Change-point detection and trend analysis in monthly, seasonal and annual air temperature and precipitation series in Bartin province in the western Black Sea region of Turkey

Abstract

Studies associated with climate change and variability are of great importance at both the global and local scale in the global climate crisis. In this study, change-point detection and trend analysis were carried out on mean, maximum, minimum air temperatures and total precipitation based on monthly, seasonal and annual scale in Bartin province located in the western Black Sea Region of Turkey. For this aim, 4-different homogeneity tests (von Neumann test, Pettitt test, Buishand range test and standard normal homogeneity test) for change-point detection, Modified Mann-Kendall test and Sen's innovative trend test for trend analysis, and Sen's slope test for the magnitude estimation of trends were used. According to the test results, the summer temperatures in particular show increasing trends at the 0.001 significance level. Mean maximum temperature in August, mean minimum temperature in June and August, and mean temperature in July and August are in increasing trend at the 0.001 significance level. Over a 51 year period (1965-2015) in Bartin province, the highest rate of change per decade in air temperatures is in August (0.55 degrees C for T-max, 0.46 degrees C for T-min and 0.43 degrees C for T-mean) based on Sen's slope. However, the study showed that apart from October precipitation, there is no significant trend in monthly, seasonal and annual precipitation in Bartin. Increasing trends in mentioned climate variables are also visually very clear and strong in Sen's innovative trend method, and they comply with the statistical results. As a result, the study revealed some evidence that temperatures will increase in the future in Bartin and its environs.