- Dona Paula, Goa, India.
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Abstract Submission No. | ABS-2022-03-0252 |
Title of Abstract | Observed variability of the East India Coastal Current on the continental slope and shelf |
Authors | Soumya Mukhopadhyay*, D. Shankar, S.G. Aparna, A. Mukherjee, V. Fernando, A. Kankonkar |
Organisation | CSIR-National Institute of Oceanography, Goa-403004 |
Address | TS Division, Indian Institute Of Tropical Meteorology, Dr. Homi Bhava Road, Pash Pune, Maharashtra, India Pincode: 411008 Mobile: 9595714129 E-mail: soumya.ju2010@gmail.com |
Country | India |
Presentation | Oral |
Abstract | We describe the variability of the East India Coastal Current (EICC) on the continental slope and shelf during 2009-2018 using data from four moorings equipped with acoustic Doppler current profilers (ADCPs). The decade-long ADCP records show that the seasonal cycle dominates the variability of the EICC on both slope and shelf. The dominance of the seasonal cycle implies that the direction of the EICC is more predictable than that of the WICC, for which intraseasonal variability is stronger than the seasonal cycle. The interannual variability, as manifest in the low-pass-filtered current, is not weak, with this component of the EICC exceeding 20 cm/s on several occasions. Upward phase propagation is common in the ADCP data, but there are instances of downward phase propagation as well. Use of HF (high-frequency) radar data for 2011-2012 from two pairs of HF radars deployed on the Indian east coast shows that the upward propagation of phase does not always extend to the surface owing to strong stratification. There is a high correlation between the EICC on the continental slope and outer shelf, but the HF radar data show that this imprint of the large-scale boundary current of the Bay of Bengal extends to the near-coastal regime. The nearshore imprint of the boundary current has an important implication for environmental impact assessments (EIAs). As the Indian economy grows, so does the number of industrial projects in the coastal zone. The EIA studies for such projects typically use small-domain model simulations, assuming that the nearshore current of interest is dominated by local processes. The ADCP and HF-radar data prove the limitation of such limited-domain model studies. |