert (SME) at UW, has provided code that can convert the L0 data from the uFrame system to create the L1 and L2 data products (

Primary Science Discipline


Research Themes

Access Data

HPIES on the Data Portal

Removing the pins holding the descent weights onto the HPIES platform at Axial Base.
Removing the pins holding the descent weights onto the HPIES platform at Axial Base. Photo Credit: NSF-OOI/UW/CSSF, Dive 1739, V14 Creative Commons License