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Intra‐ and Inter‐Annual Variability of North Brazil Current Rings Using Angular Momentum Eddy Detection and Tracking Algorithm: Observations From 1993 to 2016
- Source :
- Journal of Geophysical Research: Oceans, Journal of Geophysical Research. Oceans, Journal of Geophysical Research. Oceans, 2020, 125 (12), pp.e2019JC015921. ⟨10.1029/2019JC015921⟩, Journal of Geophysical Research. Oceans, Wiley-Blackwell, 2020, 125 (12), ⟨10.1029/2019JC015921⟩
- Publication Year :
- 2020
-
Abstract
- International audience; 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.
- Subjects :
- Angular momentum
010504 meteorology & atmospheric sciences
010505 oceanography
NBC Rings
[PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]
Tropical Atlantic
Oceanography
Geodesy
Tracking (particle physics)
01 natural sciences
AMEDA algorithm
Geophysics
Ocean eddies
13. Climate action
Space and Planetary Science
Geochemistry and Petrology
Earth and Planetary Sciences (miscellaneous)
14. Life underwater
Current (fluid)
ComputingMilieux_MISCELLANEOUS
Geology
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 21699275 and 21699291
- Database :
- OpenAIRE
- Journal :
- Journal of Geophysical Research: Oceans
- Accession number :
- edsair.doi.dedup.....1c9452960b52972509dc1c13ab463ad5
- Full Text :
- https://doi.org/10.1029/2019jc015921