Climate change trends in the Southeastern Anatolia region of Türkiye: precipitation and drought

Drought is a recurring natural disaster globally, affecting various regions around the world (Wilhite & Glantz 1985). Drought, as a multifaceted natural phenomenon, manifests through prolonged periods of below-average water availability, affecting all biotic and abiotic components dependent on water. Unlike abrupt natural disasters, the onset of drought is insidious, often eluding early detection until the impacts are severe and far reaching. The increasing frequency and intensity of drought events in the region necessitate robust scientific inquiries to forecast, manage, and mitigate their consequences (Wilhite et al. 2007). Understanding the role of drought indices and their impacts on science, agriculture, water management, and societies is critical for us to take steps towards a sustainable future on a global scale. Drought is a major challenge at a time when climate change and water resources are under pressure, and drought indices provide us with valuable tools to measure, analyse, and understand these events (Lotfirad et al. 2022; Hinis & Geyikli 2023).

Drought is a complex and multifaceted natural phenomenon that has wide-ranging impacts on human activities and ecosystems. It affects not only water resources but also agricultural production, economic stability, and the well-being of communities (Wilhite & Glantz 1985; Wilhite et al. 2007; Turkes 2020). Therefore, it is essential to conduct in-depth studies and analyses, like this one in the Southeastern Anatolia region of Türkiye, to understand the specific characteristics and dynamics of drought to develop effective mitigation strategies. Additionally, by studying the relationship between drought and desertification in the palm grove of Draa Valley in Southeastern Morocco, we can gain valuable insights into the socio-ecological impacts of these phenomena and their interconnectedness (Karmaoui 2019). These insights can inform the development of impact indicators, which will help policymakers and stakeholders assess the severity and extent of drought and desertification in the region. Furthermore, the analysis of historic drought events and their economic impacts in various regions around the world highlights the urgency of addressing agricultural drought. It underscores the need for proactive measures, such as improved water management practices, drought-resistant crop varieties, and contingency plans for agricultural communities.

One such study conducted in the Mediterranean region found that drought occurrences have been increasing in frequency and intensity over the past few decades, posing significant challenges to water resource management and agricultural sustainability (Sousa et al. 2011). Similarly, research in arid and semi-arid regions has highlighted the vulnerability of these areas to prolonged drought events, emphasizing the need for adaptive strategies and policies (Singh et al. 2014).

Furthermore, a study focusing on the socio-ecological impacts of drought and desertification in Southeastern Morocco revealed the interconnectedness of these phenomena and their adverse effects on local communities and ecosystems. Understanding the relationship between drought and desertification is crucial for developing effective impact indicators and mitigation measures (Karmaoui et al. 2021). In addition, analyses of historic drought events in various regions have underscored the economic and social impacts of drought on agricultural communities, emphasizing the urgency of implementing proactive measures to enhance resilience and sustainable agricultural practices.

