Influence of atmospheric circulation on the variability of hydroclimatic parameters in the Marmara Sea river basins

Understanding the influence of atmospheric circulation on the variability of hydroclimatic parameters can considerably contribute to water management. In this study, atmospheric dynamics on rainfall/runoff variability in Marmara Sea river basins were investigated via principal component analysis (PCA) and trend analyses. Correlation maps were obtained for rainfall/runoff PC scores and 500 hPa geopotential using ECMWF Reanalysis v5 (ERA5). The correlations between rainfall/runoff PC scores and teleconnection indices were employed to support the PCA analysis. The first component, a monopolar structure, expresses northerly atmospheric influence on the rainfall/runoff; the second component, a dipolar structure, explains the low rainfall/runoff conditions; the last component defines local properties. Teleconnections demonstrate that North Atlantic Oscillation (NAO) is highly correlated with rainfall and runoff PC scores, particularly in winter. Moreover, runoff trends are consistent with rainfall trends except for summer, and these trends and oscillations are related to the teleconnections. Therefore, the anomalies can be predicted based on atmospheric conditions.