Comparative assessment between historical and future trends in the daily maximum temperature parameter over selected stations of Iran

Objective of this study is to determine whether there are significant changes in maximum temperature trends between the current (1981-2010) and future (2011-2099) periods. To this end, statistical downscaling is used to project future changes in the maximum temperatures according to A2 and B2 scenarios of HADCM3 in the 7 selected stations of Iran. The possibilities of an accelerating trend are detected in the maximum temperature at 95% confidence level using of Mann–Kendall and Sen’s slope methods. The results showed that there is an increasing tendency in the maximum temperature trends over Iran, especially in the northern highlands for the future decades of the 21st century than the last three decades. The highest trend slopes in annual maximum temperatures are found by 0.69, 0.68, and 0.62°C per decade at Isfahan, Tabriz, and Tehran stations based on A2 scenario for the future decades (2011-2099), respectively, while the lowest trend slope is found at B-Abbas station that is equivalent to 0.14°C per decade based on B2 scenario. It is important to mention that the rate of warming trend will be accelerating based on temperature-time relations in coming decades. In this point, the future occurrences of desirable daily temperatures could be exposure in the southern coasts of Iran where it will be affected by more capacity of atmospheric humidity.