Basin-scale trends in hydro-climatic drought indices across Türkiye
REGIONAL ENVIRONMENTAL CHANGE, sa.26, ss.1-21, 2026 (SCI-Expanded, SSCI, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s10113-026-02690-z
- Dergi Adı: REGIONAL ENVIRONMENTAL CHANGE
- Derginin Tarandığı İndeksler: Natural Science Collection (ProQuest), Scopus, Science Citation Index Expanded (SCI-EXPANDED), Social Sciences Citation Index (SSCI), IBZ Online, Environment Index, Greenfile
- Sayfa Sayıları: ss.1-21
- Karadeniz Teknik Üniversitesi Adresli: Evet
Özet
This study presents a comprehensive trend analysis of hydro-climatic change across Türkiye basins using the Standardized Precipitation Index (SPI), the Standardized Precipitation Evapotranspiration Index (SPEI), the Percent of Normal Index (PNI), and the Reconnaissance Drought Index (RDI). Indices calculated at the national scale were disaggregated to basin level to assess the spatial continuity of hydro-climatic change and inter-basin differences realistically. Trends were evaluated using the Mann-Kendall test, Sen’s slope estimator, and the Innovative Trend Analysis (ITA) method, with results visualized through heat maps highlighting spatial patterns. The findings show that hydro-climatic trends are strongly timescale dependent. No statistically significant trends were identified in the SPI and PNI indices at short timescales (1–3 months) in most basins, whereas trends emerged and gained spatial continuity at medium and long timescales (6–24 months). Widespread, statistically significant negative trends were detected in the SPEI and RDI indices at the 12- and 24-month scales, most evident in the Mediterranean, Aegean, Central Anatolia, and Southeastern Anatolia basins. Despite the relative stability of precipitation-based indices, the persistent moisture deficit captured by indices incorporating the evaporation component indicates that rising temperatures and increased evaporation demand are the primary drivers of hydro-climatic stress. These results indicate a persistent hydro-climatic drying signal at medium- to long-term timescales that, while reduced in extent, remains detectable after autocorrelation correction and is independently corroborated by permutation-based trend testing, with structural breaks occurring at basin-specific times rather than a single common year. The findings suggest that drought assessment and water management strategies should be grounded in basin-scale analyses using medium- and long-term hydro-climatic indices rather than short-term indicators.