Abstract's details

Inter and intra-annual variability of the North Brazil Current rings from altimetry detected by TOEddies and comparison with in-situ measurements from the EUREC4A-OA experiment

Corentin Subirade (LMD, Laboratoire de Météorologie Dynamique, UMR 8539 CNRS, École normale supérieure, Paris, France, France)

CoAuthors

Pierre L'Hégaret (LMD, Laboratoire de Météorologie Dynamique, UMR 8539 CNRS, École normale supérieure, Paris, France, France); Sabrina Speich (LMD, Laboratoire de Météorologie Dynamique, UMR 8539 CNRS, École normale supérieure, Paris, France, France); Rémi Laxenaire (LMD and LACy (Laboratoire de Météorologie Dynamique, UMR 8539 CNRS, École normale supérieure, Paris, France / Laboratoire de L’Atmosphère et des Cyclones, UMR 8105 CNRS, Université de La Réunion, Météo-France, Saint-Denis, France), France)

Event: 2022 Ocean Surface Topography Science Team Meeting

Session: Science III: Mesoscale and sub-mesoscale oceanography

Presentation type: Type Oral

The Northwest Tropical Atlantic Ocean is a dynamical region filled with mesoscale eddies of different origins and moving at different depths, transporting various water masses across the region. These eddies have rich and diverse characteristics ranging from shallow cyclonic and anticyclonic eddies to deeper reaching subsurface structures. Some of these eddies, and in particular North Brazil Current (NBC) rings, have been previously observed and described in dedicated oceanographic experiments. The EUREC4A-OA campaign that took place in January-February 2020, brings in new details in the structures and dynamics of these mesoscale features and their imprint on the regional ocean dynamics and air-sea interactions. The EUREC4A-OA sampling strategy was based on daily analyses of NRT Absolute Dynamic Height and other variables (SST, Chl-a, SSS) satellite maps and the use of the TOEddies (Laxenaire et al., 2018) eddy detection and tracking algorithm as well as underway S-ADCP observations of subsurface (down to 1000 m of depth) currents. The large number and diversity (ship-mounted or autonomous) of observing platforms implemented in the project made it possible to innovatively sample the upper 1500 m ocean frontal scales and stratification.

This strategy allowed a high-resolution sampling of three shallow surface and two subsurface NBC rings. In the present study we will discuss the observed 3D eddy structures and their evolution. We will compare satellite synoptic observations and the TOEddies detected structures with the in-situ measurements. We will set the EUREC4A-OA synoptic observations in a statistical context by discussing NBC rings observations as derived from applying the TOEddies algorithm to the 28-year satellite altimetry record. Indeed, TOEddies provides a different intra and inter-annual variability for NBC rings compared with previous published studies. Moreover, as NBC rings characteristics change abruptly during their lifetimes, we will examine the impact of their interaction with other eddies, local topography and Amazon freshwater plumes flowing along the shelf-break.
 

Oral presentation show times:

Room Start Date End Date
Sala Grande Wed, Nov 02 2022,17:10 Wed, Nov 02 2022,17:21
Corentin Subirade
LMD, Laboratoire de Météorologie Dynamique, UMR 8539 CNRS, École normale supérieure, Paris, France
France
corentin.subirade@gmail.com