Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Şan, Murat(2)
- Bayram, Adem(1)
- Kankal, Murat(1)
- Nacar, Sinan(1)
Yayınlar
- MakaleAçık Erişim2026Development of the seasonal non-monotonic Mann-Kendall test for hydroclimatic data
Şan, Murat
Climate change can show different characteristics at low and high values of a time series, leading to non-monotonic trends. The Mann-Kendall (MK) and seasonal MK tests can only detect monotonic trends and ignore different behaviors in low and high value groups. To overcome this limitation, extending the recently proposed non-monotonic MK (NMK) test, the seasonal NMK (SNMK) test is proposed. The method was applied to four stations in Türkiye with four different climatic and topographic characteristics using monthly total precipitation data for the 1969-2020 for seasonal trend behavior. The results showed that while no significant trends were detected in entire time series, intra-seasonal and annual data, both monotonic and non-monotonic significant trends emerged in seasonal analyses. Especially in two stations, opposite changes in low and high values, increased seasonal variance and non-monotonic seasonal trends were observed. The test can be used for regional trend analysis by replacing seasonal data with regional data. It is also predicted that the SNMK test can be used as an effective decision support tool in areas with high seasonality such as water resources management, agriculture, energy planning and disaster management.
- MakaleYalnız künye2026Analysis of the Changes in River Water Quality and Quantity with Innovative Trend Methods
Şan, Murat; Nacar, Sinan; Bayram, Adem; Kankal, Murat
This study aims to investigate trends and changes in water quality (WQ) and quantity parameters under low-medium-high groups and seasonal trends employing innovative methods. The data were collected from three monitoring stations in the Broad River Basin (USA). The data spanning the years 1987–2020, on water temperature (WT), dissolved oxygen (DO), discharge (Q), and electrical conductivity (EC) parameters, were used for analysis. A combination of innovative trend analysis with binary segmentation (ITABS) was proposed for objective group separation for the purpose of group trend analysis, allowing for the capture of changes in both location and shape parameters. Recently proposed innovative polygon trend Wilcoxon significance test (IPTWST) and innovative polygon trend analysis (IPTA) were also used to examine seasonal trends for the first time, providing a graphical and qualitative analysis of seasonal behavior. The seasonal Mann-Kendall test was also used to compare them. The ITABS method grouped WQ parameters into more than one group, except for the DO parameter. Especially from EC and Q parameters, it is concluded that the trends in groups do not always contribute to the overall trend or at the same rate. Group trends, therefore, should not be ignored for water resources management. According to IPTA and IPTWST, although there is no clear trend in certain seasons, it is evident that seasonal trends exist, and the Q and EC parameters have a more complex structure. The IPTWST method has the advantage of being able to graphically show the inter-seasonal behavior, although it is identical to the seasonal Mann-Kendall method.