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Climate change–induced precipitation unpredictability has disastrous consequences for closed basins with sensitive hydrological equilibrium. Identifying changes and trends in precipitation characteristics in such catchments is an important step towards minimizing potential disasters. This study explores the precipitation variability of the Konya Closed Basin (Turkey), an over-exploited semi-arid basin. For this purpose, monthly precipitation data for the period 1971–2020 (50 years) of 11 meteorological observation gauges operated by the Turkish State Meteorological Service in the basin were utilized. Precipitation data were examined using two graphical innovative trend methods namely innovative polygon trend analysis (IPTA) and trend polygon star concept (TPSC) approaches. With these methods, periodic features in monthly precipitation data and trend transitions between months can be interpreted visually and linguistically. IPTA and TPSC methods were applied separately to both arithmetic mean data and standard deviation for each month's precipitation data of 11 stations. A general increasing trend in precipitation was obtained in most of the months for the stations used in the IPTA application. Most of the TPSC arrows, which were distributed throughout all four regions for both the arithmetic mean and standard deviation, were in the I and III regions. Based on the TPSC graphs, the longest transition arrows between two consecutives occurred in the first months of autumn (highly increasing) and summer (highly decreasing) in most of the stations. The results of this study are of great importance for the policies to be sustained regarding the ongoing climate change in the agricultural sector in KCB, which is both a water scarce basin and a region with intensive agricultural activities. [ABSTRACT FROM AUTHOR]

Understanding how temporal precipitation variability will behave in the future is crucial. Change point detection and sub-trend analysis were done on monthly total precipitation data acquired from the Coordinated Regional Climate Downscaling Experiment project in this study. Sub-periods have been determined based on the natural structure of the data set, as opposed to standard sub-period determination approaches. For the period 1971–2100, six different time series were used under three global climate models (CNRM-CERFACS-CNRM-CM5, ICHEC-EC-EARTH, MPI-M-MPI-ESM-LR) and two emission scenarios (Representative Concentration Pathway (RCP) 4.5 and RCP 8.5). The study area has been selected to be the Konya Endorheic Basin in Turkey, which has been significantly influenced by climate change and human impacts. For change point detection, the Pruned Exact Linear Time method (PELT) and Binary Segmentation (BS) were employed, for trend analysis, Mann Kendall (MK) and Şen-Innovative Trend Analysis (Şen-ITA), and for both change point detection and sub-trend analysis, the Onyutha Trend Test (OTT) was utilized. The findings revealed four change points and five sub-periods. Summer precipitation has reduced considerably at a 95% significance level. There is strong evidence that precipitation has decreased between 1981 and 2070. Precipitation decreases similarly in the middle basin for the 1981–2000 and 2041–2070 years. [ABSTRACT FROM AUTHOR]

Irregular precipitation regimes have important effects on the increase in the incidence and severity of meteorological disasters, the use of water resources, the decrease in the variety and amount of agricultural products, and on biodiversity. Therefore, investigating the temporal and spatial variations of precipitation is vital important in the future planning and management both water resources and of agricultural activities. In this study, it is aimed to investigate annual and seasonal time scales the spatial variability and temporal trends of concentration, seasonality and aggressiveness of precipitation in Seyhan Basin (Turkey), which has different topography and climate characteristics. For this purpose, nonparametric indices such as the Precipitation Concentration Index (PCI), Seasonality Index (SI) and Modified Fournier Index (MFI) were used. To calculate these indices, monthly precipitation data of 7 stations for the period 1970–2019 were used. While monotonic trends in the PCI, SI and MFI series were analyzed using the classical Mann–Kendall test, sub-trends were examined using Onyutha's test, which is an innovative method. The presence of monotonic and sub-trends was evaluated at the 5% significance level. Analyses performed on both annual and seasonal scales showed that generally higher index values were obtained at stations in the south of the basin and lower indices values were obtained in other parts of the basin. The results of MK and Onyutha trend tests applied to annual total precipitation and PCI, SI and MFI values are similar. In general, insignificant positive trends were determined in the annual total precipitation and index values at the stations in the south of the basin, while insignificant negative trends were determined in the other regions. [ABSTRACT FROM AUTHOR]