HPIES Instruments

The Horizontal Electrometer Pressure-Inverted Echosounders (HPIES) are novel instruments designed and built at the UW Applied Physics Laboratory. They utilize a bottom pressure sensor, a 12-kHz inverted echo-sounder, and a horizontal electrometer to measure the horizontal electrical field, the pressure due to the overlying ocean waters, and the vertical acoustic travel time from the seafloor to the sea surface. These properties provide insights into the vertical structure of current fields and water properties including temperature, salinity, specific volume anomaly, separation of sea surface height variation and temperature, and near-bottom water currents.

There are two HPIES instruments on the Cabled Array: one at Axial Base (LJ03A) and one at Slope Base (LJ01A).

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 (https://henry.apl.uw.edu/~dunlap/hpies-code/).

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