By synthesizing and building upon the findings of these existing studies, this research aims to contribute to the scientific understanding of meteorological drought in the Southeastern Anatolia region of Türkiye and provide practical insights for policymakers, water resource managers, and agricultural stakeholders. The findings of this literature review highlight the urgent need for proactive measures to address agricultural drought and mitigate its economic impacts (Dell et al. 2014). Several key studies have been conducted on the topic of drought and its impacts on agriculture and communities (Kiem et al. 2010; Ding et al. 2011; Potop et al. 2012; Dabanlı et al. 2017; Alsafadi et al. 2020; Dikici 2020; Lottering et al. 2021; Onuşluel Gül et al. 2022; Radmanesh et al. 2022; Serkendiz et al. 2024). These studies have provided valuable insights into the temporal and spatial patterns of drought, as well as its economic, social, and ecological consequences. Based on these studies, it was seen that drought occurrences are increasing in frequency and intensity in various regions, posing significant challenges to water resource management and agricultural sustainability (Nhemachena et al. 2020). Furthermore, these studies have highlighted the vulnerability of arid and semi-arid regions to prolonged drought events and the interconnectedness of drought and desertification. Understanding the coping mechanisms of local communities, such as crop diversification, on-farm storage, and pastoralist practices, can provide valuable insights into developing adaptive strategies and policies to mitigate the impacts of drought. Therefore, taking into consideration the knowledge gained from these studies and understanding the unique coping mechanisms of local communities, policymakers and stakeholders can develop effective strategies to enhance resilience and sustainable practices in the face of drought and desertification (Mujumdar 2013). Overall, the literature studies on drought and its impacts on agriculture and communities highlight the urgent need for proactive measures to address agricultural drought and mitigate its economic impacts (Ding et al. 2011). Additionally, these studies emphasize the importance of considering the context-specific coping mechanisms and adaptive strategies of local communities to develop effective policies. Therefore, policymakers, water resource managers, and agricultural stakeholders must utilize the findings of this literature review on drought impacts and adaptation strategies to inform their actions and implement effective drought mitigation and adaptation programmes (Olmstead 2014). The consequences of these changes are profound, influencing not only the availability of water but also the health of agricultural systems and the sustainability of local communities. Thus, understanding these impacts through reliable scientific methods and indices is paramount. In the Southeastern Anatolia region of Türkiye, a distinctive interplay of climatic factors shapes the hydrological and agricultural landscapes. As global climatic shifts influence precipitation patterns and temperature profiles, the implications for water resources and agriculture become increasingly significant. There are four predominant indices used to assess and quantify meteorological drought: the Standardized Precipitation Index (SPI), the China-Z Index (CZI), and the Standardized Precipitation Evapotranspiration Index (Wilhite 2006; Diaz et al. 2020). Out of these indices, the SPI and CZI only take precipitation into account when monitoring drought patterns. On the other hand, the SPEI focuses on the combined effect of precipitation and temperature. The indices mentioned above are widely used and recommended both globally and in Türkiye (Cavus & Aksoy 2019; Alsafadi et al. 2020; Onuşluel Gül et al. 2022; Erkol et al. 2024; Serkendiz et al. 2024). The prediction and observation of drought phases are crucial in water management due to various causes (Cavus & Aksoy 2019). This is especially true in a world that is experiencing significant changes, notably in terms of precipitation patterns (Marvel & Bonfils 2013). The effectiveness and representativeness of the studies will determine the extent to which we can accurately forecast quantitative changes in water resources, which are directly linked to water management.

The Southeastern Anatolia region of Türkiye is particularly susceptible to the impacts of drought due to its semi-arid climate and reliance on agriculture (Turkes 2020; Serkendiz et al. 2024). This study aims to provide an in-depth analysis of meteorological drought patterns in the region, shedding light on the temporal and spatial variations that have occurred over the past few decades. The findings from this research will not only contribute to the scientific understanding of drought in the region but also provide practical insights for policymakers, water resource managers, and agricultural stakeholders. By gaining a better understanding of the timing, duration, and severity of drought events in Southeastern Anatolia, we can work towards developing targeted and effective strategies for drought preparedness, response, and long-term resilience. This research is crucial for informing sustainable land-use and water resource management practices in the region, ultimately helping to build a more resilient and adaptive Southeastern Anatolia.

The Southeastern Anatolia region, characterized by its arid and semi-arid climate, is particularly susceptible to fluctuations in climatic conditions (Turkes 2020; Serkendiz et al. 2024). These regions may range from arid and semi-arid areas to those with a Mediterranean climate. The impacts of drought can be devastating, leading to water scarcity, crop failures, and ecological imbalances. To mitigate the effects of drought, it is crucial to have a comprehensive understanding of its temporal and spatial patterns. By studying the temporal and spatial assessment of meteorological drought in the Southeastern Anatolia region of Türkiye, we can gain valuable insights into the characteristics and trends of drought in this specific area. This information can be used to develop proactive strategies and policies for drought mitigation and water resource management in the region. By analysing meteorological data in the Southeastern Anatolia region, we can assess the frequency, duration, and intensity of drought events over time. This analysis can help identify areas that are more vulnerable to drought and prioritize resource allocation for water management and agricultural practices. Furthermore, understanding the spatial distribution of meteorological drought in this region can provide valuable information for land-use planning and infrastructure development.

