Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYalnız künye2026Scopus SJRQ2Depth-dependent predictability of soil temperature under Mediterranean climatic conditions: a frequency-based perspective
Guleryuz, Didem; Yıldırım, Ümit; Güler, Cüneyt
Soil-temperature predictability is inherently depth-dependent because atmospheric forcing is progressively attenuated and transformed into smoother, lower-frequency thermal dynamics with increasing depth. Under Mediterranean climatic conditions, where pronounced seasonality and strong surface forcing coexist, this depth-dependent transformation provides an informative basis for evaluating model behaviour. This study examines soil-temperature prediction at depths of 5, 10, 20, 50, and 100 cm using a multivariate dataset comprising 5,285 retained daily observations from the Mersin meteorological station on Türkiye’s eastern Mediterranean coast. Precipitation, air temperature, relative humidity, wind speed, and evaporation were used as predictors. Support vector regression, random forest, and LightGBM were evaluated using R², RMSE, and MAE. All three models performed strongly in the near-surface layers, with test R² values ranging from 0.948 to 0.954 at depths of 5–20 cm. Predictive performance declined with increasing depth as short-period variability weakened and the thermal signal became smoother and more seasonally structured. RF and LightGBM showed a greater numerical decline at 50–100 cm, whereas SVR achieved test R² values of 0.923 at 50 cm and 0.847 at 100 cm; however, inter-model differences remained modest and were interpreted descriptively. Lomb–Scargle spectral analysis, applied using the actual observation dates, indicated that short-period variability became relatively less pronounced with depth while seasonal-scale and low-frequency components remained prominent. Overall, the findings suggest that soil-temperature prediction should be interpreted in relation to depth-dependent temporal signal characteristics rather than as a search for a universally superior algorithm.
- MakaleAçık Erişim2024Scopus SJRQ1Pollution Source and Soil Quality Assessments of Heavily Contaminated Soils by Selected Potentially Toxic Elements in a Human-Degraded Wetland Area
Kurt, Mehmet Ali; Yalçın, Sezen; Güler, Cüneyt; Güven, Onur; Yıldırım, Ümit
Wetlands are transitional between terrestrial and aquatic environments and have essential ecological functions. Unfortunately, due to anthropogenic activities and climate change, the area covered by wetlands is gradually decreasing worldwide, causing deterioration and loss of their critical and vital ecological functions. One of these degraded wetlands is the Hürmetçi Sazlığı, a nationally important wetland located in the Kayseri Province of Turkey. This study aims to determine the spatial and vertical (depth profile) distribution and the sources of the potentially toxic elements (PTEs) As, Cd, Pb, and Zn in the soils around the Hürmetçi Sazlığı Wetland (HSW) and to evaluate environmental risk factors using various soil quality indicators. According to the results obtained, it was determined that some parts of the wetland soils were significantly polluted in terms of As, Cd, Pb, and Zn. The concentrations (in mg/kg) of these PTEs in the soil around the wetland ranged between 9.12 and 273.9 for As, 0.38 and 1119.46 for Cd, 3.59 and 1807.66 for Pb, and 41.68 and 77,287.5 for Zn. Several soil quality indicators, including the Enrichment Factor (EF), Contamination Factor (CF), Ecological Risk Index (ERI), and Potential Ecological Risk Index (RI), were calculated to determine the quality and pollution levels of the collected soil samples. According to the calculated RI values, 70 out of 77 sites sampled in the area around the HSW are in the “High Risk” class in terms of all studied PTEs. The soil profile samples indicated that the topsoil (0–50 cm) was heavily contaminated by all PTEs, particularly near a zinc processing plant established in 1976. In addition, parts of the wetland further away from the Zn processing plant were also affected by arsenic pollution from geogenic sources, which can be associated with Plio-Quaternary volcanic activity in the region.
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İncele - MakaleYalnız künye2021Arsenic pollution caused by Eocene volcanism in the Sivas basin: The old drinking water source of the Yalıncak village (Hafik, Sivas)
Güler, Cüneyt; Güven, Onur; Biçgel, Birsen F.; Kurt, Mehmet A.; Yıldırm, Ümit
The aim of this study is to investigate the origin of the highconcentration (1512 μg/L) of arsenic (As) in the olddrinking water source of Yalıncak village (Hafik, Sivas).For this purpose, 48 samples were collected from the rocksoutcropping in the recharge area of the drinking watersource. The major oxide contents of the rock samples weredetermined by XRF method, mineralogical compositionsby polarizing microscope and XRD methods and Asconcentrations of minerals were determined by using SEM- EDS method. As revealed by these analyses, the source ofarsenic in the waters of the region was found out to betuffite unit, containing pyroxene and plagioclase minerals,as well as volcanic glass fragments of different origins andsizes. It has been detected that arsenic oxide (As2O3)concentrations in rock samples vary between 0.01% and0.14% and some minerals contain As up to 14%. It wasdetermined that arsenic pollution in surface andgroundwater in the region was caused by the dissolution (bywater-rock interaction) of FeAsS (arsenopyrite) and BAsO4(boron arsenate) minerals found in the tuffites of theEocene age Bozbel formation in the Sivas Basin.
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İncele - MakaleAçık Erişim2021Scopus SJRQ1Modelling of the discharge response to climate change under RCP8.5 scenario in the Alata river basin (Mersin, SE Turkey)
Yıldırım, Ümit; Güler, Cüneyt; Önol, Barış; Rode, Michael; Jomaa, Seifeddine
This study investigates the impacts of climate change on the hydrological response of a Mediterranean mesoscale catchment using a hydrological model. The effect of climate change on the discharge of the Alata River Basin in Mersin province (Turkey) was assessed under the worstcase climate change scenario (i.e., RCP8.5), using the semi-distributed, process-based hydrological model Hydrological Predictions for the Environment (HYPE). First, the model was evaluated temporally and spatially and has been shown to reproduce the measured discharge consistently. Second, the discharge was predicted under climate projections in three distinct future periods (i.e., 2021–2040, 2046–2065 and 2081–2100, reflecting the beginning, middle and end of the century, respectively). Climate change projections showed that the annual mean temperature in the Alata River Basin rises for the beginning, middle and end of the century, with about 1.35, 2.13 and 4.11 °C, respectively. Besides, the highest discharge timing seems to occur one month earlier (February instead of March) compared to the baseline period (2000–2011) in the beginning and middle of the century. The results show a decrease in precipitation and an increase in temperature in all future projections, resulting in more snowmelt and higher discharge generation in the beginning and middle of the century scenarios. However, at the end of the century, the discharge significantly decreased due to increased evapotranspiration and reduced snow depth in the upstream area. The findings of this study can help develop efficient climate change adaptation options in the Levant’s coastal areas.
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