Numerical modeling of polloution distribution in the Nayban bay

In this study COHERENS which is a three-dimensional hydrodynamic model was employed in order to model and survey dispersion of pollution in Nayband bay. In this model Navier-Stokes equation, continunity equation and transport equations of salinity and temperature in 3-D are solved. Cartesian coordinate for the horizontal and sigma coordinate with five layers was used for the vertical profile. Monthly mean atmospheric parameters and 4 major tidal components (M2, S2, O1, and K1) of the bay were used as the inputs of the model. In this model, uniform grid of 79*100 was used. Once the model was adjusted and the data inserted, the model was run for the bay. Then tidal currents were validated with field observation which resulted in prediction of horizontal dispersion of pollution in different layers. The results showed that dispersion is highly affected by tidal currents. These results can be applied to predict dispersion of pollution in Nayband bay

The study of layering structure of outlfow from the Persian Gulf to Gulf of Oman and it's impact on propagation of sound with acoustic sources about outflow intrusion at spring

In this study, variations of field data such as temperature, salinity and sound of speed in horizontal and across transects of the Gulf of Oman were analyzed using CTD data acquired by international project, Joint Global Ocean Flux Study (JGOFS) during the spring of 1996. Results indicate that at all sections, at depths between 120 m to 276m in Gulf of Oman to 60 °E, finestructures were found; this indicates mixing with surrounding waters by thermohaline intrusions. These thermohaline intrusions caused temperature and salinity inversion that causes inversion of sound speed profile. Thickness inversion at the stations near the Strait of Hormuz is about 156 m and at stations far from the Strait of Hormuz (near the Oman of Sea) is about 80m. By previous studies, this outflow intrusion causes the internal waves in the Gulf of Oman. These results suggest that formation of intrusion depends on the intermittent outflow through the Strait of Hormuz. In this survey, high salinity water and high temperature water masses spread into the Persian Gulf at an intermediate level, in the Gulf of Oman. In this research, the acoustic propagation characteristics (transmission loss, amplitude of signal and travel time of signal) up, below and into, of the outflow intrusion were assessed based on the output of a range-dependant acoustic model and range independent acoustic model. In general, the occurrence of this thermohaline intrusion was found to alter the propagation characteristics

Study of tidal components amplitude distribution in the Persian Gulf, Gulf of Oman and Arabian Sea using numerical simulation

Tide is one of the most regular changes of seas and ocean levels which are offering particular importance due to the influence on the flow pattern in tidal zone. According to engineering needs and environmental protection issues in industrial-economic zone of Persian Gulf, Strait of Hormuz and Gulf of Oman, knowing tidal characteristics of this region is very important. Therefore FVCOM (a three-dimensional ocean model) was used in barotropic mode to stimulate the tidal amplitude in a wide region comprising Persian Gulf, Strait of Hormuz, Gulf of Oman and Arabian Sea. Finite volume method is applied in this model to discretize the hydrodynamic equations on triangular mesh. Uniform computational mesh is used with a resolution of 5 km in the model and one minute bathymetry data has been interpolated on this mesh. The constant values of eight diurnal and semidiurnal tidal components are prescribed along the open ocean boundary. After applying harmonic analysis on the model outputs in desired stations, the achieved amplitude of this analysis compared with results which are obtained from the analysis on the available measurement data in these stations to validate the model results. According to the measurement data and model results in these stations, meanwhile identifying the four main tidal components, the amplitude pattern of these components was determined in the whole domain. Also, by using amplitude of main components and estimating of F factor, the type of tide was predicted in the study area. According to the results obtained in this research, four types of diurnal, semidiurnal, mixed diurnal and mixed semidiurnal tides are seen in the Persian Gulf. In other areas, the tide will be mixed semidiurnal. Moreover, studying the maximum amounts of tidal velocity in the study area shows that the amount of this velocity in the Gulf of Oman and Arabian Sea is less than 0.1 m/s

Three-Dimensional Numerical Modeling Study of Thermal Pollution and its effect on dissolved oxygen and chlorophyll

1116-1122There are large volume of industrial activities in Bushehr coast (Iran).To study thermal pollution and its effects on dissolved oxygen and chlorophyll in this area, the COHERENS has been employed based on a vertical sigma coordinate. The model has been applied 120×40 grid and 5 sigma level from the surface to the bottom. The Cartesian lateral grid spaces are Δx = 1 km (east-west direction) and Δy = 1 km. We included an ecological part of the model to calculate oxygen and chlorophyll variations in the domain. The model is forced by tidal data extracted from Persian Gulf tide table and climatological monthly mean atmospheric forces (wind speed, air temperature, humidity, cloud cover, and precipitation) derived from 54 years (1952-2006) of NOAA (National Oceanic and Atmospheric Administration) data. Findings of the model suggest that temperature, oxygen and chlorophyll concentration change with the discharging of heated water in the study area. In order to prevent this pollution and its destructive impacts, similar studies can be performed before construction of industrial units and power plants

Tidal Constituents in the Persian Gulf, Gulf of Oman and Arabian Sea: a Numerical Study

1010-1016In this study, a three-dimensional coastal ocean model (FVCOM) is used in barotropic mode to simulate tidal amplitudes in the Persian Gulf, Gulf of Oman and Arabian Sea. Finite volume method is applied for solving hydrodynamic equations on an unstructured triangular mesh grid. Amplitudes and phases of 8 main tidal constituents are prescribed along the southern open-ocean boundary. To assess the model performance, the model results were compared with observational evidences. Amplitudes of tidal components observed at 9 tidal gauges in the region confirm the results of harmonic analysis performed on model outputs. Hence, it can be concluded that the amplitudes of 8 tidal components are well predicted by the model. Moreover, amphidromic points are accurately predicted from model results for these components. Also M2 and K1 are determined respectively as major semi-diurnal and diurnal constituents in entire domain. Finally, the tidal regime is classified by employing the form factor F in this area