Application of NPZAD model to numerical study of biogeochemical parameters in the Persian Gulf


Marine Science Department, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran



A three-dimensional physical-biological numerical model namely ROMS was employed to investigate seasonal variations in biological parameters of Persian Gulf. The model domain included entire Persian Gulf and Sea of Oman. The model has run with climatic data. Lateral and surface boundary conditions were prepared from COADS and WOA09, respectively. The ROMS hydrodynamics model was coupled to bio-Fennel biological model including seven state variables (N2PChlZD2). After ten years’ successive run, numerical results reached a quasi-steady-state and results of the tenth year were used for analysis. The model results revealed area of phytoplankton blooms and were in good consistency with surface chlorophyll data obtained from GMIS archive. The results showed two different peaks of chlorophyll growth in the region. The first peak occurred in spring in northwestern part of Persian Gulf where the blooms begin to grow up and expand to the middle and eastern parts of the region, and the second one occurred in late summer and early autumn in middle and southern parts. The results showed that the amount of chlorophyll in northwest and southern coastal waters was higher throughout the year in comparison to other parts of Persian Gulf, while in deep regions the role of eddies and residual currents are important in changing chlorophyll concentrations. In addition, the model showed that seasonal changes of biological parameters in Persian Gulf were nearly independent of Sea of Oman, and there was a significant relationship between biological parameters variations and seasonal changes of the region.