مقالات رزومه دکتر سهیل عطایی حسن کیاده

Measuring cross-shore profiles is very important in coastal engineering studies, since the cross-shore profile determines the behavior of the sea in the coastal area and determines the process of depth changes in this region. As a result of waves, cross-shore profiles change, which will vary in stormy waves (erosion profile) in compare to normal wave conditions (cumulative profile). Considering the great changes in the Caspian Sea level, the purposes of this study are to investigate and determine the erosion or accumulation of coastal profiles based on Sunamura and Horikawaꞌs studies , determine the number of bars in profiles by Short and Aagaardꞌs equations and also determine the relations between coastal parameters with the wave steepness and changes in water level. The results show that for all the coastal areas in the Caspian Sea, the C-parameter is above 8; in other word a stormy erosional nature is dominant. Also according to  -parameter, for all regions the values are above 100 which means a very high possibility to form multi bars profiles (three bars) very high. As the wave's steepness rises, the location of the formation of the bars moves toward the coast, and the depth of water decreases at the beginning and the ends of the bars; also, in terms of lowering in the water level with the change in the height of the waves, the position and the geometric shape of the bars will not follow a certain trend

The Caspian Sea level has experienced frequent fluctuations resulting in shoreline advance and retreat. Therefore, studying and predicting shoreline changes in the Caspian Sea are very important. The "Bruun Rule" was presented in order to predict shoreline variation due to sea level rise. In addition, to improve the predictions of the Bruun rule, added landward sediment transport to it, leading to more desirable results. In this research, the Bruun rule and its modified form, extended for landward transport, were investigated for the Caspian Sea level fall conditions. The modified equation in this study leads to the better results, which indicates that due to sea level fall and natural storms, there would be sediment deposition toward the shoreline. In terms of water level reduction, by applying the coefficient, the root mean squared error was obtained 3.447 meters for predicting shoreline changes in comparison to its natural changes. According to the results, the lowest difference in prediction is related to the Mahmudabad coast and the highest difference in prediction is related to the Dastak coast, which are equal to 0.059 and 4.849 meters, respectively. Based on this trend for forecasting shoreline changes by applying the coefficient and not having much difference in calculating the root mean square error based on the proposed equation of Rosati et al., it is possible to use the optimized equation in this study as a prediction of shoreline changes in terms of sea level fall; This coefficient has improved the forecasting trend of coastline changes in terms of water level reduction for each of the studied areas with direct deviations of D50 and HB in the equation, and the results obtained from forecasting shoreline variations show a lower difference for each area.

Due to the great importance of sea level changes especially for coastal regions, identifying and studying the factors affecting these variations makes it easier to predict changes of sea level and will help to determine the riparian zone and changes in coastal lines. In this research, precipitation-evaporation is studied based on ERA-Interim model of ECMWF in order to estimate changes in Caspian Sea (CS) level and the validity of the results is evaluated in a period between 1980 to the end of 2015. Recorded data about the rivers entering the CS were also studied for better prediction of changes in water level. According to satellite and software analyses, in average evaporation has increased with a rate of 0.89 Km3/year, while precipitation and rivers discharge have decreased by the rates of 1.09 Km3/year and 1.41 Km3/year, respectively during the 36 years. The standard deviation of the sea level change caused by Volga discharge (normally entering 249.13 Km3/year into the sea alone) is closer to the recorded standard deviation obtained from change of CS level than the other two factors. Also, the lowest and the highest correlation coefficients relative to the recorded sea level changes were calculated considering simultaneous effect of precipitation-evaporation, and simultaneous effect of all parameters, respectively. As a conclusion, it can be said that the main reason for decreasing the CS level during recent years could be attributed to the rise of evaporation in comparison to precipitation and inlet rivers discharges.