RV POSEIDON 516 cruise report/Fahrtbericht, Ponta Delgada (Azores) 29.07.2017 - Ponta Delgada (Azores) 18.08.2017. POS516-Energy Transfer

Abstract

The RV Poseidon cruise 516 (P0S516) is part of the observational program of the TRR 181 'Energy Transfers in Atmosphere and Ocean', and focussed on the energy transfer by low-mode internal waves. The goals of the cruise were to deploy a mooring to record the temporal variability of the internal wave field and associated energy fluxes, and to use time series CTD/LADCP stations to assess locally the temporal variability of mixing, dissipation, and internal wave fluxes. The region south of the Azores in the east Atlantic is ideally suited for this kind of process study, because it is an area of a strong internal tide signal radiating away from the islands. The cruise track is located along a convergence of tidal beams south of the archipelago, crossing a chain of sea mounts as well as the critical latitude for parametric subharmonic instability (PSl). During the cruise, we collected CTD/LADCP time series between 39h and 52h length on 7 stations in up to 5000 m water depth along the tidal beam between 27°30N and 37°N latitude, a total of 92 casts. The mooring equipped with of 7 current meter/temperature logger pairs and an acoustic Doppler current profiler was deployed along the track at 30°29.04N, 30°11.7W in a water depth of 4500 m (to be retrieved in 2018). All anticipated goals of the cruise were accomplished.