Signature of Indian Ocean Dipole on the western boundary current of the Bay of Bengal

Bay of Bengal Sea surface salinity variability using a decade of improved SMOS re-processing

“…The associated SLA signal (Fig. 12c) confirms that the EICC weakens during positive IOD events, in association with upwelling coastal Kelvin waves emanating from the equatorial region, as suggested by previous studies (Aparna et al, 2012, Akhil et al, 2016a, Suresh et al 2018Sherin et al, 2018). The EICC normally exports Northern BoB fresh water southward along the East Indian coast (Fig.…”

“…This river in the sea results from the southward export of the northeastern BoB freshening by the East Indian Coastal Current (hereafter, EICC), a narrow western boundary current that flows southward in boreal fall, before vertical mixing restores higher salinities during winter (Chaitanya et al, 2014;Akhil et al, 2014). The Indian Ocean Dipole (hereafter, IOD; Saji et al, 1999), an Indian Ocean interannual climate mode, modulates the "river in the sea" southward expansion, through its remote impact on the EICC (Akhil et al, 2016a;Fournier et al, 2017;Sherin et al, 2018). At smaller scales, oceanic eddies also induce meandering of the salinity front, exporting freshwater offshore (Benshila et al, 2014; Hareesh Kumar et al, 2013;Sengupta et al, 2016;Fournier et al, 2017).…”

More Than 50 Years of Successful Continuous Temperature Section Measurements by the Global Expendable Bathythermograph Network, Its Integrability, Societal Benefits, and Future

“…By linking dynamic height to cumulative baroclinic transport across an XBT section, altimetric dynamic height can be used to extend the XBT sections into a near-continuous long-term time series of baroclinic transport. The synergy between XBT temperature profiles and sea surface height measured by satellites has been used extensively to monitor several current systems and regions, including the Antarctic Circumpolar Current (ACC) south of Tasmania (Rintoul et al, 2002), the Agulhas retroflection and ACC fronts south of Africa (Swart et al, 2008), the ACC fronts in the Drake Passage (Sprintall, 2003), the East Australian Current (Zilberman et al, 2018), across the North Pacific gyre (Roemmich and Gilson, 2001), the Brazil Current (Goni and Wainer, 2001), the North Brazil Current (Fonseca et al, 2004), the East India Coastal Currents in the Bay of Bengal (Sherin et al, 2018), the Gulf Stream (Molinari, 2011), and the Florida Current (Olson et al, 1983;Domingues et al, 2018). Section Ocean currents, gyres, and ocean variability shows examples of how XBT observations are integrated with data from other observing platforms to assess the state and variability of the ocean.…”

“…During the northeast monsoon, the East India Coastal Current (EICC) is the WBC of the BoB and flows equatorward along the east coast of India to Sri Lanka. Sherin et al (2018) used 27 years of repeated XBT sections that cross the western (Chennai to Port Blair) and northwestern (Kolkata to Port Blair) regions of the BoB to study the EICC and its interannual variability. The EICC was found to be seasonally reversing, flowing poleward from February to July with a transport of 5 Sv and then flowing equatorward from October to December with a transport of 3 Sv.…”

“…The Indian Ocean Dipole (IOD) is found to have a significant influence on EICC variability. Remote wind forcing from the equatorial Indian Ocean associated with the EICC generates a northward (southward) anomalous transport of 5 Sv (7 Sv) during winter of positive (negative) IOD events (Sherin et al, 2018).…”