Characteristics of Mesoscale to Submesoscale Eddies in the Labrador Sea: Insights from Ship Observations

In this talk, we present the results highlighted in a recent publication

Bendinger, A., A. F. Dilmahamod, A. Albert, J. Le Sommer, and J. Karstensen, 2025: Characteristics of Mesoscale-to-Submesoscale Eddies in the Labrador Sea: Insights from Ship Observations. J. Phys. Oceanogr., 55, 2037–2057, https://doi.org/10.1175/JPO-D-24-0216.1

Characterisation of coherent eddies is often based on gridded satellite altimetry products. In subpolar regions, these products face limitations due to their low spatial resolution and the decreasing Rossby radius of deformation at higher latitudes, making in situ observations indispensable for eddy characterisation. Here, we present a census of mesoscale-to-submesoscale eddy characteristics in the Labrador Sea—a region where eddies play an important role in winter deep convection and subsequent restratification. Using ship-based observations, we fit an idealised eddy solution to horizontal velocity measurements acquired along ship tracks, determining an optimal eddy centre and other key eddy properties. Based on three research cruises, we reconstructed 40 eddies ranging from 3 to 39 km in radius (mean 15 km) and azimuthal velocity between 7 and 58 cm s−1 (mean 26 cm s−1). The azimuthal velocity structure implies, to a large extent, solid-body rotation in the eddy’s inner core, while opposite signs of vorticity in the outer ring suggest strong vorticity shields. When compared to ship-based observations, the eddy field representation in gridded altimetry products is significantly distorted, with many eddies being underrepresented or undetected. This is even the case for larger-scale features despite having an eddy signature in the along-track altimetry product, which appears to be suppressed in the subsequent mapping methodology. Finally, comparisons with submesoscale-permitting numerical simulation output show favourable agreement, giving confidence in both the ship-based reconstruction and the numerical model’s realism in representing high-latitude eddy dynamics.

Significance Statement

Oceanic eddies in the Labrador Sea play an important role in advecting heat, salt, and other properties to the interior basin with implications for winter deep convection and subsequent restratification of the homogenised water column. Using ship-based observations, our research provides a basinwide eddy characterization, capturing a broad range of spatial scales with radii from 3 to 39 km. We show that conventional satellite altimetry distorts eddy properties at high latitudes, where eddies are smaller in size and often remain undetected. By expanding the census of eddy characteristics in the Labrador Sea, our study offers a valuable dataset for assessing eddy dynamics in high-resolution numerical models, which often lack direct validation.

Our speaker

Fehmi Dilmahamod is a postdoctoral researcher at GEOMAR. Fehmi works on

• Oceanic (sub)-mesoscale dynamics
• Large-scale ocean circulation
• Biophysical coupled processes
• Ocean Observation

His bio is available here.

What is a Climate Coffee?

#climatecoffees are short (circa 40 min: 20 min talk + 20 min Q&A), relaxed meetings for scientists to share ideas, discuss methods, and communicate new results. They are open to speakers of all seniority; we especially encourage early-career scientists to become speakers. The Coffees are an exciting opportunity for scientists to build a network and disseminate recent results peer-to-peer. We invite researchers from across the climate science community to join us for this series of regular online knowledge exchange events.

Recording: https://youtu.be/ankPut334KQ

Register for the next event: https://www.eventbrite.dk/cc/climate-coffees-series-talks-on-and-about-climate-2655309 

Organisation: The Climate Coffees are organised by the Horizon Europe projects ObsSea4Clim, OCEAN ICE, TipESM, the National Centre for Climate Research - DMI, Danish Meteorological Institute and the European Climate Research Alliance.

Disclaimer: Funded by the European Union. Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union or European Research Executive Agency (REA). Neither the European Union nor the granting authority can be held responsible for them.