Time-Spatial Investigation of Iran's Annual Temperatures During 1961-2008

This paper investigates spatial variability of temperature trends over Iran in the last 48 years. In order to evaluate the trends, time series of minimum, maximum, and mean temperature for all synoptic and climatologic stations throughout Iran from 1961 up to 2008 were collected. With the help of the prepared data base, the isothermal maps with spatial resolution of 1515 Km were calculated and plotted by Kriging interpolation method. So that each map with 7196 pixels covered Iran’s borders. Therefore, 3(three) arrays with dimension 7196*48 were provided.For evaluating the temperature trend, parametric methods of Linear Regression and Mann-Kendall test have been used. Using such tests on each of the arrays showed that Iran’s temperature is increasing. Such increase has happened more in flat and low height areas. Among these, minimum temperature is more important and in 60% of the country shows an increasing trend, while the increasing trend of maximum temperature covers only 27% of the country. On the other hand, the trend intensity is not the same in all the zones, and for minimum trend, its intensity in Kerman province at the west of Loot desert and in Shahdad area, central parts of Semnan province, east of Khuzestan, south of Ilam province and west of Kermanshah province is more and these areas are more endangered with environmental damages resulting from increasing minimum temperature, while the provinces of North Khorasan, Hamedan, Chaharmahal Bakhtiyari are endangered with increasing trend of temperature.