Seasonal and Interannual Variability of Marine Ecosystem in the North Indian Ocean: A Model Evaluation Study

We have investigated the climatological and interannual variability of biogeochemical cycles in the north Indian Ocean with simulations of TOPAZ (Tracers Of Phytoplankton with Allometric Zooplankton) during 1949–2009. Model simulations have been carried out with climatological and interannual fluxes forcings and the results have been evaluated by using the available data from different sources in the Arabian Sea and the Bay of Bengal. The model captures significant spatial and seasonal features in surface chlorophyll and primary productivity observed in satellite data. Seasonal and interannual variations, and profiles of a few of the state variables obtained from the coupled model simulations compare well with the cruise and satellite data at a few stations for many seasons in the Arabian Sea and the Bay of Bengal. We have also studied the spatial, seasonal and interannual variations of sea surface temperature (SST) and surface chlorophyll anomalies in the north Indian Ocean using model simulation results and satellite data. It is seen that a negative surface chlorophyll anomaly correlates well with a positive SST anomaly.