This study aims to: (a) understand what the drought indices we will use, how they work, and how drought analysis via SPI, SPEI, CZI, and Effective Drought Index (EDI) methods, (b) analyse climate change trends via Mann–Kendall (MK), Sen's slope, and innovative trend analysis (ITA), (c) assess the drought trends via ITA, and (d) predict the drought via spatial analysis in the Southeastern Anatolia region of Türkiye can contribute to drought mitigation strategies.

This study covers the provinces of Siirt, Batman and Şırnak. Siirt, located in the Southeastern Anatolia region at 41°57′ east longitude and 37°55′ north latitude, is surrounded by Şırnak and Van from the east, Batman and Bitlis from the north, Batman from the west, and Mardin and Şırnak provinces from the south. Most of the province's territory is covered with mountains. The surface area of the province is 5,718 km². A continental climate prevails in Siirt, and four seasons are experienced with their most distinctive characteristics. Winters are harsher and rainier in the eastern and northern regions and warmer in the southern and southwestern regions. Summers are hot and dry. The landforms in the city mostly consist of high mountains and plateaus. Its vegetation is covered with steppes. There are many dwarf and bushy trees, but it is a province that is not rich in forests (Özyazıcı et al. 2014).

Şırnak is a province in the Southeastern Anatolia region of Türkiye and located at 37°31′ north latitude and 42°28′ east longitude. The surface area of Şırnak central district is 1,701 m², and the surface area of the city overall is 7,078 m². The city centre is located on the foothills of Namaz Mountain, and its altitude is 1,350 m. While the Cizre, İdil, and Silopi districts of the province feature flat and plain geography, the Şırnak centre, as well as Beytüşşebap, Uludere, and Güçlükonak districts, are situated in the mountainous part. Şırnak borders Mardin province to the west, Siirt province to the north, Hakkari province to the northeast, and the states of Iraq and Syria to the south. In terms of vegetation, the continental climate of the provincial territory has had an impact on the natural vegetation (Avci 2023).

In this study, daily minimum temperature (T_min), average temperature (T_ave), maximum temperature (T_max), and precipitation (P) parameters were used to calculate the values of drought indices between 1981 and 2022. The General Directorate of Meteorology provided the meteorological data. Several methods were available in the literature to calculate potential evapotranspiration (PET) values. However, the Thornthwaite method (Thornthwaite 1948) was used in the present study. SPI, CZI, and EDI use only precipitation in drought analysis. However, although they use the same parameter, there are differences between their calculation methods. Due to the differences in the calculation methods, the determination of drought classes and their sensitivities differs. In addition, by preferring the SPEI method, which uses the temperature parameter in addition to the precipitation parameter in drought analysis, the results obtained with the SPEI method of these precipitation-based methods were compared, and the compatibility of the precipitation-based methods with the temperature-based method was evaluated. These differences constituted the main motivation of the study. The pre-whitening process was performed before the MK method was applied. This is to identify whether there is autocorrelation in the precipitation data. Since autocorrelation may cause errors in determining the trend in non-parametric methods such as the MK test, the time series that exhibit autocorrelation should be subjected to pre-whitening to remove the autocorrelation effects. Correlation coefficients calculated for precipitation data used in the study and lower and upper limit values for 95% significance level are presented in Table 3.

Precipitation trend was detected via MK test, Sen's slope, and ITA. Drought values of the trend were also detected via ITA. Time series was separated into two halves in ITA theory. In this study, the first half data refer to 1981–2001, while the second half data refer to 2002–2022.

If the calculated value of |Z| is |Z| > z_α/2, the null hypothesis is rejected at the α significance level in a two-sided test. In this analysis, the null hypothesis is tested at a 95% confidence level (Brema & Anie 2018).

