The new wave of oceanographers: Arne Bendinger

PhD student in physical oceanography who is interested at the mesoscale to submesoscale eddy field and their interaction with the large-scale flow and submesoscale processes using different observational platforms, remote sensing, and high-resolution modelling.

Arne Bendinger started his career started at the University of Kiel in cooperation with the GEOMAR Helmholtz Centre for Ocean Research and specialized in physical oceanography. During his studies, he participated in several offshore, worked working as a student assistant in the GEOMAR working group, and took part in the exchange program with the university center in Svalbard, Norway. These experiences encouraged him to pursue a PhD, which he is currently carrying out in the DYNOTROP group at LEGOS.

SWOT AdAC: What is your field of research and how did you choose it?

AB: During my studies in Kiel, in fact during an offshore campaign in the Labrador Sea, I was fascinated by the dynamics of ocean turbulence, i.e. ocean eddies, and the way we can study them using in situ observations and altimetry. This is why I chose to work in the context of SWOT and SWOT-AdAC. Here at LEGOS in Toulouse, I am going even further, trying to understand how eddies interact with other small-scale dynamics. This concerns in particular the internal tides (internal waves at the tidal frequency) that are widely present around New Caledonia in the ubiquitous eddy field. Moreover, this raises the question of the distribution of energy between different spatial scales and the role of physical processes at the fine scale on the global energy balance of the ocean.

SWOT AdAC: How is your research related to SWOT?

AB: From an oceanic perspective, SWOT’s goal is to observe meso- and sub-mesoscale dynamics at scales up to 15 km in wavelength, a resolution ten times higher than current altimetry products. However, with these high scales resolved, the challenge is to disentangle the dynamics that contribute to the SSH signal. And since these dynamics can have similar wavelengths, such as eddies and internal tides, this limits our ability to observe meso- and sub-mesoscale structures. My studies attempt to contribute to the understanding of how internal tides are expressed in spectral space, i.e. in SWOT measurements, and how a correction for these internal tides can potentially increase the SWOT observability of meso- and sub-mesoscale dynamics. To do this, we first need a detailed study of the internal tidal field in my region of interest around New Caledonia. We have therefore set up a high-resolution regional numerical simulation that also serves as a reference for planning and optimizing the in-situ experiment that is conducted in SWOTALIS campaign.

SWOT AdAC: What do you find exciting about SWOT and the SWOTALIS campaign and how will you contribute to it?

AB: With respect to SWOT, I am fascinated by our ability to measure the small-scale physics associated with meso- and sub-mesoscale dynamics from space and on a global scale at a resolution never before achieved. I am also curious about the insights we will gain into energy transfer across a wide variety of scales. The SWOTALIS campaign is an excellent opportunity not only to evaluate SWOT measurements, but also to use the unique opportunity of having high resolution, high frequency (one day repeat orbit) SSH data to study the temporal evolution of local dynamics. In addition, we will be able to measure the three-dimensional water column using in situ observations, which will help us understand how local dynamics are expressed in SSH. Our SWOT-AdAC campaign will take place in southern New Caledonia. This is the region that is identified as being subject to both strong internal tides and mesoscale eddies. In addition, this region lies just below the path of SWOT when in a repeated day orbit. To accomplish this, we have planned several experiments, including oceanographic moorings, repeated hydrography and velocity sections, and fixed stations for microstructure measurements to estimate turbulence and energy dissipation. I will be participating in one of the campaigns planned for March-April 2023. My work is related to fine-scale physics measurements in the area of tidal energy propagation and dissipation. These datasets will be very valuable in furthering our understanding of the internal tidal dynamics in southern New Caledonia from an observational perspective that can also be used to evaluate our numerical simulation.

SWOT AdAC: What are your plans after the SWOTALIS campaign?

AB: After the cruise, my first goal will be to finish my PhD. However, the at-sea campaign will provide a large amount of data. In the long term, we plan to continue our collaboration to analyze the collected datasets before comparing them to the actual SSH data from SWOT. These measurements will also provide a first look at local dissipation induced by vertical mixing, which should be of great importance to New Caledonia’s ecosystem, biodiversity and marine habitats, for which New Caledonia is internationally known.