Synoptic Observations – a Nested Approach to Study Energy Transfer & Turbulence in the Ocean in the Eastern South Atlantic/Walvis Ridge

The Meteor cruise M188 SONETT II (March 7 to April 13, 2023) to the southeast Atlantic is an integrative effort within the German collaborative research centre TRR181 ‘Energy Transfers in Atmosphere and Ocean‘. It brings together observational projects with the aim to combine different process studies and observe different dynamical regimes (i.e. geostrophic motions, internal gravity waves, and turbulence.). The cruise will take place partly parallel with the ’fast-sampling’ (CalVal) phase of the Surface Water and Ocean Topography (SWOT) satellite mission.

The area around the Walvis Ridge is characterized by internal tides emanating from the ridge and (sub-)mesoscale eddy activity. The observational program includes the study of mixed-layer processes, mesoscale and submesoscale circulation, horizontal mixing processes, internal waves, and energy dissipation. It is complemented by a modelling project where a general circulation ocean model is set up with a telescoping grid for the target region to evaluate the consistency of the observations as well as validate the models against the observations. The instrumentation includes two short-term moorings, an underway CTD system, gliders, drifters, wave radar, and microstructure turbulence measurements.