Trend analysis of monthly and annual rainfall according to long-year meteorological data of Çanakkale province

Global climate change, which has a negative effect on the climate, causes drought, sea level rise and precipitation patterns to deteriorate with the increase in temperatures. For this reason, many different disciplines around the world have been using trend analysis in recent years to determine the sudden change in their parameters and trend status in climate studies. It is possible with trend analysis to reveal the changes in precipitation variable, i.e. increase or decrease movements. In this study, the trend analysis of monthly and annual precipitation data between 1929 and 2020 of 21 precipitation observation stations selected for 12 districts was carried out in order to reveal the precipitation trend of Çanakkale province. The missing data of the stations were first interpoled before the analysis was carried out. Station data completed in the missing years were subjected to 4 different homogeneity tests: SNHT, Pettitt Test, Buishand Test and Von-Neuman Test. These homogeneity tests used in the study were classified into 3 categories: suspicious, critical and homogeneous, depending on the number of tests that reflected empty hypotheses. Of the 12 district precipitation observation stations of Canakkale province, were homogeneous 5 stations according to the SNHT test, 6 stations according to the Pettitt test, 5 stations according to the Buishand test and 2 stations according to the Von-Neuman test. In general, 5 stations including Çanakkale Provincial Center, Bozcaada, Gökçeada, Lâpseki and Yenice stations gave homogeneous results within the scope of Class: 1, but the remaining 7 stations were considered suspicious within the scope of Class: 3. Linear Trend Analysis from parametric tests of precipitation data completed and tested with homogeneity tests; In non-parametric trend tests, Mann-Kendall Test, Mann-Kendall Rank Correlation Test, Sen's Slope, Şen's Innovative Trend Analysis (ITA) were subjected to 5 different trend analysis methods and monthly and annual trend situations were determined with 4 districts and 12 districts. According to the results of the monthly analysis, there is a evident decrease in precipitation in summer and winter, while increasing trends were detected in March, April and May. As a result of the annual analyses, the trend status was determined precisely in 6 districts with the same trend result of 5 tests. Increasing trend in Ayvacık, Çan, Eceabat, Ezine and Lâpseki districts; In Biga district, the decrease trend was clearly demonstrated. In the remaining 6 stations, the test results of the trend analysis were not evaluated significantly and determined according to the majority status. Accordingly, an increase trend was detected in Bozcada and Yenice districts, while a decrease was detected at Bayramiç and Gelibolu district stations. In Canakkale Center and Gökçeada district, no increasing or decreasing trends were found.