A positive value of Q_i indicates an upward or increasing trend in the time series, while a negative value of Q_i indicates a downward or decreasing trend in the time series.

The ITA method developed by Şen (2012) is a technical analysis method that shows possible general increases or decreases in a given time series. In this method, the available data are arranged sequentially and then divided into two equal series. These two series are ordered from smallest to largest. The first part of the series (X) is placed on the X-axis of the Cartesian coordinate system, and the second part (X) is placed on the Y-axis (Caloiero et al. 2018; Serinaldi et al. 2020). It is a graphical analysis method.

Here, n is the number of data, and and are the arithmetic means of the first and second half of the dependent variable.

Here, C_st is the coefficient of skewness for any t time scale (1, 3, 6, 9, 12, and 24 months), σ is the standard deviation, and n is the observation period. Station details are shown in Table 1. Drought classes for both drought indices are given in Table 2. The data obtained by the SPI and the CZI used within the scope of the study are point-based and represent meteorological stations. Inverse distance weighted (IDW) was used to prepare basin-based areal thematic maps using the data in question. The IDW interpolation technique is based on the principle that nearby points on the surface to be interpolated have more weight than distant points. This technique is far from interpolated (Köroğlu 2006; İlker et al. 2019).

Table 2

Drought classification of the CZI and the SPI (Morid et al. 2006; Barua et al. 2011)

Condition .	CZI, SPEI, and SPI .
Extremely wet	Value 2:00
Very wet	1:50 Value 2:00
Moderately wet	1:00 Value 1:50
Near normal	−1:00 Value 1:00
Moderately dry	−1:50 Value −1:00
Severely dry	−2:00 Value −1:50
Extremely dry	Value − 2:00

Condition .	CZI, SPEI, and SPI .
Extremely wet	Value 2:00
Very wet	1:50 Value 2:00
Moderately wet	1:00 Value 1:50
Near normal	−1:00 Value 1:00
Moderately dry	−1:50 Value −1:00
Severely dry	−2:00 Value −1:50
Extremely dry	Value − 2:00

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Kriging and IDW spatial interpolation techniques were used in the present study.

It applies the assumption that things closer are more similar than distances away from each other (Hodam et al. 2017). To predict a value for any unmeasured location, the IDW algorithm may use the measured values surrounding the prediction location. These measured values closest to the prediction location are likely to have more influence on the predicted value than those further away. For this reason, the IDW presumes that all measured points have a decreasing location effect with distance. The points closer are given more weight than those further away, hence the so-called inverse distance weighting.

It is a geostatistical spatial interpolation technique that estimates the degree of spatial dependence between known points in terms of semi-variance (Hodam et al. 2017).

There are three elements of a semi-variogram: nugget (semi-variance at distance 0 – spatially uncorrelated noise), range (spatially correlated part of the semi-variogram shows an increase in semi-variance with distance), and threshold (a relatively constant value beyond which the semi-variance levels out beyond the range). The semi-variogram needs to be fitted to a model, such as circular, spherical, exponential, or Gaussian, in order to be used as an interpolator in Kriging. Then, the fitted semi-variogram can be used to predict the semi-variogram at any distance. Several standard models can be linearly combined to form a nested variogram structure if the sample semi-variogram does not appear to follow any standard models. Nevertheless, this type of complex structure may lead to overfitting the sample semi-variogram and usually results in predictions that are no more accurate than those from simpler models (Hodam et al. 2017). The ordinary technique of Kriging was used in this study.

Batman presents a pattern of less pronounced precipitation variability compared to Siirt but still shows fluctuations that could influence local agricultural cycles and water availability. The temperature data for Batman indicate a gradual increase in both minimum and maximum values, aligning with broader global trends of warming and potentially contributing to increased evaporation rates, which could exacerbate drought conditions during lower precipitation periods.

