Vertical velocities are difficult to measure directly and their prediction is challenging. Identifying the 3D pathways that connect the surface ocean to the interior is one of the goals of the DRI CALYPSO project. These pathways are pivotal for predicting the distribution of pollutants, oxygen, heat, carbon, and other biogeochemical tracers. Recent studies have shown that vertical transport is influenced by flows at many scales and demonstrate that vertical motions associated with horizontal scales smaller than 10 km play a significant role in vertical exchanges.     Lagrangian instruments can cover large distances on their own, thereby reducing the need for (costly and slow) direct sampling. Due to the time-evolving nature of the flow, a Lagrangian approach is favored to study the transport and dispersion of water properties. Studying frontogenesis and subduction in the Lagrangian frame is more advantageous than in the Eulerian frame. Cluster experiments give information about the two-dimensional structure of the flow field, and the relative deformation of swarms of drifters by the velocity at multiple spatial scales.   Here we use Lagrangian trajectories from drifter observations deployed during the CALYPSO 2022 cruise on a coherent submesoscale cyclonic eddy which was sampled for 14 days. During that time several episodes of surface convergence and downwelling were observed and analyzed. The results show convergences of order -1f and reveal downwelling velocities of -60 m/day.

Primary Presenter: Daniel Tarry, IMEDEA (CSIC-UIB) (drtarry@imedea.uib-csic.es)

Authors:

Daniel R. Tarry, IMEDEA (CSIC-UIB)  (drtarry@imedea.uib-csic.es)

Ananda Pascual, IMEDEA (CSIC-UIB)  ()

Simon Ruiz, IMEDEA (CSIC-UIB)  ()

T.M. Shaun Jonhston, Scripps Institution of Oceanography  ()

Pierre-Marie Poulain, NATO-STO-CMRE  ()

Tamay Özgökmen, RSMAS University of Miami  ()

Luca Centurioni, Scripps Institution of Oceanography  ()

Amala Mahadevan, WHOI  ()

Eric D'Asaro, APL University of Washington  ()