East Pacific ocean eddies and their relationship to subseasonal variability in Central American wind jets

Chang, Chueh‐Hsin; Xie, Shang‐Ping; Schneider, Niklas; Qiu, Bo; Small, R. Justin; Zhuang, Wei; Taguchi, Bunmei; Sasaki, Hideharu; Lin, Xiaopei

doi:10.1029/2011jc007315

Cited by 21 publications

(23 citation statements)

References 90 publications

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“…These eddies were first observed by Stumpf and Legeckis () and have been the subject of many studies (Adams & Flierl, ; Chang et al, ; Farrar & Weller, ; Giese et al, ; Willett et al, ). For instance, on 1 March 2014 three of these eddies were present in the ETPac (Figure ).…”

Section: Introductionmentioning

confidence: 85%

Intraseasonal Variability of Surface Salinity in the Eastern Tropical Pacific Associated With Mesoscale Eddies

et al. 2019

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Strong variability in sea surface salinity (SSS) in the Eastern Tropical Pacific (ETPac) on intraseasonal to interannual timescales was studied using data from the Soil Moisture and Ocean Salinity, Soil Moisture Active Passive, and Aquarius satellite missions. A zonal wave number‐frequency spectral analysis of SSS reveals a dominant timescale of 50–180 days and spatial scale of 8°–20° of longitude with a distinct seasonal cycle and interannual variability. This intraseasonal SSS signal is detailed in the study of 19 individual ETPac eddies over 2010–2016 identified by their sea level anomalies, propagating westward at a speed of about 17 cm/s. ETPac eddies trap and advect water in their core westward up to 40° of longitude away from the coast. The SSS signatures of these eddies, with an average anomaly of 0.5‐pss magnitude difference from ambient values, enable the study of their dynamics and the mixing of their core waters with the surroundings. Three categories of eddies were identified according to the location where they were first tracked: (1) in the Gulf of Tehuantepec, (2) in the Gulf of Papagayo, and (3) in the open ocean near 100°W–12°N. They all traveled westward near 10°N latitude. Category 3 is of particular interest, as eddies seeded in the Gulf of Tehuantepec grew substantially in the vicinity of the Clipperton Fracture Zone rise and in a region where the mean zonal currents have anticyclonic shear. The evolution of the SSS signature associated with the eddies indicates the importance of mixing to their dissipation.

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Section: Introductionmentioning

confidence: 85%

Intraseasonal Variability of Surface Salinity in the Eastern Tropical Pacific Associated With Mesoscale Eddies

et al. 2019

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“…The pathway of the eddies matches very well with the weak maximum in SSH variance in the central BoB, indicating that eddy shedding events contribute to the high SSH ISV in the central BoB. A similar southwestward eddy shedding has been linked to coastal wave propagation off Central America in the northeast Pacific [ Zamudio et al ., ; Chang et al ., ]. The fluctuations in local winds play an important role.…”

Section: Origin Of Intraseasonal Variabilitymentioning

confidence: 99%

Intraseasonal variability of sea surface height in the Bay of Bengal

et al. 2013

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[1] Intraseasonal variability (ISV) of sea surface height (SSH) over the Bay of Bengal (BoB) is studied using altimetry data and an eddy-resolving ocean model. In both the model hindcast and satellite observations, large SSH ISV is found along the eastern and northern coasts of the BoB, in the western BoB, and in a zonal band across the Bay centered near 5 N. The ISV displays a clear seasonality. In the western BoB, it reaches its annual maximum in spring, whereas it does so in summer and autumn southeast of Sri Lanka. Driven by equatorial intraseasonal winds, equatorial Kelvin waves propagate eastward, reach the western coast of Sumatra, and reflect there to propagate around the perimeter of the BoB as coastally trapped waves. Two distinct bands of high eddy activity are detected in the western and central BoB, respectively. In both bands, isolated eddies propagate southwestward. Eddy formation in the eddy train in the central Bay is linked to the coastal wave as it bends around the corner of the Irrawaddy Delta off Myanmar. Eddy activity contributes to the high ISV in the central Bay to some extent. An energetics analysis indicates that high total eddy energy in the western BoB is due to barotropic/ baroclinic instability of the mean current.

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“…The eddy generation in the northeastern Pacific Ocean, off California and Mexico including the California Current System, was studied with high-resolution models applied to reproduce observed characteristics of the eddy field (Liang et al, 2012;Chang et al, 2012). These studies not only highlight hotspots of eddy generation associated with local wind fluctuations (e.g., over the Gulf of Tehuantepec and Papagayo), but also suggest an important role of lowfrequency wind and boundary forcing.…”

Section: Introductionmentioning

confidence: 99%

Occurrence and characteristics of mesoscale eddies in the tropical northeastern Atlantic Ocean

2016

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Abstract. Coherent mesoscale features (referred to here as eddies) in the tropical northeastern Atlantic Ocean (between 12-22 • N and 15-26 • W) are examined and characterized. The eddies' surface signatures are investigated using 19 years of satellite-derived sea level anomaly (SLA) data. Two automated detection methods are applied, the geometrical method based on closed streamlines around eddy cores, and the Okubo-Weiß method based on the relation between vorticity and strain. Both methods give similar results. Mean eddy surface signatures of SLA, sea surface temperature (SST) and sea surface salinity (SSS) anomalies are obtained from composites of all snapshots around identified eddy cores. Anticyclones/cyclones are identified by an elevation/depression of SLA and enhanced/reduced SST and SSS in their cores. However, about 20 % of all anticyclonically rotating eddies show reduced SST and reduced SSS instead. These kind of eddies are classified as anticyclonic mode-water eddies (ACMEs). About 146 ± 4 eddies per year with a minimum lifetime of 7 days are identified (52 % cyclones, 39 % anticyclones, 9 % ACMEs) with rather similar mean radii of about 56 ± 12 km. Based on concurrent in situ temperature and salinity profiles (from Argo float, shipboard, and mooring data) taken inside of eddies, distinct mean vertical structures of the three eddy types are determined. Most eddies are generated preferentially in boreal summer and along the West African coast at three distinct coastal headland regions and carry South Atlantic Central Water supplied by the northward flow within the Mauretanian coastal current system. Westward eddy propagation (on average about 3.00 ± 2.15 km d −1 ) is confined to distinct zonal corridors with a small meridional deflection dependent on the eddy type (anticyclones -equatorward, cyclones -poleward, ACMEs -no deflection). Heat and salt fluxes out of the coastal region and across the Cape Verde Frontal Zone, which separates the shadow zone from the ventilated subtropical gyre, are calculated.

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East Pacific ocean eddies and their relationship to subseasonal variability in Central American wind jets

Cited by 21 publications

References 90 publications

Intraseasonal Variability of Surface Salinity in the Eastern Tropical Pacific Associated With Mesoscale Eddies

Intraseasonal Variability of Surface Salinity in the Eastern Tropical Pacific Associated With Mesoscale Eddies

Intraseasonal variability of sea surface height in the Bay of Bengal

Occurrence and characteristics of mesoscale eddies in the tropical northeastern Atlantic Ocean

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