Cizre displays the most pronounced variability in precipitation, with high peaks suggesting intense, episodic rainfall events. This could lead to challenges in flood management and water storage, especially if not matched by consistent seasonal rainfall. Temperature trends in Cizre also show increasing maximums, which could lead to increased evapotranspiration rates and impact water sustainability and agricultural productivity.

The comprehensive analysis in Table 3 for Siirt provides a detailed examination of meteorological trends across 12 months and seasons, indicating significant variability in precipitation and temperature patterns. The correlation coefficients, along with Kendall's tau and Sen's slope values, provide an empirical basis for understanding these patterns. January and July show a relatively higher level of variability, which is indicated by their positive skewness and high kurtosis values, suggesting extreme values and a heavier tail distribution. This might be related to sporadic heavy precipitation events during these months. The correlation status for most months indicates a negative trend (indicated by ‘(−)’), with several months showing no significant trends as the p-values are higher than the typical significance level of 0.05. The winter months, with a mean precipitation level of 266.28 mm and a standard deviation of 86.49, reflect the highest variability among the seasonal categorizations, which is crucial for agricultural planning and water resource management. The annual analysis underscores a notable negative trend in precipitation with a steep decline in Sen's slope (−2.72), which is statistically significant, pointing towards a potential shift in climatic patterns over the year.

Table 4 provides a clear depiction of the climatological parameters across three key locations within the Southeastern Anatolia region: Cizre, Batman, and Siirt. The data are instrumental in understanding the regional climatic variability and its implications on environmental and agricultural planning. In Cizre, the range of precipitation varies widely, as indicated by the minimum and maximum values (0–307.40 mm), with an average precipitation of 49.89 mm. The standard deviation is relatively high at 62.23 mm, signifying a significant spread in the data, which is further supported by a skewness of 1.459, suggesting a right-skewed distribution with more frequent lower precipitation and occasional extreme events. The kurtosis value of 1.73 indicates a leptokurtic distribution, which implies a higher probability of observing extreme precipitation values compared to a normal distribution. This is critical for flood risk management in the region. Kendall's tau value of −0.091, with a statistically significant p-value of 0.003, suggests a slight but significant negative trend in precipitation over time. The Sen's slope of −0.017 further confirms a slight decrease in precipitation levels, which may influence water resource strategies in Cizre.

Batman shows less variability in precipitation with a maximum value of 259.40 mm and a mean value of 38.96 mm. The data exhibit a standard deviation of 40.94 mm, with a skewness of 1.24, indicating a less pronounced but still noticeable right-skew. The kurtosis of 1.82 suggests a distribution with more frequent extreme precipitation events than that of a normal distribution. However, Kendall's tau value of −0.029, alongside a non-significant p-value of 0.33, implies that there is no statistically significant trend in the precipitation data for Batman, indicating stable precipitation patterns over the studied period. In Siirt, the precipitation also varies widely from 0.00 to 291.10 mm, with an average value of 57.11 mm. The standard deviation and skewness values are similar to those observed in Cizre, which indicates variability and right-skewness in precipitation distribution. The kurtosis is lower than in Cizre and Batman, suggesting a slightly flatter distribution of precipitation events. Like Batman, Siirt's Kendall's tau value and p-value suggest no significant trend in precipitation changes (Table 4).

Overall, the analysis from Table 4 highlights significant climatic variability across the Southeastern Anatolia region, with implications for hydrological planning and agricultural operations. The slight negative trends in precipitation in Cizre need to be monitored for potential impacts on water availability, while the more stable conditions in Batman and Siirt suggest a different set of strategies for resource management. This underscores the necessity for region-specific approaches to address the impacts of climate variability and change.

Cizre exhibits similar trends with an enhanced drought risk evident in the second period. The shift towards lower values in the CZI and the SPI highlights an increasing trend in drier conditions, while the SPEI suggests that evapotranspiration rates are exacerbating drought impacts, likely due to higher temperatures. This comprehensive analysis suggests that Cizre is experiencing a shift towards more severe drought conditions, which could impact water resource allocation, agricultural scheduling, and ecological balance. In Batman, the indices also reflect an intensification of drought conditions, with all indices showing more frequent and severe drought occurrences in the recent period. This is particularly critical as Batman's agricultural and water resources are already under strain; thus, the increased drought severity indicated by lower SPI and SPEI values may pose significant challenges for sustainability and resource management.

