Service interruption on Monday 11 July from 12:30 to 13:00: all the sites of the CCSD (HAL, Epiciences, SciencesConf, AureHAL) will be inaccessible (network hardware connection).
Skip to Main content Skip to Navigation
Journal articles

Intra‐ and inter‐annual variability of North Brazil current rings using angular momentum Eddy detection and tracking algorithm: observations from 1993 to 2016

Abstract : In order to investigate intra- and inter-annual variability of North Brazil Current (NBC) rings, angular momentum eddy detection and tracking algorithm (AMEDA) was used for identification of their occurrence, trajectories, and parameters. Based on 24 years (1993–2016) of geopotential height and geostrophic current fields reanalysis data from ARMOR 3D (¼°), we identified an average rate of five NBC rings shed by year. The rings present an average lifetime of 15.3 (±5.4) weeks, average speed based radius ($R_{max}$) of 139.8 (±23.6) km, and mean sea surface height anomaly (SSHa) of 9.4 (±4.0) cm. The mean observed maximum azimuthal velocity ($V_{max}$) was 0.27 (±0.08) m/s, while the averaged Rossby number (Ro) value was 0.08 (±0.04) and averaged kinetic energy (KE) was of 255.3 (±154.8) cm2 /s2 . NBC rings have larger dimensions, rotate faster, live less, and transfer more energy in boreal winter months. In contrast, those shed during boreal summer and early fall last longer, have smaller diameters and carry less energy. Besides, the analysis of ring merging pointed that the interaction between NBC rings generated a significantly increase in ring energy (52%), and velocity (22%). Finally, we observed the vertical anomalies temperature and salinity profiles, which indicated a thermocline deepening and sinking of coastal and tropical waters due to NBC rings downwelling. This study emphasizes the robustness and efficiency of AMEDA for studying rings in the ocean and further theorizes possible impacts of NBC ring on ocean physical and biogeochemical features in the Western Tropical North Atlantic.
Document type :
Journal articles
Complete list of metadata

https://hal.archives-ouvertes.fr/hal-03145630
Contributor : Françoise Pinsard Connect in order to contact the contributor
Submitted on : Thursday, June 23, 2022 - 7:22:24 AM
Last modification on : Tuesday, June 28, 2022 - 11:23:54 AM

File

JGR Oceans - 2020 - Aroucha - ...
Publisher files allowed on an open archive

Identifiers

Citation

L.C. Aroucha, Dóris Veleda, F. S. Lopes, Pedro Tyaquiçã, Nathalie Lefèvre, et al.. Intra‐ and inter‐annual variability of North Brazil current rings using angular momentum Eddy detection and tracking algorithm: observations from 1993 to 2016. Journal of Geophysical Research. Oceans, Wiley-Blackwell, 2020, 125 (12), pp.e2019JC015921. ⟨10.1029/2019JC015921⟩. ⟨hal-03145630⟩

Share

Metrics

Record views

0

Files downloads

0