The effect of southern oscillation on the Black Sea rainfall data

Due to the fact that the need for water has become extremely important, the necessity of the optimum use of the available water resources and the emergence of new water resources has become one of the most important issues of the water planning studies. However, today, the global climate changes occurring due to various conditions make this planning difficult and take place at a more noticeable level than it is in the past. In order to understand the meteorological events such as Southern Oscillation (SO) etc., certain results for some geographical regions of the world should be obtained by making researches on the climatic members. The recent studies showed that the climate changes have significant effects on the components of the hydrological cycle. In this sense, understanding the mechanisms that control the variability of Southern Oscillation (SO) will also help us to understand the systems that control the climate change. Large-scale oscillations (pressure fluctuations), the result of atmospheric movement in the hydrological cycle, are the climate anomalies with periodical characteristics. Therefore, the question of whether the climate change and anomalies affect the existing water resources should be examined, and the future conditions of the resources should be investigated. In this study, it was aimed to reveal the relationship of Black Sea Region's precipitation data with the Southern Oscillation. In analyzing this relationship, the rainfall parameter's homogeneity analyses were carried out using the Standard Normal Homogeneity Test, Pettit Test, Buishand Test, Von Neumann Test and Run Test, and the trend analyses were performed using Mann-Kendall, Modified Mann-Kendall, Spearman Rho, Sen's T and Innovative-Sen Test in order to make future interpretation on the data sets, and the trend starting years were determined using Mann-Kendall Rank Correlation Method. In this context, in order to see whether the precipitation data of the El Nino years which is the strongest phase of the Southern Oscillation affect the historical data or not, the precipitation data for these years were replaced with the synthetic data generated by Feed Forward Back Propagation Artificial Neural Network Method, and then the historical and synthetic data were compared in terms of trend conditions. As a conclusion, it was determined that the El Nino and La Nina events, the extreme phases of Southern Oscillation, have effects on the statistical values of the precipitation data of Black Sea Region especially one year later. Keywords: Black Sea, Southern Oscillation, Homogeneity, Trend, Precipitation, ANN