Water characteristics and current structure at 65°E during the southwest monsoon

Sharma, G S

doi:10.1007/bf02107985

Cited by 11 publications

(12 citation statements)

References 13 publications

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“…In most of the South Indian Ocean, the salinity gradients are favorable to eastward currents in the mixed layer. However, analyses of the Turner angles and salinity contribution ratios show that salinity is of secondary importance for the southern SICC definition, in agreement with Jia et al [2011] and Sharma [1976], and in contrast to the suggestion of Siedler et al [2006] and Palastanga et al [2007].…”

Section: Discussionmentioning

confidence: 61%

“…However, analyses of the Turner angles and salinity contribution ratios show that salinity is of secondary importance for the southern SICC definition, in agreement with Jia et al . [] and Sharma [], and in contrast to the suggestion of Siedler et al . [] and Palastanga et al .…”

Section: Discussionmentioning

confidence: 99%

“…Although the SICC has only recently been recognized as a permanent feature of the SIO circulation, Sharma [1976] and Sharma et al [1978] described a shallow eastward current between 22 S and 26 S associated with a thermal front. He named that current the South Indian Tropical Countercurrent, pointing out that it was evident in all surface geopotential charts from the Indian Ocean Atlas produced by Wyrtki in 1971 and also on the surface currents maps from the Royal Netherlands Meteorological Institute in 1952.…”

Section: Introductionmentioning

confidence: 99%

“…Despite being a permanent feature of the large-scale circulation, the formation mechanism and dynamics controlling the SICC are still largely unknown [Palastanga et al, 2007;Siedler et al, 2006;Schott et al, 2009]. Since the SICC flows opposite to the direction predicted by classical theories of wind-driven circulation, and its geographic location is at the same latitude range as the subtropical countercurrents (STCC) observed in the Pacific and North Atlantic, many authors [e.g., Sharma, 1976;Siedler et al, 2006; potential vorticity (PV) regions (mode waters) at the pycnocline level and poleward of the front [e.g., Aoki et al, 2002;Kobashi et al, 2006;Kobashi and Kubokawa, 2012, and references therein].…”

Section: Introductionmentioning

confidence: 99%

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South Indian Countercurrent and associated fronts

et al. 2014

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A striking feature of the South Indian Ocean circulation is the presence of the eastward South Indian Countercurrent (SICC) that flows in a direction opposite to that predicted by the classical theories of wind-driven circulation. Several authors suggest that the SICC resembles the subtropical countercurrents (STCCs) observed in other oceans, which are defined as narrow eastward jets on the equatorward side of subtropical gyres, where the depth-integrated flow is westward. These jets are associated with subsurface thermal fronts at thermocline depths by the thermal wind relation. However, the subsurface thermal front associated with the SICC has not been described to date. Other studies conjecture an important role for salinity in controlling the SICC. In the present work, we analyze three Argo-based atlases and data from six hydrographic cruises to investigate whether the SICC is accompanied by permanent thermal and density fronts including salinity effects. The seasonal cycle of these fronts in relation to the SICC strength is also investigated. We find that the SICC is better described as composed of three distinct jets, which we name the northern, central, and southern SICC. We find that the southern SICC around 26 S has an associated thermal front at subsurface depths around 100-200 m with salinity being of secondary importance. The southern branch strength is related to mode waters poleward of the front, similar to a STCC-like current. However, the SICC multiple jet structure seems to be better described as resulting from PV staircases.

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Section: Discussionmentioning

confidence: 61%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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South Indian Countercurrent and associated fronts

et al. 2014

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“…This behaviour is in agreement with the intensification of the eastward flow near 25GS, 176°E indicated by Ridgway et al (1979). The front is therefore probably associated with a subtropical countercurrent similar to that encountered between 22°S and 26°S in the South Indian Ocean (Sharma 1976). This current should be distinguished from the South Tropical Countercurrent observed in the Coral Sea (Donguy & Henin 1975, Donguy et al 1976).…”

Section: Discussionmentioning

confidence: 79%

Some hydrological features of the South Fiji Basin

Denham¹,

Bannister²,

Guthrie³

et al. 1981

New Zealand Journal of Marine and Freshwater Research

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Expendable bathythermograph (XBT) and salinity observations were made along a northsouth section across the South Fiji Basin in March 1976, and XBT observations only were made in May 1976, January-February 1977, and July 1978. The salinity section showed a tongue of low salinity (less than 34.75%c) surface water associated with the intertropical convergence zone of winds, near 20°S. The corresponding temperature section indicated the presence of weak eddies; a warm-core eddy near 28°S, 176°E was encountered in February 1977. The main feature of the subsurface temperature structure was a thermal front between 25 C S and 26°S at depths between 100 and 400 m: the temperature at 200 m was over 18°C north of the front and below 18°C to the south of it. This front, observed on all the temperature sections, was strongest from January to March. It is ascribed to the flow of a subtropical counter-current similar to that encountered in the South Indian Ocean at about the same latitude.

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