Highlights In this research, first we identified the studied area, and then we explained about model settings as well as introduce some forces which has been applied to the model. In the following, we represent the results of simulation of coastal currents and upwelling in the western Persian Gulf. Then, we assess validation of coastal jet formation in different months and seasons in a basin-scale. Abstract The present study employed COHERENS model as a three-dimensional hydrodynamic model to

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... dress the coastal currents in the western Persian Gulf with a horizontal resolution of 2minutes of latitude and longitude. The obtained results suggested that Iranian northwestward coastal currents developed from January to April and experienced their maximum intensity from June to August. The simulation results reflected that expansions of the thermocline area began by the arrival of the warm season. Under such circumstances, some stronger coastal currents were generated in summer. Further results revealed that a coastal jet stream with a speed of about 30 cm/s appeared from May to October. The strong coastal surface current in the vicinity of the western part of Iranian coasts flew southeastward, while the reverse current flew with a northwestern direction in the seabed. However, the coastal jet stream completely appeared all over the water column from the surface to the seafloor and flew southeastward along Arabian coasts. The findings of this study showed that more kinetic energy was accumulated along Iranian coasts. Moreover, the current vectors on Iranian coasts were greater than those on Arabian coasts, which in turn resulted in the creation of the upwelling currents along western Iranian coasts.