Identify The Monthly and Annual Trend of Air and Soil Temperature Changes Using Parametric and Non-parametric Statistical Methods at Three Synoptic Stations in Southeast of Iran

Importance of climate change and global warming and effect of soil temperature on issues such as changing the hydrological behavior of the system shows that it is essential to have a clear understanding of the temperature trend especially in arid region. Therefore, in this study, the trend of air temperature and various depths of soil temperature at three central synoptic stations in southeast of Iran including Kerman, Zahedan and Bandar Abbas during the years (1957-2018) was investigated using nonparametric Mann-Kendall test, Spearman test and Pearson's correlation coefficient. For this purpose, monthly and annual air and soil temperatures data in various depths of 5, 20, 50 cm were used. Also the power test percentage method was used to evaluate the accuracy of the methods used. The results demonstrated that the trend of mean air temperature in Kerman and Zahedan station showed a significant increasing trend in annual scale. But, the air temperature at Bandar abbas station did not follow a specific trend. Also, soil surface temperature was increased from surface to depth 20 cm in annual scale at 3 stations. In the monthly scale,, the trend of soil temperature changes was incremental in depth 50 cm from august to December at 3 stations. Based on the test power percentage results, The nonparametric Mann-Kendall test was determined as the most accurate test for estimating air and soil temperature trends.