Observed year-to-year sea surface salinity variability in the Bay of Bengal during the 2009–2014 period

Chaitanya, Akurathi Venkata Sai; Durand, Fabien; Mathew, Simi; Gopalakrishna, V. V.; Papa, Fabrice; Lengaigne, Matthieu; Vialard, Jérôme; Chanda, Kranthikumar; Venkatesan, R.

doi:10.1007/s10236-014-0802-x

Cited by 47 publications

(38 citation statements)

References 43 publications

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“…Those signals both force coastal upwelling Kelvin waves that propagate anticlockwise around the rim of the BoB. The related negative sea level anomalies along the east coast of India weaken the EICC, hence limiting the seasonal southward advection of fresh water from the northern part of the Bay [ Chaitanya et al ., ; Akhil et al ., ] and resulting in a positive SSS anomaly of the order of 1 pss there. Conversely, during a negative IOD event, downwelling Kelvin waves induce an acceleration of EICC, favoring the southward advection of the fresh plume.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…The realism of the REF simulation is assessed by comparing its SSS IAV to a comprehensive SSS dataset detailed in Chaitanya et al . [], which compiles all in situ SSS measurements available over the BoB during the 2006–2012 period. It consists of six different types of data: ARGO profilers [ Roemmich et al ., ], ship‐of‐opportunity XCTD profiles and bucket measurements, RAMA moorings [ McPhaden et al ., ], OMNI moorings [ Venkatesan et al ., ], ship‐of‐opportunity thermosalinograph transects [ Alory et al ., ] and dedicated hydrographic cruises.…”

Section: Methodsmentioning

confidence: 99%

“…The scarcity of available SSS in situ observations and the lack of reliable continental freshwater fluxes did for long prevent the monitoring of the BoB SSS interannual variability (hereafter IAV). The improvement of the SSS observing system through the advent of the Argo program and the new dataset of satellite altimeter‐derived discharges of major rivers that flow into the Bay [ Papa et al ., ] recently allowed to provide a qualitative description of the year‐to‐year SSS variability over the BoB [ Chaitanya et al ., ; Pant et al ., ]. These studies reported, in particular, a strong SSS IAV in the northern BoB.…”

Section: Introductionmentioning

confidence: 99%

“…Based on a simple mixed‐layer model salt budget, both Chaitanya et al . [] and Pant et al . [] concluded that SSS IAV is mainly driven by fresh water fluxes in the northern BoB during summer season.…”

Section: Introductionmentioning

confidence: 99%

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A modeling study of processes controlling the Bay of Bengal sea surface salinity interannual variability

Akhil

Lengaigne

Vialard

et al. 2016

J. Geophys. Res. Oceans

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Recent observational studies provided preliminary insights on the interannual variability of Bay of Bengal (BoB) Sea Surface Salinity (SSS), but are limited by the poor data coverage. Here, we describe the BoB interannual SSS variability and its driving processes from a regional eddy‐permitting ocean general circulation model forced by interannually varying air‐sea fluxes and altimeter‐derived discharges of major rivers over the past two decades. Simulated interannual SSS variations compare favorably with both in situ and satellite data and are largest in boreal fall in three regions: the northern BoB, the coastal region off east India, and the Andaman Sea. In the northern BoB, these variations are independent from those in other regions and mostly driven by summer‐fall Ganga‐Brahmaputra runoff interannual variations. In fall, remote forcing from the Indian Ocean Dipole results in anticlockwise anomalous horizontal currents that drive interannual SSS variations of opposite polarity along the east coast of India and in the Southern Andaman Sea. From winter onward, these anomalies are damped by vertical mixing in the northern BoB and along the east coast of India and by horizontal advection in the Southern Andaman Sea. While river runoff fluctuations locally play a strong role near the Ganga‐Brahmaputra river mouth, wind‐driven interannual current anomalies are responsible for a large fraction of SSS interannual variability in most of the basin.

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Section: Summary and Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A modeling study of processes controlling the Bay of Bengal sea surface salinity interannual variability

Akhil

Lengaigne

Vialard

et al. 2016

J. Geophys. Res. Oceans

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“…The special feature that distinguishes the Bay of Bengal (BoB or bay) from the rest of the Indian Ocean is that it receives large quantity of freshwater from rainfall and discharge by several rivers. Owing to the enormous freshwater input, the salinity of the upper layer of the bay is remarkably low resulting in strong vertical stratification [ Shetye et al ., ; Vinayachandran et al ., ; Rao and Sivakumar , ; Yu and McPhaden , ; Chaitanya et al ., ], thereby influencing dynamics and thermodynamics of the mixed layer (ML). River discharge lowers the salinity near the river mouths and coastal regions along its pathway, whereas precipitation is distributed over a much larger area.…”

Section: Introductionmentioning

confidence: 97%

An OGCM study of the impact of rain and river water forcing on the Bay of Bengal

Behara

Vinayachandran

2016

JGR Oceans

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Individual and combined effects of rainfall and river discharge on the Bay of Bengal (BoB) is investigated using an Ocean General Circulation Model. A set of four sensitivity experiments, forced with same air‐sea heat flux, but retaining either river runoff or rainfall or both is carried out. These experiments show that the river water is exported out of the bay along the western boundary during winter and rain water along the eastern boundary during summer. Runoff leads to a large (>3 psu) decrease in salinity in the northern bay during summer and along the western boundary during winter, with a weaker contribution from rainfall. The sea surface temperature response to freshwater forcing shows large spatial variations with eastern bay showing higher differences. The northwestern bay warms by ∼1.5°C in the presence of freshwater during summer, due to greater heat absorption within a shallow mixed layer (ML). This warming is caused in nearly equal proportions by rain and river water in early summer, but the contribution by river water dominates during peak and withdrawal phases of the summer monsoon. Northeastern bay, in contrast, is cooler by 1.5–3°C in the presence of freshwater, caused primarily by river runoff, owing to the winter cooling over a thin ML. Temperature inversions form due to surface cooling of a river stratified layer during winter in the northwestern bay and due to radiation penetrating below the ML during summer in the northeastern bay.

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Winter‐time variability of the eastern Arabian Sea: A comparison between 2003 and 2013

Narvekar

D'Mello

Kumar

et al. 2017

Geophysical Research Letters

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The eastern Arabian Sea (EAS) is a region of complex interplay between several spatially and temporally varying oceanographic processes. Using two sets of in situ data collected from the same stations, separated by a decade, we show that warming and cooling in the EAS were linked to the long‐term variability of this region. Though the warming in the southern part of EAS was consistent with the basin‐wide rise in sea surface temperature in the Arabian Sea (AS), the enhanced freshening was a remote response to episodic events mediated by the strengthening of interbasin exchange between Bay of Bengal and AS through East India Coastal Current and West India Coastal Current. The increased stratification in the southern part of EAS led to the decline in the chlorophyll over the decade. In contrast, enhanced chlorophyll in the northern part of the EAS over the decade was linked to the increased wind speed.

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Observed year-to-year sea surface salinity variability in the Bay of Bengal during the 2009–2014 period

Abstract: International audienc

Cited by 47 publications

References 43 publications

A modeling study of processes controlling the Bay of Bengal sea surface salinity interannual variability

A modeling study of processes controlling the Bay of Bengal sea surface salinity interannual variability

An OGCM study of the impact of rain and river water forcing on the Bay of Bengal

Winter‐time variability of the eastern Arabian Sea: A comparison between 2003 and 2013

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