An Intrathermocline Eddy and a tropical cyclone in the Bay of Bengal

Gordon, Arnold L.; Murty, V. S. N.

doi:10.1038/srep46218

Cited by 47 publications

(43 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Gordon et al () noticed intrathermocline eddy at subsurface depths with the water characteristics of Andaman Sea in the western BoB and suggested that eastern BoB and Andaman Sea provides the source waters for eddies in the BoB. All six sampled ACEs were originated in the eastern BoB (Figure ) and advected to the west.…”

Section: Resultsmentioning

confidence: 95%

Ventilation of Oxygen to Oxygen Minimum Zone Due to Anticyclonic Eddies in the Bay of Bengal

Sridevi

Bhaskar²

2018

JGR Biogeosciences

View full text Add to dashboard Cite

Intense oxygen minimum zone (OMZ) occurs in the middepth of the Eastern Tropical Pacific (ETP), Arabian Sea (AS), and Bay of Bengal (BoB). However, the occurrence of anammox/denitrification was reported only in the ETP and AS and its absence in the BoB is attributed to presence of traces of dissolved oxygen (DO). Anticyclonic eddies (ACEs) supply high-nutrient, organic-rich, and oxygen-poor waters from the coastal upwelling regions leading to strengthening of OMZ in the offshore of AS and ETP. In the absence of western boundary upwelling, we hypothesize that the ACEs supply DO-rich water leading to weakening of OMZ in the BoB. Six ACEs were sampled by bio-argo floats and measured in situ hydrography and DO. All sampled eddies were formed in the eastern BoB, close to Andaman Sea, and moved toward west. Warm and DO-rich waters were observed in the core of OMZ (150-300 m), influenced by ACEs, by 0.5-1.46°C and 3.2-6.5 μM, respectively, than no eddy region in the BoB. Based on the mean lifetime of ACE, the rate of ventilation in the 100-300 m was estimated to be 0.07 ± 0.02 μmol/L/day, which is 3 to 4 times higher than bacterial respiration rates (0.02 μmol/L/day). Concerns of OMZ intensification leading to denitrification/anammox conditions in the BoB have been expressed, but with several ACEs forming in time and space in the BoB the denitrification occurrence is unlikely.SARMA AND UDAYA BHASKAR 2145

show abstract

Section: Resultsmentioning

confidence: 95%

Ventilation of Oxygen to Oxygen Minimum Zone Due to Anticyclonic Eddies in the Bay of Bengal

Sridevi

Bhaskar²

2018

JGR Biogeosciences

View full text Add to dashboard Cite

show abstract

“…Takikawa et al (2005) detected SSE to the southeast of the Ryukyu Islands, which had thickness and width of 300 m and 100 km, respectively. In December 2013, a subsurface lens of water from the Andaman Sea was captured in the Bay of Bengal (Gordon et al 2017). Nan et al (2017) detected an extra-large subsurface anticyclonic eddy with horizontal scale of 470 km in the Northwest Pacific subtropical gyre.…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies have proven that SSE can strongly influence intermediate or deeper ocean layers by affecting the subsurface circulation, pathways of water masses, and redistribution of heat, salt, and momentum (Andrade et al 2014;Colas et al 2012;Nan et al 2017;Pelland et al 2013). Unlike surface eddies (SEs), which can be characterized using satellite altimeter data, SSEs have weak surface expression, and they are poorly understood because of the lack of their systematic measurement (Chaigneau et al 2011;Gordon et al 2017;Johnson and McTaggart 2010). Most reported eddies have survived for a significant time (of the order of months) and traveled considerable distance (hundreds of kilometers) (Combes et al 2015;Takikawa et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Study of subsurface eddy properties in northwestern Pacific Ocean based on an eddy-resolving OGCM

Nan

2019

Ocean Dynamics

View full text Add to dashboard Cite

A method based on the Okubo-Weiss parameter was used to detect subsurface eddies (SSEs) with an eddy-resolving ocean general circulation model. Statistical analyses showed that SSEs are ubiquitous in the northwestern Pacific Ocean. Three regions were found to have high probability of SSE, which are as follows: the latitudinal band between 9°N and 17°N, the Kuroshio extension region, and the area east of the Ryukyu Islands. Although surface eddies (SEs) were found distributed widely within the zonal band of the Subtropical Counter Current, few SSEs were found there. In contrast, few SEs were found to the east of The Philippines, whereas SSEs were abundant. The kinetic energy contained within SSE was found comparable in magnitude with that of SE. During 1993, about 2569 and 2099 SSEs (at a depth of about 400 m) were observed to be anticyclonic and cyclonic, respectively; thus, SSEs tended to be anticyclonic. The mean radius, lifespan, and propagation speed of SSE in this study were about 60 km, 50 days, and 6.6 cm/s, respectively. The propagation speed showed a wave-like decrease with increasing latitude. Some long-lived SSEs were found to persist for longer than 4 months and to move thousands of kilometers. About 89% of SSEs were nonlinear for at least half their lifespan, which implies that SSE can trap interior fluid during translation. Trajectories revealed that SSEs propagate nearly due west with only small meridional deflection. The findings of this study will contribute to the enrichment of our knowledge regarding SSE in the northwestern Pacific Ocean.

show abstract

“…Cheng et al () detected two, southwest‐slanted, eddy pathways in the BoB: one located near the western boundary and the other in the central Bay (central pathway). Recently, Gordon et al () reported the existence of intrathermocline anticyclonic eddy at the subsurface depths in the central BoB, which represents the dominate influence of vertical motion of thermocline.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of Eddy Generation in the Central Bay of Bengal

et al. 2018

View full text Add to dashboard Cite

Eddy activity in the central Bay of Bengal (BoB) is revealed using satellite observations and hydrographic data. Altimetric data show that eddies are generated near the eastern boundary, propagate southwestward, and have periods predominantly in the 30-to 120-day band. Temperature profiles from the Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction (RAMA) buoy at 90°E, 15°N, have their highest amplitude in the depth range of the thermocline, indicating that the eddies are associated with a vertical motion of the thermocline (a first-baroclinic-mode response). To investigate the cause of the eddies, we obtained a suite of solutions to nonlinear and linear versions of a 1½-layer (reduced-gravity) model. They demonstrate that equatorial wind forcing, Myanmar bump and Andaman Island, and nonlinearity are all essential for eddy formation. Among the nonlinear terms, the advection terms are the primary cause.Plain Language Summary This study combines observations and model to understand eddy generation in the central Bay of Bengal. When equatorial wind-driven downwelling (upwelling) Kelvin waves propagate to the tip of the Irrawaddy Delta off Myanmar, anticyclonic (cyclonic) eddies are generated there that subsequently propagate southwestward. The eddies are mainly driven by equatorial zonal winds, with both nonlinearity and coastline geometry essential for eddy generation.

show abstract

An Intrathermocline Eddy and a tropical cyclone in the Bay of Bengal

Cited by 47 publications

References 27 publications

Ventilation of Oxygen to Oxygen Minimum Zone Due to Anticyclonic Eddies in the Bay of Bengal

Ventilation of Oxygen to Oxygen Minimum Zone Due to Anticyclonic Eddies in the Bay of Bengal

Study of subsurface eddy properties in northwestern Pacific Ocean based on an eddy-resolving OGCM

Dynamics of Eddy Generation in the Central Bay of Bengal

Contact Info

Product

Resources

About