Investigation of innovative trend approaches (ITA with significance test and IPTA) comparing to the classical trend method of monthly and annual hydrometeorological variables: a case study of Ankara region, Turkey


 The difficulty of monitoring hydrometeorological trends remains relevant because of the importance of climate change. In this study, innovative polygon trend analysis (IPTA), new graphical methods, have recently been presented, Mann-Kendall and innovative trend analysis (ITA) with significance tests are employed at monthly and annual hydrometeorological data for Ankara province in Turkey. Finally, sequential Mann-Kendall (SQ-MK), CUSUM, and standard normal homogeneity test (SNHT) are applied to detect any abrupt changes in annual time series. The results indicate that ITA with significance test, IPTA, and MK capture precipitation trends in 83, 94, and 0.2% of all months (3 stations × 12 months), temperature trends in 86, 75, and 22% of all months, relative humidity trends in 80, 80, and 30% of all months, and evapotranspiration series in 91, 80, and 47% of all months. These findings suggest that the ITA with significance test and IPTA are more sensitive than the MK test, with the precipitation series being the most sensitive and the evapotranspiration series being the least sensitive. SQ-MK, CUSUM, and SNHT tests on station 17664 were successful in detecting a change in annual evapotranspiration in 2005. The annual total evaporation series have been rising since 2005, according to the SQ-MK test.