Evaluation of wind induced currents modeling along the Southern Caspian Sea. (1st February 2018)

• Record Type: Journal Article
• Authors: Bohluly, Asghar; Esfahani, Fariba Sadat; Montazeri Namin, Masoud; Chegini, Fatemeh
• Is Part Of: Continental shelf research. Volume 153(2018)
• Page Start: 50
• Page End: 63
• Publication Date: 2018-02-01
• Subjects: Wind-driven current -- Modeling -- Caspian Sea; Continental shelf -- Periodicals; Submarine geology -- Periodicals; 551.41
• DOI: 10.1016/j.csr.2017.12.008
• Languages: English
• ISSNs: 0278-4343

Abstract

Abstract: To improve our understanding of the Caspian Sea hydrodynamics, its circulation is simulated with special focus on wind-driven currents of its southern basin. The hydrodynamic models are forced with a newly developed fine resolution wind field to increase the accuracy of current modeling. A 2D shallow water equation model and a 3D baroclinic model are applied separately to examine the performance of each model for specific applications in the Caspian Sea. The model results are validated against recent field measurements including AWAC and temperature observations in the southern continental shelf region. Results show that the 2D model is able to well predict the depth-averaged current speed in storm conditions in narrow area of southern coasts. This finding suggests physical oceanographers apply 2D modeling as a more affordable method for extreme current speed analysis at the continental shelf region. On the other hand the 3D model demonstrates a better performance in reproducing monthly mean circulation and hence is preferable for surface circulation of Caspian Sea. Monthly sea surface circulation fields of the southern basin reveal a dipole cyclonic-anticyclonic pattern, a dominant eastward current along the southern coasts which intensifies from May to November and a dominant southward current along the eastern coasts in all months except February when the flow is northward. Monthly mean wind fields exhibit two main patterns including a north-south pattern occurring at warm months and collision of two wind fronts especially in the cold months. This collision occurs on a narrow region at the southern continental shelf regions. Due to wind field complexities, it leads to a major source of uncertainty in predicting the wind-driven currents. However, this source of uncertainty is significantly alleviated by applying a fine resolution wind field. Graphical abstract: Highlights: The Caspian Sea current field is simulated using a high resolution wind field. The 2D and 3D model results are compared to examine the performance of these models. The results are compared against recent field measurements in the Southern Caspian Sea. The monthly wind pattern computed from the 31-year wind field over the Caspian Sea. The monthly mean surface circulation pattern is extracted from 3D model results.