علوم غیرزیستی دریا
Mohammad Taghi Zamanian; Masoud Sadrinasab; Mehri Fallahi
Abstract
The design of oceanic numerical model for Persian Gulf to predict oceanic phenomena and parameters is one of the most important ways of preventing or solving problems environment and designing of the oceanic model similar to it is an effective method that can explain physical response of environment ...
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The design of oceanic numerical model for Persian Gulf to predict oceanic phenomena and parameters is one of the most important ways of preventing or solving problems environment and designing of the oceanic model similar to it is an effective method that can explain physical response of environment to different situations. Purpose of this research is designing oceanic numerical model for environment similar to Persian Gulf, to predict its reaction in return effect of tide and wind. This three-dimensional model based on primitive equations in spherical coordinates system with sigma vertical coordinate. To solve equations of model is used finite difference method. Compared with similar models, model framework and calculate more logical tension between are the benefits of this model. An oceanic five-layer basin is considered with maximum and minimum depth 100m and 80.09m. The average daily wind in Persian Gulf, the average daily salinity and water temperature and the changes in the water level in Strait of Hormuz are used in this model. The two-year implementation of model showed that in this basin, the tidal force is a dominant force compared with windy force and density gradient, also the maximum current in strait is 1.98 m/s which can create anticlockwise circulation in basin. Maximum total change of water height is 2.98 m in relation to the static level. Implementation results of this model correspond to the oceanographic reality of Persian Gulf, while matches with purpose; it is the basis of suitable model for Persian Gulf.
علوم غیرزیستی دریا
Masoud Sadrinasab; Abbas Einali; Mohammad Akbarinasab; Mohammad Ali Najarpour
Abstract
Arvandrud River Plume which is the main source of fresh water in the Persian Gulf and in addition its catchment area is settlement for about 54 million people is one of the most important phenomena in costal zones. . The river is the boundary line between Iran and Iraq and its plume extended in Iran, ...
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Arvandrud River Plume which is the main source of fresh water in the Persian Gulf and in addition its catchment area is settlement for about 54 million people is one of the most important phenomena in costal zones. . The river is the boundary line between Iran and Iraq and its plume extended in Iran, Iraq and Kuwait territory in Persian Gulf. Oceanographic studies are infeasible in the river and in its mouth due to geographic, politics, and security problems in the region. Despite the lack of in-situ data, this study is a serious step to the investigation to river plume. In this study salinity, temperature and water circulation of Persian Gulf were simulated by using oceanographic hydrodynamic model, FVCOM. Then, effects of wind and river discharge on structure of Plumes were investigated. For this purpose, 14 wind and 8 river discharge conditions have been used. The results show the river has a surface-advected plume that is highly affected by wind. The river plume area decreased with increasing wind speed. Three types of plumes were formed by different wind conditions, at the mouth of the river. Plume type 1 diverted toward the northwest coast of Persian Gulf and plume type 3 diverted toward the Kuwait coast. Plume type 2 was almost straight and was not diverted to the sides. The T-S diagram of surface water mass was very similar to all three modes, as a result, the plume shape and displacement is affected by wind.
علوم غیرزیستی دریا
masoud sadrinasab; mohammad fayaz mohammadi; Vahid Chegini; amir ashtari larki
Abstract
Arvandrood is the most important shipping river at the border of Iran and Iraq at the north of the Persian Gulf. As the border is determined by the talweg of the river, the changes of the talweg, as a result of erosion and deposition, is always considering. As a reason of inertia, current of the river ...
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Arvandrood is the most important shipping river at the border of Iran and Iraq at the north of the Persian Gulf. As the border is determined by the talweg of the river, the changes of the talweg, as a result of erosion and deposition, is always considering. As a reason of inertia, current of the river tends to keep his direction forward. In meanders which the current has to change his direction, the sidewalls of the river experience severe shear stress that leads to sharp decrease of current energy and water level fluctuation, and increase of suspended sediment concentration. To simulate this in Arvandrood river, a 3D hydrodynamic model, DHI MIKE 21/3, has been employed. This model is based on a flexible mesh and the numerical solution of the two/three dimensional incompressible Reynolds averaged Navier-Stokes equations invoking the assumptions of Boussinesq and of hydrostatic pressure. In the first step, the model results were verified by the measured data in 4 stations. Comparing the water level in Faw position was shown that the Root Mean Square Error is 0.16 which is a good figure. Then, the model outputs were analyzed which show that in a straight direction of 18 kilometer from Abadan to Khosroabad, water level fluctuation and suspended sediment concentration have increased 18% and 3.8% respectively; while it is 22% and 15% in a way of 17 kilometer with two meander.
D Mansoury; M Sadrinasab; M Akbarinasab
Abstract
Seasonal and annual variability in circulation of surface waters of the Caspian Sea were studied using POM model. In this model, temperature and salinity field’s data and wind field and the flow of atmospheric data were collected from WOA and daily data bank ECMWF, respectively, with an resolution ...
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Seasonal and annual variability in circulation of surface waters of the Caspian Sea were studied using POM model. In this model, temperature and salinity field’s data and wind field and the flow of atmospheric data were collected from WOA and daily data bank ECMWF, respectively, with an resolution of 5.7 minutes and the time step of 6 hours and for Bathymetry from GEBCO08 data with an resolution of 30 seconds is used. Initially, the model for ten years (1988-1997) was carried out and, after examining the stability of the model with measurement data available (1996) were compared, that good agreement between their temperature and salinity changes observed. Then, for the last ten years (2005-2014) in two cases (with and without taking into account the flows of atmospheric wind field data and rivers) model was implemented. The results showed that changes in water flow in all seasons, in shallow areas, wind field indicates the dominant effect on the region, but in deep, wind has less effect on the flow. Changes in mean annual surface water circulation of the Caspian Sea show three of the water circulation. A relatively weak clockwise circulation is in the northern basin and a counterclockwise circulation great stronger (gyre) in the center of the middle basin and a relatively small strong clockwise circulation in South of the southern basin due to their seasonal circulations, wind force in the northern basin and shallow areas the Caspian Sea are more effective in the formation of water flows.
علوم غیرزیستی دریا
Parastoo Akbari; Masoud Sadrinasab; Vahid Chegini; Seyed Mostafa Siadat Mousavi
Abstract
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. According to engineering and environmental needs in industrial economic zone of Persian Gulf, Strait of Hormuz and Gulf of Oman, knowing the tidal characteristics ...
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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. According to engineering and environmental needs in industrial economic zone of Persian Gulf, Strait of Hormuz and Gulf of Oman, knowing the tidal characteristics of these areas is important. Therefore FVCOM (ocean model) was used to stimulate the tidal amplitude in an area comprising Persian Gulf, Strait of Hormuz, Gulf of Oman and Arabian Sea. Finite volume method is used in this model to discretize the hydrodynamic equations on triangular mesh. Uniform mesh is used with a resolution of 5 km in the model.The constant values of eight diurnal and semidiurnal tidal components are prescribed along the open boundary. In order to validate the model results, 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. According to the measurement 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. 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.