What Can We Learn From Observed Temperature and Salinity Isopycnal Anomalies at Eddy Generation Sites? Application in the Tropical Atlantic Ocean

Aguedjou, Micael; Chaigneau, Alexis; Dadou, Isabelle; Morel, Yves; Pegliasco, Cori; Da‐Allada, C. Y.; Baloïtcha, Ezinvi

doi:10.1029/2021jc017630

Cited by 9 publications

(21 citation statements)

References 96 publications

(263 reference statements)

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“…However, recent improvements in estimation of the Mean Dynamic Topography, depending on the geoid (Rio et al, 2011; allowed to provide more accurate ADT fields. Thus, following Laxenaire et al (2018) and Aguedjou et al (2021), and the recommendations of Pegliasco et al (2021), mesoscale eddies were detected on ADT fields instead of SLA. Eddy trajectories were then reconstructed using the tracking method developed by Pegliasco et al (2015).…”

Section: Altimetry Data and Eddy Trackingmentioning

confidence: 74%

“…These temperature and salinity vertical profiles are available at https://www.coriolis.eu.org/Observing-the-Ocean/ARGO. Vertical profiles from the Argo program in the Tropical Atlantic are available after 2000 (e.g., Aguedjou et al, 2021), reason why we limit our analysis to 2000-2018.…”

Section: Argo Dataset and Classification Of Argo Profilesmentioning

confidence: 99%

“…Then, a composite analysis of the eddy vertical structures were performed following Aguedjou et al (2021). First, we retained only vertical profiles with at least 30 data between 15 m and 950 m depth, and with no significant vertical gap between each data (see Aguedjou et al (2021) for more details). In the study region, 6134 profiles were retained (Figure 1).…”

Section: Argo Dataset and Classification Of Argo Profilesmentioning

confidence: 99%

“…Moreover, on their pathway, they can influence ocean-atmosphere exchanges by affecting heat-fluxes at the air-sea interface, winds, cloud cover and precipitations (e.g., Frenger et al, 2013;Villas Boâs et al, 2015). They can also affect temperature, salinity and velocity fields from the sea surface to ~1000 m depth (Kang and Curchitser, 2015;Pegliasco et al, 2015;Keppler et al, 2018;Aguedjou et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

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Mesoscale eddies in the southwestern tropical Atlantic

Dossa

Silva²,

Hernández

et al. 2022

Front. Mar. Sci.

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The southwestern tropical Atlantic is a region of complex ocean dynamic where originates the strong western boundary current system composed of North Brazil current and North Brazil undercurrent. The region includes a variety of features including the Atoll das Rocas (AR) and Fernando de Noronha (FN) ridge that may favour mesoscale eddy dynamics. However, origin, occurrence and characteristics of mesoscale eddies were still not described in the region. Using satellite altimetry data from 1993 to 2018 off Northeast Brazil (37-25°W; 13-1°S), we reconstruct eddy trajectories and analyse the main eddy surface characteristics (e.g., size, amplitude, polarity) and their spatiotemporal variations. The study reveals two distinct dynamic regions before quantifying mesoscale eddies characteristics. Approximately 2000 mesoscale eddies crossed the region during the study period, among which 76% were generated inside the region, with amplitudes and radii ranging between 1 and 2 cm and 25 and 205 km, respectively. Eddies are preferentially formed between August and September and propagate westward. In the region around the FN Archipelago (36-26°W; 6-1°S), the formation of cyclonic eddies is likely favoured by barotropic instabilities of surface currents and the wind stress curl. On the other hand, in the south of the region (36-26°W; 12-8°S), eddies formation is likely associated with the barotropic instabilities, wind stress curl and the meandering of surface currents. Based on vertical temperature and salinity profiles from Argo floats’ data, we determined that in average, the core of cyclonic eddies is centred at ~ 130 m (140 m) in the northern (southern) region while the core of anticyclonic eddies is centred at ~90 m (125 m) in the northern (southern) region. Moreover, mesoscale eddies formed in the tropical Atlantic do not connect the eastern tropical Atlantic and northeast Brazil.

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Section: Altimetry Data and Eddy Trackingmentioning

confidence: 74%

Section: Argo Dataset and Classification Of Argo Profilesmentioning

confidence: 99%

Section: Argo Dataset and Classification Of Argo Profilesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mesoscale eddies in the southwestern tropical Atlantic

Dossa

Silva²,

Hernández

et al. 2022

Front. Mar. Sci.

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“…More recently, eddy abundance and seasonality, as well as their hydrographic properties have been investigated by H. M. A. Aguedjou et al (2019) and H. Aguedjou et al (2021), respectively on the basis of the recent multimission satellite altimetry observations and Argo profilling floats, over a relatively larger geographical domain (70°W-10°E, 30°S-30°N). The identification of several mesoscale eddies in this region (H. M. A.…”

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confidence: 99%

Mesoscale Variability, Critical Latitude and Eddy Mean Properties in the Tropical South‐East Atlantic Ocean

et al. 2023

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Equatorward decrease of mesoscale eddy abundance, and meridional variations of their mean properties in the tropical South‐East Atlantic Ocean have been investigated on the basis of horizontal length‐scales of geostrophic flows, and theories of two‐dimensional geostrophic turbulence on a β‐plane. Meridional variations of satellite‐derived altimetric eddy kinetic energy density spectra were assessed in bins of 5°, from 5°S to 25°S, zonally averaged between 8°W and 15°E. They revealed two latitudinal bands of minimum eddy energy spectra: one in the northern Angola Basin (5°S–10°S) and the other across the Angola Benguela Front (15°S–20°S). In the latter, both the eddy forcing scale and the Rhines scale were observed at wavelengths of 300 and 350 km respectively, suggesting that only a small spectral range exists for eddies to grow. On the other hand, in the former, the eddy forcing scale and the Rhines scale were observed at wavelengths of 454 and 520 km respectively. The ratio between the Rhines scale and the first baroclinic Rossby radius revealed an onset of a critical latitude at about 11.4°S. Consistently, maps of eddy frequency of occurrence computed from eddies identified in the region has shown a notable decay in signal of the eddy density distribution around that latitude. This could explain the sharp equatorward transition of mesoscale processes observed in this region, which seems to shift from nonlinear eddies to linear Rossby waves, potentially explaining why fewer eddies are observed in the region when compared to other regions of the world oceans.

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An “objective” definition of potential vorticity. Generalized evolution equation and application to the study of coastal upwelling instability

Morel,

Morvan,

Benshila

et al. 2023

Ocean Modelling

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What Can We Learn From Observed Temperature and Salinity Isopycnal Anomalies at Eddy Generation Sites? Application in the Tropical Atlantic Ocean

Abstract:  On density-coordinates, both CEs and AEs can exhibit significant positive, negative or non-significant isopycnal θ/S anomalies. We discuss the relationship between isopycnal θ/S and PV anomalies and how they can inform us on their generation mechanisms.

Cited by 9 publications

References 96 publications

Mesoscale eddies in the southwestern tropical Atlantic

Mesoscale eddies in the southwestern tropical Atlantic

Mesoscale Variability, Critical Latitude and Eddy Mean Properties in the Tropical South‐East Atlantic Ocean

An “objective” definition of potential vorticity. Generalized evolution equation and application to the study of coastal upwelling instability

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