Summary of Abstract Submission

Abstract Submission No. IO50-08-0002PresentationOral

UPWELLING DYNAMICS ALONG THE SOUTHERN COAST OF SRI LANKA AND THE SRI LANKA DOME

Danielle Su*1

1 University of Western Australia, Australia

ABSTRACT :

The Northern Indian Ocean is characterized by reversing ocean currents that respond to bi-annually reversing monsoon winds, which induce upwelling particularly during the south-west monsoon. In addition to the classical mechanism of wind driven Ekman dynamics, upwelling can also be supported via alternative mechanisms such as flow convergence and flow curvature induced secondary circulation.This is evidenced by the processes along the southern coast of Sri Lanka where upwelling is prevalent throughout the year,despite the variation and reversal in wind strength and direction during the different monsoon periods. Sri Lanka has a unique oceanographic setting due to its location within the equatorial belt in the Northern Indian Ocean.This puts it in direct contact with the eastward flowing Southwest monsoon current during the Southwest monsoon period from June to October. Similarly, the island interacts with the westward flow from the Northeast monsoon current during the Northeast monsoon from December to April. Flow topography interaction with the island results in the żIsland mass effect', had been previously proposed as the dominant mechanism for the upwelling, supported by satellite observations and numerical models. In this presentation, we undertake idealized three-dimensional numerical simulations using the Regional Ocean Modelling System (ROMS) to investigate the relative importance of different processes: Coriolis effect,flow curvature, separation, convergence and divergence on upwelling along the southern coast of Sri Lanka,in order to quantify their contribution to upwelling intensity.