Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYalnız künye2026The Trend of Monthly Mean Streamflow Values and Regimes in the Susurluk Basin (Türkiye) with Mountain and Semi-Arid Climates
Yıldız, Mehmet Berkant; Toğrul, Burçe; Kankal, Murat; Akçay, Fatma; Şan, Murat; Nacar, Sinan
This study diagnoses monthly trends in streamflow magnitude and regime for the Susurluk Basin (Türkiye), which spans semi-arid and mountainous sub-climates. Monthly records from 1990 to 2019 were analyzed at 14 stream gauges and nine precipitation stations. Trends are assessed with the Mann–Kendall (MK) test alongside recent graphical approaches, Improved Visualization for Innovative Trend Analyses (IV-ITA) to resolve value class-based (low/high) behavior, and Innovative Polygon Trend Analysis (IPTA) with the Star Concept to quantify intra-annual transitions. Before the trend analyses, the stations were tested to determine whether their values were homogeneous, and any inhomogeneous stations were excluded from the study. The consistency between the trends of nine precipitation stations and the streamflow data in the basin was analyzed. Across the basin, the average streamflow increased by approximately 40–60% between January and March at many measurement points. However, it then decreased by around 80% in April, albeit at a more moderate rate in December. This suggests significant rebalancing occurred during the December–April period, when most of the annual streamflow occurs. IV-ITA exhibits broadly similar trends for both low and high streamflow classes, with notable exceptions in January–February. Precipitation–streamflow trend directions are largely consistent in the high-flow season (December–April), supporting the notion that climatic control influences the detected shifts. To contextualize these signals, basin-wide land-use/land-cover shifts (1990–2018), notably urban growth, forest expansion, and cropland reconfiguration, provide process context, indicating that a larger fraction of rainfall is routed as fast surface runoff while infiltration and base streamflow recharge decline, alongside seasonally modified water demand. Collectively, the MK+IV-ITA+IPTA framework reveals class-specific and intra-annual dynamics that are obscured by monolithic tests alone and provides decision-relevant evidence for allocation, drought–flood risk, and operations in an intensively managed basin.
- MakaleYalnız künye2025Spatial and temporal patterns of drought under different scenarios for Türkiye in the 21st century
Yıldız, Mehmet Berkant; Nacar, Sinan; Şan, Murat; Kankal, Murat
This study investigates the impact of climate change on drought conditions in Türkiye for two distinct future periods: the near future (2021–2050) and the far future (2071–2100), under two emission scenarios (RCP4.5 and RCP8.5). High-resolution regional climate projections from 19 GCM-RCM combinations within the EURO-CORDEX framework were evaluated. Based on performance analysis against ERA5-Land data, the four best-performing models were selected for multi-model ensemble averaging (MMEA). Drought conditions were assessed using the Standardized Precipitation Index (SPI) at 3-, 6-, and 12-month time scales. Three trend analysis methods, Innovative Trend Analysis (ITA), Modified Mann-Kendall (MMK), and Sen's Slope, were applied to examine spatiotemporal drought patterns. SPI-based analyses show a significant increase in short- and medium-term variability (SPI-3 and SPI-6) and long-term droughts (SPI-12), especially in the Central Anatolia, Southeastern and Eastern regions. The applied trend detection methods consistently point to a widespread drying tendency, with more pronounced changes projected in the latter half of the century. Under the RCP4.5 scenario, although the drought signals are less severe, the persistence of negative trends highlights that Türkiye will still be at risk, even with moderate efforts to mitigate climate change. These findings underscore the urgent need for integrating climate-driven drought projections into national and regional planning efforts.
- MakaleYalnız künye2023Trend analysis of precipitation using innovative approaches in northwestern Turkey
Körük, Ali Emre; Kankal, Murat; Yıldız, Mehmet Berkant; Akçay, Fatma; Şan, Murat; Nacar, Sinan
Precipitation is highly sensitive to climate change, and monitoring its trends over time is essential for understanding the effects of global warming on the Earth's water cycle. This study investigates the effects of climate change on monthly precipitation in the Susurluk Basin located in northwestern Turkey, using innovative trend analysis methods. Innovative Polygon Trend Analysis (IPTA) using star graphics and Improved Visualization for Innovative Trend Analysis (IV-ITA) techniques were used to analyze precipitation data from nine stations in the basin over 50 years (1970–2019), and the findings were compared to classical Mann-Kendall (MK) results. According to the trend analysis results, the MK method detected significant trends in only two months in the decreasing direction. In these decreasing trends observed at Simav and Keles stations in November, z values were calculated as −2.38 and −2.05, respectively. IPTA method detected increasing trends in 54 months and decreasing trends in 40 months; this means there is a change of more than 5% between two half series. The IV-ITA method indicated an increase of more than 40% in the low values for January, March, August, and September. In addition, there was an increasing trend of more than 40% in the high values observed in September at all stations. It was observed that mean precipitation heights increased from September to December and then decreased throughout the basin. It is predicted that decreases in precipitation during dry seasons may put intense pressure on agricultural water use and affect water quality. In addition, the increase in precipitation in spring months may increase flood events. It was determined that graphical innovative trend analysis methods are more effective in trend identification than MK, and these methods' results have much higher visual inspection and linguistic interpretation possibilities. Innovative methods allow for more flexible and in-depth analysis using different statistical parameters.