Summary of Abstract Submission

Abstract Submission No. IO50-04-0033PresentationPoster

IMPACT OF THE VERTICAL RESOLUTION IN AN OCEAN GENERAL CIRCULATION MODEL ON THE SIMULATION OF THE EAST INDIA COASTAL CURRENT

A. Mukherjee*1, P. A. Francis1, A. Chatterjee1, K. Chakraborty1, A. Paul1

1 Indian National Centre for Ocean Information Services, India

ABSTRACT :

The relative performance of the high resolution (1/12 x 1/12 degree) Regional Ocean Modeling System (ROMS) with two different vertical resolutions in simulating the characteristics of the East India Coastal Current (EICC) is analyzed here. Observations from ADCPs in Gopalpur (86E, 19N) and Kakinada (82.5E, 16.5N) are used to validate the simulation of EICC in the study. In the first setup (ROMS40), there are 40 sigma levels in vertical, out of which 23 levels are in the top 200 m in the continental slope region where as in the second setup (ROMS60), there are 60 vertical levels out of which 40 levels are in the top 200m in the same region. It is observed that ROMS60 outperform ROMS40 in simulating the EICC. At Kakinada, ROMS60 model captured observed strong alongshore current during spring 2011 quite realistically while at Gopalpur, ROMS60 model simulated the observed changes in the direction of the EICC during March to September more accurately than the ROMS40. Further analysis suggested that the strong current during spring 2011 at Kakinada is due to the presence of strong eddy kinetic energy (EKE) while the accurate representation of the summer current at Gopalpur by ROMS60 model is due to eddy potential energy (EPE). Weak EKE and EPE were found during the spring season at Gopalpur, but ROMS60 model simulated relatively shallow mixed layer depth and depth of 20C isotherm compared to ROMS40 during this season, which led to the dominance of higher order modes.