The effect of climate variability on the rainfall erosivity power and its relationship with oscillations in Türkiye

One of the factors affecting erosion is the amount and intensity of rainfall. Periodic repeated atmospheric oscillations are one of the leading cause of factors affecting rainfall. Strong and weak phases of atmospheric oscillations can cause an increase or decrease in the amounts of precipitation. Therefore, the study was conducted in order to determine the effect of atmospheric oscillations on the erosive power of precipitation in Türkiye. For the study, monthly precipitation data from the General Directorate of Meteorology for the years 1970-2021, the rainfall erosivity factor (R) values of the 1993-2007 calculated by Erpul et al. (2009), and Nino3, Nino3.4 and Nino4 indices representing the El Nino Southern Oscillation and NAOI representing the North Atlantic Oscillation were used. Firstly, in order to calculate the R values of the past periods, linear and nonlinear regression analysis was applied between R and precipitation values and the prediction equations were created for each station. As a result of regression analysis, it was determined that the use of exponential model was suitable for Türkiye. With these equations, new R values (Ry) were calculated between 1970 and 2021. Mann Kendall trend analysis was used to determined the trend of these calculated values and rainfall. Finally, correlation coefficient analysis was applied to determine the relationship between Ry values, rainfall and oscillations. As a result of the correlation analysis, statistically significant 95% confidence interval relationships were found.