Abstract and keywords
Abstract (English):
Storm surges and wind waves are ones of the most important hydrological characteristics, which determine dynamics of the Sea of Azov. Extreme storm surges in Taganrog Bay and flooding in the Don Delta can be formed under the effect of strong western winds. In this work the sea level oscillations and wind waves in the Taganrog Bay were simulated by means of the coupled SWAN+ADCIRC numerical model, taking into account the flooding and drying mechanisms. The calculations were carried out on an unstructured mesh with high resolution. The wind and atmospheric pressure fields for the extreme storm from 20 to 28 of September, 2014 obtained from WRF regional atmospheric model were used as forcing. The analysis of simulation results showed the following. The western and northern parts of the Don Delta were the most flood-prone during the storm. The size of the flooded area of the Don Delta exceeded 50%. Interaction of storm surge and wind wave accelerated the flooding process, increased the size of the flooded area and led to the intensification of wind waves in the upper of Taganrog Bay due to the general rise of the sea level.

Keywords:
the Sea of Azov, storm surge, wind waves, flooding, SWAN, ADCIRC, wetting/drying, parallel computing.
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I. INTRODUCTION

Storm surges and wind waves are ones of the most important hydrological characteristics, which determine dynamics of the Sea of Azov on synoptic scales. Extreme storm surges of 2–3 m height in Taganrog Bay [1, 2] and flooding in the Don Delta can be formed under the effect of strong western winds. There have been several such cases over the past 20 years: April 12, 1997; March 1, 2005; September 30, 2010; March 24, 2013; September 24, 2014. The two latter cases are described in [2, 3].

In [4], a numerical simulation technology of storm surges and wind waves in the Sea of Azov is presented by means of tightly-coupled SWAN+ADCIRC model [5]. The model validation has shown that it adequately describes the Sea of Azov level variations during intense storms.

Characteristics of storm surge and wind waves in the Taganrog Bay during the extreme storm of September 24–25, 2014, are studied in this work with the mesh of abovementioned technology. High resolution unstructured computational mesh has been created for this purpose. The mesh describes bathymetry and topography of the Don Delta in detail.

 

 

II. MODEL DESCRIPTION

The coupled model SWAN+ADCIRC integrates two models – SWAN (Simulation Waves Nearshore) [6, 7] and ADCIRC (Advanced Circulation Model for Shelves Coasts and Estuaries) [8, 9]. Both models are used to simulate the wind waves and storm surge.

The ADCIRC model basic equations are defined as follows

References

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2. G.G. Matishov “The Kerch Strait and the Don Delta: the Security of Communications and Population”, Vestnik Yuzhnogo Nauchnogo Tsentra, 11(1), 2015, pp. 6 - 15. (In Russian).

3. G.G. Matishov, A.L. Chikin, S.V. Berdnikov, I.V. Sheverdyaev, A.V. Kleshchenkov et al., “Extreme flooding of the Don Delta in spring 2013: chronology, formation conditions, and consequences”, Vestnik Yuzhnogo Nauchnogo Tsentra, 10(1), 2014. pp. 17-24. (In Russian).

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