Seasonal and annual precipitation characteristics of Türkiye and the influence of atmospheric-ocean interactions

Abstract

This study explores the relationship between T & uuml;rkiye's precipitation series and major climate indices, including AMO, PDO, and Nino 3.4. The analysis reveals significant spatial variability in precipitation across T & uuml;rkiye, with coastal regions like the Black Sea and Mediterranean receiving higher rainfall compared to Central Anatolia. The seasonal distribution shows a distinct north-south gradient, with winter precipitation concentrated in the west and south, while summer precipitation is more intense in the southern and southeastern regions. Precipitation Concentration Index (PCI) and Coefficient of Variation (CV) analyses highlight the diverse hydroclimate across the country. Coastal areas, particularly in the south and west, exhibit high seasonal concentration and variability, while the Black Sea coast experiences more uniform precipitation year-round. Decadal analysis of the PCI reveals shifts in precipitation patterns over the past four decades, with notable changes in the 1980s, 2000s, and 2010s. Cross-Wavelet Transform (XWT) analyses show that the AMO (Atlantic Multidecadal Oscillation) exerts a long-term influence on precipitation, particularly in the Mediterranean and Eastern Anatolia regions, while the PDO (Pacific Decadal Oscillation) significantly impacts Southeastern Anatolia. However, Nino 3.4 exhibits more intermittent effects. Same-year correlations between these indices and precipitation are generally stronger than lagged correlations, indicating more immediate impacts. As a result of XWT, the post-2000 period shows shifts in climate dynamics and teleconnections, suggesting evolving influences on T & uuml;rkiye's precipitation, and underscoring the need for adaptive water management strategies.