Batman exhibits similar trends with increasing drought severity, particularly in the summer and fall months. SPEI-3, which accounts for both precipitation and evapotranspiration, shows a marked decrease, reflecting the impact of rising temperatures on water availability. This trend is corroborated by the EDI-3 and SPI-3, which also show a downward trajectory, signalling a long-term shift towards harsher drought conditions during these months.

Cizre shows the most pronounced changes in the fall and winter, with all indices reflecting a significant move towards more severe drought conditions. The negative trends in the SPEI-3 and EDI-3 are particularly alarming, indicating a substantial decrease in moisture availability. This could have profound implications for agricultural productivity and water resource management in the region, necessitating immediate and effective adaptation strategies.

Batman exhibits a similar pattern, with all four indices showing trends towards greater drought severity. The decrease in SPI and SPEI values particularly highlights the reduction in precipitation relative to evaporation, a critical indicator of increasing water stress. This trend is alarming as it suggests a long-term climatic shift towards drier conditions, which could have serious implications for the agricultural sectors and urban water supplies in the region. The consistent downward trend in these indices suggests the need for enhanced drought preparedness and resilience strategies to mitigate the impacts of these changes.

Cizre also shows a significant trend towards increased drought severity, with notable decreases in both the SPI and the SPEI. This region seems to be particularly vulnerable to changes in precipitation patterns, which are exacerbated by increasing temperatures as reflected in the SPEI. The EDI and the CZI further confirm the increasing frequency and intensity of drought conditions, highlighting a critical need for adaptive measures in agricultural practices and water usage to address the growing challenges of water scarcity.

The analyses reveal significant temporal and spatial variability in precipitation and temperature patterns, with clear evidence of a general trend towards drier and warmer conditions across the Southeastern Anatolia region. These trends are crucially reflected in the increasing severity and frequency of drought events as demonstrated by the changes in drought indices (SPI, SPEI, CZI, and EDI) over the last four decades. Particularly notable is the marked increase in drought severity during the latter half of the study period, underscoring a likely response to global climate change phenomena including increased temperatures and altered precipitation patterns.

Gumus et al. (2021) conducted a study for the Southeastern Anatolia Project (Güneydoğu Anadolu Projesi/GAP) region to detect the trend in climate variables with the MK test. They found that significant decreasing trends were detected at different time scales at Ergani, Akçakale, Çermik, Kilis, Mardin, Nusaybin, and Şanlıurfa stations. In addition, significant decreasing trends were mostly concentrated in the regions close to the Syrian border where agricultural activities were high.

Keskiner & Çetin (2023) reported that drought severity is increasing in Şanlıurfa, which is located in the GAP region, and drought has started to become dominant based on MK and Sen's slope methods. Similarly, Özfidaner & Topaloğlu (2020) conducted a drought study for the Southeastern Anatolia region. They determined the SPI results for Siirt province for the 1-month shift period between 1968 and 2007. Rainy periods are quite high and severe drought was not determined. It was stated that wet and dry periods followed each other between 2002 and 2007 for Siirt province. Furthermore, Agha & Şarlak (2016) utilized non-parametric tests to analyse the trends of precipitation, maximum and lowest temperature values, and other climatic indicators in Iraq from 1980 to 2011. Data on precipitation in this study showed a declining tendency, they found. Gümüş et al. (2023) assessed the meteorological trend via the MK test, Sen's slope, and ITA in Southeastern Anatolia in Türkiye. Similarly, they found that temperature values tend to increase the trend. As discussed above, similar results were obtained for the present study.

