The effect of southern oscillation on the precipitation data of Central Anatolia

The changes occurring in the world's climate year by year are seen randomly; however, during the studies carried on the historical data it has been proved that one of the many reasons of these changes was ocean-atmosphere interaction repeating in every few years in the Tropical Pacific.Even though these severe ocean-atmosphere events take place in the Tropical Pacific, their influences can be seen many kilometers away from the Pacific. In this study, the influences of the Southern Oscillation that is an ocean-atmosphere event were searched on the annual total precipitation trends of the Central Anatolia Region. For this purpose, 14 stations in the Central Anatolia were used. Out of homogeneity methods, Standard Normal Homogeneity Test, Pettitt, Buishand, Von Neumann's Ratio Test and Run were used in the analyses. Mann Kendall, Modified Mann Kendall, Mann–Kendall Rank Statistics, Spearman's Rho, Sen's T-test, Innovative-Şen method and Sen's Estimator of Slope trend methods were used to determine the trends of the precipitation data of the stations. As a result of the homogeneity analysis, 89% of the data were observed as homogeneous. The changing years were determined in non-homogenous stations. When the trend analysis results are analyzed, the precipitation tendencies in the northern and eastern parts of the region increased and the precipitation tendencies in the western and southern parts decreased. Although the effects of El Nino and La Nina on precipitation trends do not show similarity, it is generally found that the effect of La Nina increases the tendencies of precipitation and the effect of El Nino decreases the tendencies of precipitation.