Investigation of Geostrophic and Ekman Surface Current Using Satellite Altimetry Observations and Surface Wind in Persian Gulf and Oman Sea

Abstract

The rise of satellite altimetry is a revolution in the ocean sciences. Due to its global coverage and its high resolution, altimetry classically outperforms in situ water level measurement. Ekman and geostrophic currents are large parts of the ocean's current, playing a vital role in global climate variations. According to the classic oceanography, Ekman and geostrophic currents can be calculated through the pressure gradient force as well as the friction force assuming that the water's density is constant. Investigation of Ekman and geostrophic currents existence along with the determination of their velocities can profoundly affect the various events of oceanography and different interactive processes between the atmosphere and the ocean. Additionally, the measurement of sea currents can be useful in determination of contamination transport, seawater exchange, fisheries, oil transfer, immigration of aquatic animals and several marine activities (e.g. military, telecommunication, fishing and research activities) and also has different effects on the regional climate. In the current study, local and climatic conditions, Ekman and geostrophic currents and their velocities have been investigated based on the solution of Ekman and geostrophic equilibrium equations in the region of the Persian Gulf and the Oman Sea. To this end, using data of Saral and Jeason-2 altimetry satellites and surface wind data measured by ASCAT satellite, velocities values of v and u as well as the value and the direction of Ekman and geostrophic currents were extracted in forms of monthly data. The results were compared with obtained measurements by AVISO and NOAA for the region of the Persian Gulf and the Oman Sea, and based on the obtained results of this study, the difference in the value of these currents is about 1 cm/s.