Over the course of the research cruise, the science team, led by Magdalena Andres of Woods Hole Oceanographic Institution, will deploy several pressure sensor equipped inverted echo sounders (PIESs). The small, easily deployed oceanographic instruments sit on the seabed and use a pressure sensor and an acoustic echo sounder to measure the overlying sea surface height and thermocline depth. In addition, many of the instruments being deployed on the PEACH project are equipped with a single point current sensor on a 50 meter tether floating above the device. These devices are called current pressure sensor equipped inverted echosounders, or CPIESs. By pairing individual CPIESs together in a network, the instruments can provide oceanographers with an accurate overall picture of the ocean currents at the surface and below. Using the slope of the thermocline measured by the network of CPIESs, projects scientists can infer overall current flow and direction. On the PEACH project, CPIESs are being used to better understand the Gulf Stream and the transport of shelf water into the deep ocean.
CPIESs are deployed on a metal stand with ballast weight attached, both of which are sacrificial. After their 18-month deployment, special acoustic releases are triggered from the surface with a topside transducer system, releasing the CPIES from its stand and ballast. Floatation found located in the top of the CPIE brings the device to the surface, where blinking lights and a radio beacon assist in its recovery.
CPIESs are valuable oceanographic instruments used by the research team on the PEACH Project. The CPIES network used in the PEACH project will provide oceanographers with an unprecedented look at the shelf water exchange into the deep ocean, along with valuable information on the net flow of the Gulf Stream.