Summary of Abstract Submission

Abstract Submission No. IO50-06-0018PresentationOral

A COUPLED PHYSICAL BIOLOGICAL MODEL OF THE NORTH INDIAN OCEAN

V. Vijith*1, P. N. Vinayachandran1, S. Sreeja1

1 CAOS, Indian Institute of Science, Bangalore, India

ABSTRACT :

In this study, we use an Oceanic General Circulation Model (OGCM) to simulate the biophysical processes in the north Indian Ocean (NIO). The physical model is based on a quarter-degree resolution (Regional Ocean Modeling System) ROMS and the biological model is based on Fennel's model. The model is forced with winds, radiative fluxes and other atmospheric variables at the surface of the ocean. The data are from Scatterometer, ERA and NCEP. We carry out simulations using three different combinations of these data, viz., Scatterometer winds and ERA fluxes; Scatterometer winds and NCEP fluxes; and winds and fluxes from ERA. The performance of the model is also examined for two different vertical mixing schemes, Mellor-Yamada 2.5 and K-profile parametrization. In short, we have carried out six different simulations to assess the sensitivity of the model to different forcings and mixing parametrizations. A test of critical ability of any ocean coupled physical biological model to simulate biological fields depends on its success in realistic reproduction of the spatio-temporal variation of mixed layer depth (MLD). The skill of the model is assessed against available observations, such as RAMA moorings, ARGO, hydrographic and climatological data that provide a view of MLD in NIO. Our preliminary results suggest that the best configuration of the model is given by a combination of Scatterometer winds, ERA fluxes and K-profile parametrization. Finally, the evolution of chlorophyll as given by the best model-configuration is presented.