Abstract:
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.
Machine summary:
"Comparative assessment between historical and future trends in the daily maximum temperature parameter over selected stations of Iran Mohsen Abbasnia; Ph. D in Climatology, Department of Physical Geography and Environmental Planning, University of Sistan and Baluchestan, P.
2. Climatic scenarios generation After preparing the database, correlation analyses in the SDSM software are used to identify the strongest significant correlations between the large-scale atmospheric variables as predictors and observational maximum temperature as predicted at each study station, which include: correlation matrix analysis, partial correlation, scatter plot, and proportion of explained variance between all variable groups (Mahmood and Babel, 2014; Liu and Xu, 2015).
Results and Discussion In this study, after assessing the ability of SDSM model for statistical downscaling of HADCM3 outputs and uncertainty analysis onto all scenario outputs of HADCM3 model at the station scale, it is worth noting that the obtained results based on each studied scenarios represent a more increasing rate of maximum temperature in all of studied stations for the future decades than the observation decades (Table 6).
Also in the future periods, the analyzing results of Z value in maximum temperature series showed that the highest positive trend will respectively happen at Ahvaz, Tabriz, and Tehran stations based on A2 scenario and at Zahedan and Tehran stations based on B2 scenario, while the lowest positive trends have been found at B-Abbas station during the whole time period which is located in the southern coasts of Iran."