Impact of Initial and Boundary Conditions on Coupled Model Simulations for Bay of Bengal

Abstract

This study investigates the response of a high resolution coupled physical-ecosystem model simulations to initial and boundary conditions (IBCs) from various sources. For this purpose, we used physical parameters from the data sets World Ocean Atlas (WOA09), CSIRO Atlas of Regional Seas (CARS09) and North Indian Ocean Atlas (NIOA). Evaluating model simulated fields with standard validation data suggests that all three experiments could resolve most of the known surface and subsurface features of the Bay of Bengal (BoB) but with considerable differences in salinity and chlorophyll-a (Chl-a) and negligible differences in temperature among model simulations with various IBCs. The modeled Chl-a is well simulated with WOA09 as compared to NIOA and CARS09 data for climatological model simulations, with a correlation of 0.52 for the BoB. Moreover, the vertical distribution of Chl-a is found to be a function of nutrient supply to the base of the euphotic layer and mixed layer. These results significantly highlight the implicit and explicit use of IBCs for better representation of Chl-a concentration in the BoB from a high-resolution coupled model.

Keywords:

• ROMS
• NPZD
• initial and boundary conditions
• Bay of Bengal

Acknowledgments

The work is supported by a research project ‘Ref.: SAC/EPSA/4.19/2017’ funded by SAC. Authors thank Dr. Sourav Sil for his help in set up of the ROMS model. Authors would like to thank editors and the anonymous reviewers, whose suggestions helped us to improve content of the manuscript significantly.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data openly available in a public repository that does not issue DOIs: Shortwave radiation & longwave radiation taken from Objectively Analyzed Air-sea Fluxes (OAFlux) International Satellite Cloud Climatology Project (ISCCP) http://oaflux.whoi.edu. Precipitation obtained from National Centers for Atmospheric Research (NCAR) https://data1.gfdl.noaa.gov/nomads/forms/core/COREv2/CNYF_v2.html. Temperature and salinity obtained from metoffice https://www.metoffice.gov.uk/hadobs/en4/download‐en4‐2‐1.html.