The Investigation of Mashhad Extremum Temperature in Different Scales

Mashhad is Iran second most populous city، where in terms of tourism، economy and agriculture is very important. Regarding to the importance of the change of climatic factors and its effect on future policy، in this study the max and minimum temperature changes in the scale of yearly، seasonally، monthly and daily، was investigated by means of SNHT، Buishand، Pettitt، Von-neumann and kendall-tau. The results of this study indicate a temperature increase of Mashhad، comparison of the results showed that during the past 60 years (1951-2010)، minimum temperature increased 2times more than maximum temperature (0. 062 versus 0. 031). Test results also showed temperature increasing in all seasons، but just winter maximum temperature increasing trend was not significant in 95% confidence level. Also the highest rate of temperature increasing was belonged to autumn minimum temperature، with the slope of 0. 074. Like the difference between annual series، in all season minimum temperature increasing trend is higher than maximum trend، comparing trends in monthly maximum and minimum temperatures show similar results. It also was shown that the minimum temperature trend rose approximately near the year 1985، while maximum temperature break point is near 1995.