01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-02-0244 |
| Title of Abstract | Drivers of upwelling in the Eastern Arabian Sea: Role of eddies, wind and remote forcing |
| Authors | Vishnu N. N. S, Arun V S, Smitha B R, Shirin J Jadhav*, Muhammad Shafeeque, Rasheed K |
| Organisation | CMLRE Kochi |
| Address | CMLRE Kochi, Kerala, India Pincode: 682508 E-mail: smitha@cmlre.gov.in |
| Country | India |
| Presentation | Oral |
| Abstract | Coastal upwelling is a major physical process in the Eastern Arabian Sea (EAS) basin, as it regulates the major fishery potential and biogeochemistry of the region. The dynamics of the upwelling process in response to prevailing monsoonal winds and remote forcing (coastal Kelvin and Rossby waves) along the EAS have been explored in detail in many studies using ship-borne in-situ and satellite/reanalysis data. This work discusses the causative factor responsible for initiating early (February-March) subsurface upwelling signals along the South Eastern Arabian Sea (SEAS), particularly in Kochi (10°N) and Mangalore (13°N). The coastal upwelling during May to October is heterogeneous in space and time due to the variation in forcing mechanisms and intensity. The upwelling mode of the Kelvin wave is formed due to local winds in Sri Lanka that reach EAS during the same period. The combined effect of monsoonal winds and the upwelling mode of the Kelvin wave triggers upwelling from May to October. Past studies explained the early subsurface upwelling in the SEAS due to remote forcing. Analysis of recent data along the EAS shows that the upsloping of subsurface isotherm in SEAS during February-March (late winter monsoon) is due to recurring cyclonic eddies and weakening of the downwelling mode of Kelvin wave. These observations ruled out the possibility of the influence of wind and remote forcing causing early upwelling (February/March) in SEAS. To summarise, the upwelling system in the EAS cannot be considered as a continuous process occurring from late winter to late summer periods, but can be identified as two different processes, one driven by eddies and weak remote forcing (Kelvin wave) during the late winter monsoon, and the other due to monsoonal winds and remote forcing during the summer monsoon. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Upwelling, Eastern Arabian Sea, Wind, Remote forcing, Eddies |
| For Awards | no |