Preprints
https://doi.org/10.5194/essd-2021-300
https://doi.org/10.5194/essd-2021-300

  17 Sep 2021

17 Sep 2021

Review status: this preprint is currently under review for the journal ESSD.

META3.1exp : A new Global Mesoscale Eddy Trajectories Atlas derived from altimetry

Cori Pegliasco1, Antoine Delepoulle1, Rosemary Morrow2, Yannice Faugère1, and Gérald Dibarboure3 Cori Pegliasco et al.
  • 1CLS, Ramonville Saint Agne, 31250, France
  • 2LEGOS, Toulouse, 31400, France
  • 3CNES, 18 Avenue Edouard Belin, Toulouse, 31400, France

Abstract. This paper presents the new global Mesoscale Eddy Trajectories Atlases (META3.1exp DT all-satellites, https://doi.org/10.24400/527896/a01-2021.001, Pegliasco et al., 2021a and META3.1exp DT two-satellites, https://doi.org/10.24400/527896/a01-2021.002, Pegliasco et al., 2021b), composed of the eddies’ identifications and trajectories produced with altimetric maps. The detection method used is a heritage of the py-eddy-tracker algorithm developed by Mason et al. (2014), optimized to manage with efficiency large datasets, and thus long time series. These products are an improvement of the META2.0 product, produced by SSALTO/DUACS and distributed by AVISO+ (https://aviso.altimetry.fr) with support from CNES, in collaboration with Oregon State University with support from NASA and based on Chelton et al. (2011). META3.1exp provides supplementary information such as the mesoscale eddy shapes with the eddy edges and their maximum speed contour, and the eddy speed profiles from the center to the edge. The tracking algorithm used is based on overlapping contours, includes virtual observations and acts as a filter with respect to the shortest trajectories. The absolute dynamic topography field is now used for eddy detection, instead of the sea level anomaly maps, to better represent the ocean dynamics in the more energetic areas and close to coasts and islands.

To evaluate the impact of the changes from META2.0 to META3.1exp, a comparison methodology has been applied. The similarity coefficient is based on the ratio between the eddies' overlap and their cumulative area, and allows an extensive comparison of the different datasets in terms of geographic distribution, statistics over the main physical characteristics, changes in the lifetime of the trajectories, etc. After evaluating the impact of each change separately, we conclude that the major differences between META3.1exp and META2.0 are due to the change in the detection algorithm. META3.1exp contains smaller eddies and trajectories lasting at least 10 days that were not available in the distributed META2.0 product. Nevertheless, 55 % of the structures in META2.0 are similar in META3.1exp, ensuring the continuity between the two products, and the physical characteristics of the common eddies are close. Geographically, the eddy distribution mainly differs in the strong current regions, where the mean dynamic topography gradients are sharp. The additional information on the eddy contours allows more accurate collocation of mesoscale structures with data from other sources, so META3.1exp is recommended for multi-disciplinary applications.

Cori Pegliasco et al.

Status: open (until 12 Nov 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on essd-2021-300', Anonymous Referee #1, 19 Oct 2021 reply

Cori Pegliasco et al.

Data sets

Mesoscale Eddy Trajectories Atlas Delayed-Time two satellites: version META3.1exp DT twosat Pegliasco, C., Delepoulle, A., and Faugère, Y https://doi.org/10.24400/527896/a01-2021.002

Mesoscale Eddy Trajectories Atlas Delayed-Time all satellites: version META3.1exp DT allsat Pegliasco, C., Delepoulle, A., and Faugère, Y https://doi.org/10.24400/527896/a01-2021.001

Cori Pegliasco et al.

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Short summary
The new global Mesoscale Eddy Trajectories Atlases (META3.1exp) provide the eddies' identification and trajectories from altimetry maps. These atlases are an improvement and the continuity of the historical META2.0 product. Changes in the detection parameters and tracking were tested by comparing the eddies from the different datasets. In particular, the eddy contours available in META3.1exp are un asset for multi-disciplinary studies.