These findings are consistent with those of Mohammed et al. (2020), Gumus et al. (2021), Agha & Şarlak (2016), Katipoğlu et al. (2022), Katipoğlu et al. (2022), and Gümüş et al. (2023), who also found that drought values were rising in the region's southern half. The observed variability in meteorological data, characterized by significant seasonal fluctuations and extreme weather events, suggests a complex interaction between regional climatic systems and larger-scale atmospheric processes. The increase in temperature, combined with decreasing precipitation, points towards an enhanced risk of prolonged drought periods, which could have profound implications for water resource management, agricultural sustainability, and ecological balance.

Additionally, the spatial distribution of drought conditions, analysed through IDW and Kriging methods, provides essential insights into the geographical variability of drought impacts. This spatial analysis highlights the importance of localized adaptive strategies that consider the specific needs and vulnerabilities of different areas within the region. Given these findings, policymakers and stakeholders must develop comprehensive management strategies that incorporate both mitigation and adaptation measures. These strategies could include enhancing the efficiency of water use in agriculture, investing in drought-resistant crop varieties, improving the accuracy of meteorological forecasting, and reinforcing water conservation infrastructure.

In conclusion, this discussion emphasizes the need for a proactive approach to managing the increasing risk of drought in the Southeastern Anatolia region, driven by an evidence-based understanding of the temporal and spatial dynamics of climate variables and their impacts on regional hydrology and agriculture. The integration of advanced drought assessment tools and indices, as well as the strategic planning of resource management practices, will be crucial in safeguarding the region against the adverse effects of future climatic variability.

In this study, the temperature, precipitation, and meteorological drought trends of the Southeastern Anatolia region of Türkiye were analysed with classical and innovative methods. Parameters measured between 1981 and 2021 at Batman, Cizre and Siirt stations in the study region were used. The SPI, SPEI, CZI, and EDI methods are preferred in the analysis of drought. MK, Sen's slope, and ITA methods were used to determine the trend of drought and meteorological parameters. The success of Kriging and IDW techniques in predicting index values obtained with different meteorological drought analysis methods was compared. The findings obtained as a result of the study are listed below:

• The decreasing trend in precipitation in Cizre and the limited change in Batman and Siirt stations reveal the necessity of region-specific approaches to address the effects of climate variability and change in the study region.

• It shows a significant increase in extreme weather events in the second half of the study period at the Cizre station. At the Batman station, the change is more subtle, with moderate increases in average temperatures but a more pronounced variability in precipitation. Climate data at the Siirt station revealed that temperatures had increased steadily throughout the year, while there was a slight decrease in precipitation.

• In the precipitation data at the Siirt station, it was observed that there was a decreasing trend in the peak summer months using the ITA method. At the Batman station, there was an increasing trend in the winter, and at the Cizre station, there was no increasing or decreasing trend in the spring and autumn seasons.

• Annual trends in index values obtained by SPI, SPEI, EDI, and CZI methods at Batman, Cizre, and Siirt stations show a general decrease. As a result, the drought severity in the study region increased.

• The Kriging method gave more consistent results in mapping meteorological drought compared to the IDW method.

It has been determined that changes in meteorological parameters in the study region increased the risk of drought in the region, and in addition, the change in drought index values should be seriously considered in the planning of water resources and agricultural activities in the region.

The authors especially thank the General Directorate of Meteorology (MGM) for providing the database used in this study and the TUBITAK Scientific and Technological Research Council of Türkiye (BIDEB).

V.K. conceptualized the work, performed the methodology, edited, and visualized the work. K.K. validated the work and conducted multiple regression analysis. S.A. investigated the work and analyzed the resources. S.A. and O.S. edited and wrote the original draft. V.S.Y. and S.A. wrote the draft, performed the methodology, and prepared the draft. The authors read and agreed to the published version of the manuscript.

This study was supported within the scope of the 2209-A University Students Research Projects Support Programme carried out by the TUBITAK Scientific and Technological Research Council of Türkiye (BİDEB). The project number is 1919B012320270.

Data cannot be made publicly available; readers should contact the corresponding author for details.

The authors declare there is no conflict.